Evaluating Selective Apical Electrode Deactivation for Improving Cochlear Implant Outcomes

This prospective study investigated the potential benefits of deactivating the second most apical electrode to improve access to lower-frequency pitch and first formant information to help improve speech and music outcomes with a cochlear implant. Twenty-one adults (30 ears) with cochlear implants completed an A-B-A-B study to compare the participant's clinical map with all electrodes active (A) and their clinical map with the second most apical electrode deactivated (B). Test measures included pitch discrimination, speech understanding in noise, and subjective musical sound quality and enjoyment ratings. This study also investigated the impact of participant demographic and electrode placement factors on the degree of benefit derived from the experimental map (B). There was no significant difference between the two conditions on any measure at the group level. However, individual participants demonstrated improvements in pitch discrimination (33.3%), speech perception in noise (43.3%), musical sound quality (50.0%), and musical enjoyment (40.0%). Musical sound quality and enjoyment ratings were strongly correlated, and speech perception correlated with musical enjoyment but not sound quality. Electrodes outside scala tympani, smaller electrode-to-modiolus distances, and certain device manufacturers (Cochlear and MED-EL) predicted greater benefit from deactivating the second-most apical electrode. Certain adult cochlear implant users may benefit from selective apical electrode deactivation, depending on their demographic and electrode placement profile. Clinicians could consider deactivating the second most apical electrode with patients, who report poor musical sound quality or those who have disengaged from music since receiving their CI to assess potential benefits individually.