Optokinetic test comprising both acceleration and constant velocity stimulation (ACV-OKN test).

Normal subjects were exposed to two kinds of optokinetic stimulation, viz. at speeds of 60 degrees/s and 90 degrees/s preceded by acceleration at 6 degrees/s2 and 4.5 degrees/s2, respectively. In most subjects the speed of the eye in the slow nystagmus phase equalled the speed of the rotating device during the acceleration at velocities up to about 60 degrees/s. The eye then lagged behind the speed of the optokinetic stimulus. The upper limit for linear increase in the eye speed of the slow nystagmus phase has been named the "optokinetic fatigue threshold". A new clinical test permitting quantitative assessment of the optokinetic response has been introduced. The maximum eye speed in the slow nystagmus phase has been found to be the most appropriate parameter. Presentation of the results in the form of special charts, named optokinograms, is recommended. Optokinetic disturbances of varying kinds were noted mostly in patients with CNS disorders, but also in patients with diseases of the inner ear.