Use of the Visual Analogue Parkinson’s Disease Sleep Scale in Nigeria.

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Olusegun Adediran, Olufisayo Elugbadebo, Hephzibah Oyedapo-Ishola, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6383451/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background. Sleep disturbances are common in persons with Parkinson’s disease (PD) but often go undetected by attending physicians. Due to its simplicity, the visual analogue PD Sleep Scale (PDSS) could be valuable in the detection and management of sleep disturbances in contexts such as Nigeria where text heavy self-report assessments are difficult to implement due to limited formal education. We aim to test the utility of the PDSS in identifying nocturnal sleep problems in Nigerians with PD. Methods. We evaluated a dataset comprising information collected as part of a two-centre prevalence and case control study of behavioural disturbances among persons with PD in southwestern Nigeria. Nocturnal sleep problems in PD were assessed using the PDSS. We also independently administered the Neuropsychiatric Inventory Questionnaire (NPI-Q). We examined indicators of construct validity by comparing the PDSS with the NPI-Q nighttime behavioural subscale, known group validity by comparing with Hoehn and Yahrs stages of PD, and discriminant validity by comparing PDSS scores in cases and controls. We generated Spearman correlation coefficients, Games-Howell post hoc adjustments in ANOVA, and step-down Bonferroni corrections for multiple comparisons. Results. Among 150 persons with PD and 150 matched neurologically healthy controls, PDSS scores were discriminated in 13 out of the 15 items (step-down Bonferroni corrected p<0.003). Ten items demonstrated statistical correlations with the NPI-Q (r=0.45 to 0.49 for overall sleep quality, sleep onset insomnia, sleep maintenance insomnia, and sleep related hallucinations). PDSS scores worsened as motor severity increased (Games-Howell post hoc adjusted p<0.05 for Early to Severe PD). Conclusion. The PDSS was useful in identifying a variety of nocturnal sleep problems in people living with PD. These results provide support for the utility of the tool in Nigeria and similar contexts where many patients have limited or no formal education. Figures Figure 1 Figure 2 Figure 3 INTRODUCTION Idiopathic Parkinson’s disease (PD) is the second most common neurodegenerative disorder in old age[ 1 ] and, along with Alzheimer’s disease, represent a significant health concern in Africa. This is given current projections suggesting that the population of older people in Africa is set to undergo the most rapid increase of any region in the world[ 2 ]. Sleep disturbances are common but often missed non-motor symptoms of PD 5 . They occur in over 90% of persons with the disorder[ 3 , 4 ], may precede motor symptoms, and worsen with progression of disease[ 5 ]. Sleep disturbances also significantly impact the quality of life of persons living with PD[ 6 ]. Early identification of sleep disturbances in PD can contribute to addressing the burden they impose. Several tools have been developed for assessing sleep disturbances in PD[ 7 , 8 ]. However, some conventional clinical measures such as the modified version of the Epworth Sleepiness Scale (ESS)[ 8 ] and Pittsburgh Sleep Quality Index (PSQI)[ 7 ] are limited in terms of sensitivity, accuracy and comprehensiveness in quantifying the various aspects of nocturnal sleep disturbances in PD. Also, the Unified Parkinson’s Disease Rating Scale (UPDRS) and the 39-item Parkinson’s Disease Quality of Life scale (PDQ-39) were observed to both have insufficient questions to cover the range of sleep disturbances in PD[ 9 ]. The visual analogue Parkinson’s Disease Sleep Scale (PDSS)[ 9 ] and its revised version, PDSS-2[ 10 ], are widely used due to their comprehensive coverage of sleep-related symptoms, and patient-centered approach. Many persons with PD in Nigeria have limited or no formal education, making text-heavy, self-administered tools challenging[ 11 ]. In these settings, visual analogue scales might serve as an intuitive and accessible means for sleep assessment. The PDSS[ 9 ] is a self-reported 15-item visual analogue scale that evaluates overall sleep quality and the variety of nocturnal sleep disturbances in PD. Due to its simplicity, the PDSS could be valuable in the detection and management of sleep disturbances in Nigerian patients with PD. While the PDSS was briefly used in Nigeria[ 12 ], indicators of its validity for the assessment of sleep disturbances in PD is yet to be described in the country setting. In the present study, we evaluated the use of the PDSS in a Nigerian cohort of persons with PD. We aimed to assess indicators of discriminant and construct validity, respectively by comparing scores on the PDSS in 150 persons with PD and 150 matched controls, and with scores on the Neuropsychiatric Inventory Questionnaire (NPI-Q)[ 13 ] nighttime behaviour subscale which captures sleep disturbances and nocturnal behavioural problems. METHODS Study design and settings We evaluated a dataset comprising information collected as part of a two-centre prevalence and case control study of behavioural manifestations among persons with PD in southwestern Nigeria. The study took place at the specialist neurology clinics of the University College Hospital (UCH), Ibadan Oyo state and Federal Medical Centre, Abeokuta Ogun state. The two general tertiary hospitals are owned and operated by the Federal Government of Nigeria. The study procedures were approved by the Joint Ethical Committees of the University of Ibadan and the UCH Ibadan, Nigeria. Participants In each study site, we sought to consecutively recruit over a one-year period all clinic attendees aged ≥ 40 years with a diagnosis of PD established by the attending neurologists. PD was diagnosed according to the United Kingdom Parkinson’s Disease Society (UKPDS) Brain Bank Clinical Diagnostic Criteria[ 14 ]. Exclusion criteria were history of use of neuroleptic drugs, stroke or transient ischaemic attack, repeated head injury, atypical presentation (e.g., bilateral symptoms at onset, early onset of autonomic dysfunction, poor initial levodopa response) or where there was no convincing historical evidence of progression in symptoms over time. The primary caregiver of an index cases was also recruited to be part of the study. Controls were attendees at general outpatient clinics in the same hospital as persons with PD. They were matched for age (± 5 years of index case), sex, and education (± 1 year of index case). Exclusion criteria for controls were case record evidence of diagnoses or treatment for a condition listed in chapters VI (Mental, behavioural and neurodevelopmental disorders), VII (Sleep-wake cycle disorder), VIII (Diseases of the nervous system), and IX (Disease of the visual system) in the 11th edition of the International statistical Classification of Diseases and related health problems (ICD 11)[ 15 ]. Decisions to include persons with PD and controls were jointly made by the study psychiatrist and neurologists. Cases and controls with severe morbidities capable of causing neuropsychiatric symptoms (e.g. chronic kidney disease, cardiac, and liver diseases) were additionally excluded. Caregivers were excluded if they did not live with the person with PD or been involved in their care for at least 6 months. Written informed consent was obtained from all eligible individuals after the procedure of the study was explained to them either in English or the local Yoruba language. Capacity to provide consent was assessed by trained researcher assistants. Measures. Parkinson’s Disease Sleep Scale (PDSS)[ 9 ]. The PDSS is a visual analogue scale comprising 15 commonly reported symptoms associated with sleep disturbance in people with PD (Supplementary Figure I). These symptoms include overall quality of night’s sleep (item1), sleep onset and maintenance insomnia (items 2 and 3), nocturnal restlessness (items 4 and 5), nocturnal psychosis (items 6 and 7), nocturia (items 8 and 9), nocturnal motor symptoms (items 10–13), sleep refreshment (item14), and daytime dozing (item15). The PDSS demonstrated criterion validity when compared with the Epworth sleepiness scale (ESS), and discriminant validity by clearly differentiating people with early PD from those with severe disorder[ 9 ]. Completing the PDSS The PDSS was completed according to the recommendation of Chaudhuri and Colleagues[ 9 ]. Participants with PD and controls completed the PDSS based on their experiences in the past week. They were asked to fill in the PDSS during clinical interview in a quiet consultation room. The severity of symptoms was reported by marking a cross along a10cm line (labelled from worst to best state). Responses were quantified by measuring the distance along each line to the intersection with the cross in centimetres, to the nearest 0.1cm. Scores for each item range from 0 (symptom severe and always experienced) to 10 (symptom-free). The maximum cumulative score for the PDSS is 150 (patient is free of all symptoms). In line with the original description of the PDSS[ 9 ], we chose a score of < 5 on any item of the PDSS as evidence of severe sleep disturbance in the present study. Neuropsychiatric Inventory (NPI-Q)[ 13 ]. The NPI-Q was also independently administered within 15–20 minutes of the PDSS. The NPI-Q is the 12-item version of the Neuropsychiatry Inventory (NPI), which is a caregiver-based structured interview administered to a caregiver who is familiar with patient’s behaviour to assess for behavioural and psychological symptoms associated with Parkinson’s disease. The neuropsychiatric symptoms assessed by the NPI-Q include delusions, hallucinations, agitation/aggression, depression, anxiety, elation, apathy, disinhibition, irritability, aberrant motor behaviour, nighttime disturbance and appetite change. Bothe the parent NPI and the NPI-Q has been widely used by our team in Nigeria[ 16 , 17 ]. The motor Subscale of the Unified Parkinson’s Disease Rating Scale (UPDRS III)[ 18 ]. Detail examination of motor signs and severity in persons with PD was carried out using the UPDRS. The UPDRS motor scale is a 27-item scale that is widely used for detailed examination of motor signs in PD. This scale has been previously validated in a cohort of Nigerian patients with PD[ 16 ]. In the present study, UPDRS III scores were converted to Hoehn and Yahr stages (Early, mild-moderate, and severe) using previously validated formula[ 19 ]. Chart extraction. A purpose-designed semi-structured questionnaire was used to extract data on clinical characteristics, including records of diagnoses and treatment for hypertension, diabetes or other chronic medical conditions. Also noted were case records