Influence of hearing in the non-implanted ear and age on long-term speech recognition benefit for adult cochlear implant users with asymmetric hearing loss

Vollständiger Abstract

Worum geht es in dieser Arbeit?

Most cochlear implant (CI) users with normal hearing or mild to moderately-severe hearing loss in the non-implanted ear, known as asymmetric hearing loss (AHL), experience significant benefits in spatial hearing as compared to pre-operative abilities, though individual outcomes vary. This study analyzed the influence of the hearing in the non-implanted ear and age on long-term outcomes for 35 adult CI users with AHL. Unaided thresholds were measured behaviorally at annual post-activation visits and were used to calculate a pure-tone average (PTA; 0.5, 1, 2, 4 kHz). Sentence recognition in noise was assessed with the AzBio sentences in a 10-talker masker with the target presented from the front loudspeaker and the masker presented 90° toward the implanted ear, 90° towards the non-implanted ear, or co-located with the target. Spatial release from masking was calculated as the benefit in speech recognition when the masker was presented towards the implanted ear (SRMci) or the non-implanted ear (SRMcontra) as compared to the co-located configuration. Spatial release from masking did not change significantly after 1-year post-activation for SRMci and continued to significantly improve for SRMcontra. Hearing in the non-implanted ear significantly influenced SRMci. Age at surgery significantly influenced SRMcontra. Six (17%) participants experienced a PTA decline of ≥ 15 dB HL in the non-implanted ear, which negatively influenced spatial hearing. For those, performance generally improved with adjustments to the hearing aid fitting or after bilateral cochlear implantation. Long-term outcomes for adult CI users with AHL are significantly influenced by hearing in the non-implanted ear and age – though differentially across speech-in-noise configurations.