Association Between Freezing of Gait and Sleep Quality in People with Parkinson’s Disease

Background/Objectives: Freezing of gait (FOG) and sleep disturbances are common in people with Parkinson's disease (PwPD). A bidirectional association between them has been suggested, but quantitative evaluations are scarce. This study aimed to compare sleep disturbances in mild-to-moderate PwPD with (PD+FOG) and without FOG (PD-FOG), and to assess the association between FOG severity and sleep parameters. Methods: Data from 54 PwPD with disease stage <4 and no severe cognitive decline were included (27 PD+FOG and 27 propensity score-matched for age, sex, and disease duration PD-FOG). Demographics and clinical variables were collected. Clinical assessment included the new freezing of gait questionnaire (NFOG-Q), Parkinson's Disease Sleep Scale (PDSS-2), Epworth Sleepiness Scale (ESS) and Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Mann-Whitney U, Fisher's exact and Spearman's tests were used for group comparisons and correlations, respectively. Results: Significant differences were observed between PD+FOG and PD-FOG groups in MDS-UPDRS part II (p = 0.011) and part IV (p = 0.011), with higher scores in PD+FOG participants. No significant differences were found in PDSS-2 or ESS between the two groups. A significant moderate positive correlation was found between NFOG-Q score and PDSS-2 (ρ = 0.416; p = 0.044) in PD+FOG participants. Conclusions: FOG severity was positively associated with sleep disturbances within the PD+FOG group. However, no significant difference in sleep quality or excessive daytime sleepiness was found between PD+FOG and PD-FOG after propensity score matching. PD+FOG participants experienced more severe motor complications and greater impairment in daily activities compared to PD-FOG.