Accurate sound localization relies on the transformation of binaural cues into stable spatial representations, yet the neural mechanisms supporting this process remain incompletely understood. Mild stroke provides a unique opportunity to study the vulnerability of auditory spatial processing within distributed neural networks. We investigated azimuthal sound localization in chronic-phase survivors of mild stroke without hearing aid use using broadband, low-frequency, and high-frequency noise and compared it against a headphone-based lateralization task. Most patients exhibited localization accuracy comparable to healthy listeners. However, 4 of 14 patients showed a striking alteration of auditory spatial perception: instead of a continuous mapping of azimuth, responses clustered into bi- or trimodal (left-center-right) categorical patterns. Comparable deficits were also observed in one of the five age-matched control participants. To our knowledge, such localization patterns have not been reported in listeners without neurological disease. Atypical localization was most pronounced with low-frequency stimuli, suggesting a different role of the respective binaural cues in forming a spatial representation of sound. Differences between loudspeaker-based localization and existing headphone-based lateralization data further suggest that these paradigms engage distinct auditory spatial representations. The findings support the view that auditory space is constructed through higher-order, supramodal spatial mechanisms that are particularly vulnerable to right-hemispheric damage. Overall, the data highlight the challenges of quantifying spatial hearing of stroke survivors both on an individual and on a population level. Challenges include previously undocumented stimulus and method dependencies, an unknown mixing of auditory and neurological factors, and the absence of normative data for a nonstroke control cohort.
Dietz et al. (Thu,) studied this question.