Binaural masking level difference on hearing impairments compensating by hearing aids

Abstract

Many researchers reported that the Binaural masking level differences are reduced in pathological conditions, such as sensorineural hearing loss, retro-cochlear hearing loss, central nervous system disease, and so on. In former studies revealed that the amount of BMLDs are about 2–3 dB or in minus. However, for sensorineural hearing loss, the adaptive method may be limited by the hearing thresholds of subjects. Therefore, to eliminate limitation of hearing thresholds, we delivered stimuli by a pair of sound chambers and receiving by hearing aids fitting with NAL-NL1 formula through headphones to subjects. There were eight mild to moderate sensorineural hearing loss subjects (6 females and 2 males, average 62.2 y/o, std. 9.7) participating in this study. With white noise as masker, we conducted pure tone detection thresholds for 125, 250, 500, 1000 and 2000 Hz in S0N0 and STTN0 conditions. The pilot results showed that the threshold differences (S0N0—STTN0) are 4, 6.3, 4.1, 6.9, and 6.3 dB from 125 to 2k Hz. The pilot results revealed that there are BMLDs on SNHLs with compensating by hearing aids. That is to say, this testing method may be used to rule out supra-threshold deficits from sensorineural hearing losses.