Harmonic acceleration tests in yaw plane were performed in 14 normal subjects, with the head centered or in an eccentric position 90 cm from the axis of rotation in an investigation of the influence of additional linear acceleration on the canal-ocular reflex. Pendular rotation in the eccentric position produces the same angular stimulation and, in addition, involves linear centrifugal and tangential acceleration vectors which act on the otolith organs. In the eccentric position, all subjects showed an in crease in gain of slow phase eye movements at 0.32 Hz and 0.64 Hz, when compared with the results in the head centered position. For the high frequency range in eccentric pendular rotation, the value of tangential acceleration was larger than that of centrifugal acceleration. In the eccentric position, tangential acceleration is sensed mainly by the utriculus. Therefore it appeares that gain enhancement at high frequencies in eccentric pendular rotation is derived from tangential acceleration acting on the utriculus.
