title: Set-size procedures for controlling variations in speech-reception performance with a fluctuating masker.
abstract: Adaptive signal-to-noise ratio (SNR) tracking is often used to measure speech reception in noise. Because SNR varies with performance using this method, data interpretation can be confounded when measuring an SNR-dependent effect such as the fluctuating-masker benefit (FMB) (the intelligibility improvement afforded by brief dips in the masker level). One way to overcome this confound, and allow FMB comparisons across listener groups with different stationary-noise performance, is to adjust the response set size to equalize performance across groups at a fixed SNR. However, this technique is only valid under the assumption that changes in set size have the same effect on percentage-correct performance for different masker types. This assumption was tested by measuring nonsense-syllable identification for normal-hearing listeners as a function of SNR, set size and masker (stationary noise, 4- and 32-Hz modulated noise and an interfering talker). Set-size adjustment had the same impact on performance scores for all maskers, confirming the independence of FMB (at matched SNRs) and set size. These results, along with those of a second experiment evaluating an adaptive set-size algorithm to adjust performance levels, establish set size as an efficient and effective tool to adjust baseline performance when comparing effects of masker fluctuations between listener groups.
authors.affiliation: Audiology and Speech Center, Walter Reed National Military Medical Center, Bethesda, Maryland 20889, USA. joshua.g.bernstein.civ@health.mil
authors.forename: Joshua G W
authors.initials: JG
authors.lastname: Bernstein
authors.forename: Van
authors.initials: V
authors.lastname: Summers
authors.forename: Nandini
authors.initials: N
authors.lastname: Iyer
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Brungart
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D000704:Analysis of Variance; D001309:Auditory Threshold; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test; D055815:Young Adult