The Effect of Hearing Aid Bandwidth and Configuration of Hearing Loss on Bimodal Speech Recognition in Cochlear Implant Users.
Arlene C Neuman, Annette Zeman, Jonathan Neukam and 2 others
PMID 30067559WHAT IT FOUND
For cochlear implant users who heard better with the implant, adding hearing aid information improved sentence recognition, and wider bandwidth was not worse.
For users who heard better with the hearing aid, narrowing the aid reduced performance. Audiogram shape mattered.
Key findings
01For participants who heard better with the implant alone, bimodal listening improved sentence recognition over implant alone, and the wideband setting was not significantly better than restricted bandwidths overall.
02For participants who heard better with the hearing aid alone, narrowing the hearing aid bandwidth reduced sentence recognition compared with the wideband hearing aid, while bimodal wideband was about the same as hearing aid alone.
03The hearing aid bandwidth needed to match the audiogram: people with steeper sloping or poorer mid-frequency hearing gained sentence benefit even with restricted bandwidths, while flatter hearing required wider amplification.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Participants were tested acutely with an experimental hearing aid, not their own devices, and had no time to acclimate to the wideband or narrow settings. The hearing aid used NAL-RP targets, not the newer NAL-NL2 prescription, and the programmed response may differ from a personal hearing aid fitting. For 10 implant-better participants, the wideband setting could not reach target gain above 2 or 3 kHz, so the wideband condition was not equally wide for everyone. Cochlear dead regions were not measured, although previous work suggests they can make wideband amplification harmful. The hearing aid volume was set only for the wideband condition; narrower bandwidths may have been less loud, and re-balancing loudness could have changed performance. Testing was frontal speech recognition only; it did not assess localization or other bilateral benefits that may matter in daily life. The hearing-aid-better group was small: 10 participants on sentences and 8 on words.
Declared interests
No author conflict-of-interest statement appears in the supplied text. The article metadata lists research support from NIH and non-U.S. government sources.
The easy way to misread this
Do not conclude that a narrow hearing aid bandwidth is always better for bimodal speech. In implant-better users, restricted bandwidths still improved sentence scores, but in aid-better users, narrowing the bandwidth reduced performance, and some flatter audiograms needed wideband amplification.