Auditory Space Perception in the Blind: Horizontal Sound Localization in Acoustically Simple and Complex Situations

Abstract

Even though it is widely believed that cross-modal neuroplasticity in blindness results in enhanced auditory spatial abilities, a growing number of studies also indicate disadvantages of blind persons for specific, more demanding audiospatial tasks. Here, the effects of blindness on horizontal sound localization were compared for simple localization of target sounds presented in isolation and target localization in an acoustically complex (cocktail-party) situation with multiple distractor sounds. While performances of blind and sighted subjects were similar in the cocktail-party setting, a significant disadvantage of blind subjects was found for simple localization of sound sources presented in the center of the frontal space, with the mean absolute error being more than twice that of controls for targets in the median plane. The latter result could be due to the lack of visual calibration of auditory space, which may, in sighted persons, be most effective in the region of maximum visual acuity. On the other hand, the normal performance of blind persons in cocktail-party localization could be explained by the fact that this task, in addition to genuine spatial analysis, critically involved spectrotemporal analysis of the auditory scene to separate different sources for which superior performance is known from previous research.

Short-Term Audiovisual Spatial Training Enhances Electrophysiological Correlates of Auditory Selective Spatial Attention

“…Inspired by animal studies, which demonstrated similar (though more long-term) plasticity of auditory and visual neural representations ( Knudsen and Knudsen, 1985 , 1989 ; Brainard and Knudsen, 1993 ; Knudsen, 1999 ; Hyde and Knudsen, 2000 , 2002 ; Zheng and Knudsen, 2001 ), experiments on this phenomenon led to the conception that vision calibrates human auditory spatial perception ( Recanzone, 1998 ; Lewald, 2002b ). Results obtained in blind and blindfolded sighted humans as well as in patients with visual-field loss demonstrating specific alterations of sound localization were in accordance with this view (e.g., Zwiers et al, 2001a , b ; Lewald, 2002a , c , 2013 ; Lewald et al, 2009a , b , 2013 ; Feierabend et al, 2019 ).…”

A framework to account for the effects of visual loss on human auditory abilities.

“…Feierabend et al (2019) reported that blind participants (a mixture of early and late onset) performed more poorly than sighted participants when localizing sounds at azimuths between −45° and +45°. This is the only study that we are aware of showing an effect in this direction for judgments of azimuth.…”

“…Similarities in group performance have been attributed to ceiling effects due to the relatively low task difficulty when localizing single sounds from a limited number of possible source locations (Leclerc, et al, 2000). Feierabend, Karnath, and Lewald (2019) reported that blind participants (a mixture of early and late onset) performed more poorly than sighted participants when localizing sounds at azimuths between -45° and +45°. This is the only study that we are aware of showing an effect in this direction for judgments of azimuth.…”

Short-term audiovisual spatial training enhances electrophysiological correlates of auditory selective spatial attention

“…Inspired by animal studies, which demonstrated similar (though more long-term) plasticity of auditory and visual neural representations (Knudsen & Knudsen, 1985, 1989Brainard & Knudsen, 1993;Knudsen, 1999;Hyde & Knudsen, 2000Zheng & Knudsen, 2001), experiments on this phenomenon led to the conception that vision calibrates human auditory spatial perception (Recanzone, 1998;Lewald, 2002b). Results obtained in blind and blindfolded sighted humans as well as in patients with visual-field loss demonstrating specific alterations of sound localization were in accordance with this view (e.g., Zwiers et al, 2001a, b;Lewald, 2002aLewald et al, 2009aLewald et al, , b, 2013Feierabend et al, 2019).…”