Freezing of gait is associated with increased saccade latency and variability in Parkinson's disease
Samuel T Nemanich1, Gammon M Earhart2
1Program in Physical Therapy, Washington University School of Medicine in St. Louis, 4444 Forest Park Ave., Campus Box 8502, St. Louis, MO 63108, USA.
Objective:
Freezing of gait (FOG) is a locomotor disturbance in Parkinson disease (PD) related to impaired motor automaticity. In this study, we investigated the impact of freezing on automaticity in the oculomotor system using an anti-saccade paradigm.
Methods:
Subjects with PD with (PD-FOG, n=13) and without (PD-NON, n=13) FOG, and healthy age-matched controls (CTRL, n=12) completed automatic pro-saccades and non-automatic anti-saccades. Primary outcomes were saccade latency, velocity, and gain.
Results:
PD-FOG (pro-saccade latency=271ms, anti-saccade latency=412ms) were slower to execute both types of saccades compared to PD-NON (253ms, 330ms) and CTRL (246ms, 327ms). Saccade velocity and gain variability was also increased in PD-FOG.
Conclusions:
Saccade performance was affected in PD-FOG for both types of saccades, indicating differences in automaticity and control in the oculomotor system related to freezing.
Significance:
These results and others show that FOG impacts non-gait motor functions, suggesting global motor impairment in PD-FOG.
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