Daily light exposure habits of youth with migraine: A prospective pilot study

Daily light exposure habits of youth with migraine: A prospective pilot study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Daily light exposure habits of youth with migraine: A prospective pilot study Carlyn Patterson Gentile, Ryan Shah, Blanca Marquez de Prado, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6682653/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Photophobia is a common symptom in youth with migraine, but it is unknown if it leads to light avoidant behavior, and if such behaviors worsen disease burden. We conducted a feasibility study between November and March 2024 measuring light exposure using wearable light logger pendants in 20 youth with migraine (10–21 years old) while migraine symptoms were tracked with a text-based daily diary. On average, participants received recommended light exposure during only 14.5% +/- SD 7.0 of daylight hours but were consistently below the recommended maximum light levels 3 hours prior to bed (77.5% +/- 21.6 of the time), and at night (99.1% +/- 2.9 of the time). Daily light exposure patterns that were phase shifted 60 minutes later in youth with chronic (compared to non-chronic) migraine. Measuring daily light exposure is feasible in pediatric populations with photophobia and reveals intriguing trends that warrant further study. Biological sciences/Neuroscience/Visual system Biological sciences/Neuroscience/Diseases of the nervous system migraine adolescents photophobia light exposure light logging circadian cycle Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Variation in visual diet (i.e. the intensity and timing of light exposure during daily life) has been associated with health outcomes. Exposure to brighter days and darker nights is known to confer reduced mortality risk, 1 perhaps related to the effect that light has upon circadian biology. 2 Insufficient daytime melanopic illuminance (short wavelength “blue light”) and evening melanopic illuminance from artificial light both have the potential to disrupt circadian entrainment. 3 , 4 In support of this, multiple studies have associated nighttime screen use with poorer health-related quality of life and sleep disruption. 5 – 7 Photophobia (i.e. light sensitivity) is a common symptom of multiple neurologic and ophthalmologic conditions including migraine, 8 9 which may influence the visual diet through avoidance of high intensity visual environments. 10 There has, however, been limited empirical study of how visual diet is altered and potentially influences symptoms in people with photophobia. Recently developed, wearable light loggers now provide the ability to address these questions using quantified measures of visual diet during daily life. 11 – 13 These small, battery-powered devices record the absolute level of light falling upon a detector over a period of many days. These recordings provide the relative amount of light across wavelengths, supporting inferences regarding the types of light encountered (natural vs. artificial) and the biological effect upon different classes of retinal photoreceptors (melanopsin containing cells vs. cones). We measured the visual diet for 20 youth with migraine using wearable light loggers that continuously tracked ambient light exposure over 7 days during a typical week. We hypothesized that continuous measurement of the visual diet in youth with migraine would be feasible and yield intriguing associations with disease burden in youth with migraine. Specifically, we predicted that a restricted and poorly timed visual diet (i.e., overall less and poorly timed light) would be associated with worse photophobia, chronic migraine, and worse headache-related disability. Materials and Methods Study Design This single-center prospective observational pilot study was conducted within the pediatric headache program within the Children’s Hospital of Philadelphia (CHOP) neurology department between October 2024 and March 2025. The protocol received approval from the Institutional Review Board at CHOP. Participants Potentially eligible participants were identified by screening patients being seen in upcoming headache clinics via chart review. Participants were included if they were between the ages 10 to 21 years, ICHD-3 defined migraine with or without aura given by a headache specialist of any headache frequency and consented (≥ 18 years) or assented with parent consent (< 18 years) to participate in the study. Exclusion criteria were history of major neurological conditions besides migraine (e.g. history of epilepsy, stroke, multiple sclerosis), recent history of concussion (< 3 months), or were starting or weaning off a headache preventive medication (supplement or prescription) without being on a stable dose for at least 1 month prior to enrollment. Data Collection : Devices were shipped to the participants’ home and once received, a virtual visit was conducted to review the proper use of the wearable devices and text-diary before recording began. At this visit, participants completed baseline questionnaires through REDCap (Research Electronic Data Capture) 14 , 15 hosted by the institution. The first full day of recording (12 am – 11:59 pm) was considered “Day 1,” and data collection ran for 7 full days. During these 7 days, diary questions were texted between 7pm and 11pm based on participant preference. During data collection, participants continuously wore the light logger while responding to headache diary prompts each evening. The light logger was removed while sleeping to avoid choking or the light logging device being obscured by bedsheets. Participants were instructed to keep the light logger on a bedside table, which is standard for light logger studies. 16 At a scheduled clinic visit after the recording week, participants returned the wearable devices and filled out REDCap-based questionnaires. If participants had personal eyewear, they wore to filter light (e.g. blue light blocking, sunglasses), the light transmittance of this personal eyewear was measured. Demographic, medical history, clinical characteristics, and treatment were gathered. Standardized and validated survey data included the CHOP Headache Questionnaire, 17 including number of any headache days per month and number of bad headache days per month. Light sensitivity was measured using the Visual Light Sensitivity Questionnaire (VLSQ-8), which is an 8-question validated measurement of light sensitivity with possible scores ranging from 8–40. 18 Fear of Pain Questionnaire for Children (FOPQ-C) is a validated metric which was used to measure fear-avoidant responses to pain. After the week of data collection, headache-related disability over the previous month was assessed with the Pediatric Migraine Disability Assessment (PedMIDAS). PedMIDAS has a maximum score of 80 (1-month version), 19 with scores of 3 or less indicating no disability, 3–9 indicating mild disability, 10–16 indicating moderate disability, and > 16 indicating severe disability. PROMIS Sleep Disturbance questionnaire was also filled out to capture the perception of sleep quality and the PROMIS Sleep-Related Impairment questionnaire, which captured symptoms of insufficient sleep (e.g. daytime sleepiness). PROMIS rates no, mild, moderate, and severe symptoms based on T-scores. 20 Data were also collected on chronotype and weekday versus weekend sleep/wake habits using the standardized chronotype questionnaire. 21 Daily migraine symptoms, acute medication use, and function were recorded with a validated text-based Daily Headache Diary 22 with additional questions to capture device wear compliance, and light-blocking lens use. Daily headache diaries were filled out via text message using the HIPAA-compliant Twilio platform hosted at CHOP. Specific questions included “Have you had a headache today” (yes or no), “Has your headache gotten in the way of your school, home, or social life today” (yes or no), and “Rate your light sensitivity (0–5).” Light Logger Data Device wear and data collection ActLumus devices (Condor Instruments, São Paolo, Brazil) are wearable light loggers that provide 24-hour continuous collection of photopic illuminance and mEDI (Fig. 1 ). ActLumus devices were worn as a pendant around the neck, providing more ecologically valid measurements that are not obscured by shirt sleeves and are closer to the visual plane, which is critical for capturing non-image forming effects of light. 12 , 23 Data were collected at a sampling rate of 1/minute to maximize temporal resolution while still providing for 7 days of continuous recording. 13 Data processing Data were visually inspected and excluded if participants reported not wearing and being away from the Actlumus device for more than 2 hours in a day. ActLumus data were pre-processed using ActiLab Software (Condor Instruments, São Paolo, Brazil). Specifically, melanopic and photopic lux values were derived from 10 light sensing channels that detect different wavelengths of light for every minute of data capture. The intention was to adjust measurements based on light filtering glasses wear as determined by change in light transmittance levels, but these data were not accurately measured during data collection so this step could not be pursued. Clinical data, as well as melanopic and photopic illuminance was processed using custom software developed in Matlab (Mathworks). Log transformation was performed on melanopic and photopic illuminance values to accommodate large shifts in illuminance levels. 11 Light metrics : Two features of the visual diet were considered: 1) the intensity of light exposure, 2) the timing of light exposure. Light metrics were chosen that summarize continuous light exposure data to capture these two features of the visual diet. 11 , 24 Light intensity was represented by photopic luminous exposure and time spent exposed to bright light levels. Photopic luminous exposure captures the total 24-hour photopic light exposure (kilolux*hr), which provides a measurement of overall light exposure. Bright light was defined as photopic illuminance > 1,000 lux because outdoor light ranges from 1,000 lux on a cloudy day to 100,000 lux on a bright sunny day, while indoor light is generally below 500 lux. 24 – 26 Light timing was defined by percent time spent within recommended mEDI limits. A minimum 250 melanopic lux is recommended during daytime hours, while a maximum of 10 lux in the evening 3 starting three hours before bedtime, and 1 lux or less at night is recommended to support optimal timed melatonin release. 