Improving Speech Recognition in Bilateral Cochlear Implant Users by Listening With the Better Ear.
Alan Kan
PMID 29708063WHAT IT FOUND
For bilateral cochlear implant users, laboratory testing showed that sending the target talker to the better ear and background to the other ear improved speech-in-noise scores.
The better-ear condition outperformed the same algorithm used as noise reduction in both ears.
Key findings
01All listeners showed better SRTs when the target was sent to one ear and the maskers to the other, with median SRT -4.1 dB for the better ear and 2.2 dB with no strategy.
02In the seven-listener comparison, using the algorithm as noise reduction in both ears gave mean SRT -0.1 dB, significantly poorer than the better-ear condition.
03No ear was consistently dominant across the group, so each listener's better ear had to be identified by testing both configurations.
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 11 listeners, so the result may not generalize to all bilateral CI users. Seven listeners returned for the algorithm-only comparison, which is a small subset. The task was closed-set, with limited word choices, which may have made performance easier. Both ears were tested with the strategy, and the better result was selected, which can inflate the apparent benefit. No reliable objective method was available to predict which ear would be better before testing. The algorithm assumed the target talker's location was known, which is hard in moving real-world conversations. The strategy sends the target to one ear and background to the other, so spatial hearing is lost. The study used virtual auditory space and direct connection to processors, not everyday listening. It is unclear how reverberation affects the algorithm.
Declared interests
Funded by National Institute on Deafness and Other Communication Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development, and Hearing Health Foundation. No author conflicts of interest are stated in the supplied text.
The easy way to misread this
Do not conclude that bilateral cochlear implant users should use this better-ear strategy in daily life. It was tested only in a laboratory with a closed-set task, the target location was assumed known, and using it sends the target to one ear while background goes to the other, which removes spatial hearing.