Abstract
Tests of visual fixation during head movements were evaluated.
The subjects were asked to fix a visual target while the head was oscillated. Head and eye movements and the sum of both movements were recorded with a polygraph and stored in a microcomputer. From the stored data, transfer function was calculated with head movements as input and eye movements as output. As conditions of head movements, the following three head oscillations were studied. 1) "1 Hz method" in which the head was oscillated at 1 Hz ; 2) "acceleration-deceleration method", in which oscillation of the head started at 0.3 Hz, accelerated gradually until it was as rapid as possible, then decelerated gradually ; 3) "pseudo-random method", in which oscillation of the head was as random as possible.
In the "acceleration-deceleration method", visual fixation ability at 0.3 to 5 Hz was examined and the frequency at which failure of visual fixation occurred was easily noted, since the change of the frequency of head oscillation was sequential. Transfer function obtained from the "acceleration-deceleration method" was similar to that obtained from the "pseudo-random method".
These results indicate that the "acceleraion-deceleration method" is the best of the tests of visual fixation during head oscillation.