27 These recommendations were based on expert-scientific consensus and supported by the sensitivity of human “non-visual” responses to ocular light. In this study, we chose fixed definitions of “day” defined as 7 am – 5 pm, “pre-bedtime” defined as 8 pm – 11 pm, and “night” defined as 12 am – 6 am, based on the diurnal motion of the sun and the structured schedule imposed by school. Gaps in time were left between “day,” “pre-bed,” and “night” definitions to allow for some variability across individual schedules. Validation of Light Logger measurements We validated the tabular spectral sensitivity functions of the ActLumus device. To do so, we measured a standard light source using both the ActLumus and a calibrated spectrophotometer (SpectraScan® PR-670, JADAK, North Syracuse, NY). The light source was the output of an 8-channel, digital light synthesizer (CombiLED, Prizmatix, Tel Aviv, Israel) delivered via liquid light guide into a light integrating sphere (LabSphere, North Sutton, NH). The spectral radiance of the light source was measured at 2 nm resolution using the PR-670. Combining this spectrum with the ActLumus tabular sensitivity functions (provided by the manufacturer), and converting from radiance to irradiance, provided a model prediction of the ActLumus sensor counts. We then measured the light source using the ActLumus, and compared the obtained and predicted sensor counts. We found the ActLumus counts to be in excellent agreement with the prediction (Pearson’s R = 0.9982). We were, however, limited to validating 9 of the 10 ActLumus channels, as the PR-670 does not measure the infra-red sampling range of the 10th channel. Data Analysis No a priori sample size calculations were performed as this was a pilot study to determine sample size for future studies. Descriptive statistics for continuous variables included median with interquartile range for non-normal continuous distributions and mean with standard deviation for continuous variables with normal distribution. Proportions were reported for categorical variables. Continuous light logger data was graphically represented as the mean with 95% confidence intervals (CI) determined by bootstrap analysis. Shifts in the temporal profile between weekdays and weekends and between youth with and without chronic migraine were estimated by determining the correlation between a shifted version (+/-100 minutes) of the first group and the second group and taking the highest correlation value (which was r > 0.98 for both comparisons). Results Clinical and Headache Diary data Twenty youth with migraine participated in this study. Demographics and clinical characteristics were reported (Table 1 ). Participants were a median age of 17 years old [IQR 16, 19] and were 70% female, and reported a median of 17 [IQR 6, 30] days per month of any headache, and 5 [IQR 2, 15] days per month of bad headache for the previous month at the start of recording. Headache-related disability (measured by 1-month PedMIDAS scores) was moderate on average with a median PedMIDAS score of 16 [IQR 8, 29]. 19 , 28 Median fear-of-pain (FOPQ-C) score was 39 [31, 54], placing most youth in the moderate-to-severe range, consistent with chronic pain conditions, including migraine. 29 All participants were on at least one, and many were on a combination of pharmacologic agents for headache prevention. Supplements, OnabotulinumtoxinA, antidepressants, and calcitonin gene-related peptide blocking agents were the most common. This is representative of patients seen in the CHOP headache clinic, who have more severe and refractory migraine compared to the general population of adolescents with migraine. Table 1 Participant demographics, baseline headache characteristics, and treatment. a For the two participants who indicated they were Hispanic, both selected “prefer not to answer” for race. b Sleep impairment measures symptoms of poor sleep including fatigue and daytime sleepiness, while sleep disturbance measures difficulties falling and staying asleep. PedMIDAS = Pediatric Migraine Disability Assessment, moderate/severe was defined as a score of 10 or greater. FOPQ-C = Fear of Pain Questionnaire for Children, moderate/severe is defined as a score of 30 or greater, based on FOPQ-C definition; VLSQ-8 = visual light sensitivity questionnaire, moderate/severe light sensitivity was defined as a score > 24, which is the midpoint score. Demographics and Headache Characteristics Age [IQR] 17 [16, 19] Sex n (%) F 14 (70), M 6 (30) Race Ethnicity Hispanic a n (%) Non-Hispanic Black n (%) Non-Hispanic White n (%) Pref. not to answer n (%) 2 (10) 2 (10) 15 (75) 1 (5) Validated questionnaires Headache d/mo. [IQR] 17 [6, 30] Bad Headache days/month [IQR] 5 [2, 15] Continuous headache n (%) 12 (60) PedMIDAS (1 mo.) [IQR] Moderate/Severe n (%) 16 [8, 29] 14 (70) FOPQ-C [IQR] Moderate/Severe n (%) 39 [31, 54] 16 (80) VLSQ-8 [IQR] Moderate/Severe n (%) 23 [19, 27] 7 (35) PROMIS - Sleep None (%) Mild n (%) Moderate n (%) Severe n (%) Impairment b 7 (35) 3 (15) 4 (20) 6 (30) Disturbance b 10 (50) 1 (5) 4 (20) 5 (25) All participants had 100% compliance with headache diary prompts. Headache diary responses were consistent with validated questionnaire responses. Youth reported a median of 6 headache days [IQR 3, 7], and 3 migraine days [IQR 1, 6], indicating they had high any headache and bad headache frequency during recording week. Median daily light sensitivity score was 2 [IQR 1, 3] indicating mild light sensitivity, and median pain score was 4 [0, 6] indicating moderate pain. Light logging Overall, compliance with light logger wear was high. Each participant completed 7 days of recording for a total of 140 days. For one participant, 4 days of recording were excluded due to being away from their ActLumus device for more than 2 hours and/or visual inspection was indicative of non-device wear. This left 136/140 (97.1%) of days with usable light logging data across 20 participants. Seven participants reported using light blocking lenses (blue light filtered and/or sunglasses). Of those, only one used light filtering glasses continuously, with the remainder using glasses a maximum of 1–2 hours a day on an as needed basis. The lens transmittance measurements did not record during data collection, so light exposure levels were not able to be adjusted for based on light blocking lens use. 24-hour light exposure profiles We evaluated patterns of photopic and melanopic illuminance across the 24-hour circadian cycle (Figure 2). We compared light exposure on weekdays and weekends, as substantial differences have been noted in adolescent populations given the structure imposed by school. 30 Photopic and melanopic illuminance demonstrated high correlation throughout the day (Figure 2a). However, there was a relative increase in photopic compared to melanopic illuminance that was most pronounced starting around 6 pm until 10 pm. As expected, average light exposure levels were delayed by 49 minutes on the weekends compared to the weekdays. This shift was consistent with later and more variable bedtimes, sleep times, and wake-up times, and longer sleep durations reported in the Chronotype Questionnaire (Figure 2b). Light exposure summary metrics Summary metrics were calculated to capture daily light intensity and light timing based on our findings across the 24-hr light profile, and prior studies. 11 , 13 , 16 , 27 Two metrics of photopic illuminance were used to characterize daily light intensity (Fig. 3 a). Total photopic luminous exposure was calculated, which represents the integrated exposure to photopic light in a 24-hour period. The mean total luminous exposure across participants was 6.2 klux*hr, with a wide range between 0.2 and 16.9 klux*hr. Time youth spent in bright light was also estimated, which was defined as light exposure of 1,000 lux photopic illuminance or greater, as indoor light is typically below 500 lux. The mean total time spent in bright light across participants was 42 minutes per day [range 0 to 108 minutes]. Percent time spent within recommended light levels across a 24-hour period was used to capture light timing (Fig. 3 b). Different levels of light exposure have been recommended for healthy adults based on the time of day: a minimum light exposure of 250 melanopic lux during daytime hours; a maximum of 10 lux starting three hours before bedtime; and 1 lux or less at night is recommended. 27 These criteria were used because similar recommendations have not been developed for the adolescent population. We therefore calculated the proportion of time within these recommended limits during daytime (7a – 5p), pre-bedtime (8a – 11p), and nighttime (12a – 6a) hours. Timing was selected based on typical school schedules, the diurnal pattern of the sun at the location of the study. These definitions were supported by the timing of light exposure observed across participants within a 24-hour period. Participants spent an average of 14.5% +/- SD 7.0% of daytime exposed to the recommended minimum mEDI of 250 lux (Fig. 3 b). Percent time spent within recommended levels improved substantially in the pre-bedtime and night hours, with youth spending an average of 77.5% +/- SD 21.6% of the time the maximum recommended mEDI of light pre-bedtime, and 99.1% +/- SD 2.9% of the time during night hours. Chronic migraine To determine if there were any emerging differences in youth with migraine based on headache frequency, we compared the temporal profiles of melanopic illuminance of youth with chronic migraine (15 or more headache days per month with 8 or more bad headache days per month; 31 n = 8) to youth who did not meet these criteria ( n = 12; Fig. 4 ). Youth with chronic migraine demonstrated an average temporal profile that was delayed by 60 minutes, and a subtle increase in the intensity of melanopic illuminance compared to those without chronic migraine. A similar pattern was observed for photopic illuminance. We did not pursue additional statistical testing as the goal of this study was to determine sample sizes needed to appropriately power future research. Instead, we conducted power analyses to determine sample sizes needed for group comparisons of youth with migraine (e.g. youth chronic migraine versus lower frequency migraine, those with high versus low headache-related disability, or high versus low light sensitivity) across light logger metrics (see Supplemental Materials ). We found that sample sizes of 50 to 150 would be sufficient for most comparisons. Participant Feedback Seventeen (85%) participants agreed or strongly agreed with the statement “I would recommend somebody to participate in this study,” while 3 (15%) strongly disagreed. Specific comments included liking the text reminders for the diary and to remember to wear the devices (1). Participants offered ways of improving the study including making the device smaller and addressing challenges with the headache diary only being once a day but experiencing multiple headache spikes a day. Discussion We conducted a pilot study monitoring light exposure during everyday life of 20 youth with migraine, most with high migraine disease burden. To our knowledge, this is the first study demonstrating light exposure habits in a population with migraine using wearable light logger technology. Here, we review intriguing trends we observed in youth with migraine in the context of other studies, and how these findings should inform future study design. We found that participants spent only about 15% of the daytime (~ 1.5 hours per day) at or above the recommended minimum daylight levels for healthy adults. By comparison, they spent most of their time below the recommended maximum light levels 3 hours before bed, and during the night (78% and 99% on average, respectively). It is important to note that these recommended light levels are based on optimal light intensity and timing needed for appropriate circadian fluctuations of melanopsin. 