Influence of Head Position on the Vestibulo-ocular Reflex During Rotational Testing

Abstract

The influence of two static head positions on the horizontal nystagmus induced by sinusoidal rotational stimulation in a group of 24 healthy subjects was investigated. The rotation test was performed with the subject's head in the primary position (upright) and with the head 30° pitched down. Computerized electronystagmography was used to measure the maximum slow component velocity of the horizontal nystagmus and to calculate gain, phase and asymmetry. The vestibulo-ocular reflex (VOR) gain obtained during rotation with the head in the primary position was significantly higher than with the head bent 30° forward. No other significant differences were found.