title: Visual scanning and cognitive performance in prediagnostic and early-stage Huntington's disease.
abstract: The objective of this study was to evaluate visual scanning strategies in carriers of the Huntington disease (HD) gene expansion and to test whether there is an association between measures of visual scanning and cognitive performance. The study sample included control (NC, n = 23), prediagnostic (PDHD, n = 21), and subjects recently diagnosed with HD (HD, n = 19). All participants completed a uniform clinical evaluation that included examination by neurologist and molecular testing. Eye movements were recorded during completion of the Digit Symbol Subscale (DS) test. Quantitative measures of the subject's visual scanning were evaluated using joint analysis of eye movements and performance on the DS test. All participants employed a simple visual scanning strategy when completing the DS test. There was a significant group effect and a linear trend of decreasing frequency and regularity of visual scanning from NC to PDHD to HD. The performance of all groups improved slightly and in a parallel fashion across the duration of the DS test. There was a strong correlation between visual scanning measures and the DS cognitive scores. While all individuals employed a similar visual scanning strategy, the visual scanning measures grew progressively worse from NC to PDHD to HD. The deficits in visual scanning accounted, at least in part, for the decrease in the DS score.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA. tblekher@iupui.edu
authors.forename: Tanya
authors.initials: T
authors.lastname: Blekher
authors.forename: Marjorie R
authors.initials: MR
authors.lastname: Weaver
authors.forename: Jeanine
authors.initials: J
authors.lastname: Marshall
authors.forename: Siu
authors.initials: S
authors.lastname: Hui
authors.forename: Jacqueline Gray
authors.initials: JG
authors.lastname: Jackson
authors.forename: Julie C
authors.initials: JC
authors.lastname: Stout
authors.forename: Xabier
authors.initials: X
authors.lastname: Beristain
authors.forename: Joanne
authors.initials: J
authors.lastname: Wojcieszek
authors.forename: Robert D
authors.initials: RD
authors.lastname: Yee
authors.forename: Tatiana M
authors.initials: TM
authors.lastname: Foroud
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000150:complications* / Q000175:diagnosis* / Q000235:genetics; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology; D013057:Spectrum Analysis / Q000379:methods; D014795:Visual Pathways / Q000503:physiopathology; D014796:Visual Perception