Aiming at the investigation of the smooth pursuit ability of the human eye toward the target movement, we developed a new sinusoidal target wave and analysed the results quantitatively.
The target wave we developed consisted of 20 continuous sinusoidal waves which lasted from 0.1 Hz to 2.0 Hz. The frequency increased at the peak of each wave so that target moved smoothly. The amplitude was 10 degrees (20 degrees in total amplitude).
This target wave was made with a microcomputer (CBM 8032) by BASIC and ASSEMBLER, and was transferred to the target projection instrument (KN 52 Nagashima) via an 8 bit D/A converter. In this report we performed this examination in the horizontal direction.
The eye movements which were stimulated by this target wave were analysed with a mini-computer (PDP 11/34) and three parameters were obtained quantitatively. The first parameter (velocity ratio) was the ratio between the maximum eye velocity and the mean eye velocity. The second parameter (phase difference) was obtained by the calculation of time difference between the target wave and the eye movement at 4 points (peak, bottom and two belleys) for each sinusoidal wave. The third parameter (amplitude difference) was calculated by the subtraction of total amplitude of the eye movement from total amplitude of target wave (20 degress). These three parameters were obtained for each 20 sinusoidal waves and the average and 95, 05 confidential range were calculated and dispalyed on CRT of PDP 11/34.
Three parameters were included between the 95% confidential range on the patients with peripheral lesions. The patients with central lesions showed abnormalities in three parameters. One case with alcoholic cerebellar atrophy demonstrated abnormal findings on this examination even though routine equilibrium examinations had detected no abnormalities.
