Comparison of multichannel wide dynamic range compression and ChannelFree processing in open canal hearing instruments.
BACKGROUND
Multichannel wide dynamic range compression (WDRC) and ChannelFree processing have similar goals yet differ significantly in terms of signal processing. Multichannel WDRC devices divide the input signal into separate frequency bands; a separate level is determined within each frequency band; and compression in each band is based on the level within each band. ChannelFree processing detects the wideband level, and gain adjustments are based on the wideband signal level and adjusted up to 20,000 times per second. Although both signal processing strategies are currently available in hearing aids, it is unclear if differences in these signal processing strategies affect the performance and/or preference of the end user.


OBJECTIVE
The purpose of the research was to determine the effects of multichannel wide dynamic range compression and ChannelFree processing on performance and/or preference of listeners using open-canal hearing instruments.


METHODS
An experimental study in which subjects were exposed to a repeated measures design was utilized.


METHODS
Fourteen adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr).


METHODS
Participants completed two 5 wk trial periods for each signal processing strategy. Probe microphone, behavioral and subjective measures were conducted unaided and aided at the end of each trial period.


RESULTS
Behavioral and subjective results for both signal processing strategies were significantly better than unaided results; however, behavioral and subjective results were not significantly different between the signal processing strategies.


CONCLUSIONS
Multichannel WDRC and ChannelFree processing are both effective signal processing strategies that provide significant benefit for hearing instrument users. Overall preference between the strategies may be related to the degree of hearing loss of the user, high-frequency in-situ levels, and/or acceptance of background noise.
Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, TN, USA. pplyler@utk.edu
Patrick N
PN
Plyler
Monika Bertges
MB
Reber
Amanda
A
Kovach
Elisabeth
E
Galloway
Elizabeth
E
Humphrey
D000368:Aged; D004424:Ear Canal; D005260:Female; D006310:Hearing Aids; D006319:Hearing Loss, Sensorineural / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise; D057240:Patient Preference; D017060:Patient Satisfaction; D011474:Prosthesis Design; D012815:Signal Processing, Computer-Assisted; D013067:Speech Perception