27 Large observational studies using this metric are needed to determine if there is a broader impact on general health if these recommendations are not met, or are only met some of the time. We suspect the low light exposure levels we observed in this study are due to multiple factors. Perhaps one of the largest contributors to low daytime light exposure—not unique to individuals with photophobia—is the tendency in the modern societies to spend most of the time in indoor lighting environments that are darker than outdoor environments. Lucas and colleagues conducted a similar study in 59 generally healthy, mostly younger adults, providing an important reference point. They found participants spent 33% of daylight hours at or above recommended light levels, but 66% of the time at or below recommended light levels 3 hours before bed. 16 Results across the two studies are similar, however participants in our study were exposed to lower light levels at each point in the 24-hour cycle. Additionally, youth with migraine spent less time exposed to bright light: the adults spent an average of 1.7 hours per day under bright light conditions 16 compared to an average of 40 minutes per day in our study. These differences are present even though Lucas and colleagues used wrist watches that can underestimate light exposure compared to pendant wear. While it is possible that low light exposure reflects light avoidance driven by migraine-related photophobia in our study population, there are other explanations. First, it is currently unknown if adolescents behave similarly to adults in light exposure habits and normative data in younger populations are needed. Additionally, Lucas and colleagues completed recording February through July, while we recorded November through March, biasing our study towards the winter months when light exposure tends to be lower. Illustrating this, a study including 15 adults in Amsterdam found a 4-fold increase in the time spent above 250 lux mEDI between the winter and summer. 11 We also found that bright light exposure was variable across participants, ranging from 0 to 2 hours a day. This may reflect differences in other factors (e.g. participation in outdoor sports) that could influence light exposure. Clearly, simultaneous measurements of study and control populations will be needed to support stronger claims of altered visual diet in migraine. We observed light exposure profiles shifted later on the weekends compared to the weekdays. This corresponded with reported sleep/wake times and is consistent with prior studies in adolescents. 30 We also observed that the entire temporal light profile was shifted an hour later for youth with higher frequency migraine attacks (i.e. chronic migraine) in this preliminary sample. Later chronotype has been associated with more frequent headache in youth, 32 which is consistent with these findings. The causal direction of these emerging associations is unknown. It is possible, for example, that youth with chronic migraine rise later due to severe symptoms, producing a shifted sleep schedule, resulting in greater artificial light exposure in the evening and before bed. These effects may also reflect sleep disruption influenced by exposure to evening and nighttime screens. This is consistent with the finding that increased headache frequency in youth is associated with prolonged screen use. 32 , 33 Further study is needed to confirm and understand these associations. Strengths and Limitations To our knowledge, this is the first study to report objective measurements of light exposure combined with a daily diary to track migraine symptoms in real time. We used a light logger with 10 channels of differing spectral sensitivities allowing for the separation of photopic and melanopic illuminance, while light loggers with a single channel provide only a non-specific measure of overall illuminance. The multi-channel measurements allow for more mechanistic hypothesis testing. We observed that the relative strengths of photopic and melanopic illuminance diverged during the evening hours. This may reflect differences artificial lighting environments where these signals can dissociate, 34 and highlights the importance of collecting both measurements. Overall, diary and device compliance were high providing a complete dataset for analysis, and participants generally had positive feedback on the study design. Limitations include small sample size and the lack of a control group. Furthermore, participants were established patients of a pediatric headache clinic receiving active treatment, limiting the generalizability of the results. There may be bias in that youth willing to participate in the study may be more likely to already be working on healthy headache habits, while those still struggling with daily habits may be less likely to participate. While light filtering lens use was captured by survey data, we did not correct our measurements for the continuous use of blue light filtering glasses for one participant. Finally, data collection occurred in the winter months when light exposure is lower in the Philadelphia area, thus it is unclear if results are generalizable to different times of year. Future Directions Studies that include larger sample sizes and control comparison to migraine-free peers are needed. Prior reports have offered that significant differences between winter and summer light exposure should be found with sample sizes as small as 3 individuals. 11 Our calculations in youth with migraine indicate differences within disease states may be more subtle; we found sample sizes of 50 to 150 will be needed to detect group differences based on subjective report of migraine burden and sleep for most light metrics (see Supplemental Materials ). Controlling for time of year is also critical as there are dramatic differences in light exposure between the summer and winter months at greater latitudes. 35 This cycle may contribute to the seasonal variation observed in migraine, where migraine symptoms to be worse in the late fall and winter months, 36 – 39 and seasonal comparison offers a unique opportunity for within-participant measurement. Ultimately, insufficient and/or poorly timed light exposure may offer a modifiable risk factor for increased disease burden in youth with migraine. If larger observational studies confirm a relationship between migraine disease burden and light exposure, then clinical trials focused on interventions that address visual diet could be pursued. Multiple participants expressed interest in having access to their data, suggesting this may be a viable target for behavioral intervention. Conclusion Like prior studies in a general adult population, youth with migraine receive less than recommended daytime light exposure but do tend to achieve recommended levels of darkness during the evening and night. Measuring daily light exposure in youth with migraine is feasible and promising avenue for larger observational studies. Abbreviations CHOP – Children’s Hospital of Philadelphia ICHD-3 – International Classification of Headache Disorders 3 rd Edition IQR – interquartile range mEDI – Melanopic Equivalent Daylight Illuminance SD – standard deviation Declarations Conflict of interest statement: Commercial Relationships Disclosures: C.P.G.: Dr. Patterson Gentile is currently funded by the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS124986) and the CHOP Foerderer Institutional grant. C.L.S.: Dr. Szperka has received research/grant support from the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS102521), and PCORI. Dr. Szperka or her institution have received compensation for her consulting work for Eli Lilly; Teva Pharmaceutical Industries Ltd; Upsher-Smith Laboratories, LLC; and Abbvie. A.D.H.: Dr. Hershey or his institution have received compensation for serving as a consultant for AbbVie, Amgen, Biohaven, Eli Lilly, Lundbeck, Supernus, Teva, Theranica and Upsher-Smith. His institution has also received research support from Amgen, Biohaven, Eli Lilly, Theranica, Upsher-Smith, and the NIH NINDS/NICHDS. G.K.A.: Dr. Aguirre receives funding/grant support from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, and the Binational Science Foundation. R.S., B.M.P., and N.R. do not have conflicts of interest. Financial support: This work was supported by the Children’s Hospital of Philadelphia Foerderer Grant, and by the National Institutes of Health National Institute of Neurological Disorders and Stroke (K23NS124986 to C.P.G) and The National Eye Institute (P30EY001583). Acknowledgements: We would like to thank the participants for contributing their time and feedback to this study. References Windred DP, Burns AC, Lane JM, et al. Brighter nights and darker days predict higher mortality risk: A prospective analysis of personal light exposure in >88,000 individuals. Proceedings of the National Academy of Sciences. 2024;121. Ruby NF, Brennan TJ, Xie X, et al. Role of Melanopsin in Circadian Responses to Light. Science (1979). 2002;298:2211–2213. Lu J, Zou R, Yang Y, et al. Association between nocturnal light exposure and melatonin in humans: a meta-analysis. Environmental Science and Pollution Research. 2023;31:3425–3434. Smolensky MH, Sackett-Lundeen LL, Portaluppi F. 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Dautovich ND, Schreiber DR, Imel JL, et al. A systematic review of the amount and timing of light in association with objective and subjective sleep outcomes in community-dwelling adults. Sleep Health. 2019;5:31–48. Michael PR, Johnston DE, Moreno W. A conversion guide: solar irradiance and lux illuminance. Journal of Measurements in Engineering. 2020;8:153–166. Knoop M, Stefani O, Bueno B, et al. Daylight: What makes the difference? Lighting Research & Technology. 2020;52:423–442. Brown TM, Brainard GC, Cajochen C, et al. Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLoS Biol. 2022;20:e3001571. Hershey AD, Powers SW, Vockell A-LB, LeCates S, Kabbouche MA, Maynard MK. PedMIDAS. Neurology. Epub 2001. Simons LE, Sieberg CB, Carpino E, Logan D, Berde C. The Fear of Pain Questionnaire (FOPQ): Assessment of Pain-Related Fear Among Children and Adolescents With Chronic Pain. J Pain. 2011;12:677–686. Estevan I, Tassino B, Vetter C, Silva A. Bidirectional association between light exposure and sleep in adolescents. J Sleep Res. 2022;31. International Headache Society. The international classification of headache disorders, 3rd edition. Cephalalgia. 2018;38:1–211. Nilles C, Williams J V., Patten SB, Pringsheim TM, Orr SL. Lifestyle Factors Associated With Frequent Recurrent Headaches in Children and Adolescents. Neurology. 2024;102. Montagni I, Guichard E, Carpenet C, Tzourio C, Kurth T. Screen time exposure and reporting of headaches in young adults: A cross-sectional study. Cephalalgia. 2016;36:1020–1027. Longcore T, Rodríguez A, Witherington B, Penniman JF, Herf L, Herf M. Rapid assessment of lamp spectrum to quantify ecological effects of light at night. J Exp Zool A Ecol Integr Physiol. 2018;329:511–521. Thorne HC, Jones KH, Peters SP, Archer SN, Dijk D-J. Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans. Chronobiol Int. 2009;26:854–866. Shin Y, Park H, Shim J, Oh M, Kim M. Seasonal Variation, Cranial Autonomic Symptoms, and Functional Disability in Migraine: A Questionnaire‐Based Study in Tertiary Care. Headache: The Journal of Head and Face Pain. 2015;55:1112–1123. Pakalnis A, Heyer GL. Seasonal Variation in Emergency Department Visits Among Pediatric Headache Patients. Headache: The Journal of Head and Face Pain. 2016;56:1344–1347. Caperell K, Pitetti R. Seasonal Variation of Presentation for Headache in a Pediatric Emergency Department. Pediatr Emerg Care. 2014;30:174–176. Radziwon J, Waszak P. Seasonal changes of internet searching suggest circannual rhythmicity of primary headache disorders. Headache: The Journal of Head and Face Pain. 2022;62:811–817. Additional Declarations Competing interest reported. C.P.G.: Dr. Patterson Gentile is currently funded by the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS124986) and the CHOP Foerderer Institutional grant. C.L.S.: Dr. Szperka has received research/grant support from the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS102521), and PCORI. Dr. Szperka or her institution have received compensation for her consulting work for Eli Lilly; Teva Pharmaceutical Industries Ltd; Upsher-Smith Laboratories, LLC; and Abbvie. A.D.H.: Dr. Hershey or his institution have received compensation for serving as a consultant for AbbVie, Amgen, Biohaven, Eli Lilly, Lundbeck, Supernus, Teva, Theranica and Upsher-Smith. His institution has also received research support from Amgen, Biohaven, Eli Lilly, Theranica, Upsher-Smith, and the NIH NINDS/NICHDS. G.K.A.: Dr. Aguirre receives funding/grant support from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, and the Binational Science Foundation. R.S., B.M.P., and N.R. do not have conflicts of interest. Supplementary Files VisualDietPilotStudybiotimingandsleepSupplemental.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 17 Jun, 2025 Reviews received at journal 16 Jun, 2025 Reviews received at journal 11 Jun, 2025 Reviewers agreed at journal 05 Jun, 2025 Reviews received at journal 30 May, 2025 Reviewers agreed at journal 29 May, 2025 Reviewers agreed at journal 29 May, 2025 Reviewers invited by journal 28 May, 2025 Editor assigned by journal 22 May, 2025 Submission checks completed at journal 22 May, 2025 First submitted to journal 16 May, 2025 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. 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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-6682653","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":463517806,"identity":"8800cf31-43e1-48d8-929b-afa540e6f7bd","order_by":0,"name":"Carlyn Patterson Gentile","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYHAD5gPMEEYCQZWMDRAGWwLJWngMiNNizn7++IOPe+rkzNnPfPxcUHGHgZ89xwCvFsueZMbGGc8OG1v25G6WnnHmGYNkzxv8WgwOJDM28xw4kLjhBu82Zt62wwwGNwjYYnD+MWPznwN1QC08z8Ba7AlquQG0heEAM0gLG8QWCUJ+mfHYcGbPgcPGBmfSjKV5zjzjkTjzrACvFnP+xAcffhyokzM4fvjhZ56KO3L87ckb8DsMjX+AB69yrFoI6hgFo2AUjIKRBwAb8kp+XOhOSQAAAABJRU5ErkJggg==","orcid":"","institution":"Children's Hospital of Philadelphia","correspondingAuthor":true,"prefix":"","firstName":"Carlyn","middleName":"Patterson","lastName":"Gentile","suffix":""},{"id":463517807,"identity":"6e5ad3d7-3b06-4718-b40e-d92b5652354d","order_by":1,"name":"Ryan Shah","email":"","orcid":"","institution":"Thomas Jefferson University","correspondingAuthor":false,"prefix":"","firstName":"Ryan","middleName":"","lastName":"Shah","suffix":""},{"id":463517808,"identity":"d9515348-608a-48ca-b2d7-538cb31965d6","order_by":2,"name":"Blanca Marquez de Prado","email":"","orcid":"","institution":"Children's Hospital of Philadelphia","correspondingAuthor":false,"prefix":"","firstName":"Blanca","middleName":"Marquez","lastName":"de Prado","suffix":""},{"id":463517809,"identity":"92d4d099-36a0-4da2-a06f-7a8115241ade","order_by":3,"name":"Nichelle Raj","email":"","orcid":"","institution":"Children's Hospital of Philadelphia","correspondingAuthor":false,"prefix":"","firstName":"Nichelle","middleName":"","lastName":"Raj","suffix":""},{"id":463517810,"identity":"139879f6-3fe0-43cb-8f7c-62a9651f3d9a","order_by":4,"name":"Christina Szperka","email":"","orcid":"","institution":"Children's Hospital of Philadelphia","correspondingAuthor":false,"prefix":"","firstName":"Christina","middleName":"","lastName":"Szperka","suffix":""},{"id":463517811,"identity":"55784081-39f8-413a-acb2-1ad6c23abedd","order_by":5,"name":"Andrew Hershey","email":"","orcid":"","institution":"Cincinnati Children's Hospital Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Andrew","middleName":"","lastName":"Hershey","suffix":""},{"id":463517812,"identity":"7f210bb0-2331-42c0-b98a-f00b905aa664","order_by":6,"name":"Geoffrey Aguirre","email":"","orcid":"","institution":"University of Pennsylvania","correspondingAuthor":false,"prefix":"","firstName":"Geoffrey","middleName":"","lastName":"Aguirre","suffix":""}],"badges":[],"createdAt":"2025-05-16 17:23:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6682653/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6682653/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83812705,"identity":"ef760033-c847-4b61-941f-1839a1fe68b4","added_by":"auto","created_at":"2025-06-03 07:14:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":364226,"visible":true,"origin":"","legend":"\u003cp\u003eActLumus data collection. Illustration of the ActLumus light sensor consisting of 10 Channels with different spectral sensitivities that sample at a rate of 1/minute. These measurements are differentially combined to derive melanopic illuminance that is important in circadian rhythm signaling and photopic illuminance that is the basis for image forming daylight color vision. (b) An example participant’s continuously recorded photopic and melanopic illuminance over a 24-hour recording period. Light exposure increases to measurable levels (≥ 0.01 lux) starting at 7am and then drops below measurable levels at 11pm that follows a typical 24-hour sleep/wake cycle.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/f41174ff8c0fcc5003d8b587.png"},{"id":83812706,"identity":"2ee3be41-8946-423e-bb27-44516101c310","added_by":"auto","created_at":"2025-06-03 07:14:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":516499,"visible":true,"origin":"","legend":"\u003cp\u003e24-hr circadian light exposure patterns and sleep/wake times. (a) Photopic (orange) and melanopic (light blue) illuminance were compared for the weekdays (left) and weekends (right). The difference (photopic – melanopic illuminance) is also shown (gray). Each 1-minute timepoint was calculated across a sliding 30-minute window. The central tendency represents the mean, and error bars represent 95% confidence intervals by bootstrap analysis. (b) Reported bedtime (dark blue vertical line), sleep period (black bar), and wake times (thin gray line) reported in the Chronotype questionnaire. Each row represents one participant during the weekday (left) and weekend (right).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/599214a8ea773db9da5bea79.png"},{"id":83812708,"identity":"94dde4c0-b02f-4cc7-89f0-0820d4d4af33","added_by":"auto","created_at":"2025-06-03 07:14:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":410304,"visible":true,"origin":"","legend":"\u003cp\u003eLight exposure summary metrics. (a) Light intensity. Photopic illuminance was used to calculate light intensity metrics as these have been used as the standard for designing lighting spaces. Each participant represents the mean photopic luminous exposure (left panel) and the mean time spent in bright light levels (right panel) across the 7-day period for each participant. The mean (black line) is also shown. (b) Melanopic illuminance (light blue) was used to measure the timing of light exposure because this is important for circadian entrainment. Percent time spent within recommended mEDI based on time of day: above 250 lux mEDI during the day (left), below 10 lux starting 3 hours prior to bed (middle), and below 1 lux at night during sleep (right). Mean across participants (black) and individual participants averaged across 7 days (light blue circle) are shown. mEDI = melanopic equivalent daylight illuminance.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/ad381412bf7c8a120300077f.png"},{"id":83812709,"identity":"7e15bcc2-9f71-4fde-9ea0-c616bf4a7b0a","added_by":"auto","created_at":"2025-06-03 07:14:54","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":237629,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of mEDI across participants with chronic migraine defined as at least 15 headahe days per month, with at least 8 of those days being bad headache (dark teal) compared to those who did not meet criteria for chronic migraine (light teal). mEDI for each minute was averaged using a sliding window (width 30 minutes). Central tendency represents the mean. Error bars represent 95% CI by bootstrap analysis. CM = chronic migraine; mEDI = melanopic equivalent daylight illuminance.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/b0b3717e67da9d74642c1364.png"},{"id":83814714,"identity":"172a9894-758e-49f0-8213-eff3bee7a42c","added_by":"auto","created_at":"2025-06-03 07:30:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2411808,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/461dad2d-482d-4c8a-8dea-c9f2a4a896db.pdf"},{"id":83813351,"identity":"6d0363ed-874c-42e1-9202-f30852d8910a","added_by":"auto","created_at":"2025-06-03 07:22:54","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":361162,"visible":true,"origin":"","legend":"","description":"","filename":"VisualDietPilotStudybiotimingandsleepSupplemental.docx","url":"https://assets-eu.researchsquare.com/files/rs-6682653/v1/2e13df6721308920a8a9bf17.docx"}],"financialInterests":"Competing interest reported. C.P.G.: Dr. Patterson Gentile is currently funded by the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS124986) and the CHOP Foerderer Institutional grant. \nC.L.S.: Dr. Szperka has received research/grant support from the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS102521), and PCORI. Dr. Szperka or her institution have received compensation for her consulting work for Eli Lilly; Teva Pharmaceutical Industries Ltd; Upsher-Smith Laboratories, LLC; and Abbvie.\nA.D.H.: Dr. Hershey or his institution have received compensation for serving as a consultant for AbbVie, Amgen, Biohaven, Eli Lilly, Lundbeck, Supernus, Teva, Theranica and Upsher-Smith. His institution has also received research support from Amgen, Biohaven, Eli Lilly, Theranica, Upsher-Smith, and the NIH NINDS/NICHDS.\nG.K.A.: Dr. Aguirre receives funding/grant support from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, and the Binational Science Foundation.\nR.S., B.M.P., and N.R. do not have conflicts of interest.","formattedTitle":"Daily light exposure habits of youth with migraine: A prospective pilot study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eVariation in visual diet (i.e. the intensity and timing of light exposure during daily life) has been associated with health outcomes. Exposure to brighter days and darker nights is known to confer reduced mortality risk,\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e perhaps related to the effect that light has upon circadian biology.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Insufficient daytime melanopic illuminance (short wavelength \u0026ldquo;blue light\u0026rdquo;) and evening melanopic illuminance from artificial light both have the potential to disrupt circadian entrainment.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e In support of this, multiple studies have associated nighttime screen use with poorer health-related quality of life and sleep disruption.\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003ePhotophobia (i.e. light sensitivity) is a common symptom of multiple neurologic and ophthalmologic conditions including migraine,\u003csup\u003e8 9\u003c/sup\u003e which may influence the visual diet through avoidance of high intensity visual environments.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e There has, however, been limited empirical study of how visual diet is altered and potentially influences symptoms in people with photophobia. Recently developed, wearable light loggers now provide the ability to address these questions using quantified measures of visual diet during daily life.