Effects of Expanding Envelope Fluctuations on Consonant Perception in Hearing-Impaired Listeners.
Alan Wiinberg, Johannes Zaar, Torsten Dau
PMID 29756553WHAT IT FOUND
Expanding 10-20 Hz speech-envelope fluctuations only where speech was present improved consonant recognition by 2.1 percentage points.
Expanding all noisy speech did not help, and some consonants worsened.
Key findings
01Expansion of clean speech before noise and expansion only in speech-present regions improved overall consonant recognition by 1.8 and 2.1 percentage points, respectively, relative to linear processing.
02Envelope expansion applied to the whole noisy mixture did not significantly improve overall consonant recognition relative to linear processing.
03The average improvement was mainly driven by six listeners; the other 14 listeners changed by less than 5 percentage points.
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 only 8 normal-hearing and 12 hearing-impaired listeners, so it cannot show how most listeners would respond. The task used consonant-vowel nonsense syllables in stationary Gaussian noise, not sentences or fluctuating noise. The average improvement was small and was driven by six listeners. Some consonant groups worsened, so the effect was not uniformly helpful. The authors state that the tested expansion settings may have been suboptimal and that acclimatization might affect benefit. The effect may be smaller in fluctuating background noise than in the stationary noise used here.
The easy way to misread this
Do not conclude that this processing is a proven hearing-aid feature for hearing-impaired listeners. The average gain was 1.8 to 2.1 percentage points, some consonants worsened, and six listeners drove the overall improvement.