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

• Cortical phase synchrony, as measured by inter-trial coherence (ITC), decreases as sensorineural hearing loss (SNHL) increases.
• Auditory neuropathy spectrum disorder (ANSD) is associated with lower levels of cortical phase synchrony relative to normal hearing and SNHL.
• Cortical phase synchrony increases after cochlear implantation in children with ANSD as a function of experience with the device.

ObjectiveAlthough 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.MethodsSingle 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.ResultsIn 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.ConclusionsCortical phase coherence is significantly reduced as a result of both severe-to-profound SNHL and ANSD.SignificanceITC provides a window into the brain oscillations underlying the averaged cortical auditory evoked response. Our results provide a first description of deficits in cortical phase synchrony in children with SNHL and ANSD.