\u003csup\u003e\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e These small, battery-powered devices record the absolute level of light falling upon a detector over a period of many days. These recordings provide the relative amount of light across wavelengths, supporting inferences regarding the types of light encountered (natural vs. artificial) and the biological effect upon different classes of retinal photoreceptors (melanopsin containing cells vs. cones).\u003c/p\u003e \u003cp\u003eWe measured the visual diet for 20 youth with migraine using wearable light loggers that continuously tracked ambient light exposure over 7 days during a typical week. We hypothesized that continuous measurement of the visual diet in youth with migraine would be feasible and yield intriguing associations with disease burden in youth with migraine. Specifically, we predicted that a restricted and poorly timed visual diet (i.e., overall less and poorly timed light) would be associated with worse photophobia, chronic migraine, and worse headache-related disability.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design\u003c/h2\u003e \u003cp\u003eThis single-center prospective observational pilot study was conducted within the pediatric headache program within the Children\u0026rsquo;s Hospital of Philadelphia (CHOP) neurology department between October 2024 and March 2025. The protocol received approval from the Institutional Review Board at CHOP.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eParticipants\u003c/strong\u003e \u003cp\u003ePotentially eligible participants were identified by screening patients being seen in upcoming headache clinics via chart review. Participants were included if they were between the ages 10 to 21 years, ICHD-3 defined migraine with or without aura given by a headache specialist of any headache frequency and consented (\u0026ge;\u0026thinsp;18 years) or assented with parent consent (\u0026lt;\u0026thinsp;18 years) to participate in the study. Exclusion criteria were history of major neurological conditions besides migraine (e.g. history of epilepsy, stroke, multiple sclerosis), recent history of concussion (\u0026lt;\u0026thinsp;3 months), or were starting or weaning off a headache preventive medication (supplement or prescription) without being on a stable dose for at least 1 month prior to enrollment.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eData Collection\u003c/span\u003e: Devices were shipped to the participants\u0026rsquo; home and once received, a virtual visit was conducted to review the proper use of the wearable devices and text-diary before recording began. At this visit, participants completed baseline questionnaires through REDCap (Research Electronic Data Capture)\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e hosted by the institution. The first full day of recording (12 am \u0026ndash; 11:59 pm) was considered \u0026ldquo;Day 1,\u0026rdquo; and data collection ran for 7 full days. During these 7 days, diary questions were texted between 7pm and 11pm based on participant preference. During data collection, participants continuously wore the light logger while responding to headache diary prompts each evening. The light logger was removed while sleeping to avoid choking or the light logging device being obscured by bedsheets. Participants were instructed to keep the light logger on a bedside table, which is standard for light logger studies.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e At a scheduled clinic visit after the recording week, participants returned the wearable devices and filled out REDCap-based questionnaires. If participants had personal eyewear, they wore to filter light (e.g. blue light blocking, sunglasses), the light transmittance of this personal eyewear was measured.\u003c/p\u003e \u003cp\u003eDemographic, medical history, clinical characteristics, and treatment were gathered. Standardized and validated survey data included the CHOP Headache Questionnaire,\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e including number of any headache days per month and number of bad headache days per month. Light sensitivity was measured using the Visual Light Sensitivity Questionnaire (VLSQ-8), which is an 8-question validated measurement of light sensitivity with possible scores ranging from 8\u0026ndash;40.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Fear of Pain Questionnaire for Children (FOPQ-C) is a validated metric which was used to measure fear-avoidant responses to pain. After the week of data collection, headache-related disability over the previous month was assessed with the Pediatric Migraine Disability Assessment (PedMIDAS). PedMIDAS has a maximum score of 80 (1-month version),\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e with scores of 3 or less indicating no disability, 3\u0026ndash;9 indicating mild disability, 10\u0026ndash;16 indicating moderate disability, and \u0026gt;\u0026thinsp;16 indicating severe disability. PROMIS Sleep Disturbance questionnaire was also filled out to capture the perception of sleep quality and the PROMIS Sleep-Related Impairment questionnaire, which captured symptoms of insufficient sleep (e.g. daytime sleepiness). PROMIS rates no, mild, moderate, and severe symptoms based on T-scores.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e Data were also collected on chronotype and weekday versus weekend sleep/wake habits using the standardized chronotype questionnaire.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eDaily migraine symptoms, acute medication use, and function were recorded with a validated text-based Daily Headache Diary\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e with additional questions to capture device wear compliance, and light-blocking lens use. Daily headache diaries were filled out via text message using the HIPAA-compliant Twilio platform hosted at CHOP. Specific questions included \u0026ldquo;Have you had a headache today\u0026rdquo; (yes or no), \u0026ldquo;Has your headache gotten in the way of your school, home, or social life today\u0026rdquo; (yes or no), and \u0026ldquo;Rate your light sensitivity (0\u0026ndash;5).\u0026rdquo;\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eLight Logger Data\u003c/h3\u003e\n\u003cp\u003e \u003cstrong\u003eDevice wear and data collection\u003c/strong\u003e \u003cp\u003eActLumus devices (Condor Instruments, S\u0026atilde;o Paolo, Brazil) are wearable light loggers that provide 24-hour continuous collection of photopic illuminance and mEDI (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). ActLumus devices were worn as a pendant around the neck, providing more ecologically valid measurements that are not obscured by shirt sleeves and are closer to the visual plane, which is critical for capturing non-image forming effects of light.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e Data were collected at a sampling rate of 1/minute to maximize temporal resolution while still providing for 7 days of continuous recording.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eData processing\u003c/strong\u003e \u003cp\u003eData were visually inspected and excluded if participants reported not wearing and being away from the Actlumus device for more than 2 hours in a day. ActLumus data were pre-processed using ActiLab Software (Condor Instruments, S\u0026atilde;o Paolo, Brazil). Specifically, melanopic and photopic lux values were derived from 10 light sensing channels that detect different wavelengths of light for every minute of data capture. The intention was to adjust measurements based on light filtering glasses wear as determined by change in light transmittance levels, but these data were not accurately measured during data collection so this step could not be pursued. Clinical data, as well as melanopic and photopic illuminance was processed using custom software developed in Matlab (Mathworks). Log transformation was performed on melanopic and photopic illuminance values to accommodate large shifts in illuminance levels.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eLight metrics\u003c/span\u003e: Two features of the visual diet were considered: 1) the intensity of light exposure, 2) the timing of light exposure. Light metrics were chosen that summarize continuous light exposure data to capture these two features of the visual diet.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e Light intensity was represented by photopic luminous exposure and time spent exposed to bright light levels. Photopic luminous exposure captures the total 24-hour photopic light exposure (kilolux*hr), which provides a measurement of overall light exposure. Bright light was defined as photopic illuminance\u0026thinsp;\u0026gt;\u0026thinsp;1,000 lux because outdoor light ranges from 1,000 lux on a cloudy day to 100,000 lux on a bright sunny day, while indoor light is generally below 500 lux.\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e Light timing was defined by percent time spent within recommended mEDI limits. A minimum 250 melanopic lux is recommended during daytime hours, while a maximum of 10 lux in the evening 3 starting three hours before bedtime, and 1 lux or less at night is recommended to support optimal timed melatonin release.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e These recommendations were based on expert-scientific consensus and supported by the sensitivity of human \u0026ldquo;non-visual\u0026rdquo; responses to ocular light. In this study, we chose fixed definitions of \u0026ldquo;day\u0026rdquo; defined as 7 am \u0026ndash; 5 pm, \u0026ldquo;pre-bedtime\u0026rdquo; defined as 8 pm \u0026ndash; 11 pm, and \u0026ldquo;night\u0026rdquo; defined as 12 am \u0026ndash; 6 am, based on the diurnal motion of the sun and the structured schedule imposed by school. Gaps in time were left between \u0026ldquo;day,\u0026rdquo; \u0026ldquo;pre-bed,\u0026rdquo; and \u0026ldquo;night\u0026rdquo; definitions to allow for some variability across individual schedules.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eValidation of Light Logger measurements\u003c/strong\u003e \u003cp\u003eWe validated the tabular spectral sensitivity functions of the ActLumus device. To do so, we measured a standard light source using both the ActLumus and a calibrated spectrophotometer (SpectraScan\u0026reg; PR-670, JADAK, North Syracuse, NY). The light source was the output of an 8-channel, digital light synthesizer (CombiLED, Prizmatix, Tel Aviv, Israel) delivered via liquid light guide into a light integrating sphere (LabSphere, North Sutton, NH). The spectral radiance of the light source was measured at 2 nm resolution using the PR-670. Combining this spectrum with the ActLumus tabular sensitivity functions (provided by the manufacturer), and converting from radiance to irradiance, provided a model prediction of the ActLumus sensor counts. We then measured the light source using the ActLumus, and compared the obtained and predicted sensor counts. We found the ActLumus counts to be in excellent agreement with the prediction (Pearson\u0026rsquo;s R\u0026thinsp;=\u0026thinsp;0.9982). We were, however, limited to validating 9 of the 10 ActLumus channels, as the PR-670 does not measure the infra-red sampling range of the 10th channel.