Hearing-impaired listeners’ poor spatial hearing may not reflect actual spatial-processing deficits.

Evidence

These studies demonstrate how audibility can affect measures of SRM using the symmetric masker paradigm, and suggest that reduced access to target speech information might in some cases contribute to the “spatial” deficit observed in listeners with hearing loss. This highlights the importance of adequate stimulus audibility for optimal performance in spatialized speech mixtures, although this is not always feasible due to loudness discomfort in HI listeners, and technical limitations of hearing aids. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1721

Figure 3 shows 50 % thresholds extracted from logistic fits to the data. Performance was better overall with two maskers as compared to four maskers, and for NH than HI listeners. With two maskers, the difference in thresholds between groups was 11 dB in the natural condition, and 9 dB in the glimpsed mixture condition. For four maskers these deficits were 7 and 9 dB, respectively. In other words, the group differences present in the natural binaural condition were similar when listeners were presented with the good time-frequency glimpses only. In the control condition where the glimpses contained only target energy, the group differences were even larger (12.6 and 10.8 dB). This suggests that the HI deficit is related to the ability to access or use the available target information and not to difficulties with spatial processing or segregation. Individual performance for natural stimuli was strongly correlated with performance for glimpsed stimuli (r = 0.92), again suggesting a common limit on performance in the two conditions. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1763

Categorization

• QUESTION: If audibility confounds spatial-release-from-masking measures, how many published HI spatial deficits are actually audibility artifacts?
• SEED: An essay angle: clinical tests of hearing impairment may systematically misattribute an audibility limitation to a ‘higher’ perceptual deficit, with implications for how hearing-loss phenotypes are labeled.
• XREF: The r=0.92 correlation between natural and glimpsed performance connects to broader models of speech-in-noise as limited by glimpsing/cue access rather than perceptual grouping.
• DEFINE: Clarifies that the glimpsed-mixture paradigm separates availability of target information from binaural spatial processing as experimental factors.
• corroborated: 5 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1721; Dijk, Pim van, Physiology, Psychoacoustics and…, 1763