Increase of optical illusion in demented patients.
Assuming a particular psychological function of optical gestalt perception, its impairment would lead to a decreasing extent of gestalt related optical illusion. An increase of optical illusion would be expected in the case of a loss of adaptability and cognitive compensation, usually revising the phenomenon of optical illusion. 16 demented out-patients were compared to 16 hospitalized schizophrenics by a 'Computerized Assessment of Change in Optical Illusion' (CACOI), measuring the extent of optical illusion by patient's assessment of 12 variations of the figure of Mueller-Lyer, differing in baseline length. The results showed a significant increase of optical illusion in demented patients compared to the schizophrenic controls (p = 0.019). Taking into account that the extent of optical illusion by the figure of Mueller-Lyer usually is decreasing with age and was found to be increased in schizophrenics, our results support the hypothesis of an early loss of adaptability and cognitive compensation in dementia.
Weber
B
B
Department of Psychiatry and Psychotherapy I, Johann Wolfgang Goethe University, Frankfurt/Main, Federal Republic of Germany.
Frölich
L
L
Helbing
N
N
Simminger
D
D
Fritze
J
J
Maurer
K
K
D000368:Aged; D000544:Alzheimer Disease / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology / Q000523:psychology; D003704:Dementia / Q000523:psychology*; D015140:Dementia, Vascular / Q000523:psychology*; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008297:Male; D009903:Optical Illusions; D012565:Schizophrenic Psychology