\u003c/p\u003e \u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eNo \u003cem\u003ea priori\u003c/em\u003e sample size calculations were performed as this was a pilot study to determine sample size for future studies. Descriptive statistics for continuous variables included median with interquartile range for non-normal continuous distributions and mean with standard deviation for continuous variables with normal distribution. Proportions were reported for categorical variables. Continuous light logger data was graphically represented as the mean with 95% confidence intervals (CI) determined by bootstrap analysis. Shifts in the temporal profile between weekdays and weekends and between youth with and without chronic migraine were estimated by determining the correlation between a shifted version (+/-100 minutes) of the first group and the second group and taking the highest correlation value (which was r\u0026thinsp;\u0026gt;\u0026thinsp;0.98 for both comparisons).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eClinical and Headache Diary data\u003c/h2\u003e \u003cp\u003eTwenty youth with migraine participated in this study. Demographics and clinical characteristics were reported (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Participants were a median age of 17 years old [IQR 16, 19] and were 70% female, and reported a median of 17 [IQR 6, 30] days per month of any headache, and 5 [IQR 2, 15] days per month of bad headache for the previous month at the start of recording. Headache-related disability (measured by 1-month PedMIDAS scores) was moderate on average with a median PedMIDAS score of 16 [IQR 8, 29].\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e Median fear-of-pain (FOPQ-C) score was 39 [31, 54], placing most youth in the moderate-to-severe range, consistent with chronic pain conditions, including migraine.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e All participants were on at least one, and many were on a combination of pharmacologic agents for headache prevention. Supplements, OnabotulinumtoxinA, antidepressants, and calcitonin gene-related peptide blocking agents were the most common. This is representative of patients seen in the CHOP headache clinic, who have more severe and refractory migraine compared to the general population of adolescents with migraine.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eParticipant demographics, baseline headache characteristics, and treatment.\u003c/span\u003e\u003csup\u003ea\u003c/sup\u003eFor the two participants who indicated they were Hispanic, both selected \u0026ldquo;prefer not to answer\u0026rdquo; for race. \u003csup\u003eb\u003c/sup\u003eSleep impairment measures symptoms of poor sleep including fatigue and daytime sleepiness, while sleep disturbance measures difficulties falling and staying asleep. PedMIDAS\u0026thinsp;=\u0026thinsp;Pediatric Migraine Disability Assessment, moderate/severe was defined as a score of 10 or greater. FOPQ-C\u0026thinsp;=\u0026thinsp;Fear of Pain Questionnaire for Children, moderate/severe is defined as a score of 30 or greater, based on FOPQ-C definition; VLSQ-8\u0026thinsp;=\u0026thinsp;visual light sensitivity questionnaire, moderate/severe light sensitivity was defined as a score\u0026thinsp;\u0026gt;\u0026thinsp;24, which is the midpoint score.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eDemographics and Headache Characteristics\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAge [IQR]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e17 [16, 19]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSex \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eF 14 (70), M 6 (30)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eRace Ethnicity\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHispanic\u003csup\u003ea\u003c/sup\u003e \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003cp\u003eNon-Hispanic Black \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003cp\u003eNon-Hispanic White \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003cp\u003ePref. not to answer \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e2 (10)\u003c/p\u003e \u003cp\u003e2 (10)\u003c/p\u003e \u003cp\u003e15 (75)\u003c/p\u003e \u003cp\u003e1 (5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"6\" rowspan=\"7\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eValidated questionnaires\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeadache d/mo. [IQR]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e17 [6, 30]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBad Headache days/month [IQR]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e5 [2, 15]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eContinuous headache \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e12 (60)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePedMIDAS (1 mo.) [IQR]\u003c/p\u003e \u003cp\u003eModerate/Severe \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e16 [8, 29]\u003c/p\u003e \u003cp\u003e14 (70)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFOPQ-C [IQR]\u003c/p\u003e \u003cp\u003eModerate/Severe \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e39 [31, 54]\u003c/p\u003e \u003cp\u003e16 (80)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVLSQ-8 [IQR]\u003c/p\u003e \u003cp\u003eModerate/Severe \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e23 [19, 27]\u003c/p\u003e \u003cp\u003e7 (35)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ePROMIS - Sleep\u003c/span\u003e\u003c/p\u003e \u003cp\u003eNone (%)\u003c/p\u003e \u003cp\u003eMild \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003cp\u003eModerate \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003cp\u003eSevere \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImpairment\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e7 (35)\u003c/p\u003e \u003cp\u003e3 (15)\u003c/p\u003e \u003cp\u003e4 (20)\u003c/p\u003e \u003cp\u003e6 (30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDisturbance\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e10 (50)\u003c/p\u003e \u003cp\u003e1 (5)\u003c/p\u003e \u003cp\u003e4 (20)\u003c/p\u003e \u003cp\u003e5 (25)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAll participants had 100% compliance with headache diary prompts. Headache diary responses were consistent with validated questionnaire responses. Youth reported a median of 6 headache days [IQR 3, 7], and 3 migraine days [IQR 1, 6], indicating they had high any headache and bad headache frequency during recording week. Median daily light sensitivity score was 2 [IQR 1, 3] indicating mild light sensitivity, and median pain score was 4 [0, 6] indicating moderate pain.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eLight logging\u003c/h2\u003e \u003cp\u003eOverall, compliance with light logger wear was high. Each participant completed 7 days of recording for a total of 140 days. For one participant, 4 days of recording were excluded due to being away from their ActLumus device for more than 2 hours and/or visual inspection was indicative of non-device wear. This left 136/140 (97.1%) of days with usable light logging data across 20 participants. Seven participants reported using light blocking lenses (blue light filtered and/or sunglasses). Of those, only one used light filtering glasses continuously, with the remainder using glasses a maximum of 1\u0026ndash;2 hours a day on an as needed basis. The lens transmittance measurements did not record during data collection, so light exposure levels were not able to be adjusted for based on light blocking lens use.\u003c/p\u003e \u003c/div\u003e\u003cp\u003e\u003cem\u003e24-hour light exposure profiles\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWe evaluated patterns of photopic and melanopic illuminance across the 24-hour circadian cycle (Figure 2). We compared light exposure on weekdays and weekends, as substantial differences have been noted in adolescent populations given the structure imposed by school.\u003csup\u003e30\u003c/sup\u003e Photopic and melanopic illuminance demonstrated high correlation throughout the day (Figure 2a). However, there was a relative increase in photopic compared to melanopic illuminance that was most pronounced starting around 6 pm until 10 pm. As expected, average light exposure levels were delayed by 49 minutes on the weekends compared to the weekdays. This shift was consistent with later and more variable bedtimes, sleep times, and wake-up times, and longer sleep durations reported in the Chronotype Questionnaire (Figure 2b).\u003c/p\u003e\n\u003ch3\u003eLight exposure summary metrics\u003c/h3\u003e\n\u003cp\u003eSummary metrics were calculated to capture daily light intensity and light timing based on our findings across the 24-hr light profile, and prior studies.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e Two metrics of photopic illuminance were used to characterize daily light intensity (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). Total photopic luminous exposure was calculated, which represents the integrated exposure to photopic light in a 24-hour period. The mean total luminous exposure across participants was 6.2 klux*hr, with a wide range between 0.2 and 16.9 klux*hr. Time youth spent in bright light was also estimated, which was defined as light exposure of 1,000 lux photopic illuminance or greater, as indoor light is typically below 500 lux. The mean total time spent in bright light across participants was 42 minutes per day [range 0 to 108 minutes].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePercent time spent within recommended light levels across a 24-hour period was used to capture light timing (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb). Different levels of light exposure have been recommended for healthy adults based on the time of day: a minimum light exposure of 250 melanopic lux during daytime hours; a maximum of 10 lux starting three hours before bedtime; and 1 lux or less at night is recommended.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e These criteria were used because similar recommendations have not been developed for the adolescent population. We therefore calculated the proportion of time within these recommended limits during daytime (7a \u0026ndash; 5p), pre-bedtime (8a \u0026ndash; 11p), and nighttime (12a \u0026ndash; 6a) hours. Timing was selected based on typical school schedules, the diurnal pattern of the sun at the location of the study. These definitions were supported by the timing of light exposure observed across participants within a 24-hour period. Participants spent an average of 14.5% +/- SD 7.0% of daytime exposed to the recommended minimum mEDI of 250 lux (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb). Percent time spent within recommended levels improved substantially in the pre-bedtime and night hours, with youth spending an average of 77.5% +/- SD 21.6% of the time the maximum recommended mEDI of light pre-bedtime, and 99.1% +/- SD 2.9% of the time during night hours.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eChronic migraine\u003c/h2\u003e \u003cp\u003eTo determine if there were any emerging differences in youth with migraine based on headache frequency, we compared the temporal profiles of melanopic illuminance of youth with chronic migraine (15 or more headache days per month with 8 or more bad headache days per month;\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;8) to youth who did not meet these criteria (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;12; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Youth with chronic migraine demonstrated an average temporal profile that was delayed by 60 minutes, and a subtle increase in the intensity of melanopic illuminance compared to those without chronic migraine. A similar pattern was observed for photopic illuminance.