Speech recognition in noise for hearing-impaired subjects: effects of an adaptive filter hearing aid

Speech-recognition thresholds (SRTs) were obtained in nine sensorineural hearing-impaired subjects wearing an adaptive-filter hearing aid under four separate listening conditions. The SRT was obtained with the filter in and out of the circuit in order to relate the effects of noise reduction to speech recognition performance. The noise level was held constant while the speech level varied (transformed up-down method). For the majority of the subjects tested, the activation of the noise-suppression circuit in the aid resulted in performance equivalent to or worse than that obtained without the circuit activated. For the group, a significant improvement (less than 0.05) in recognition was observed only in low-frequency noise competition.