Prefrontal cortex supports speech perception in listeners with cochlear implants.
Arefeh SherafatiNoel DwyerAahana BajracharyaMahlega Samira HassanpourAdam T EggebrechtJill B FirsztJoseph P CulverJonathan E PeellePublished in: eLife (2022)
Cochlear implants are neuroprosthetic devices that can restore hearing in people with severe to profound hearing loss by electrically stimulating the auditory nerve. Because of physical limitations on the precision of this stimulation, the acoustic information delivered by a cochlear implant does not convey the same level of acoustic detail as that conveyed by normal hearing. As a result, speech understanding in listeners with cochlear implants is typically poorer and more effortful than in listeners with normal hearing. The brain networks supporting speech understanding in listeners with cochlear implants are not well understood, partly due to difficulties obtaining functional neuroimaging data in this population. In the current study, we assessed the brain regions supporting spoken word understanding in adult listeners with right unilateral cochlear implants (n=20) and matched controls (n=18) using high-density diffuse optical tomography (HD-DOT), a quiet and non-invasive imaging modality with spatial resolution comparable to that of functional MRI. We found that while listening to spoken words in quiet, listeners with cochlear implants showed greater activity in the left prefrontal cortex than listeners with normal hearing, specifically in a region engaged in a separate spatial working memory task. These results suggest that listeners with cochlear implants require greater cognitive processing during speech understanding than listeners with normal hearing, supported by compensatory recruitment of the left prefrontal cortex.
Keyphrases
- hearing loss
- prefrontal cortex
- working memory
- soft tissue
- high density
- high resolution
- white matter
- magnetic resonance imaging
- resting state
- healthcare
- functional connectivity
- early onset
- photodynamic therapy
- magnetic resonance
- autism spectrum disorder
- electronic health record
- cerebral ischemia
- subarachnoid hemorrhage
- single molecule
- blood brain barrier
- diffusion weighted imaging
- drug induced