Audiometric Findings in Brain Stem Lesions

Abstract

The findings obtained from a personal case-material of 24 subjects allowed for definition of a clinical audiometric pattern of brain-stem lesions. The analysis of these data showed the following facts: (1) In BS pathology, the tone threshold is frequently altered (different aspects of neural-type loss without recruitment). (2) In some cases with little or no alteration of the tone threshold a poor discrimination of normal speech is present (tone-speech dissociation). (3) Poor articulation curves for low-redundancy (or sensitized) speech tests are frequently found and there exist some quantitative and qualitative discordancies between the different tests: even discrimination of swinging speech is often altered. (4) In many cases, the hearing defect is bilateral, although it is always prevalent on one side only, thus showing its derivation from a lesion of the hearing paths. (5) The affected ear (or the prevalently impaired ear) has been found to be homo- or contralateral to the site where the lesion of the b.s. prevails in an equal number of cases. (6) Although all the elements of a complete audiometric investigation lead to a general diagnosis of lesion of the central hearing paths in the b.s., the precise localization can be established with the aid of other neurological signs.