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. © 2008 Movement Disorder Society

Abnormal Visual Scanning of Emotionally Evocative Natural Scenes in Huntington’s Disease

“…Firstly, several previous eye-tracking studies in HD found alterations in visual scanning behavior during the completion of cognitive tasks, including tasks measuring attention (Fielding et al, 2006), inhibitory control (Henderson et al, 2011), or processing speed and memory (Blekher et al, 2009). Secondly, certain alterations in visual processing appear to occur as a correlate of processing emotional stimuli, which may be related to alterations in scanning behavior.…”

The visual cortex and visual cognition in Huntington’s disease: An overview of current literature

“…13,24 Different neuropsychological assessments were used to measure visual scanning and attentional deficits in HD patients in several studies. 24,34,61,72,73 The Cancelation Task and Line Bisection Test did not show any differences in visual attentional function between healthy controls, premanifest, and manifest HD gene carriers. 61 In a longitudinal study, decline in performance on the Map Search attentional task was only observed in more advanced HD patients after a 12 months follow-up period.…”

“…Eight studies specifically investigated visuospatial function, visual attention or visual scanning in HD patients. 13,24,34,61,[70][71][72][73] One study assessed a wide range of visuospatial tasks in HD patients and controls. 70 Factor analyses showed that overall visuospatial processing capacity (measured using the Another study also examined the ability to spatially rotate a mental image (i.e.…”

Behavioral Measures of Saccade Latency and Inhibition in Manifest and Premanifest Huntington's Disease

“…However, the addition of behavioral measures of saccades to a comprehensive evaluation could prove useful in improving detection of early phenotype changes and monitoring change associated with progression and treatment. Moreover, a recent study by Blekher et al (2009) showed that poor performance on a test of information processing speed in premanifest and manifest HD appeared to be driven by inefficient eye movements, further highlighting the importance of eye movement assessment in this population.…”