Cochlear implant electrode place and pulse rate discrimination improve with training without cross cue transfer

Cochlear implant (CI) users typically have poor pitch resolution compared to normal-hearing individuals. This study investigated whether training on electrode place or pulse-rate cues could improve pitch discrimination in CI users (n = 12; four females, eight males) and whether such training generalized across place, rate, and congruently combined place-rate cues. Half of the participants began with place-pitch training and the other half with rate-pitch training for 2 weeks, then switched to training on the alternate cue for 2 weeks. Discrimination thresholds were measured using a two-interval, forced-choice, pitch-ranking task at baseline, weekly, and post-training for place, rate, and combined cues. Testing was performed at 110, 220, 440, and 880 Hz using a standardized research frequency allocation on each participant's active cochlear nucleus electrode array. These frequencies were typically assigned to electrodes 20, 17, 14, and 11. Post-training performance significantly improved on the specific cue trained during each block, with no evidence of cross-cue generalization. Similarly, training on either cue did not significantly improve combined place-rate discrimination thresholds within individual training blocks, though performance improved across the entire training period. Thus, longitudinal training improved CI users' pitch-ranking abilities, but effects were largely cue specific, suggesting that targeted pitch training can enhance perceptual acuity with limited generalization across pitch cues.