Impact of Aging and the Electrode-to-Neural Interface on Temporal Processing Ability in Cochlear-Implant Users: Amplitude-Modulation Detection Thresholds.
Maureen J Shader, Sandra Gordon-Salant, Matthew J Goupell
PMID 32833587WHAT IT FOUND
Older cochlear implant users were worse at detecting sound-volume changes in the implant signal.
Electrode-to-neural estimates did not explain this. Age-related timing limits may affect speech understanding.
Key findings
01Among the 22 cochlear implant users, younger participants detected amplitude modulation 87% of the time, middle-aged participants 78%, and older participants 70%.
02Chronological age predicted poorer amplitude modulation detection, while ECAP slope did not significantly predict detection.
03Detection improved with larger modulation depth and lower modulation frequency, and the faster 4000 pps carrier rate reduced detection slightly.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study included 22 participants, so the finding is limited to a small research sample. Age was confounded with age at onset and etiology; younger participants tended to have earlier onset and more genetic deafness. Participants with Montreal Cognitive Assessment scores of 22 to 25, which indicates risk for mild cognitive impairment, were not excluded. The electrode-to-neural slope measure used only two selected electrodes per participant, and the difference between steep and shallow electrodes varied widely. All participants had Cochlear-brand devices. Testing used direct stimulation and a research sound processor, not the participant's everyday clinical processor. The study measured amplitude modulation detection, not everyday speech recognition.
Declared interests
The supplied text names funding from the National Institute on Deafness and Other Communication Disorders and the National Institute on Aging. It does not provide an author conflict-of-interest statement or a commercial sponsor role.
The easy way to misread this
Do not conclude that poorer amplitude modulation detection in older cochlear implant users is caused by a worse electrode-to-neural interface. The slope measure from the implant did not predict detection, and age was correlated with that slope, so this study cannot separate peripheral and central contributions.