Signal-to-Noise-Ratio-Aware Dynamic Range Compression in Hearing Aids.
Tobias May, Borys Kowalewski, Torsten Dau
PMID 30117366WHAT IT FOUND
A hearing-aid algorithm that compresses speech quickly and noise slowly kept speech compression similar to fast compression and left the output speech more separated from noise than fast compression did in simulated tests.
No people were tested.
Key findings
01The new compressor compressed speech about as much as fast compression, with effective compression ratios up to 1.4, and barely compressed noise, with ratios close to 1 ±0.1.
02The new compressor gave a higher output speech-to-noise balance than fast compression, with a benefit of about 2 dB at higher input signal-to-noise ratios.
03The speech detector was less accurate in low-frequency channels, with hit rate minus false alarm rate not higher than 34.7%, and more accurate at higher center frequencies, up to 59.0%.
STILL TO COME
How it was doneWhat they found
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
No patients or listeners were studied, so the paper does not show whether people understand speech better or like the sound better. The comparison used objective signal-processing metrics, not clinical outcomes such as speech recognition scores, loudness discomfort, or hearing-aid satisfaction. The algorithm was tested on simulated noisy speech mixtures, not on hearing aids worn in real rooms by real users. Speech detection was imperfect, especially in the lowest frequency channels, so the ideal behaviour may not be achieved in all conditions. The gain settings were based on a standard audiogram for a flat and moderately sloping hearing loss, not on a range of patient hearing losses.
Declared interests
The supplied text does not report author conflicts of interest or who paid for the work. The publication metadata lists Research Support, Non-U.S. Gov't.
The easy way to misread this
Do not conclude that this compression scheme improves speech understanding or hearing-aid satisfaction in patients. The study tested only objective signal-processing metrics on recorded noisy speech and did not perform behavioral listening tests.