Monitoring the Efficacy of Auditory Training through Changes in Brainstem and Cortical Auditory Evoked Potentials: A Systematic Review

Auditory training (AT) exercises as the main part of auditory rehabilitation have emerged as a promising method for enhancing auditory perception and communication skills in individuals with hearing impairments or difficulties in auditory processing. Through AT, the central auditory nervous system (CANS) undergoes changes that optimize neural circuits, resulting in improved auditory perception. Auditory-evoked potentials (AEPs), including the auditory brainstem responses (ABRs) and cortical auditory-evoked potentials (CAEPs), offer objective measurements of neural responses and serve as valuable biomarkers to assess the effectiveness of AT. For this systematic review, we conducted a comprehensive search in multiple databases, including MEDLINE (via PubMed), Science Direct, Web of Science, and SciELO, up until August 18, 2023. There were no study type restrictions or limitations on publication time. Following a careful assessment of the article quality and their alignment with the inclusion and exclusion criteria, a total of 25 articles were selected for inclusion in this study. Based on the findings of the reviewed studies, it has been reported that AT exercises lead to an increase in the amplitude of waves in both brainstem and cortical AEPs, with the exception of P1 and N2 waves. Furthermore, it has been observed that the latency of these responses decreases following AT. The application of brainstem and cortical AEPs as objective electrophysiological tools holds promise in assessing the effectiveness of AT exercises and confirming the selected approach for AT.