Relationships between freezing of gait severity and cognitive deficits in Parkinson’s disease

Objective Evidence supports an association between freezing of gait (FOG) severity and cognitive functioning in patients with Parkinson’s disease (PD); however, results are varied. Here we sought to explore the differences in cognitive measurements via multivariable statistical models in patients with PD. Methods PD patients with (PDFOG+, n=41) and without FOG (PDFOG–, n=39) and control healthy subjects (n=41) participated in the study. The NIH toolbox cognition battery, Montreal cognitive assessment (MoCA), and interval timing task were used to test cognitive domains. Measurements were compared between groups using multivariable models and adjusting for covariates. Correlation analyses, linear regression, and mediation models were applied to examine relationships among disease duration and severity, FOG severity, and cognitive functioning. Results Significant differences were observed between controls and PD patients for all cognitive domains. PDFOG+ and PDFOG– exhibited differences in the dimensional change card sort (DCCS) test, interval timing task, and MoCA scores. After adjusting for covariates in two different models, PDFOG+ and PDFOG– differed in both MoCA and DCCS scores. In addition, significant relationships between FOG severity and cognitive function (MoCA, DCCS, and interval timing) were also found. Regression models suggest that FOG severity may be a predictor of cognitive impairment, and mediation models show the effects of cognitive impairment on the relationship between disease severity and FOG severity. Conclusions Overall, this study provides insight into the relationship between cognitive and FOG severity in patients with PD, which could aid in the development of therapeutic interventions to manage both.