Apparent change of masking functions with compression-type digital hearing aid.
Signal perception ability under conditions of a narrow band masker in subjects with hearing aids was examined using a theoretical model of the auditory nerve fibre (ANF) with a deteriorated tuning curve in addition to measurements of actual masking function in subjects wearing hearing aids. The results obtained indicate that the apparent masking function could be affected by the frequency-gain character as well as by the degree of compression. Usually, the compression-type of amplification with flat and/or high-frequency weighted characteristics improves not only the apparent thresholds but also the apparent masked thresholds under conditions of lower frequency masking. On the other hand, a low-frequency masker amplified by a higher gain with low-frequency weighted amplification could cause larger upward-masking effects on the signal perception of the higher frequency signal in some conditions. The present study may contribute to our understanding of the underlying mechanisms of the effects of different amplification by the aid.
Sasaki
N
N
Department of Otolaryngology, Tohoku University School of Medicine, Sendai, Japan.
Kawase
T
T
Hidaka
H
H
Ogura
M
M
Takasaka
T
T
Ozawa
K
K
Suzuki
Y
Y
Sone
T
T
D000161:Acoustic Stimulation / Q000295:instrumentation; D001309:Auditory Threshold / Q000502:physiology; D003056:Cochlear Nerve / Q000502:physiology; D012048:Correction of Hearing Impairment; D004867:Equipment Design; D005260:Female; D006310:Hearing Aids; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology; D010470:Perceptual Masking; D017755:Prosthesis Fitting; D013067:Speech Perception / Q000502:physiology