[Stapedial reflexes in presbyacusis and occupational deafness]

Acoustic reflex thresholds were measured on 251 subjects (418 ears) with varying degrees of sensorineural hearing loss. The subjects are divided in three groups according to the pathology involved: presbyacusis and noise-induced hearing loss and combined hearing loss caused by both presbyacusis and noise exposure. The dynamic range of hearing was found to be reduced for all cases and at all frequencies. The decrease in dynamic range was proportional to the severity of the hearing loss. The sensation levels of the acoustic reflex thresholds seem to be dependent on the degree of hearing loss and not on the aetiology. Practical conclusions are drawn concerning the prediction of thresholds of hearing and the diagnosis of recruitment based on reflex measurements.