Dual Sensory Impairment: Impact of Central Vision Loss and Hearing Loss on Visual and Auditory Localization.

Purpose: In the United States, AMD is a leading cause of low vision that leads to central vision loss and has a high co-occurrence with hearing loss. The impact of central vision loss on the daily functioning of older individuals cannot be fully addressed without considering their hearing status. We investigated the impact of combined central vision loss and hearing loss on spatial localization, an ability critical for social interactions and navigation. Methods: Sixteen older adults with central vision loss primarily due to AMD, with or without co-occurring hearing loss, completed a spatial perimetry task in which they verbally reported the directions of visual or auditory targets. Auditory testing was done with eyes open in a dimly lit room or with a blindfold. Twenty-three normally sighted, age-matched, and hearing-matched control subjects also completed the task. Results: Subjects with central vision loss missed visual targets more often. They showed increased deviations in visual biases from control subjects as the scotoma size increased. However, these deficits did not generalize to sound localization. As hearing loss became more severe, the sound localization variability increased, and this relationship was not altered by coexisting central vision loss. For both control and central vision loss subjects, sound localization was less reliable when subjects wore blindfolds, possibly due to the absence of visual contextual cues. Conclusions: Although central vision loss impairs visual localization, it does not impair sound localization and does not prevent vision from providing useful contextual cues for sound localization.