title: Effects of reverberation and masker fluctuations on binaural unmasking of speech.
abstract: In daily life, listeners use two ears to understand speech in situations which typically include reverberation and non-stationary noise. In headphone experiments, the binaural benefit for speech in noise is often expressed as the difference in speech reception threshold between diotic (N(0)S(0)) and dichotic (N(0)S(π)) conditions. This binaural advantage (BA), arising from the use of inter-aural phase differences, is about 5-6 dB in stationary noise, but may be lower in everyday conditions. In the current study, BA was measured in various combinations of noise and artificially created diotic reverberation, for normal-hearing and hearing-impaired listeners. Speech-intelligibility models were applied to quantify the combined effects. Results showed that in stationary noise, diotic reverberation did not affect BA. BA was reduced in conditions where the masker fluctuated. With additional reverberation, however, it was restored. Results for both normal-hearing and hearing-impaired listeners were accounted for by assuming that binaural unmasking is only effectively realized at low instantaneous speech-to-noise ratios (SNRs). The observed BA was related to the distribution of SNRs resulting from fluctuations, reverberation, and peripheral processing. It appears that masker fluctuations and reverberation, both relevant for everyday communication, interact in their effects on binaural unmasking and need to be considered together.
authors.affiliation: VU University Medical Center, ENT/Audiology EMGO+ Institute for Health and Care Research, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.
authors.forename: Erwin L J
authors.initials: EL
authors.lastname: George
authors.forename: Joost M
authors.initials: JM
authors.lastname: Festen
authors.forename: S Theo
authors.initials: ST
authors.lastname: Goverts
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D016022:Case-Control Studies; D032882:Comprehension; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology*; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test; D013997:Time Factors; D014732:Vibration; D055815:Young Adult