of diagnoses or treatment for conditions in the following ICD 11 categories [ 15 ]: Mental, behavioural and neurodevelopmental disorders, sleep-wake cycle disorder, diseases of the nervous system, and disease of the visual system. Records of other relevant covariates of PD and psychosis spectrum symptoms were also made. These included levodopa equivalent dosages and use of anticholinergic agent. Other data collection The following information was obtained from all participants using a standardized questionnaire: demographic data, marital status, years of formal education, personal history of smoking, alcohol consumption. We ascertained economic status using asset based measures relevant to developing countries [ 20 ]. Social network and social support were assessed with the relevant items in the World Mental Health Survey version of the World Health Organisation Composite International Diagnostic Interview (CIDI)[ 21 ]. Statistical analyses. We summarized socio-demographic characteristics using frequencies and percentages, means and standard deviations (SD), or median and interquartile range as appropriate. PDSS total and items scores were also summarized using means and standard deviations (SD) or standard errors of the mean, or median and interquartile range as appropriate. To examine discriminant validity, we compared the mean PDSS items scores between persons with PD and controls. For these analyses, we adjusted for multiple comparison using a step-down Bonferroni correction. We also compared the proportion of cases and controls with severe sleep disturbances. PDSS items scores were also compared across three Hoehn and Yahr stages (Early, mild-moderate, and severe) using a one-way ANOVA method. Due to unequal sample sizes of the Hoen and Yahn stages, Games-Howell post hoc analysis was used to adjust analyses and account for the differences in sample sizes and variances across groups when alpha was < 0.05 in one way ANOVA comparison. To investigate construct validity, we plotted scores of the NPI nighttime behaviour subscale with the PDSS total and items scores using a Spearman’s correction method. All analyses were conducted using Stata MP version 16.0[ 22 ]. RESULTS We consecutively recruited 150 eligible persons with PD (cases). The demographic and clinical characteristics of cases and controls are presented in Table 1 . Age, sex and education were similar for cases and controls, reflecting matching by these variables. There were variations among cases and controls in the extent of social network (Poor: cases, 34%; controls, 24%), social support (Poor: cases, 34%; controls, 50%), and use of tobacco (cases, 22.7%; controls, 16.7%). Table 1 Characteristics of persons with Parkinson’s disease and controls Characteristics Parkinson’s, n (%) Controls, n (%) ᵡ 2 statistic p-value Age group, years <60 years ≥60 years Mean (SD), Years 34 (22.7) 116 (77.3) 66.2 (9.5) 30 (20.0) 120 (80.0) 66.7 (9.7) 0.31 .572 Sex Male Female 109 (72.7) 41 (27.3) 112 (74.7) 38 (25.3) 0.15 .694 Formal Education, years 0–6 7–12 >12 Mean (SD), Years 41 (27.3) 35 (23.3) 74 (49.3) 11.9 (5.0) 41 (27.3) 28 (18.7) 81 (54.0) 12.4 (5.0) 1.09 .578 Marital status Married Separated a 124 (82.7) 26 (17.3) 115 (76.7) 35 (23.3) 1.66 .196 Alcohol use Current/former users Never users 94 (62.7) 56 (37.3) 91 (60.7) 59 (39.3) 0.12 .721 Tobacco use Current/former users Never users 34 (22.7) 116 (77.3) 25 (16.7) 125 (83.3) 1.70 .191 Social network b Good Poor 99 (66.0) 51 (34.0) 114 (76.0) 36 (24.0) 3.64 .056 Social Support c Good Poor 99 (66.0) 51 (34.0) 75 (50.0) 75 (50.0) 7.88 .004 Probable dementia d Yes No 14 (9.3) 136 (90.7) 2 (1.3) 148 (98.7) 9.50 .002 Multimorbidity e Yes No 49 (32.7) 101 (67.3) 43 (28.7) 107 (71.3) 0.56 .452 Severe sleep disturbance Yes No 69 (46.0) 81 (54.0) 27 (18.0) 123 (82.0) 27.02 3.9, e ≥3 chronic conditions including Parkinson’s disease. Persons with PD were mostly male (72.7%), with a mean age at presentation and UPDRS motor subscale score of 66.2 (± 9.5) years and 43.1 (± 16.4), respectively. The mean age at onset of PD was 61.2 (± 9.0) years. The median duration of illness and levodopa equivalent doses were 36.0 months and 412.5 mg/day, respectively. Nearly half of the participants with PD were currently exposed to anticholinergic agents, while 9.3% were proxy assessed as persons with probable dementia. The mean total PDSS score obtained from participants with PD was 65.5 (± 19.1). Scores of individual items are shown in Fig. 1 . The scores for persons with PD mostly ranged from 5–9 (Nine items) or 4–8 (five items). The most severe rating was recorded for item 8 (Nocturia/‘getting up at night to pass urine’). Scores for all items in the PDSS were more severe in persons with PD compared with controls (Fig. 1 ). None of the controls had a mean score less than 5 on any PDSS item. In the PD group, only the mean score of item 8 was less than 5. Compared with controls (N = 27, 18%), 69 (46.0%) persons with PD had severe sleep disturbance (p < 0.001). Table 2 shows the stepdown Bonferroni probability values derived from comparing scores in persons with PD and controls. In this Table, seven PDSS items demonstrated statistical differences between persons with PD and controls. In order of severity, these symptoms include fidgeting in bed, daytime sleepiness, difficulty staying asleep, sleep related hallucinations, awakening painful posturing, awakening tremors, and awake tiredness/sleepiness (Table 2 ). Table 2 Stepdown Bonferroni probability values of Parkinson’s disease sleep scale (PDDS) scores obtained from cases and controls PDSS items scores a Parkinson’s Mean (SD Controls Mean (SD) Bonferroni p-values 1. Overall quality of night’s sleep 7.2 (2.1) 7.7 (1.6) 0.028 2. Difficulty falling asleep each night 7.4 (2.0) 7.8 (1.6) 0.048 3. Difficulty staying asleep 7.0 (2.1) 7.8 (1.6) 0.001 4. Restlessness in legs or arms at night or in the evening disrupt sleep 6.7 (2.4) 7.5 (1.7) 0.098 5. Fidget in bed 6.3 (2.4) 8.2 (1.5) < 0.001 6. Distressing dreams at night 6.4 (2.7) 7.1 (2.5) 0.379 7. Distressing hallucinations at night 7.1 (2.2) 8.6 (1.3) 0.002 8. Get up at night to pass urine? 4.8 (2.3) 5.5 (1.5) 0.149 9. Incontinence of urine because unable to move due to “off” symptoms 5.6 (2.7) 7.9 (2.1) 0.022 10. Numbness or tingling in arms or legs, which wakes you from sleep at night 6.1 (2.0) 6.8 (2.3) 0.257 11. Painful muscle cramps in arms or legs which wake you from sleep at night 6.1 (2.4) 7.0 (2.2) 0.081 12. Wake early in the morning with painful posturing of arms or legs 7.3 (2.3) 8.1 (1.8) 0.001 13. Tremor on waking 7.4 (2.4) 9.1 (1.5) < 0.001 14. Tired and sleepy after waking in the morning 7.4 (2.3) 8.5 (1.6) < 0.001 15. Unexpectedly falls asleep during the day 6.4 (2.1) 7.3 (1.9) < 0.001 a Lower scores = more severe sleep disturbance, b Critical value for Bonferroni correction: alpha level/no. of tests performed = 0.05/15 = 0.003. In Figure II, PDSS scores were similar between persons with early PD and controls. Among cases, PDSS scores worsened as motor symptom severity increased (Figure II). Analyses of variance comparing PDSS scores across stages of PD severity indicate that scores for three PDSS items were markedly different between early to severe PD (Table 3 ). In order of percentage change in severity, these symptoms include sleep related hallucinations, ‘off symptoms’ associated incontinence, and awake tiredness/sleepiness (Table 3 ). Table 3 One-way Anova of Parkinson’s Disease Sleep scale (PDSS) scores across the stages of Parkinson’s disease motor severity Modified Hoen and Yahr stages Mean (SD) PDSS Items a Early Mild-Moderate Severe One-way Anova (P-values) 1. Overall quality of night’s sleep 7.5 (2.1) 7.3 (1.9) 6.3 (2.4) 0.060 2. Difficulty falling asleep each night 7.4 (2.2) 7.6 (1.7) 6.8 (2.3) 0.197 3. Difficulty staying asleep 7.3 (2.2) 7.1 (2.1) 6.3 (2.3) 0.153 4. Restlessness in legs or arms at night or in the evening disrupt sleep 7.3 (2.7) 6.7 (2.2) 5.7 (2.3) 0.269 5. Fidget in bed 7.4 (2.3) 5.8 (2.4) 5.9 (2.4) 0.137 6. Distressing dreams at night 7.2 (3.0) 6.0 (2.8) 6.5 (2.2) 0.418 7. Distressing hallucinations at night 8.6 (1.9) 7.1 (1.9) 5.6 (2.0) 0.002* 8. Get up at night to pass urine 4.7 (2.0) 4.9 (2.6) 4.7 (2.1) 0.971 9. Incontinence of urine due to “off” symptoms 7.8 (2.8) 6.2 (2.5) 5.1 (2.4) 0.044* 10. Numbness or tingling in arms or legs, which wakes you from sleep at night 6.9 (2.3) 5.7 (1.8) 5.8 (1.9) 0.215 11. Painful muscle cramps in arms or legs which wake you from sleep at night 6.2 (2.6) 6.4 (2.4) 5.1 (2.1) 0.315 12. Wake early in the morning with painful posturing of your arms or legs 7.8 (2.2) 7.3 (2.2) 6.5 (2.4) 0.078 13. Tremor on waking 7.5 (2.4) 7.7 (2.3) 6.6 (2.9) 0.139 14. Feel tired and sleepy after waking in the morning 7.7 (1.8) 7.5 (2.4) 6.3 (2.4) 0.035* 15. Unexpectedly fall asleep during the day 6.7 (2.0) 6.4 (2.2) 5.9 (2.4) 0.288 a Lower scores = more severe sleep disturbance. Due to unequal sample size of the Hoen and Yahn stages, Games-Howell post hoc analysis was used adjust analyses and account for the differences in sample sizes and variances across groups when one way Anova comparison alpha < 0.05; Distressing hallucinations at night: Early – Severe, P = 0.004; Incontinence of urine because unable to move due to “off” symptoms: Early – Severe, P = 0.048; Tired and sleepy after waking in the morning: Early – Severe, P = 0.040. In Table 4 , the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale. This indicate that low scores on the PDSS items 1 to 3 (i.e., more severe insomnia and overall quality of sleep) was associated with high scores on the NPI nighttime behaviours subscale. Also in Table 4 , ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. Figure III is a scatter plot showing the correlation between PDSS overall quality of sleep item and the NPI nighttime behaviour subscale. Table 4 Spearman correlation of Parkinson’s disease sleep scale (PDSS) scores and Neuropsychiatric Inventory (NPI) Nighttime behaviour scores obtained from cases with Parkinson’s disease PDSS Items a NPI Nighttime Behavior b rho (p-values) 1. Overall quality of night’s sleep -0.45 (< 0.001) 2. Difficulty falling asleep each night -0.46 (< 0.001) 3. Difficulty staying asleep -0.49 (< 0.001) 4. Restlessness in legs or arms at night or in the evening disrupt sleep -0.32 (0.02) 5. Fidget in bed -0.18 (0.232) 6. Distressing dreams at night -0.16 (0.286) 7. Distressing hallucinations at night -0.45 (0.002) 8. Get up at night to pass urine -0.13 (0.413) 9. Incontinence of urine because unable to move due to “off” symptoms -0.27 (0.075) 10. Numbness or tingling in arms or legs, which wakes you from sleep at night -0.36 (0.018) 11. Painful muscle cramps in arms or legs which wake you from sleep at night -0.02 (0.885) 12. Wake early in the morning with