Inter-trial coherence as a marker of cortical phase synchrony in children with sensorineural hearing loss and auditory neuropathy spectrum disorder fitted with hearing aids and cochlear implants

Objective: Although brainstem dys-synchrony is a hallmark of children with auditory neuropathy spectrum
disorder (ANSD), little is known about how the lack of neural synchrony manifests at more central
levels. We used time–frequency single-trial EEG analyses (i.e., inter-trial coherence; ITC), to examine cortical
phase synchrony in children with normal hearing (NH), sensorineural hearing loss (SNHL) and ANSD.
Methods: Single trial time–frequency analyses were performed on cortical auditory evoked responses
from 41 NH children, 91 children with ANSD and 50 children with SNHL. The latter two groups included
children who received intervention via hearing aids and cochlear implants. ITC measures were compared
between groups as a function of hearing loss, intervention type, and cortical maturational status.
Results: In children with SNHL, ITC decreased as severity of hearing loss increased. Children with ANSD
revealed lower levels of ITC relative to children with NH or SNHL, regardless of intervention. Children
with ANSD who received cochlear implants showed significant improvements in ITC with increasing
experience with their implants.