Vestibular findings in sensorineural hearing disorders. Results of caloric, oculomotor and hearing tests in 205 patients with unilateral hearing dysfunction

In 205 patients with unilateral hearing loss, 117 of cochlear and 88 of retrocochlear origin, thorough audiovestibular examinations were performed to establish the occurrence and severity of vestibular dysfunction. The results were also analysed with the aim of determining the relationships between the severity of the hearing loss, the etiology and the topical location of the hearing disorder, on the one hand, and vestibular dysfunction, recorded as reduced caloric sensitivity and occurrence of oculomotor disturbances, on the other. No correlation was found between severity of hearing loss and recordable vestibular dysfunction, in either the cochlear or retrocochlear group of patients, or in the etiological subgroups of these main groups. With respect to the relations between the topic locations of the lesions and the results of vestibular tests, distinct characteristics were observed. In the affected ears, totally extinguished caloric reactions were more than six times as frequent in the retrocochlear group as in the cochlear group and appeared as a specific but rather insensitive sign of acoustic neurinoma. Oculomotor disturbances were only exceptionally observed in patients with cochlear lesions, but were noted in nearly half of the retrocochlear group; when only those patients with lesions of the brain stem or cerebellum were considered, all were found to exhibit such disturbances. The relations between audiometric hearing test pattern, caloric sensitivity and oculomotor disturbances seem to form interesting diagnostic paradigms of great value for the topical localization of audiovestibular disorders.