title: Visual search in Dementia with Lewy Bodies and Alzheimer's disease.
abstract: Visual search is an aspect of visual cognition that may be more impaired in Dementia with Lewy Bodies (DLB) than Alzheimer's disease (AD). To assess this possibility, the present study compared patients with DLB (n = 17), AD (n = 30), or Parkinson's disease with dementia (PDD; n = 10) to non-demented patients with PD (n = 18) and normal control (NC) participants (n = 13) on single-feature and feature-conjunction visual search tasks. In the single-feature task participants had to determine if a target stimulus (i.e., a black dot) was present among 3, 6, or 12 distractor stimuli (i.e., white dots) that differed in one salient feature. In the feature-conjunction task participants had to determine if a target stimulus (i.e., a black circle) was present among 3, 6, or 12 distractor stimuli (i.e., white dots and black squares) that shared either of the target's salient features. Results showed that target detection time in the single-feature task was not influenced by the number of distractors (i.e., "pop-out" effect) for any of the groups. In contrast, target detection time increased as the number of distractors increased in the feature-conjunction task for all groups, but more so for patients with AD or DLB than for any of the other groups. These results suggest that the single-feature search "pop-out" effect is preserved in DLB and AD patients, whereas ability to perform the feature-conjunction search is impaired. This pattern of preserved single-feature search with impaired feature-conjunction search is consistent with a deficit in feature binding that may be mediated by abnormalities in networks involving the dorsal occipito-parietal cortex.
authors.affiliation: Department of Neurosciences, University of California, San Diego, CA, United States.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Landy
authors.affiliation: Department of Neurosciences, University of California, San Diego, CA, United States. Electronic address: dsalmon@ucsd.edu.
authors.forename: David P
authors.initials: DP
authors.lastname: Salmon
authors.affiliation: Department of Psychiatry, University of California, San Diego, CA, United States; Psychology Service, Veterans Affairs San Diego Healthcare System, CA, United States.
authors.forename: J Vincent
authors.initials: JV
authors.lastname: Filoteo
authors.affiliation: Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, RI, United States.
authors.forename: William C
authors.initials: WC
authors.lastname: Heindel
authors.affiliation: Department of Neurosciences, University of California, San Diego, CA, United States; Neurology Service, Veterans Affairs San Diego Healthcare System, CA, United States.
authors.forename: Douglas
authors.initials: D
authors.lastname: Galasko
authors.affiliation: Department of Neurosciences, University of California, San Diego, CA, United States.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Hamilton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D003071:Cognition / Q000502:physiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*
keywords: Alzheimer's disease; Dementia with Lewy Bodies; Feature-conjunction; Visual attention; Visual search