painful posturing of your arms or legs -0.22 (0.007) 13. Tremor on waking -0.29 (< 0.001) 14. Feel tired and sleepy after waking in the morning -0.21 (0.011) 15. Unexpectedly fall asleep during the day -0.21 (0.009) a Lower scores represents more severe sleep disturbance; b Higher scores represents more severe nighttime behaviour disturbance; alpha is significant at p < 0.05 DISCUSSION We found in the present study that PDSS scores were differentiated between persons with PD and neurologically healthy controls who were matched for age, sex, education and outpatient status. Many individual items demonstrated statistical discriminatory power between persons with PD and controls. Among cases, PDSS scores worsened as motor severity increased. We also found that ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. In particular, the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale. The PDSS is a visual analogue scale and has the advantage of ease of administration. It addresses the limitation of text-heavy, self-administered tools in settings such as Nigeria where many persons with PD have limited education[ 11 ]. The PDSS does not require patients to be able to read or write, and in this study, we have shown that it is effective in the identification of sleep disturbances in Nigerians with PD. In the original description of the PDSS[ 9 ], the tool successfully discriminated between persons with PD and healthy controls in 13 out of the 15 items. In so far as the mean PDSS scores for persons with PD in the present study were approximately one point lower than for matched controls in 13 out of the 15 items, the tool provided initial indication of discriminant validity for these items in our cohort. Conversely, the PDSS was poor in discriminating persons with PD and controls in overall sleep quality (item 1). Also, while there was no stepped down statistical difference in cases and controls in item 2 (Sleep onset insomnia), item 3 (sleep maintenance insomnia) showed critical discrimination between the two groups. Findings similar to those reported in the present study were interpreted in both the original design of the PDSS[ 9 ] and its subsequent replication in the United State[ 23 ] to mean that these non-discriminatory items are not unique to PD. Similar to these previous studies[ 9 , 23 ], the poorer PDSS scores observed with advancing Hoehn and Yahr stages in the present study may suggest that sleep disturbances become worse as PD progresses. Our findings indicated that ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. In particular, the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale. This finding may indicate that nighttime behavioural disturbances in PD may be due to problems with overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucinations. Conversely, persons with PD and controls in our sample woke up at night to pass urine since both groups had their lowest PDSS mean scores for item 8 (nocturia). This is similar to findings reported in previous cohorts of persons with PD[ 9 , 23 ], as well as in the general population[ 24 ]. Clinical and Public Health Implications. Our findings have important clinical and public health implications. Given the high frequency of sleep disturbances in PD, and limited use of validated sleep assessment tools for PD in Nigeria, the PDSS proved an effective, accessible option for evaluating sleep dysfunction in our study cohort. Many Nigerians with PD have limited formal education, making text-heavy, self-administered tools often challenging[ 11 ]. The format of the PDSS facilitates self-reporting, even among individuals with limited formal education, potentially improving early detection and management of sleep disorders in Nigeria. With the observed scarcity of mental and neurological healthcare specialist in Nigeria[ 25 ], it may be prudent to shift attention to simplified treatment strategies that equip non-specialised healthcare workers in clinical diagnosis and management of PD at the primary care level. The PDSS tool could come in handy for assessing sleep disturbances among persons with PD following clinical diagnosis, and the institution of symptomatic treatment. Similar strategies have been used in more developed healthcare systems around the world[ 26 ]. Our study thus underscores the need for holistic management approaches integrating sleep assessments into routine clinical and multidisciplinary care for patients with PD in our setting. The present study has limitations. First, although the NPI nighttime behaviour scale potentially captures sleep disturbances and nocturnal behavioural problems, it has notable limitations. Specifically, it does not assess specific sleep disorders. It also relies solely on caregiver reports, which may be subject to bias. Secondly, while the PDSS provides a subjective measure of sleep disturbances, objective sleep assessments, such as polysomnography, could have given more objective insights. Future research incorporating subjective and objective measures could provide more comprehensive information on the pattern of sleep disturbances in PD patients. Additionally, while our study demonstrated the utility of the PDSS tool in a Nigerian cohort, further studies are needed in our setting to assess the impact of its use in PD management over time. Conclusion Sleep disorders are common non-motor symptoms among Nigerians living with PD. This is particularly so in the advanced stages of the disorder. This study highlights the potential utility of the PDSS in identifying PD-related sleep disturbances in Nigeria where many persons with the disorder have limited formal education. Patients scoring poorly on the PDSS may merit referral for objective sleep assessments, such as polysomnography, as well as evidence-based management of nocturnal symptoms in PD. Declarations Informed consent: Informed consent was obtained from all individual participants included in the study. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Author Contribution OA: Formal analysis, Writing - Original Draft, Review & Editing; AO: Conceptualization, Methodology, Funding acquisition, Supervision, Formal analysis, Writing - Original Draft, Review & Editing. HO: Data Curation, Formal analysis, Review & Editing. OE: Methodology, Writing - Original Draft, Review & Editing. AB: Resources, Review & Editing. Data Availability Data is provided within the manuscript or supplementary information files. Additional information will be provided upon reasonable request. References Savica R, et al. Incidence and pathology of synucleinopathies and tauopathies related to parkinsonism. JAMA Neurol. 2013;70(7):859–66. Rizig M, et al. 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World Health Organisation: Geneva; 2003. pp. 747–60. C. Murray and D. Evans, Editors. Kessler RC, Ustun TB. The World Mental Health (WMH) Survey Initiative Version of the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI). Int J Methods Psychiatr Res. 2004;13(2):93–121. StataCorp. Stata Statistical Software. StataCorp LLC: College Station, TX:; 2019. Tse W, et al. Clinical usefulness of the Parkinson's disease sleep scale. Parkinsonism Relat Disord. 2005;11(5):317–21. Milsom I, et al. How widespread are the symptoms of an overactive bladder and how are they managed? A population-based prevalence study. BJU Int. 2001;87(9):760–6. Ajoseh S, et al. Navigating brain drain: understanding public discourse on legislation to retain medical professionals in Nigeria. Global Health. 2024;20(1):80. Nunes SFL, Alvarez AM, Valcarenghi RV. Parkinson's disease in primary health care and nursing care: a scoping review. Rev Esc Enferm USP. 2022;56:e20210367. Additional Declarations No competing interests reported. Supplementary Files SupplementaryFigureI.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6383451","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":438884762,"identity":"4aaf987c-17b9-4b37-88c7-1e03a97ca62c","order_by":0,"name":"Olusegun Adediran","email":"","orcid":"","institution":"Department of Ophthamology, College of Medicine, University of Ibadan.","correspondingAuthor":false,"prefix":"","firstName":"Olusegun","middleName":"","lastName":"Adediran","suffix":""},{"id":438884763,"identity":"0ad75411-d6ae-4c90-a802-f142fa55c81b","order_by":1,"name":"Olufisayo Elugbadebo","email":"","orcid":"","institution":"WHO Collaborating Centre for Research and Training in Neurosciences, Mental Health and Substance Abuse, Department of Psychiatry, College of Medicine University of Ibadan","correspondingAuthor":false,"prefix":"","firstName":"Olufisayo","middleName":"","lastName":"Elugbadebo","suffix":""},{"id":438884764,"identity":"77c163b6-0d98-4be0-b596-0e5bf5c8dc52","order_by":2,"name":"Hephzibah Oyedapo-Ishola","email":"","orcid":"","institution":"WHO Collaborating Centre for Research and Training in Neurosciences, Mental Health and Substance Abuse, Department of Psychiatry, College of Medicine University of Ibadan","correspondingAuthor":false,"prefix":"","firstName":"Hephzibah","middleName":"","lastName":"Oyedapo-Ishola","suffix":""},{"id":438884765,"identity":"e08b25d3-dd39-4ef1-a822-e8808425bd90","order_by":3,"name":"Amina Bakare","email":"","orcid":"","institution":"Department of Medicine, Federal Medical Centre, Abeokuta.","correspondingAuthor":false,"prefix":"","firstName":"Amina","middleName":"","lastName":"Bakare","suffix":""},{"id":438884766,"identity":"d41f4de0-caa5-4788-90b2-0a12734e3034","order_by":4,"name":"Akin Ojagbemi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYDCCAwzMDAkMbAwMEkBOQgUDgwGJWs4QqwUMQFoY24jQwnf78GODhzv45OWjm49ueDjvsLw5e/MBhh8V23BqkTyXZpyQeIbNcOOdY2k3ErcdNtzZcyyBsefMbZxaDM4wGB9IbGNj3DgjxwykhXHDjRwDZsY2fFrYP4O02G+ckf/tRuKcw/ZEaOEBOqyNLXG+RA7bjcSGw4kEtUie4Sk2AGpJ3iBzzOxGwrH05A1njiUcxOcXvjPsmyV/th2znT+7+dnNHzXWthuONx988KMCtxYoOMZgcADMaAaTBwipB4IaBvkGMKOOCMWjYBSMglEw0gAARTVkfBkr9lYAAAAASUVORK5CYII=","orcid":"","institution":"WHO Collaborating Centre for Research and Training in Neurosciences, Mental Health and Substance Abuse, Department of Psychiatry, College of Medicine University of Ibadan","correspondingAuthor":true,"prefix":"","firstName":"Akin","middleName":"","lastName":"Ojagbemi","suffix":""}],"badges":[],"createdAt":"2025-04-05 18:08:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6383451/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6383451/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":80145848,"identity":"61a90660-e7ac-4e7d-adc5-4010b5ecfa71","added_by":"auto","created_at":"2025-04-08 12:29:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":41080,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eParkinson’s disease sleep scale scores obtained from cases and controls\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: PDSS=Parkinson’s disease sleep scale; lower scores represent more severe sleep disturbance\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6383451/v1/19b49457b46a0e8730b20738.png"},{"id":80144967,"identity":"29527f64-8876-453c-84bb-8203c4c91ebc","added_by":"auto","created_at":"2025-04-08 12:21:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":28151,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBox plot showing Parkinson’s disease sleep scale scores obtained from controls and cases at different stages of Parkinson’s disease motor severity.