Hearing Aid Usage: Relationship Between Auditory Plasticity and Audiological Measures

Abstract

The present study aimed to evaluate the effects of plasticity in behavioural and electrophysiological measures in naïve monaural hearing aid users before and after a period of hearing aid usage. Eight participants were evaluated in two phases, i.e., at the time of hearing aid fitting (baseline) and a follow-up after two to three months. Behavioural measures included aided and unaided speech identification scores (SIS) and signal-to-noise ratio 50 (SNR-50). Electrophysiological measures were unaided speech-evoked ABR and LLR. The results revealed no significant difference between baseline and follow-up evaluations for unaided SIS, SNR-50, amplitude and latency of peak V, P1, N1, P2, N2 in the unaided ear. However, in the aided ear, there was a significant difference between baseline and follow-up for unaided and aided SIS, aided SNR-50, amplitude of N1-P2 complex. Better synchronization of nerve fibres and acclimatization to listening to sounds at a higher presentation level might be the reasons for improvement noted in the aided ear. In the aided and the unaided ear, though changes were seen in the evoked potentials, no significant differences were noted. More changes were seen in the cortical potentials than the brainstem potentials. This information will be useful in counseling naïve monaural hearing aid users to wear their hearing aids for a longer time, use binaural hearing aids or to alternate the hearing aid between the two ears.