Objectives: To evaluate feedback-dependent vocal control in cochlear implant patients using pitch-shifted auditory feedback.
Methods: Twenty-three CI recipients with at least 6 months of implant experience were enrolled. Vocal recordings were performed while subjects repeated the vowel /e/ and vocal signals were altered in real-time using a digital effects processor to introduce a pitch-shift, presented back to subjects using headphones. Recordings were analyzed to determine pitch changes following the pitch-shifted feedback, and results compared to the magnitude of the shift as well as patient demographics.
Results: Consistent with previous results, CI patients' voices had higher pitches with their implant turned off, a change explainable by increases in vocal loudness without the CI. CI patients rapidly compensated for pitch-shifted feedback by changing their vocal pitch, but only for larger shifts. Considerable inter-subject variability was present, and weakly correlated with the duration of implant experience and implant sound thresholds.
Conclusions: CI patients, like normal hearing individuals, are capable of real-time feedback-dependent control of their vocal pitch. However, CI patients are less sensitive to small feedback changes, possibly a result of courser CI frequency precision, and may explain poorer than normal vocal control in these patients.
Level of evidence: Level 3b.
Keywords: Cochlear implant; hearing loss; vocal control; vocal production; voice.
© 2020 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.