Abstract
Smooth pursuit eye movements when tracking sine waveform target movement of 30° amplitude and 1/3 Hz frequency (eye tracking test: ETT) were quantitatively assessed in 108 normal subjects and 47 patients with various central lesions. Normal subjects were divided into three age groups. Young volunteers were 20 to 39 years old, middle aged volunteers were 40 to 59 years old and elderly volunteers were over 60 years old. Four parameters (absolute error of eye position, absolute error of eye velocity, phase, summation of saccadic eye movents) were calculated. Smooth pursuit eye movements were linearly impaired with senescence. All patients with cerebellar and cerebellobrainstem lesions showed abnormal values in the parameters. Directional preponderance to the lesion side was seen in half the patients with hemispheric lesion. Patients with CP angle tumors without brain stem compression did not have impaired smooth pursuit. The absolute error of eye velocity increased in the ETT recordings when a saccadic pattern was present, while the absolute error of eye position increased in the ETT with an ataxic pattern.
