Commentary: Environmental Sound Training in Cochlear Implant Users

Cochlear implants (CIs) are prosthetic devices developed for listeners with profound bilateral hearing loss. Despite considerable advances in CI hearing technology allowing for improved speech and language recognition, several studies have reported that the identification of common environmental sounds—even years after implantation plus high speech perception scores—prove difficult for most listeners (e.g., Loebach and Pisoni, 2008; Shafiro et al., 2011, 2015). The literature suggests explanations for environmental sound identification difficulty in CI users: The chief difficulty is that CI signals are highly degraded compared to the frequency-rich neural signal in normal-hearing (NH) listeners. CIs typically include 4 to 22 electrodes; this electrode array, while constituting a drastic improvement from early CIs containing 1 to 4 electrodes, still represents less than 1% of hair cells in a healthy cochlea contributing to sound-frequency information (Wilson, 2004). Besides the degraded signal provided by even state-of-the-art CIs, Shafiro et al. (2015) described other factors complicating environmental sound identification, namely, the likelihood of degraded representations of memory for environmental sounds caused by years of hearing loss. To help address these concerns, I propose a modification of the environmental sound training procedure initially developed by Shafiro et al. (2015). The aim is to utilize multisensory cues, sounds presented in noise to enhance ecological validity, and a same-different discrimination phase prior to closed-set identification. This modified procedure should enhance neural plasticity, and consequently reconstruct auditory representations that have become degraded after years of CI use.