[Computer-assisted vestibular tests].

Abstract

The labyrinth is a sensor of vibration. Therefore, multifrequency vestibular stimulation proves indispensable in obtaining a more accurate study of the VOR. We chose to use a pseudo-random binary sequence, generated on a mini computer. The angular velocity instructions are made up of eight repetitive sequences, the spectrum of energy in which is adapted to the frequency range of VOR. A process eliminating the quick phases, the blinking and other artefacts is applied to the nystagmic response, in order to observe only the slow phase velocity. The velocity of eye and chair are compared and the transfer function of VOR is performed. Gain, phase, coherence function and predominance of the mean slow phase velocity between left and right responses are the four indices which define VOR function. The multifrequency rotatory test is interesting for topographic diagnosis, and makes out three diagnostic ranges: a mechanical peripheral, a neurosensory peripheral and a central one. Two practical measures could help the propagation of this method: a simpler vestibular stimulation in order to suppress the rotatory chair, a simplified method of data processing using a personal computer.