In 8 cases of chronic chorea, 5 of which were of familial nature, the 'smooth pursuit' ocular movements were recorded by means of 'eye tracking', comparing them with those of a group of normal subjects of the same age devoid of neuropsychiatric pathology. The recording of the ocular movements of choreic subjects turned out to be quite different from the normal recordings in which the oculogram (EOG) is a continuous and regular sinusoid. In choreics the EOG was an irregular tracing with changes that affected the entire test, or part of it. The recording of the first of the EOG, which expresses the velocity of the movement, showed in choreics 'arrests' and 'positive errors' of velocity in a significantly higher number than in normal subjects
