Challenges of Cochlear Implant Use for Spatial Hearing in Children and Adolescents With Asymmetric Hearing Including Single Sided Deafness.

This study aimed to determine hearing benefits and challenges for children using cochlear implants (CIs) in one ear and acoustic hearing in the other (bimodal hearing) through hearing aids (HA-CI) or normal hearing (single-sided deafness/SSD-CI). Participants were 34 children with CIs [MAge (SD)=12.2 (3.2) years] and 6 peers with typical hearing/controls [MAge (SD)=13.8 (1.7) years]. Side of better hearing (aural preference) was measured by word recognition in quiet and noise, and spondee-word recognition thresholds in noise co-located/0° or separated (left/right 90°). Self-reported hearing was measured using the Speech, Spatial and Qualities of Hearing Scale (SSQ). Localization of stationary and moving sound (and unrestricted head movements) and sensitivity to interaural level and timing cues were measured (separate controls [n=5, MAge (SD)=14.0 (1.6) years]). Speech perception using the CI alone was similar in children with SSD-CI and HA-CI (p=0.84) but SSD-CI users had greater aural preference in their acoustic ear (p<0.01). CI users had high errors localizing stationary sound and poor moving sound detection (p<0.001) which was associated with earlier onset of hearing loss, and poor access to interaural cues (p<0.001) compared to controls. Head movements in children with CIs tended to favour their non-implanted ear (p<0.05). Results indicate that children with asymmetric hearing gain speech perception with their CI but have aural preference for the non-implanted ear, particularly in the presence of good residual hearing and later onset of hearing loss. Bimodal listeners had poor access to binaural cues, poor spatial hearing with slightly better results in children with later onset of hearing loss and ineffective gaze movements.