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePDSS= \u003c/strong\u003eParkinson’s disease sleep scale: lower scores indicate more severe sleep disturbance\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6383451/v1/4efb5f881f7621aa157ae00c.png"},{"id":80144968,"identity":"4fdcbab5-2f75-40a9-a2d1-e3a29cdecfef","added_by":"auto","created_at":"2025-04-08 12:21:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":10606,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScatter plot of relationship between Parkinson’s disease sleep scale (PDSS) overall quality of sleep items and the Neuropsychiatric Inventory (NPI) Nighttime behaviour subscale.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePDSS= Parkinson’s disease sleep scale where lower scores indicate more severe sleep disturbance; NPI=Neuropsychiatric Inventory where higher scores represents more severe nighttime behaviour disturbance.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6383451/v1/7dd7d6bd3fcdd7700d8693ab.png"},{"id":80923779,"identity":"0775b5b0-cdfd-444e-b707-85671892a7e7","added_by":"auto","created_at":"2025-04-18 22:31:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1107910,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6383451/v1/d4ca0fb8-9c45-4803-ba24-fb560836966b.pdf"},{"id":80144973,"identity":"abe7fa70-6841-47c6-8c0f-f507ccf4f428","added_by":"auto","created_at":"2025-04-08 12:21:33","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":94662,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryFigureI.docx","url":"https://assets-eu.researchsquare.com/files/rs-6383451/v1/2de1c39ef8212c75fbadd06b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Use of the Visual Analogue Parkinson’s Disease Sleep Scale in Nigeria.","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eIdiopathic Parkinson\u0026rsquo;s disease (PD) is the second most common neurodegenerative disorder in old age[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and, along with Alzheimer\u0026rsquo;s disease, represent a significant health concern in Africa. This is given current projections suggesting that the population of older people in Africa is set to undergo the most rapid increase of any region in the world[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Sleep disturbances are common but often missed non-motor symptoms of PD\u003csup\u003e5\u003c/sup\u003e. They occur in over 90% of persons with the disorder[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], may precede motor symptoms, and worsen with progression of disease[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Sleep disturbances also significantly impact the quality of life of persons living with PD[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Early identification of sleep disturbances in PD can contribute to addressing the burden they impose.\u003c/p\u003e \u003cp\u003eSeveral tools have been developed for assessing sleep disturbances in PD[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, some conventional clinical measures such as the modified version of the Epworth Sleepiness Scale (ESS)[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and Pittsburgh Sleep Quality Index (PSQI)[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] are limited in terms of sensitivity, accuracy and comprehensiveness in quantifying the various aspects of nocturnal sleep disturbances in PD. Also, the Unified Parkinson\u0026rsquo;s Disease Rating Scale (UPDRS) and the 39-item Parkinson\u0026rsquo;s Disease Quality of Life scale (PDQ-39) were observed to both have insufficient questions to cover the range of sleep disturbances in PD[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The visual analogue Parkinson\u0026rsquo;s Disease Sleep Scale (PDSS)[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] and its revised version, PDSS-2[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], are widely used due to their comprehensive coverage of sleep-related symptoms, and patient-centered approach.\u003c/p\u003e \u003cp\u003eMany persons with PD in Nigeria have limited or no formal education, making text-heavy, self-administered tools challenging[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In these settings, visual analogue scales might serve as an intuitive and accessible means for sleep assessment. The PDSS[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] is a self-reported 15-item visual analogue scale that evaluates overall sleep quality and the variety of nocturnal sleep disturbances in PD. Due to its simplicity, the PDSS could be valuable in the detection and management of sleep disturbances in Nigerian patients with PD.\u003c/p\u003e \u003cp\u003eWhile the PDSS was briefly used in Nigeria[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], indicators of its validity for the assessment of sleep disturbances in PD is yet to be described in the country setting. In the present study, we evaluated the use of the PDSS in a Nigerian cohort of persons with PD. We aimed to assess indicators of discriminant and construct validity, respectively by comparing scores on the PDSS in 150 persons with PD and 150 matched controls, and with scores on the Neuropsychiatric Inventory Questionnaire (NPI-Q)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] nighttime behaviour subscale which captures sleep disturbances and nocturnal behavioural problems.\u003c/p\u003e "},{"header":"METHODS","content":"\u003ch3\u003eStudy design and settings\u003c/h3\u003e\n\u003cp\u003eWe evaluated a dataset comprising information collected as part of a two-centre prevalence and case control study of behavioural manifestations among persons with PD in southwestern Nigeria. The study took place at the specialist neurology clinics of the University College Hospital (UCH), Ibadan Oyo state and Federal Medical Centre, Abeokuta Ogun state. The two general tertiary hospitals are owned and operated by the Federal Government of Nigeria. The study procedures were approved by the Joint Ethical Committees of the University of Ibadan and the UCH Ibadan, Nigeria.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003eIn each study site, we sought to consecutively recruit over a one-year period all clinic attendees aged\u0026thinsp;\u0026ge;\u0026thinsp;40 years with a diagnosis of PD established by the attending neurologists. PD was diagnosed according to the United Kingdom Parkinson\u0026rsquo;s Disease Society (UKPDS) Brain Bank Clinical Diagnostic Criteria[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Exclusion criteria were history of use of neuroleptic drugs, stroke or transient ischaemic attack, repeated head injury, atypical presentation (e.g., bilateral symptoms at onset, early onset of autonomic dysfunction, poor initial levodopa response) or where there was no convincing historical evidence of progression in symptoms over time. The primary caregiver of an index cases was also recruited to be part of the study.\u003c/p\u003e \u003cp\u003eControls were attendees at general outpatient clinics in the same hospital as persons with PD. They were matched for age (\u0026plusmn;\u0026thinsp;5 years of index case), sex, and education (\u0026plusmn;\u0026thinsp;1 year of index case). Exclusion criteria for controls were case record evidence of diagnoses or treatment for a condition listed in chapters VI (Mental, behavioural and neurodevelopmental disorders), VII (Sleep-wake cycle disorder), VIII (Diseases of the nervous system), and IX (Disease of the visual system) in the 11th edition of the International statistical Classification of Diseases and related health problems (ICD 11)[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDecisions to include persons with PD and controls were jointly made by the study psychiatrist and neurologists. Cases and controls with severe morbidities capable of causing neuropsychiatric symptoms (e.g. chronic kidney disease, cardiac, and liver diseases) were additionally excluded. Caregivers were excluded if they did not live with the person with PD or been involved in their care for at least 6 months.\u003c/p\u003e \u003cp\u003e Written informed consent was obtained from all eligible individuals after the procedure of the study was explained to them either in English or the local Yoruba language. Capacity to provide consent was assessed by trained researcher assistants.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMeasures.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eParkinson\u0026rsquo;s Disease Sleep Scale (PDSS)[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe PDSS is a visual analogue scale comprising 15 commonly reported symptoms associated with sleep disturbance in people with PD (Supplementary Figure I). These symptoms include overall quality of night\u0026rsquo;s sleep (item1), sleep onset and maintenance insomnia (items 2 and 3), nocturnal restlessness (items 4 and 5), nocturnal psychosis (items 6 and 7), nocturia (items 8 and 9), nocturnal motor symptoms (items 10\u0026ndash;13), sleep refreshment (item14), and daytime dozing (item15). The PDSS demonstrated criterion validity when compared with the Epworth sleepiness scale (ESS), and discriminant validity by clearly differentiating people with early PD from those with severe disorder[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompleting the PDSS\u003c/strong\u003e \u003cp\u003eThe PDSS was completed according to the recommendation of Chaudhuri and Colleagues[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Participants with PD and controls completed the PDSS based on their experiences in the past week. They were asked to fill in the PDSS during clinical interview in a quiet consultation room. The severity of symptoms was reported by marking a cross along a10cm line (labelled from worst to best state). Responses were quantified by measuring the distance along each line to the intersection with the cross in centimetres, to the nearest 0.1cm. Scores for each item range from 0 (symptom severe and always experienced) to 10 (symptom-free). The maximum cumulative score for the PDSS is 150 (patient is free of all symptoms). In line with the original description of the PDSS[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], we chose a score of \u0026lt;\u0026thinsp;5 on any item of the PDSS as evidence of severe