title: Evaluation of the monaurally evoked brainstem response in the diagnosis of sensorineural hearing loss.
abstract: The auditory brainstem responses (ABRs) obtained in 47 subjects with asymmetric hearing loss (12 with surgically confirmed cerebello-pontine angle tumours, 35 without otoneurologic and/or neuroradiologic evidence of tumour) were evaluated by means of an index named delta V. The calculation of this index was based upon the patient's wave V absolute latency obtained at a fixed intensity of 90 dB HL and the value of latency predictable by means of the normative data. The index clearly separates retrocochlear from cochlear sites of lesion. Moreover delta V values obtained in defined cochlear lesions show a linear relation with the patient's pure tone hearing loss at 2 and 4 kHz; this behaviour is probably due to a reduction of the auditory dynamic range in the recruiting ears. delta V appears to have clinical usefulness because of two main points: first it is based upon an evaluation of the monaurally evoked ABR; second, it improves the diagnostic specificity of the responses. The rate of false positive results can be further reduced by combining delta V and IT5 values.
mesh_terms: D001300:Audiometry, Evoked Response / Q000379:methods; D001933:Brain Stem / Q000502:physiology; D002528:Cerebellar Neoplasms / Q000175:diagnosis; D005072:Evoked Potentials, Auditory; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis*; D006801:Humans