Virtual image grasping in patients with Alzheimer-type dementia

• Published in: Neuroscience letters Vol. 299; no. 1; pp. 101 - 104
• Main Authors: Massing, Walter, Kenklies, Marlene, Hager, Klaus
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 16.02.2001; Elsevier
• Subjects: Aged; Aged, 80 and over; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - physiopathology; Alzheimer-type dementia; Biological and medical sciences; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - pathology; Cerebral Cortex - physiopathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Functional Laterality - physiology; Hallucinations - etiology; Hallucinations - physiopathology; Humans; Male; Medical sciences; Middle Aged; Mirror image; Neurology; Perceptual Disorders - metabolism; Perceptual Disorders - physiopathology; Psychomotor Performance - physiology; Space Perception - physiology; Tomography, Emission-Computed, Single-Photon; Virtual image grasping; Alzheimer-type dementia; Mirror image; Virtual image grasping; Human; Gripping; Nervous system diseases; Alzheimer disease; Central nervous system disease; Virtual image; Degenerative disease; Cerebral disorder
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(01)01500-2

Patients with various neuropsychiatric disorders who confused virtual images with real objects have recently been described. When asked to take objects from an investigator's hand while looking in a mirror, these patients reached directly into the mirror for the object's image. To investigate whether the phenomenon occurs in patients with Alzheimer's disease, we studied 127 cases, of whom 67 were suspected of having Alzheimer-type dementia (DAT). The phenomenon in question was not observed in either of two control groups, but whereas 38 (57%) of the DAT patients responded correctly, 17 (25%) of them grasped at the mirror image. Characteristically, none of the eight patients who grasped into the mirror and underwent single photon emission computed tomography analysis showed symmetric activity. We also analyzed the behaviour and verbal utterances of the DAT patients in front of the mirror.