Cortical and subcortical processing of speech in cochlear implant recipients with auditory neuropathy spectrum disorder

Abstract

uditory neuropathy spectrum disorder (ANSD) is a condition caused by a deficiency of synchronous neural activity of the cochlear nerve and is related to injuries that can affect the inner hair cell synapse, spiral ganglion, axon, the myelin sheath, and/or nerve dendrite (Nikolopoulos, 2014). Although auditory neuropathy was formally defined around 20 years ago, this form of hearing loss continues to cause controversy and challenges in decision making over appropriate means of habilitation. Cochlear implantation may be an option for hearing rehabilitation. Although the outcome of cochlear implantation in children with AN/AD might vary, it is favorable in most cases. Cochlear implantation seems a justified hearing rehabilitation option for children with AN/AD and limited benefits from conventional hearing aids. Psychophysical measures can be used to study performance variability. Cortical auditory evoked potentials (CAEPs) are objective tests that reflect the neural detection and/or discrimination of sound underlying speech perception. Therefore, it is beneficial to assess outcome variability with CI. CAEPs include obligatory evoked potentials such as P1, N1, and P2, and discriminative potentials such as Acoustic change complex (ACC), mismatch negativity (MMN) and P300. The latency and morphology of CAEP can provide information about the maturation of central auditory pathways (Sharma et al., 2004).