Estimation of Behavioural Threshold Using Click Evoked ALR in Normal and Hearing Impaired Population

Abstract

Establishing frequency specific threshold has significant importance in reaching appropriate diagnosis and planning individualized rehabilitation program. Auditory evoked potentials are used to predict behavioural threshold in difficult to test population when audiologist fails to obtain frequency specific behavioural threshold. Among auditory evoked potentials ALR require lesser neural synchrony than ABR for recording, so ALR could be a better objective tool to estimate the threshold. The current study investigated the ALR as objective tool to assess behavioural threshold in normal hearing and other clinical population. ALR was recorded from 20 ears with normal hearing, 16 ears with sensorineural hearing and 20 ears with auditory dys-synchrony .ALR recording was initiated at 80 dBnHL and gradually reduced the intensity. The lowest intensity at which N1-P2 complex was observed was considered as ALR threshold. Statistical analysis revealed that a significant positive correlation between ALR threshold and pure tone average in sensorineural hearing loss individuals. However a weak positive correlation was obtained in normal hearing group and auditory dys synchrony group. It can be concluded that ALR can closely estimate the behavioural threshold in sensorineural hearing loss individuals.