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWe did not pursue additional statistical testing as the goal of this study was to determine sample sizes needed to appropriately power future research. Instead, we conducted power analyses to determine sample sizes needed for group comparisons of youth with migraine (e.g. youth chronic migraine versus lower frequency migraine, those with high versus low headache-related disability, or high versus low light sensitivity) across light logger metrics (see \u003cem\u003eSupplemental Materials\u003c/em\u003e). We found that sample sizes of 50 to 150 would be sufficient for most comparisons.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eParticipant Feedback\u003c/h2\u003e \u003cp\u003eSeventeen (85%) participants agreed or strongly agreed with the statement \u0026ldquo;I would recommend somebody to participate in this study,\u0026rdquo; while 3 (15%) strongly disagreed. Specific comments included liking the text reminders for the diary and to remember to wear the devices (1). Participants offered ways of improving the study including making the device smaller and addressing challenges with the headache diary only being once a day but experiencing multiple headache spikes a day.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe conducted a pilot study monitoring light exposure during everyday life of 20 youth with migraine, most with high migraine disease burden. To our knowledge, this is the first study demonstrating light exposure habits in a population with migraine using wearable light logger technology. Here, we review intriguing trends we observed in youth with migraine in the context of other studies, and how these findings should inform future study design. We found that participants spent only about 15% of the daytime (~\u0026thinsp;1.5 hours per day) at or above the recommended minimum daylight levels for healthy adults. By comparison, they spent most of their time below the recommended maximum light levels 3 hours before bed, and during the night (78% and 99% on average, respectively). It is important to note that these recommended light levels are based on optimal light intensity and timing needed for appropriate circadian fluctuations of melanopsin. \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e Large observational studies using this metric are needed to determine if there is a broader impact on general health if these recommendations are not met, or are only met some of the time.\u003c/p\u003e \u003cp\u003eWe suspect the low light exposure levels we observed in this study are due to multiple factors. Perhaps one of the largest contributors to low daytime light exposure\u0026mdash;not unique to individuals with photophobia\u0026mdash;is the tendency in the modern societies to spend most of the time in indoor lighting environments that are darker than outdoor environments. Lucas and colleagues conducted a similar study in 59 generally healthy, mostly younger adults, providing an important reference point. They found participants spent 33% of daylight hours at or above recommended light levels, but 66% of the time at or below recommended light levels 3 hours before bed.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Results across the two studies are similar, however participants in our study were exposed to lower light levels at each point in the 24-hour cycle. Additionally, youth with migraine spent less time exposed to bright light: the adults spent an average of 1.7 hours per day under bright light conditions\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e compared to an average of 40 minutes per day in our study. These differences are present even though Lucas and colleagues used wrist watches that can underestimate light exposure compared to pendant wear.\u003c/p\u003e \u003cp\u003eWhile it is possible that low light exposure reflects light avoidance driven by migraine-related photophobia in our study population, there are other explanations. First, it is currently unknown if adolescents behave similarly to adults in light exposure habits and normative data in younger populations are needed. Additionally, Lucas and colleagues completed recording February through July, while we recorded November through March, biasing our study towards the winter months when light exposure tends to be lower. Illustrating this, a study including 15 adults in Amsterdam found a 4-fold increase in the time spent above 250 lux mEDI between the winter and summer.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e We also found that bright light exposure was variable across participants, ranging from 0 to 2 hours a day. This may reflect differences in other factors (e.g. participation in outdoor sports) that could influence light exposure. Clearly, simultaneous measurements of study and control populations will be needed to support stronger claims of altered visual diet in migraine.\u003c/p\u003e \u003cp\u003eWe observed light exposure profiles shifted later on the weekends compared to the weekdays. This corresponded with reported sleep/wake times and is consistent with prior studies in adolescents.\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e We also observed that the entire temporal light profile was shifted an hour later for youth with higher frequency migraine attacks (i.e. chronic migraine) in this preliminary sample. Later chronotype has been associated with more frequent headache in youth,\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e which is consistent with these findings. The causal direction of these emerging associations is unknown. It is possible, for example, that youth with chronic migraine rise later due to severe symptoms, producing a shifted sleep schedule, resulting in greater artificial light exposure in the evening and before bed. These effects may also reflect sleep disruption influenced by exposure to evening and nighttime screens. This is consistent with the finding that increased headache frequency in youth is associated with prolonged screen use.\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e Further study is needed to confirm and understand these associations.\u003c/p\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and Limitations\u003c/h2\u003e \u003cp\u003eTo our knowledge, this is the first study to report objective measurements of light exposure combined with a daily diary to track migraine symptoms in real time. We used a light logger with 10 channels of differing spectral sensitivities allowing for the separation of photopic and melanopic illuminance, while light loggers with a single channel provide only a non-specific measure of overall illuminance. The multi-channel measurements allow for more mechanistic hypothesis testing. We observed that the relative strengths of photopic and melanopic illuminance diverged during the evening hours. This may reflect differences artificial lighting environments where these signals can dissociate,\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e and highlights the importance of collecting both measurements. Overall, diary and device compliance were high providing a complete dataset for analysis, and participants generally had positive feedback on the study design.\u003c/p\u003e \u003cp\u003eLimitations include small sample size and the lack of a control group. Furthermore, participants were established patients of a pediatric headache clinic receiving active treatment, limiting the generalizability of the results. There may be bias in that youth willing to participate in the study may be more likely to already be working on healthy headache habits, while those still struggling with daily habits may be less likely to participate. While light filtering lens use was captured by survey data, we did not correct our measurements for the continuous use of blue light filtering glasses for one participant. Finally, data collection occurred in the winter months when light exposure is lower in the Philadelphia area, thus it is unclear if results are generalizable to different times of year.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eFuture Directions\u003c/h2\u003e \u003cp\u003eStudies that include larger sample sizes and control comparison to migraine-free peers are needed. Prior reports have offered that significant differences between winter and summer light exposure should be found with sample sizes as small as 3 individuals.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Our calculations in youth with migraine indicate differences within disease states may be more subtle; we found sample sizes of 50 to 150 will be needed to detect group differences based on subjective report of migraine burden and sleep for most light metrics (see \u003cem\u003eSupplemental Materials\u003c/em\u003e). Controlling for time of year is also critical as there are dramatic differences in light exposure between the summer and winter months at greater latitudes.\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e This cycle may contribute to the seasonal variation observed in migraine, where migraine symptoms to be worse in the late fall and winter months,\u003csup\u003e\u003cspan additionalcitationids=\"CR37 CR38\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e and seasonal comparison offers a unique opportunity for within-participant measurement.\u003c/p\u003e \u003cp\u003eUltimately, insufficient and/or poorly timed light exposure may offer a modifiable risk factor for increased disease burden in youth with migraine. If larger observational studies confirm a relationship between migraine disease burden and light exposure, then clinical trials focused on interventions that address visual diet could be pursued. Multiple participants expressed interest in having access to their data, suggesting this may be a viable target for behavioral intervention.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eLike prior studies in a general adult population, youth with migraine receive less than recommended daytime light exposure but do tend to achieve recommended levels of darkness during the evening and night. Measuring daily light exposure in youth with migraine is feasible and promising avenue for larger observational studies.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCHOP \u0026ndash; Children\u0026rsquo;s Hospital of Philadelphia\u003c/p\u003e\n\u003cp\u003eICHD-3 \u0026ndash; International Classification of Headache Disorders 3\u003csup\u003erd\u003c/sup\u003e Edition\u003c/p\u003e\n\u003cp\u003eIQR \u0026ndash; interquartile range\u003c/p\u003e\n\u003cp\u003emEDI \u0026ndash; Melanopic Equivalent Daylight Illuminance\u003c/p\u003e\n\u003cp\u003eSD \u0026ndash; standard deviation\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eConflict of interest statement:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCommercial Relationships Disclosures:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eC.P.G.: Dr. Patterson Gentile is currently funded by the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS124986) and the CHOP Foerderer Institutional grant.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eC.L.S.: Dr. Szperka has received research/grant support from the National Institutes of Health/National Institute of Neurological Disorders and Stroke (K23 NS102521), and PCORI. Dr. Szperka or her institution have received compensation for her consulting work for Eli Lilly; Teva Pharmaceutical Industries Ltd; Upsher-Smith Laboratories, LLC; and Abbvie.