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Abstract:
Objective: The purpose of this study is to quantitative
analysis of spatial and temporal distribution of visual attention.
We describe a patient (NG) who shows visual disorientation and
right hemineglect without psychic paralysis of fixation of gaze. He
was diagnosed probable Alzheimer's disease (AD). His visual
inattention was too serious to evaluate visual acuity and visual
field. MRI and PET revealed atrophy of left parieto-occipital lobes
and a diffuse decrease of regional cerebral glucose metabolism in
the bilateral temporo-parieto-occipital region, predominantly left
hemisphere. Methods: We investigated the relationship between
fixation position(retinal position) -based and body-centered
neglect on a target-detection task. The fixation point presented in
front of the body-center, and it relocated to subject's light or
right relative to the body axis. Subjects asked to follow it and
detect target. NG and seven normal subjects were given the tasks
under four different conditions. Results: Unlike the controls, NG's
spatial attention biased left body-centered hemi space, when he
could move his fixation point to the right hemi space. Conclusion:
The results suggest that body-centered spatial relationship causes
the spatial bias of attentional distribution in this case.
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