sleep disturbance in the present study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eNeuropsychiatric Inventory (NPI-Q)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe NPI-Q was also independently administered within 15\u0026ndash;20 minutes of the PDSS. The NPI-Q is the 12-item version of the Neuropsychiatry Inventory (NPI), which is a caregiver-based structured interview administered to a caregiver who is familiar with patient\u0026rsquo;s behaviour to assess for behavioural and psychological symptoms associated with Parkinson\u0026rsquo;s disease. The neuropsychiatric symptoms assessed by the NPI-Q include delusions, hallucinations, agitation/aggression, depression, anxiety, elation, apathy, disinhibition, irritability, aberrant motor behaviour, nighttime disturbance and appetite change. Bothe the parent NPI and the NPI-Q has been widely used by our team in Nigeria[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe motor Subscale of the Unified Parkinson\u0026rsquo;s Disease Rating Scale (UPDRS III)[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDetail examination of motor signs and severity in persons with PD was carried out using the UPDRS. The UPDRS motor scale is a 27-item scale that is widely used for detailed examination of motor signs in PD. This scale has been previously validated in a cohort of Nigerian patients with PD[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In the present study, UPDRS III scores were converted to Hoehn and Yahr stages (Early, mild-moderate, and severe) using previously validated formula[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eChart extraction.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA purpose-designed semi-structured questionnaire was used to extract data on clinical characteristics, including records of diagnoses and treatment for hypertension, diabetes or other chronic medical conditions. Also noted were case records of diagnoses or treatment for conditions in the following ICD 11 categories [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]: Mental, behavioural and neurodevelopmental disorders, sleep-wake cycle disorder, diseases of the nervous system, and disease of the visual system. Records of other relevant covariates of PD and psychosis spectrum symptoms were also made. These included levodopa equivalent dosages and use of anticholinergic agent.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eOther data collection\u003c/h3\u003e\n\u003cp\u003eThe following information was obtained from all participants using a standardized questionnaire: demographic data, marital status, years of formal education, personal history of smoking, alcohol consumption. We ascertained economic status using asset based measures relevant to developing countries [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Social network and social support were assessed with the relevant items in the World Mental Health Survey version of the World Health Organisation Composite International Diagnostic Interview (CIDI)[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical analyses.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eWe summarized socio-demographic characteristics using frequencies and percentages, means and standard deviations (SD), or median and interquartile range as appropriate. PDSS total and items scores were also summarized using means and standard deviations (SD) or standard errors of the mean, or median and interquartile range as appropriate.\u003c/p\u003e \u003cp\u003eTo examine discriminant validity, we compared the mean PDSS items scores between persons with PD and controls. For these analyses, we adjusted for multiple comparison using a step-down Bonferroni correction. We also compared the proportion of cases and controls with severe sleep disturbances. PDSS items scores were also compared across three Hoehn and Yahr stages (Early, mild-moderate, and severe) using a one-way ANOVA method. Due to unequal sample sizes of the Hoen and Yahn stages, Games-Howell post hoc analysis was used to adjust analyses and account for the differences in sample sizes and variances across groups when alpha was \u0026lt;\u0026thinsp;0.05 in one way ANOVA comparison.\u003c/p\u003e \u003cp\u003eTo investigate construct validity, we plotted scores of the NPI nighttime behaviour subscale with the PDSS total and items scores using a Spearman\u0026rsquo;s correction method. All analyses were conducted using Stata MP version 16.0[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eWe consecutively recruited 150 eligible persons with PD (cases). The demographic and clinical characteristics of cases and controls are presented in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Age, sex and education were similar for cases and controls, reflecting matching by these variables. There were variations among cases and controls in the extent of social network (Poor: cases, 34%; controls, 24%), social support (Poor: cases, 34%; controls, 50%), and use of tobacco (cases, 22.7%; controls, 16.7%).\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eCharacteristics of persons with Parkinson\u0026rsquo;s disease and controls\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003eParkinson\u0026rsquo;s,\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eControls,\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eᵡ\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003estatistic\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eAge group, years\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u0026lt;60 years\u003c/p\u003e\n \u003cp\u003e\u0026ge;60 years\u003c/p\u003e\n \u003cp\u003eMean (SD), Years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e34 (22.7)\u003c/p\u003e\n \u003cp\u003e116 (77.3)\u003c/p\u003e\n \u003cp\u003e66.2 (9.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e30 (20.0)\u003c/p\u003e\n \u003cp\u003e120 (80.0)\u003c/p\u003e\n \u003cp\u003e66.7 (9.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.572\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eSex\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e109 (72.7)\u003c/p\u003e\n \u003cp\u003e41 (27.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e112 (74.7)\u003c/p\u003e\n \u003cp\u003e38 (25.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.694\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eFormal Education, years\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e0\u0026ndash;6\u003c/p\u003e\n \u003cp\u003e7\u0026ndash;12\u003c/p\u003e\n \u003cp\u003e\u0026gt;12\u003c/p\u003e\n \u003cp\u003eMean (SD), Years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e41 (27.3)\u003c/p\u003e\n \u003cp\u003e35 (23.3)\u003c/p\u003e\n \u003cp\u003e74 (49.3)\u003c/p\u003e\n \u003cp\u003e11.9 (5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e41 (27.3)\u003c/p\u003e\n \u003cp\u003e28 (18.7)\u003c/p\u003e\n \u003cp\u003e81 (54.0)\u003c/p\u003e\n \u003cp\u003e12.4 (5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e1.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.578\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eMarital status\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003eMarried\u003c/p\u003e\n \u003cp\u003eSeparated\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e124 (82.7)\u003c/p\u003e\n \u003cp\u003e26 (17.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e115 (76.7)\u003c/p\u003e\n \u003cp\u003e35 (23.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.196\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eAlcohol use\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003eCurrent/former users\u003c/p\u003e\n \u003cp\u003eNever users\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e94 (62.7)\u003c/p\u003e\n \u003cp\u003e56 (37.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e91 (60.7)\u003c/p\u003e\n \u003cp\u003e59 (39.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.721\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eTobacco use\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003eCurrent/former users\u003c/p\u003e\n \u003cp\u003eNever users\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e34 (22.7)\u003c/p\u003e\n \u003cp\u003e116 (77.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e25 (16.7)\u003c/p\u003e\n \u003cp\u003e125 (83.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e1.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.191\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eSocial network\u003c/em\u003e\u003csup\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eGood\u003c/p\u003e\n \u003cp\u003ePoor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e99 (66.0)\u003c/p\u003e\n \u003cp\u003e51 (34.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e114 (76.0)\u003c/p\u003e\n \u003cp\u003e36 (24.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e3.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.056\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eSocial Support\u003c/em\u003e\u003csup\u003e\u003cem\u003ec\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eGood\u003c/p\u003e\n \u003cp\u003ePoor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e99 (66.0)\u003c/p\u003e\n \u003cp\u003e51 (34.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e75 (50.0)\u003c/p\u003e\n \u003cp\u003e75 (50.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e7.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eProbable dementia\u003c/em\u003e\u003csup\u003e\u003cem\u003ed\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e14 (9.3)\u003c/p\u003e\n \u003cp\u003e136 (90.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003cp\u003e148 (98.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e9.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eMultimorbidity\u003c/em\u003e\u003csup\u003e\u003cem\u003ee\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e49 (32.7)\u003c/p\u003e\n \u003cp\u003e101 (67.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e43 (28.7)\u003c/p\u003e\n \u003cp\u003e107 (71.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e.452\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 36.4029%;\"\u003e\n \u003cp\u003e\u003cem\u003eSevere sleep disturbance\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 21.2949%;\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e69 (46.0)\u003c/p\u003e\n \u003cp\u003e81 (54.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e27 (18.0)\u003c/p\u003e\n \u003cp\u003e123 (82.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e27.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e\u003csup\u003ea\u003c/sup\u003eDeath or divorce, \u003csup\u003eb\u003c/sup\u003eFrequent contacts with friends, \u003csup\u003ec\u003c/sup\u003eRelies on family or friends for support\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e\u003csup\u003ed\u003c/sup\u003eInformant Questionnaire on Cognitive Decline in the Elderly (IQ-CODE) scores\u0026thinsp;\u0026gt;\u0026thinsp;3.9, \u003csup\u003ee\u003c/sup\u003e\u0026ge;3 chronic conditions including Parkinson\u0026rsquo;s disease.