A crew of listeners with no more than "slight" hearing loss who exhibit binaural deficits also exhibit higher levels of stimulus-independent internal noise.

ABSTRACT

Listeners having, at most, "slight" hearing loss may exhibit deficits in binaural detection which appear to stem from increased levels of stimulus-dependent, additive internal noise [Bernstein and Trahiotis, J. Acoust. Soc. Am. 140, 3540-3548 (2016); J. Acoust. Soc. Am. 144, 292-307 (2018)]. This study reports that a small crew of such listeners also exhibits increased levels of low-level, stimulus-independent, additive internal noise. Detection thresholds were measured in (1) the NoSπ configuration as a function of masker level; (2) the NρSπ configuration as a function of masker interaural correlation (ρ); (3) "the quiet" for So and Sπ tonal signals. Those measures were combined suitably to yield estimates of stimulus-independent, additive internal noise, separately, at center frequencies of 250, 500, and 4000 Hz. Derived levels of internal noise were found to be elevated, by about 5 dB at 250 and 500 Hz, and by about 9 dB at 4 kHz, for the group of listeners having no more than slight hearing loss and who exhibited deficits in binaural detection. The new findings, taken together with earlier investigations by the authors (which included data obtained from dozens of listeners), provide evidence that such listeners have greater levels of both stimulus-dependent and stimulus-independent, additive internal noise.