1988 Volume 47 Issue 4 Pages 420-427
In the present study, the values of parameters, such as peak velocity and amplitude of the fast phase of optokinetic nystagmus (OKN), were measured quantitatively in 5 normal subjects by a microcomputer, and the effects of several methodological factors on nystagmus parameters were investigated.
1) The relationship between peak velocities and amplitude of the fast phase of OKN could be obtained from a bestfit exponential equation, i. e., velocity=K (1-exp [-amplitude/L]), where K is the asymptotic maximum velocity and L is a curvature parameter.
2) Analog filters with highcutoff frequencies affected the computation of peak velocities of the fast phase of OKN. The results showed that the analog filter should be about 10Hz or higher.
3) Sampling frequencies influenced the velocity of the fast phase of OKN, and it was shown that the analog data should be digitized at a rate of 200 samples/sec or more.
4) It was recognized that the value of the velocity at each amplitude obtained from a best-fit exponenntial equation could be used as an index for the evaluation of the fast phase of OKN.
