title: Visual perception in Parkinson disease dementia and dementia with Lewy bodies.
abstract: OBJECTIVE
  To quantify visual discrimination, space-motion, and object-form perception in patients with Parkinson disease dementia (PDD), dementia with Lewy bodies (DLB), and Alzheimer disease (AD).
  
  
  METHODS
  The authors used a cross-sectional study to compare three demented groups matched for overall dementia severity (PDD: n = 24; DLB: n = 20; AD: n = 23) and two age-, sex-, and education-matched control groups (PD: n = 24, normal controls [NC]: n = 25).
  
  
  RESULTS
  Visual perception was globally more impaired in PDD than in nondemented controls (NC, PD), but was not different from DLB. Compared to AD, PDD patients tended to perform worse in all perceptual scores. Visual perception of patients with PDD/DLB and visual hallucinations was significantly worse than in patients without hallucinations.
  
  
  CONCLUSIONS
  Parkinson disease dementia (PDD) is associated with profound visuoperceptual impairments similar to dementia with Lewy bodies (DLB) but different from Alzheimer disease. These findings are consistent with previous neuroimaging studies reporting hypoactivity in cortical areas involved in visual processing in PDD and DLB.
authors.affiliation: Institute for Ageing and Health, Wolfson Research Centre, Newcastle General Hospital, Newcastle upon Tyne NE4 6BE, UK. u.p.mosimann@ncl.ac.uk
authors.forename: U P
authors.initials: UP
authors.lastname: Mosimann
authors.forename: G
authors.initials: G
authors.lastname: Mather
authors.forename: K A
authors.initials: KA
authors.lastname: Wesnes
authors.forename: J T
authors.initials: JT
authors.lastname: O'Brien
authors.forename: D J
authors.initials: DJ
authors.lastname: Burn
authors.forename: I G
authors.initials: IG
authors.lastname: McKeith
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D015331:Cohort Studies; D004192:Discrimination, Psychological; D005116:Extrapyramidal Tracts / Q000503:physiopathology; D005260:Female; D005556:Form Perception; D006212:Hallucinations / Q000209:etiology; D006801:Humans; D020961:Lewy Body Disease / Q000150:complications* / Q000523:psychology; D008297:Male; D009039:Motion Perception; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology; D010468:Perceptual Disorders / Q000209:etiology*; D011597:Psychomotor Performance; D012021:Reflex, Abnormal; D012720:Severity of Illness Index; D013028:Space Perception; D014787:Vision Tests; D014796:Visual Perception