Abstract
Abstract: :
Purpose: To characterize oculomotor control in a sample of individuals recently diagnosed with Huntington disease (HD), presymptomatic HD gene carriers (PSGC) and nongene carriers (NGC). Methods: Eye movements of 8 patients diagnosed with HD in the past 1-2 years, 9 PSGC, and 19 NGC were recorded with a video based system. Eye movement tests elicited visually guided and internally mediated saccades (memory guided, predictable, and anti-saccades), vertical and horizontal pursuit, and optokinetic nystagmus (OKN). Latencies, peak velocities, fraction of correct saccades, pursuit and OKN gain were quantified. Eye movements were also recorded while subjects performed the Digit Symbol subscale of the Wechsler Adult Intelligence Survey-Revised (WAIS-R). The overall number of vertical and horizontal saccades during the performance of the Digit Symbol test was evaluated. Nonparametric tests were used to evaluate performance of the HD, PSGC, and NGC groups. Results: The HD patients demonstrated a delay in the initiation and slowing of saccades, a decreased fraction of correct internally mediated saccades, and a low gain of OKN as compared to NGC. The HD participants also demonstrated a reduced number of vertical and horizontal saccades during the performance of the Digit Symbol test. The PSGC group exhibited a subtle deficit in internally mediated saccades. Conclusions: This study demonstrates that sensitive quantitative variables of oculomotor function are abnormal among individuals who are recently diagnosed with HD.
Keywords: eye movements: saccades and pursuits • neuro-ophthalmology: diagnosis • clinical (human) or epidemiologic studies: ris