Distance judgement in individuals with vision and hearing loss.

Distance judgement is essential for safe navigation. People with vision loss (VL) increasingly rely on hearing for distance judgement. However, it is unclear how well auditory cues compensate for visual deficits, especially in those with additional hearing loss (dual sensory loss, DSL). This study evaluated the visual, auditory and audiovisual distance judgement in VL and DSL, by both verbally estimating and walking to remembered target locations. Fifty adults (16 controls, 19 VL, 15 DSL) estimated the distances of visual, auditory, and audiovisual targets across six distances (0.9-5.4 m) in a normal acoustic room, by verbally report the distances or walk to the perceived locations. The visual stimuli were flashing red lights. The auditory stimuli were pulsing tones. Accuracy was measured with root mean squared error, and bias was assessed by regression slopes between actual and estimated distances. In our task, visual judgement remained accurate among VL and DSL participants, matching controls. Auditory estimates showed greater errors and biases for all groups, especially for DSL. With audiovisual cues, the VL and DSL groups performed worse than using vision alone. The agreement between verbal reports and walking responses were strong for visual and audiovisual conditions (r