Differential Effects of Binaural Pitch Fusion Range on the Benefits of Voice Gender Differences in a "Cocktail Party" Environment for Bimodal and Bilateral Cochlear Implant Users.
Yonghee Oh, Nirmal Kumar Srinivasan, Curtis L Hartling and 2 others
PMID 36395512WHAT IT FOUND
For bimodal cochlear implant users, broad binaural pitch fusion strongly predicts reduced ability to separate voices by gender in noise.
Users with fusion ranges of 3 octaves or greater lost their bimodal advantage. Bilateral users showed no such relationship, as their benefits were minimal.
Key findings
01Bimodal CI users with broad binaural pitch fusion showed significantly reduced benefits from voice gender differences in noise, with fusion range explaining 35.7% to 76% of the variance in masking release.
02Bimodal CI users with binaural fusion ranges of 3 octaves or greater did not have any benefit in voice gender release from masking over bilateral CI users.
03Bilateral CI users exhibited overall poorer masking release from voice gender differences than bimodal users, and fusion range did not predict their performance.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study had a small sample size (12 per group), which limits generalizability. Binaural fusion was measured only for place pitch, not temporal pitch, which may also play a role in voice perception. The two groups could not be directly compared on fusion ranges because different stimuli were used for bimodal (acoustic/electric) versus bilateral (electric/electric) testing. The study did not include longitudinal data to confirm if switching from bimodal to bilateral CIs actually causes the predicted loss of benefit in patients with narrow fusion.
Declared interests
The study was supported by the National Institutes of Health (NIH). The authors declared no conflicts of interest.
The easy way to misread this
Do not assume that all bimodal CI users are gaining a speech-in-noise advantage from their acoustic hearing. Patients with broad binaural pitch fusion (≥3 octaves) showed no better voice gender separation than bilateral CI users, meaning the bimodal benefit is not universal and depends on the patient's specific fusion characteristics.