Factors Affecting Bimodal Benefit in Pediatric Mandarin-Speaking Chinese Cochlear Implant Users.
Yang-Wenyi Liu, Duo-Duo Tao, Bing Chen and 4 others
PMID 30882534WHAT IT FOUND
Adding a hearing aid did not improve Mandarin CI children's speech recognition in steady noise or competing talkers in the main test.
It worsened male-to-male competition, and helped only in a harder task.
Key findings
01In Experiment 1, mean SRTs did not significantly differ between CI-only and bimodal listening in steady noise (-5.3 dB vs -5.4 dB) or male-female competing speech (2.7 dB vs 2.4 dB); for male-male competing speech, CI-only mean SRT was significantly lower (2.5 dB) than bimodal mean SRT (4.1 dB).
02In Experiment 2, bimodal listening significantly improved SRTs only for the 5-keyword condition, with mean SRTs of -1.2 dB bimodal and 0.7 dB CI-only; the 2-keyword condition showed no significant bimodal difference (-5.4 dB bimodal, -5.3 dB CI-only).
03With bimodal listening, SRTs were significantly lower for male-female competing speech than for male-male competing speech, but male-female bimodal SRTs were not significantly lower than CI-only SRTs.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Only eleven children took part, so the findings may not represent all Mandarin-speaking CI children. The children were tested in a laboratory closed-set speech task, not in real classroom or home listening situations. The non-implanted ear was not occluded during CI-only testing, so residual acoustic hearing may have contributed to CI-only performance. Outliers in unaided thresholds were removed before correlation analyses, and multiple comparisons were corrected, so some threshold relationships depend on excluded data. Experiment 2 could not test the five-keyword task with competing speech, so bimodal effects under high demand and speech maskers were not measured. The authors discuss possible mechanisms, including working memory and binaural fusion, but the study did not test them.
Declared interests
The article metadata lists research support from N.I.H. Extramural and non-U.S. government sources. The supplied text does not state author conflicts or commercial sponsorship.
The easy way to misread this
Do not conclude that a hearing aid in the non-implanted ear is useless. The children did not benefit in most of the first experiment's conditions, and they did worse when both talkers were male, but they did benefit in the harder task.