Binaural Pitch Fusion in Bilateral Cochlear Implant Users.
Lina A J Reiss, Jennifer R Fowler, Curtis L Hartling and 1 others
PMID 28945657WHAT IT FOUND
Bilateral cochlear implant users showed broad binaural pitch fusion, with some fusing across much of the electrode array and others not at all.
This can average pitch cues between ears and may interfere with speech perception.
Key findings
01Fusion ranges in bilateral cochlear implant users varied widely, from 0 to 12 mm, with average ranges of 5.8, 6.5, and 5.9 mm for apical, middle, and basal reference electrodes.
02Fusion range was not significantly correlated with subject factors such as age, onset age of moderate-to-severe hearing loss, hearing aid or implant experience, or within-ear electrode pitch ranking ability.
03For middle reference electrodes, fusion center offset was positively correlated with interaural electrode pitch mismatch (r=0.70, p=0.0036).
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 18 adults, so individual variability may not represent all bilateral cochlear implant users. It measured pitch fusion in a laboratory task, not everyday speech perception, so it cannot show how much fusion affects communication. Some basal pitch matches could not be obtained, limiting analysis of basal electrodes. Subject histories came from self-report and medical records, and no direct measures of current spread or cochlear anatomy were used.
Declared interests
The authors reported no conflicts of interest.
The easy way to misread this
Do not conclude that broad fusion causes speech perception deficits or that altering cochlear implant programming will improve communication. The study measured pitch fusion in a laboratory task, not speech outcomes, and it did not test any treatment.