Visually guided exploration in Huntington disease.

We compared 24 patients in various stages of Huntington disease (HD) with 26 control patients free from cerebral disorders using a simple visual saccadic tracking test. The two groups were well matched in regard to age, sex, verbal IQ and years of schooling. Test results differed widely. On a time versus error plot, sensitivity (96%) and specificity (100%) were high and the results did not depend on age, education, or disease duration, although an influence of disease stage could be observed. This study shows that a simple saccadic tracking task may be useful in detecting visuomotor disturbances in HD.