Acoustically Evoked Compound Action Potentials Recorded From Cochlear Implant Users With Preserved Acoustic Hearing.
Jeong-Seo Kim, Carolyn J Brown
PMID 36882917WHAT IT FOUND
A rising chirp sound produced a clearer, larger auditory nerve response than clicks at loud levels, while 500 Hz tones often did not.
This is a test-method finding, not a treatment result.
Key findings
01CAPs were identifiable for at least two of the three main stimuli in 15 of 19 participants, and response shape varied widely.
02At high stimulation levels, the chirp evoked measurable CAP responses in 92.98% of participants, clicks in 73.68%, and 500 Hz tone bursts in 22.81%; chirp and clicks differed significantly.
03The custom chirp sweep rate had a significant overall effect on amplitude, but only chirp Nk=4 was significantly larger than chirp Nk=3, and it was not significantly better than the original chirp or other intermediate chirps.
STILL TO COME
How it was doneWhat they found
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What it does not show
The study included 19 participants, and the extended custom chirp protocol was completed by only 8 participants, so these stimulus comparisons are small. All participants used the same Nucleus Hybrid L24 implant and had preserved low-frequency hearing, so results may not apply to other cochlear implant users or electrode types. The study measured CAP waveforms, not speech perception, hearing aid fitting, or therapy outcomes, so it does not show a clinical benefit. Response morphology varied widely: 4 good, 5 fair, 6 poor, and 4 no response, so a single protocol may not be reliable.
Declared interests
The authors declared no conflicts of interest. The publication types list NIH extramural research support.
The easy way to misread this
Do not read the larger chirp-evoked CAP responses as evidence that the chirp improves hearing, speech perception, or clinical care. The study only compared physiological response size and waveform clarity in a small group, and the custom chirp differences were mostly not significant.