title: Freezing of gait is associated with increased saccade latency and variability in Parkinson's disease.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  These results and others show that FOG impacts non-gait motor functions, suggesting global motor impairment in PD-FOG.
authors.affiliation: Program in Physical Therapy, Washington University School of Medicine in St. Louis, 4444 Forest Park Ave., Campus Box 8502, St. Louis, MO 63108, USA.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Nemanich
authors.affiliation: Program in Physical Therapy, Washington University School of Medicine in St. Louis, 4444 Forest Park Ave., Campus Box 8502, St. Louis, MO 63108, USA; Department of Neuroscience, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., Campus Box 8108, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., Campus Box 8111, St. Louis, MO 63110, USA. Electronic address: earhartg@wustl.edu.
authors.forename: Gammon M
authors.initials: GM
authors.lastname: Earhart
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D009043:Motor Activity; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time; D012438:Saccades
keywords: Freezing of gait; Motor automaticity; Parkinson’s disease; Saccades