Perceived sound localization abilities in blind individuals

There is extensive research on sound localization performance of blind individuals in laboratory settings. However, less is known about their spatial hearing experiences in more complex everyday environments. This study aims to assess the perceived sound localization abilities in blind individuals in common everyday tasks, which is a critical determinant of confidence and engagement in such tasks (e.g., independent travel).

Fifty-eight adults with total or near-total blindness, including 28 with self-reported normal hearing and 30 with self-reported hard of hearing participated in this study. They completed the Dual Sensory Spatial Localization Questionnaire (DS-SLQ), a recently developed instrument that evaluates perceived difficulty in everyday localization tasks using vision and hearing. Properties of the DS-SLQ for blind individuals, including whether its items measure a single attribute (i.e., unidimensionality) and whether item difficulties match blind individuals' perceived abilities (i.e., targeting), were validated using Rasch analysis. Multivariable regression models and correlation analysis evaluated the impacts of the onset of blindness, residual vision, hearing status, onset of hearing loss, use of hearing aids, and echolocation skills on perceived sound localization abilities.

The DS-SLQ showed excellent targeting and good unidimentionality for blind individuals. Individuals with later onset of blindness reported significantly lower perceived sound localization abilities. The presence of hearing loss, particularly early onset, was associated with further reductions in perceived sound localization ability. Those who reported higher echolocation skills also reported better perceived sound localization abilities, regardless of their hearing status. Residual vision and use of hearing aids were not associated with perceived sound localization abilities.

Beyond frequently studied vision factors, hearing loss and its onset further affect perceived sound localization abilities and the likelihood of an individual being an echolocator. It is critical to consider hearing status in the rehabilitation of blind individuals for maintaining and enhancing spatial localization skills.