title: Movement sequencing in Huntington disease.
abstract: OBJECTIVE
  To examine longitudinal changes in movement sequencing in prodromal Huntington's disease (HD) participants (795 prodromal HD; 225 controls) from the PREDICT-HD study.
  
  
  METHODS
  Prodromal HD participants were tested over seven annual visits and were stratified into three groups (low, medium, high) based on their CAG-Age Product (CAP) score, which indicates likely increasing proximity to diagnosis. A cued movement sequence task assessed the impact of advance cueing on response initiation and execution via three levels of advance information.
  
  
  RESULTS
  Compared to controls, all CAP groups showed longer initiation and movement times across all conditions at baseline, demonstrating a disease gradient for the majority of outcomes. Across all conditions, the high CAP group had the highest mean for baseline testing, but also demonstrated an increase in movement time across the study. For initiation time, the high CAP group showed the highest mean baseline time across all conditions, but also faster decreasing rates of change over time.
  
  
  CONCLUSIONS
  With progress to diagnosis, participants may increasingly use compensatory strategies, as evidenced by faster initiation. However, this occurred in conjunction with slowed execution times, suggesting a decline in effectively accessing control processes required to translate movement into effective execution.
authors.affiliation: School of Psychological Sciences, Monash University , Wellington Road, Clayton, Victoria , Australia.
authors.forename: Nellie
authors.initials: N
authors.lastname: Georgiou-Karistianis
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Long
authors.forename: Spencer G
authors.initials: SG
authors.lastname: Lourens
authors.forename: Julie C
authors.initials: JC
authors.lastname: Stout
authors.forename: James A
authors.initials: JA
authors.lastname: Mills
authors.forename: Jane S
authors.initials: JS
authors.lastname: Paulsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D062706:Prodromal Symptoms; D011597:Psychomotor Performance / Q000502:physiology*; D012720:Severity of Illness Index; D019680:Trinucleotide Repeat Expansion / Q000235:genetics; D055815:Young Adult
keywords: Huntington disease; basal ganglia; movement; predictive testing; sequencing