Visual cognition and its disability （including geographic disorientation）

Kazumi Hirayama¹⁾, Hiroaki Hosokawa²⁾

¹⁾Department of Occupational Therapy, Yamagata Prefectural University of Health Sciences
²⁾Department of Behavioural Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine

Neurodegenerative diseases cause characteristic visual perception impairment for each disease.　In Alzheimer’s disease, topographical disorientation, and perceptual disturbance of radial optic flow occur frequently.　In visual variant of Alzheimer’s disease, visual inattention that is inability to visualize more than one object in the visual field at a time, ‘optische Ataxie’ that is the lack of coordination between visual input and hand movements, and psychic paralysis of gaze that is the difficulty of moving the gaze from the object the patient is watching occur frequently.　In dementia with Lewy bodies and Parkinson’s disease, impairment of color vision, visual hallucination, and visual illusion occur frequently.

Address correspondence to Dr. Kazumi Hirayama, Department of Occupational Therapy, Yamagata Prefectural University of Health Sciences（260 Kamiyanagi, Yamagata City, Yamagata 990-2212, Japan）