The frequency-response of the maculo-ocular reflex related to horizontal sinusoidal linear accelerations in three different directions (i.e. forwards and backwards, binaurally and diagonally to the head) was studied in normal human subjects. Materials and Method
In 74 normal subjects, eye movements induced by horizontal sinusoidal linear accelerations along the binaural axis, were studied by using an electrically driven chair. A subject was asked to sit down on the chair with head and body restrained. Horizontal linear accelerations produced by using oscillations with an amplitude of 25cm, and frequencies of 0.25, 0.33 and 0.5Hz. The induced eye movements were recorded electronystagmographically with eyes covered.
In all cases, both the gain and phase difference of the eye position versus the head position in the horizontal direction, were calculated from the averaged response of five consecutive swings for each frequency.
In the second stage, the frequency responses related to the sinusoidal linear accelerations in three different directions (forwards-backwards, binaurally, and diagonally) were compared in 20 normals (10 males, 10 females). The gain and phase differences were again calculated in the above-mentioned way, and a statistical test by analysis of variance was used to detect the influence of the following factors; sex, stimulus direction, and frequency of the swing motions. Results
The averaged amplitudes, viz. peak to peak values of the compensatory eye movements induced by passive sinusoidal motions of the head along the binaural axis, with frequencies of 0.25, 0.33 and 0.5Hz, were 3, 4, and 7 degrees, respectively. The gain increased with a slope of about 6 dB/oct in the frequency range from 0.25 to 0.5Hz. The phase difference of about zero degrees did not change significantly.
The gain was largest in cases of the stimulation along the binaural axis, and less, when stimulation was along the diagonal axis (p<0.05). It was negligible in the cases of stimulation along the forwards-backwards axis. However, the significant change in phase difference was not obtained in any of the trials. The responses in both sexes did not show any difference.
抄録全体を表示