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003ePersons with PD were mostly male (72.7%), with a mean age at presentation and UPDRS motor subscale score of 66.2 (\u0026plusmn;\u0026thinsp;9.5) years and 43.1 (\u0026plusmn;\u0026thinsp;16.4), respectively. The mean age at onset of PD was 61.2 (\u0026plusmn;\u0026thinsp;9.0) years. The median duration of illness and levodopa equivalent doses were 36.0 months and 412.5 mg/day, respectively. Nearly half of the participants with PD were currently exposed to anticholinergic agents, while 9.3% were proxy assessed as persons with probable dementia.\u003c/p\u003e\n\u003cp\u003eThe mean total PDSS score obtained from participants with PD was 65.5 (\u0026plusmn;\u0026thinsp;19.1). Scores of individual items are shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The scores for persons with PD mostly ranged from 5\u0026ndash;9 (Nine items) or 4\u0026ndash;8 (five items). The most severe rating was recorded for item 8 (Nocturia/\u0026lsquo;getting up at night to pass urine\u0026rsquo;).\u003c/p\u003e\n\u003cp\u003eScores for all items in the PDSS were more severe in persons with PD compared with controls (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). None of the controls had a mean score less than 5 on any PDSS item. In the PD group, only the mean score of item 8 was less than 5. Compared with controls (N\u0026thinsp;=\u0026thinsp;27, 18%), 69 (46.0%) persons with PD had severe sleep disturbance (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\n\u003cp\u003eTable \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e shows the stepdown Bonferroni probability values derived from comparing scores in persons with PD and controls. In this Table, seven PDSS items demonstrated statistical differences between persons with PD and controls. In order of severity, these symptoms include fidgeting in bed, daytime sleepiness, difficulty staying asleep, sleep related hallucinations, awakening painful posturing, awakening tremors, and awake tiredness/sleepiness (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eStepdown Bonferroni probability values of Parkinson\u0026rsquo;s disease sleep scale (PDDS) scores obtained from cases and controls\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePDSS items scores\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eParkinson\u0026rsquo;s\u003c/p\u003e\n \u003cp\u003eMean (SD\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eControls\u003c/p\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eBonferroni p-values\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1. Overall quality of night\u0026rsquo;s sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.2 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.7 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.028\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2. Difficulty falling asleep each night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.4 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.8 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.048\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3. Difficulty staying asleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.0 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.8 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4. Restlessness in legs or arms at night\u003c/p\u003e\n \u003cp\u003eor in the evening disrupt sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.7 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.5 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.098\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5. Fidget in bed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.3 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.2 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6. Distressing dreams at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.4 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.379\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7. Distressing hallucinations\u003c/p\u003e\n \u003cp\u003eat night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.6 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8. Get up at night to pass urine?\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.8 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.5 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.149\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9. Incontinence of urine because unable to move due to \u0026ldquo;off\u0026rdquo; symptoms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.6 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.9 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10. Numbness or tingling in arms or legs, which wakes you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.1 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.8 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.257\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11. Painful muscle cramps in arms or legs which wake you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.1 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.0 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.081\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12. Wake early in the morning with painful posturing of arms or legs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.1 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13. Tremor on waking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.4 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.1 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14. Tired and sleepy after waking in the morning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.4 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.5 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15. Unexpectedly falls asleep during the day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.4 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e\u003csup\u003ea\u003c/sup\u003eLower scores\u0026thinsp;=\u0026thinsp;more severe sleep disturbance, \u003csup\u003eb\u003c/sup\u003eCritical value for Bonferroni correction: alpha level/no. of tests performed\u0026thinsp;=\u0026thinsp;0.05/15\u0026thinsp;=\u0026thinsp;0.003.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eIn Figure II, PDSS scores were similar between persons with early PD and controls. Among cases, PDSS scores worsened as motor symptom severity increased (Figure II). Analyses of variance comparing PDSS scores across stages of PD severity indicate that scores for three PDSS items were markedly different between early to severe PD (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). In order of percentage change in severity, these symptoms include sleep related hallucinations, \u0026lsquo;off symptoms\u0026rsquo; associated incontinence, and awake tiredness/sleepiness (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eOne-way Anova of Parkinson\u0026rsquo;s Disease Sleep scale (PDSS) scores across the stages of Parkinson\u0026rsquo;s disease motor severity\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eModified Hoen and Yahr stages\u003c/p\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePDSS Items\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eEarly\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eMild-Moderate\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSevere\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eOne-way Anova\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(P-values)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1. Overall quality of night\u0026rsquo;s sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.5 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.3 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.060\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2. Difficulty falling asleep each night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.4 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.6 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.8 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.197\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3. Difficulty staying asleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.3 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.153\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4. Restlessness in legs or arms at night or in the evening disrupt sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.7 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.7 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.269\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5. Fidget in bed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.4 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.8 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.9 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.137\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6. Distressing dreams at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.2 (3.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.0 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.5 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.418\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7. Distressing hallucinations at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.6 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.6 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.002*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8. Get up at night to pass urine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.7 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.9 (2.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.7 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.971\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9. Incontinence of urine due to \u0026ldquo;off\u0026rdquo; symptoms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.8 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.2 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.1 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.044*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10. Numbness or tingling in arms or legs, which wakes you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.9 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.8 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.215\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11. Painful muscle cramps in arms or legs which wake you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.2 (2.