Effect of conductive hearing loss on the vestibulo-collic reflex

The vestibulo-collic reflex represents a promising test for evaluating the integrity of otolith function. We have investigated the threshold of this r esponse in a group of normal subjects, and the effect of a conductive heari ng loss. A positive response was recorded in 31 of 32 normal subjects. The threshold of the vestibulo-collic reflex varied from 80 to 97 dBHL in these subjects with a 95% response rate at a threshold at 96 dBHL. A total of 23 ears with a conductive hearing loss in 17 patients were also investigated. The average conductive hearing loss (at 0.5, 1, 2 and 4 kHz) ranged from 8 .75 to 40 dBHL (average 24.46 dBHL). A positive response was recorded in on ly two ears. Therefore, the vestibulo-collic reflex has a high stimulus thr eshold which is dependant on reliable transmission of the click stimulus to the inner ear thus limiting is clinical use.