Computer Analysis of the Optokinetic Pattern Test in Acoustic Tumors, Brain Stem and Cerebellar Lesions: Slow and fast phase velocities of optokinetic nystagmus

Abstract

Optokinetic pattern (OKP) abnormalities in 36 patients with infratentorial lesions were analyzed by microcomputer (7T18 Nihondenki-Sanei). The parameters used for analysis consisted of slow phase velocity (S-VEL) and fast phase velocity (F-VEL) in optokinetic nystagmus. In 16 patients with acoustic tumors, S-VELs were normal or borderline when the tumors were less than 2 cm in diameter, but when the tumors were more than 2 cm, S-VELs were severely impaired. In 20 patients with brain stem and/or cerebellar lesions, S-VELs were abnormal in all the patients with the exception of 3. F-VEL abnormalities were seen in only 5 patients with brain stem lesions, especially pontine lesions. These findings suggest that S-VEL is a sensitive indicator of infratentorial lesions and F-VEL an important indicator of pontine lesions.

Key Words:

• optokinetic pattern test
• computer analysis
• slow and fast phase velocities of OKN
• infratentorial lesion