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.4 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.1 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.315\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12. Wake early in the morning with painful posturing of your arms or legs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.8 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.5 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.078\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13. Tremor on waking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.5 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.7 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.6 (2.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.139\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14. Feel tired and sleepy after waking in\u003c/p\u003e\n \u003cp\u003ethe morning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.5 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.3 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.035*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15. Unexpectedly fall asleep during\u003c/p\u003e\n \u003cp\u003ethe day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.7 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.4 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.9 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.288\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e\u003csup\u003ea\u003c/sup\u003eLower scores\u0026thinsp;=\u0026thinsp;more severe sleep disturbance.\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eDue to unequal sample size of the Hoen and Yahn stages, Games-Howell post hoc analysis was used adjust analyses and account for the differences in sample sizes and variances across groups when one way Anova comparison alpha\u0026thinsp;\u0026lt;\u0026thinsp;0.05; Distressing hallucinations at night: Early \u0026ndash; Severe, P\u0026thinsp;=\u0026thinsp;0.004; Incontinence of urine because unable to move due to \u0026ldquo;off\u0026rdquo; symptoms: Early \u0026ndash; Severe, P\u0026thinsp;=\u0026thinsp;0.048; Tired and sleepy after waking in the morning: Early \u0026ndash; Severe, P\u0026thinsp;=\u0026thinsp;0.040.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eIn Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e, the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale. This indicate that low scores on the PDSS items 1 to 3 (i.e., more severe insomnia and overall quality of sleep) was associated with high scores on the NPI nighttime behaviours subscale. Also in Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e, ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. Figure III is a scatter plot showing the correlation between PDSS overall quality of sleep item and the NPI nighttime behaviour subscale.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eSpearman correlation of Parkinson\u0026rsquo;s disease sleep scale (PDSS) scores and Neuropsychiatric Inventory (NPI) Nighttime behaviour scores obtained from cases with Parkinson\u0026rsquo;s disease\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePDSS Items\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNPI Nighttime Behavior\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003erho (p-values)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1. Overall quality of night\u0026rsquo;s sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.45 (\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2. Difficulty falling asleep each night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.46 (\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3. Difficulty staying asleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.49 (\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4. Restlessness in legs or arms at night or in the evening disrupt sleep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.32 (0.02)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5. Fidget in bed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.18 (0.232)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6. Distressing dreams at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.16 (0.286)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7. Distressing hallucinations at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.45 (0.002)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8. Get up at night to pass urine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.13 (0.413)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9. Incontinence of urine because unable to move due to \u0026ldquo;off\u0026rdquo; symptoms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.27 (0.075)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10. Numbness or tingling in arms or legs, which wakes you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.36 (0.018)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11. Painful muscle cramps in arms\u003c/p\u003e\n \u003cp\u003eor legs which wake you from sleep at night\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.02 (0.885)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12. Wake early in the morning with painful posturing of your arms or legs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.22 (0.007)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13. Tremor on waking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.29 (\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14. Feel tired and sleepy after waking in the morning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.21 (0.011)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15. Unexpectedly fall asleep during\u003c/p\u003e\n \u003cp\u003ethe day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-0.21 (0.009)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\"\u003e\u003csup\u003ea\u003c/sup\u003eLower scores represents more severe sleep disturbance; \u003csup\u003eb\u003c/sup\u003eHigher scores represents more severe nighttime behaviour disturbance; alpha is significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eWe found in the present study that PDSS scores were differentiated between persons with PD and neurologically healthy controls who were matched for age, sex, education and outpatient status. Many individual items demonstrated statistical discriminatory power between persons with PD and controls. Among cases, PDSS scores worsened as motor severity increased. We also found that ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. In particular, the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale.\u003c/p\u003e \u003cp\u003eThe PDSS is a visual analogue scale and has the advantage of ease of administration. It addresses the limitation of text-heavy, self-administered tools in settings such as Nigeria where many persons with PD have limited education[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The PDSS does not require patients to be able to read or write, and in this study, we have shown that it is effective in the identification of sleep disturbances in Nigerians with PD.\u003c/p\u003e \u003cp\u003eIn the original description of the PDSS[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], the tool successfully discriminated between persons with PD and healthy controls in 13 out of the 15 items. In so far as the mean PDSS scores for persons with PD in the present study were approximately one point lower than for matched controls in 13 out of the 15 items, the tool provided initial indication of discriminant validity for these items in our cohort. Conversely, the PDSS was poor in discriminating persons with PD and controls in overall sleep quality (item 1). Also, while there was no stepped down statistical difference in cases and controls in item 2 (Sleep onset insomnia), item 3 (sleep maintenance insomnia) showed critical discrimination between the two groups. Findings similar to those reported in the present study were interpreted in both the original design of the PDSS[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] and its subsequent replication in the United State[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] to mean that these non-discriminatory items are not unique to PD. Similar to these previous studies[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], the poorer PDSS scores observed with advancing Hoehn and Yahr stages in the present study may suggest that sleep disturbances become worse as PD progresses.\u003c/p\u003e \u003cp\u003eOur findings indicated that ten (66.7%) of the 15 PDSS items demonstrated statistical correlations with the NPI nighttime behaviour sub-scale. In particular, the PDSS overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucination items demonstrated moderate correlations (0.45 to 0.49) with the NPI nighttime behaviour sub-scale. This finding may indicate that nighttime behavioural disturbances in PD may be due to problems with overall sleep quality, sleep onset and sleep maintenance insomnia, as well as sleep related hallucinations. Conversely, persons with PD and controls in our sample woke up at night to pass urine since both groups had their lowest PDSS mean scores for item 8 (nocturia). This is similar to findings reported in previous cohorts of persons with PD[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], as well as in the general population[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eClinical and Public Health Implications.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eOur findings have important clinical and public health implications. Given the high frequency of sleep disturbances in PD, and limited use of validated sleep assessment tools for PD in Nigeria, the PDSS proved an effective, accessible option for evaluating sleep dysfunction in our study cohort. Many Nigerians with PD have limited formal education, making text-heavy, self-administered tools often challenging[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The format of the PDSS facilitates self-reporting, even among individuals with limited formal education, potentially improving early detection and management of sleep disorders in Nigeria.\u003c/p\u003e \u003cp\u003eWith the observed scarcity of mental and neurological healthcare specialist in Nigeria[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], it may be prudent to shift attention to simplified treatment strategies that equip non-specialised healthcare workers in clinical diagnosis and management of PD at the primary care level. The PDSS tool could come in handy for assessing sleep disturbances among persons with PD following clinical diagnosis, and the institution of symptomatic treatment. Similar strategies have been used in more developed healthcare systems around the world[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Our study thus underscores the need for holistic management approaches integrating sleep assessments into routine clinical and multidisciplinary care for patients with PD in our setting.