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(22) BINOCULAR STEREOPSIS IN ALZHEIMER'S DISEASE
¡¡¡¡¡¡35th Annual Meeting of the Society for Neuroscience,2005-11
Visual perception of surrounding space was important to do daily behavior. The disturbance in binocular depth perception contribute to the difficulty of getting around in their environments, orienting themselves in space, or recognizing visual objects. In Alzheimerfs Disease (AD), we observed abnormal behavior based on the disturbances of binocular depth perception. This study was designed to assess the binocular depth perception in AD. It was well known that both cues of binocular disparity and vergence angle are necessary for getting the distance of depth with accuracy. Subjects were 13 patients with mild-to-moderate AD and 16 controls matched for age, sex, and education. We studied their local stereopsis and global stereopsis by using random dots stereogram which was related to binocular disparity and also binocular depth perception based on vergence angle cue by using computer tool task, in which the stimuli was presented on a screen of cathode-ray tube and subjects wore the liquid crystal shutter glasses. AD had significantly worse performance on depth perception than controls in both local and global stereopsis experiments about binocular disparity cue (p<0.01) and vergence angle cue (p<0.01). In vergence angle experiment, the distance of depth was significantly longer in AD than in HC. There was no correlation with depth perception in AD between vergence angle cue and local stereopsis, however, there was significantly correlation (p<0.05) between vergence angle cue and global stereopsis. These results suggested that AD had important of depth perception based on binocular disparity cue and vergence angle cue. The mechanism of depth perception in local stereopsis might be different from the depth perception mechanism in global stereopsis.
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