Alterations of visual search strategy in Alzheimer's disease and aging.
Visual search, characterized by eye fixation patterns, was examined in 8 patients with Alzheimer's disease (AD), 8 cognitively intact, age-matched individuals, and 8 young control participants as they searched for a number among a nonlinear array of letters on a large computer screen. Among the 3 groups, target detection accuracy differed and detection time increased linearly. There were more fixations, and fixation duration was significantly longer in the AD patients than in the other 2 groups. These factors contributed to the lengthening of target detection time. This qualitative difference in the architecture of visual search between AD and aging may reflect a specific deficit in the disengagement of visual spatial attention, a prolongation of saccade initiation, or inefficiency in planning a search strategy.
Department of Psychiatry, University Hospital, Basel, Switzerland.
A
A
Rösler
M E
ME
Mapstone
A K
AK
Hays
M M
MM
Mesulam
A
A
Rademaker
D R
DR
Gitelman
S
S
Weintraub
D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D000544:Alzheimer Disease / Q000523:psychology*; D003463:Cues; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*