\u003c/p\u003e \u003cp\u003eThe present study has limitations. First, although the NPI nighttime behaviour scale potentially captures sleep disturbances and nocturnal behavioural problems, it has notable limitations. Specifically, it does not assess specific sleep disorders. It also relies solely on caregiver reports, which may be subject to bias. Secondly, while the PDSS provides a subjective measure of sleep disturbances, objective sleep assessments, such as polysomnography, could have given more objective insights. Future research incorporating subjective and objective measures could provide more comprehensive information on the pattern of sleep disturbances in PD patients. Additionally, while our study demonstrated the utility of the PDSS tool in a Nigerian cohort, further studies are needed in our setting to assess the impact of its use in PD management over time.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSleep disorders are common non-motor symptoms among Nigerians living with PD. This is particularly so in the advanced stages of the disorder. This study highlights the potential utility of the PDSS in identifying PD-related sleep disturbances in Nigeria where many persons with the disorder have limited formal education. Patients scoring poorly on the PDSS may merit referral for objective sleep assessments, such as polysomnography, as well as evidence-based management of nocturnal symptoms in PD.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eInformed consent:\u003c/h2\u003e \u003cp\u003e Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthical approval:\u003c/strong\u003e \u003cp\u003e All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eOA: Formal analysis, Writing - Original Draft, Review \u0026amp; Editing; AO: Conceptualization, Methodology, Funding acquisition, Supervision, Formal analysis, Writing - Original Draft, Review \u0026amp; Editing. HO: Data Curation, Formal analysis, Review \u0026amp; Editing. OE: Methodology, Writing - Original Draft, Review \u0026amp; Editing. AB: Resources, Review \u0026amp; Editing.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData is provided within the manuscript or supplementary information files. Additional information will be provided upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSavica R, et al. Incidence and pathology of synucleinopathies and tauopathies related to parkinsonism. JAMA Neurol. 2013;70(7):859\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRizig M, et al. The International Parkinson Disease Genomics Consortium Africa. Lancet Neurol. 2021;20(5):335.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchutz L, Sixel-Doring F, Hermann W. Management of Sleep Disturbances in Parkinson's Disease. J Parkinsons Dis. 2022;12(7):2029\u0026ndash;58.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStefani A, Hogl B. Sleep in Parkinson's disease. Neuropsychopharmacology. 2020;45(1):121\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRadad K, et al. Pathophysiology of non-motor signs in Parkinson\u0026rsquo;s disease: some recent updating with brief presentation. Explor Neuroprotective Therapy. 2023;3:24\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmara AW, et al. Longitudinal assessment of excessive daytime sleepiness in early Parkinson's disease. J Neurol Neurosurg Psychiatry. 2017;88(8):653\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBuysse DJ, et al. Relationships between the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and clinical/polysomnographic measures in a community sample. J Clin Sleep Med. 2008;4(6):563\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991;14(6):540\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChaudhuri KR, et al. The Parkinson's disease sleep scale: a new instrument for assessing sleep and nocturnal disability in Parkinson's disease. J Neurol Neurosurg Psychiatry. 2002;73(6):629\u0026ndash;35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTrenkwalder C, et al. Parkinson's disease sleep scale\u0026ndash;validation of the revised version PDSS-2. Mov Disord. 2011;26(4):644\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDotchin CL, Msuya O, Walker RW. The challenge of Parkinson's disease management in Africa. Age Ageing. 2007;36(2):122\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOguntoye R. Sleep Patterns in Relation to Disease Severity in Parkinson\u0026rsquo;s Disease: A Study of 84 Ibadan Patients. Movement Disorder Society Virtual Congress. International Parkinson's and Movement Disorder Society; 2020.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKaufer DI, et al. Validation of the NPI-Q, a brief clinical form of the Neuropsychiatric Inventory. J Neuropsychiatry Clin Neurosci. 2000;12(2):233\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGibb WR. The relevance of the Lewy body to the pathogenesis of idiopathic Parkinson\u0026rsquo;s disease. J Neurol Neurosurg Psychiatry. 1998;51(6):745\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWorld Health Organization. International Statistical Classification of Diseases and Related Health Problems. World Health Organization: Geneva; 2019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOjagbemi AA, Akinyemi RO, Baiyewu O. Neuropsychiatric symptoms in Nigerian patients with Parkinson's disease. Acta Neurol Scand. 2013;128(1):9\u0026ndash;16.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOjagbemi A, et al. Prevalence, predictors, and prognoses of prestroke neuropsychiatric symptoms at 3 months poststroke. Int Psychogeriatr. 2021;33(8):827\u0026ndash;34.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFahn S, Elton RL et al. \u003cem\u003eUPDRS Program Members. Unified Parkinson's disease rating scale.\u003c/em\u003e, in \u003cem\u003eRecent developments in Parkinson's disease\u003c/em\u003e, S. Fahn, Editors. 1987, Macmillan Healthcare Information: Florham Park, NJ; 1987. pp. 153\u0026ndash;163, 293\u0026ndash;304.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScanlon BK, et al. A formula for the conversion of UPDRS-III scores to Hoehn and Yahr stage. Parkinsonism Relat Disord. 2008;14(4):379\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFerguson B, Tandon A, Gakidou E. Estimating Permanent income using Indicator variables. Health systems Performance Assessment: diabetes, methods and empericism. World Health Organisation: Geneva; 2003. pp. 747\u0026ndash;60. C. Murray and D. Evans, Editors.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKessler RC, Ustun TB. The World Mental Health (WMH) Survey Initiative Version of the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI). Int J Methods Psychiatr Res. 2004;13(2):93\u0026ndash;121.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStataCorp. Stata Statistical Software. StataCorp LLC: College Station, TX:; 2019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTse W, et al. Clinical usefulness of the Parkinson's disease sleep scale. Parkinsonism Relat Disord. 2005;11(5):317\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMilsom I, et al. How widespread are the symptoms of an overactive bladder and how are they managed? A population-based prevalence study. BJU Int. 2001;87(9):760\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAjoseh S, et al. Navigating brain drain: understanding public discourse on legislation to retain medical professionals in Nigeria. Global Health. 2024;20(1):80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNunes SFL, Alvarez AM, Valcarenghi RV. Parkinson's disease in primary health care and nursing care: a scoping review. Rev Esc Enferm USP. 2022;56:e20210367.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6383451/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6383451/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSleep disturbances are common in persons with Parkinson’s disease (PD) but often go undetected by attending physicians. Due to its simplicity, the visual analogue PD Sleep Scale (PDSS) could be valuable in the detection and management of sleep disturbances in contexts such as Nigeria where text heavy self-report assessments are difficult to implement due to limited formal education. We aim to test the utility of the PDSS in identifying nocturnal sleep problems in Nigerians with PD.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe evaluated a dataset comprising information collected as part of a two-centre prevalence and case control study of behavioural disturbances among persons with PD in southwestern Nigeria. Nocturnal sleep problems in PD were assessed using the PDSS. We also independently administered the Neuropsychiatric Inventory Questionnaire (NPI-Q). We examined indicators of construct validity by comparing the PDSS with the NPI-Q nighttime behavioural subscale, known group validity by comparing with Hoehn and Yahrs stages of PD, and discriminant validity by comparing PDSS scores in cases and controls. We generated Spearman correlation coefficients, Games-Howell post hoc adjustments in ANOVA, and step-down Bonferroni corrections for multiple comparisons.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong 150 persons with PD and 150 matched neurologically healthy controls,\u003cstrong\u003e \u003c/strong\u003ePDSS scores were discriminated in 13 out of the 15 items (step-down Bonferroni corrected p\u0026lt;0.003). Ten items demonstrated statistical correlations with the NPI-Q (r=0.45 to 0.49 for overall sleep quality, sleep onset insomnia, sleep maintenance insomnia, and sleep related hallucinations). PDSS scores worsened as motor severity increased (Games-Howell post hoc adjusted p\u0026lt;0.05 for Early to Severe PD).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe PDSS was useful in identifying a variety of nocturnal sleep problems in people living with PD. These results provide support for the utility of the tool in Nigeria and similar contexts where many patients have limited or no formal education.\u003c/p\u003e","manuscriptTitle":"Use of the Visual Analogue Parkinson’s Disease Sleep Scale in Nigeria.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-08 12:21:28","doi":"10.21203/rs.3.rs-6383451/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a56aabe1-9db7-44a1-a654-756a04c450cd","owner":[],"postedDate":"April 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-04-18T22:23:10+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-08 12:21:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6383451","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6383451","identity":"rs-6383451","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}