title: Saccades in presymptomatic and early stages of Huntington disease.
abstract: OBJECTIVE
  To evaluate quantitative measures of eye movements as possible biomarkers in prediagnostic and early stages of Huntington disease (HD).
  
  
  METHODS
  The study sample (n = 215) included individuals both at risk and recently diagnosed with HD. All participants completed a uniform clinical evaluation which included administration of the Unified Huntington's Disease Rating Scale (UHDRS) by a movement disorder neurologist and molecular testing to determine HD gene status. A high resolution, video-based eye tracking system was employed to quantify measures of eye movement (error rates, latencies, SD of latencies, velocities, and accuracies) during a computerized battery of saccadic and steady fixation tasks.
  
  
  RESULTS
  Prediagnostic HD gene carriers and individuals with early HD demonstrated three types of significant abnormalities while performing memory guided and anti-saccade tasks: increased error rate, increased saccade latency, and increased variability of saccade latency. The eye movement abnormalities increased with advancing motor signs of HD.
  
  
  CONCLUSIONS
  Abnormalities in eye movement measures are a sensitive biomarker in the prediagnostic and early stages of Huntington disease (HD). These measures may be more sensitive to prediagnostic changes in HD than the currently employed neurologic motor assessment.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis 46202-5251, USA. tblekher@iupui.edu
authors.forename: T
authors.initials: T
authors.lastname: Blekher
authors.forename: S A
authors.initials: SA
authors.lastname: Johnson
authors.forename: J
authors.initials: J
authors.lastname: Marshall
authors.forename: K
authors.initials: K
authors.lastname: White
authors.forename: S
authors.initials: S
authors.lastname: Hui
authors.forename: M
authors.initials: M
authors.lastname: Weaver
authors.forename: J
authors.initials: J
authors.lastname: Gray
authors.forename: R
authors.initials: R
authors.lastname: Yee
authors.forename: J C
authors.initials: JC
authors.lastname: Stout
authors.forename: X
authors.initials: X
authors.lastname: Beristain
authors.forename: J
authors.initials: J
authors.lastname: Wojcieszek
authors.forename: T
authors.initials: T
authors.lastname: Foroud
mesh_terms: D005133:Eye Movements; D020022:Genetic Predisposition to Disease; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D012438:Saccades / Q000502:physiology*