\u003c/p\u003e\n\u003cp\u003eA.D.H.: Dr. Hershey or his institution have received compensation for serving as a consultant for AbbVie, Amgen, Biohaven, Eli Lilly, Lundbeck, Supernus, Teva, Theranica and Upsher-Smith. His institution has also received research support from Amgen, Biohaven, Eli Lilly, Theranica, Upsher-Smith, and the NIH NINDS/NICHDS.\u003c/p\u003e\n\u003cp\u003eG.K.A.: Dr. Aguirre receives funding/grant support from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, and the Binational Science Foundation.\u003c/p\u003e\n\u003cp\u003eR.S., B.M.P., and N.R. do not have conflicts of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFinancial support:\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Children\u0026rsquo;s Hospital of Philadelphia Foerderer Grant, and by the National Institutes of Health National Institute of Neurological Disorders and Stroke (K23NS124986 to C.P.G) and The National Eye Institute (P30EY001583).\u003c/p\u003e\n\u003cp\u003eAcknowledgements: We would like to thank the participants for contributing their time and feedback to this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWindred DP, Burns AC, Lane JM, et al. Brighter nights and darker days predict higher mortality risk: A prospective analysis of personal light exposure in \u0026amp;gt;88,000 individuals. Proceedings of the National Academy of Sciences. 2024;121. \u003c/li\u003e\n\u003cli\u003eRuby NF, Brennan TJ, Xie X, et al. Role of Melanopsin in Circadian Responses to Light. Science (1979). 2002;298:2211\u0026ndash;2213. \u003c/li\u003e\n\u003cli\u003eLu J, Zou R, Yang Y, et al. Association between nocturnal light exposure and melatonin in humans: a meta-analysis. Environmental Science and Pollution Research. 2023;31:3425\u0026ndash;3434. \u003c/li\u003e\n\u003cli\u003eSmolensky MH, Sackett-Lundeen LL, Portaluppi F. Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases. Chronobiol Int. 2015;32:1029\u0026ndash;1048. \u003c/li\u003e\n\u003cli\u003eMireku MO, Barker MM, Mutz J, et al. Night-time screen-based media device use and adolescents\u0026rsquo; sleep and health-related quality of life. Environ Int. 2019;124:66\u0026ndash;78. \u003c/li\u003e\n\u003cli\u003e\u0026Scaron;motek M, F\u0026aacute;rkov\u0026aacute; E, Mankov\u0026aacute; D, Kopřivov\u0026aacute; J. Evening and night exposure to screens of media devices and its association with subjectively perceived sleep: Should \u0026ldquo;light hygiene\u0026rdquo; be given more attention? Sleep Health. 2020;6:498\u0026ndash;505. \u003c/li\u003e\n\u003cli\u003eVijakkhana N, Wilaisakditipakorn T, Ruedeekhajorn K, Pruksananonda C, Chonchaiya W. Evening media exposure reduces night-time sleep. Acta Paediatr. 2015;104:306\u0026ndash;312. \u003c/li\u003e\n\u003cli\u003eDigre KB, Brennan KC. Shedding light on photophobia. Journal of Neuro-Ophthalmology 2012. \u003c/li\u003e\n\u003cli\u003ePatterson Gentile C, Szperka CL, Hershey AD. Cluster Analysis of Migraine‐associated Symptoms (CAMS) in youth: A retrospective cross‐sectional multicenter study. Headache: The Journal of Head and Face Pain. 2024;64:1230\u0026ndash;1243. \u003c/li\u003e\n\u003cli\u003eRogers D, Protti T, Ngo B, et al. Interictal Avoidance Of Migraine-Related Stimuli. J Pain. 2023;24:48\u0026ndash;49. \u003c/li\u003e\n\u003cli\u003eZauner J, Udovicic L, Spitschan M. Power analysis for personal light exposure measurements and interventions. PLoS One. 2024;19:e0308768. \u003c/li\u003e\n\u003cli\u003eSpitschan M, Smolders K, Vandendriessche B, et al. Verification, analytical validation and clinical validation (V3) of wearable dosimeters and light loggers. Digit Health. 2022;8:205520762211448. \u003c/li\u003e\n\u003cli\u003eGuidolin C, Udovicic L, Broszio K, et al. Protocol for a prospective, multi-centric, cross-sectional 2 cohort study to assess personal light exposure. Medrxiv. Epub 2024. \u003c/li\u003e\n\u003cli\u003eHarris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)\u0026mdash;A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform [online serial]. 2009;42:377\u0026ndash;381. Accessed at: https://linkinghub.elsevier.com/retrieve/pii/S1532046408001226.\u003c/li\u003e\n\u003cli\u003eHarris PA, Taylor R, Minor BL, et al. The REDCap consortium: Building an international community of software platform partners. J Biomed Inform [online serial]. 2019;95:103208. Accessed at: https://linkinghub.elsevier.com/retrieve/pii/S1532046419301261.\u003c/li\u003e\n\u003cli\u003eDidikoglu A, Mohammadian N, Johnson S, et al. Associations between light exposure and sleep timing and sleepiness while awake in a sample of UK adults in everyday life. 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Sleep Health. 2019;5:31\u0026ndash;48. \u003c/li\u003e\n\u003cli\u003eMichael PR, Johnston DE, Moreno W. A conversion guide: solar irradiance and lux illuminance. Journal of Measurements in Engineering. 2020;8:153\u0026ndash;166. \u003c/li\u003e\n\u003cli\u003eKnoop M, Stefani O, Bueno B, et al. Daylight: What makes the difference? Lighting Research \u0026amp; Technology. 2020;52:423\u0026ndash;442. \u003c/li\u003e\n\u003cli\u003eBrown TM, Brainard GC, Cajochen C, et al. Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLoS Biol. 2022;20:e3001571. \u003c/li\u003e\n\u003cli\u003eHershey AD, Powers SW, Vockell A-LB, LeCates S, Kabbouche MA, Maynard MK. PedMIDAS. Neurology. Epub 2001. \u003c/li\u003e\n\u003cli\u003eSimons LE, Sieberg CB, Carpino E, Logan D, Berde C. The Fear of Pain Questionnaire (FOPQ): Assessment of Pain-Related Fear Among Children and Adolescents With Chronic Pain. J Pain. 2011;12:677\u0026ndash;686. \u003c/li\u003e\n\u003cli\u003eEstevan I, Tassino B, Vetter C, Silva A. Bidirectional association between light exposure and sleep in adolescents. J Sleep Res. 2022;31. \u003c/li\u003e\n\u003cli\u003eInternational Headache Society. The international classification of headache disorders, 3rd edition. Cephalalgia. 2018;38:1\u0026ndash;211. \u003c/li\u003e\n\u003cli\u003eNilles C, Williams J V., Patten SB, Pringsheim TM, Orr SL. Lifestyle Factors Associated With Frequent Recurrent Headaches in Children and Adolescents. Neurology. 2024;102. \u003c/li\u003e\n\u003cli\u003eMontagni I, Guichard E, Carpenet C, Tzourio C, Kurth T. Screen time exposure and reporting of headaches in young adults: A cross-sectional study. Cephalalgia. 2016;36:1020\u0026ndash;1027. \u003c/li\u003e\n\u003cli\u003eLongcore T, Rodr\u0026iacute;guez A, Witherington B, Penniman JF, Herf L, Herf M. Rapid assessment of lamp spectrum to quantify ecological effects of light at night. J Exp Zool A Ecol Integr Physiol. 2018;329:511\u0026ndash;521. \u003c/li\u003e\n\u003cli\u003eThorne HC, Jones KH, Peters SP, Archer SN, Dijk D-J. Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans. Chronobiol Int. 2009;26:854\u0026ndash;866. \u003c/li\u003e\n\u003cli\u003eShin Y, Park H, Shim J, Oh M, Kim M. Seasonal Variation, Cranial Autonomic Symptoms, and Functional Disability in Migraine: A Questionnaire‐Based Study in Tertiary Care. Headache: The Journal of Head and Face Pain. 2015;55:1112\u0026ndash;1123. \u003c/li\u003e\n\u003cli\u003ePakalnis A, Heyer GL. Seasonal Variation in Emergency Department Visits Among Pediatric Headache Patients. Headache: The Journal of Head and Face Pain. 2016;56:1344\u0026ndash;1347. \u003c/li\u003e\n\u003cli\u003eCaperell K, Pitetti R. Seasonal Variation of Presentation for Headache in a Pediatric Emergency Department. Pediatr Emerg Care. 2014;30:174\u0026ndash;176. \u003c/li\u003e\n\u003cli\u003eRadziwon J, Waszak P. Seasonal changes of internet searching suggest circannual rhythmicity of primary headache disorders. Headache: The Journal of Head and Face Pain. 2022;62:811\u0026ndash;817. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"npj-biological-timing-and-sleep","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [npj Biological Timing and Sleep](https://www.nature.com/npjbts)","snPcode":"44323","submissionUrl":"https://submission.springernature.com/new-submission/44323/3","title":"npj Biological Timing and Sleep","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"migraine, adolescents, photophobia, light exposure, light logging, circadian cycle","lastPublishedDoi":"10.21203/rs.3.rs-6682653/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6682653/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePhotophobia is a common symptom in youth with migraine, but it is unknown if it leads to light avoidant behavior, and if such behaviors worsen disease burden. We conducted a feasibility study between November and March 2024 measuring light exposure using wearable light logger pendants in 20 youth with migraine (10\u0026ndash;21 years old) while migraine symptoms were tracked with a text-based daily diary. On average, participants received recommended light exposure during only 14.5% +/- SD 7.0 of daylight hours but were consistently below the recommended maximum light levels 3 hours prior to bed (77.5% +/- 21.6 of the time), and at night (99.1% +/- 2.9 of the time). Daily light exposure patterns that were phase shifted 60 minutes later in youth with chronic (compared to non-chronic) migraine. Measuring daily light exposure is feasible in pediatric populations with photophobia and reveals intriguing trends that warrant further study.\u003c/p\u003e","manuscriptTitle":"Daily light exposure habits of youth with migraine: A prospective pilot study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 07:14:49","doi":"10.21203/rs.3.rs-6682653/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-06-17T09:44:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-16T13:03:08+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-11T14:23:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"90209791218866717511750188055348326072","date":"2025-06-05T06:02:42+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-30T11:26:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"169429240880359986034372317723793483596","date":"2025-05-29T08:39:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"252009659286126774435086734286036908661","date":"2025-05-29T08:38:56+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-28T16:18:31+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-22T14:19:10+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-22T07:56:06+00:00","index":"","fulltext":""},{"type":"submitted","content":"npj Biological Timing and Sleep","date":"2025-05-16T17:09:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-biological-timing-and-sleep","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [npj Biological Timing and Sleep](https://www.nature.com/npjbts)","snPcode":"44323","submissionUrl":"https://submission.springernature.com/new-submission/44323/3","title":"npj Biological Timing and Sleep","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b8194de1-1fa4-41cb-a4de-ee8bf057941c","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":49218434,"name":"Biological sciences/Neuroscience/Visual system"},{"id":49218435,"name":"Biological sciences/Neuroscience/Diseases of the nervous system"}],"tags":[],"updatedAt":"2025-09-09T18:23:21+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 07:14:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6682653","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6682653","identity":"rs-6682653","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}