Hearing Loss and Brain Plasticity: The Hyperexcitability Phenomenon

Many aging adults experience some form of hearing problem that may arise from auditory peripheral damage. However, it has been increasingly acknowledged that hearing loss is not only a dysfunction of the auditory periphery but results from changes within the entire auditory system, from periphery to cortex. Damage to the auditory periphery is associated with an increase in excitability of neural populations at various stages throughout the auditory pathway. Here, we review neurophysiological evidence of hyperexcitability, auditory perceptual difficulties that may result from hyperexcitability, and outline open conceptual and methodological questions related to the study of hyperexcitability. We suggest that hyperexcitability alters all aspects of hearing – including spectral, temporal, spatial hearing – and, in turn, impairs speech comprehension when background sound is present. By focusing on the perceptual consequences of hyperexcitability and the potential challenges of investigating hyperexcitability in humans, we hope to bring animal and human electrophysiologists closer together to better understand hearing problems in older adulthood.