title: Relative preservation of MMSE scores in autopsy-proven dementia with Lewy bodies.
abstract: BACKGROUND
  Recent studies raised questions about the severity of cognitive impairment associated with dementia with Lewy bodies (DLB). However, there have been few analyses of large, multicenter data registries for clinical-pathologic correlation.
  
  
  METHODS
  We evaluated data from the National Alzheimer's Coordinating Center registry (n = 5,813 cases meeting initial inclusion criteria) and the University of Kentucky Alzheimer's Disease Center autopsy series (n = 527) to compare quantitatively the severity of cognitive impairment associated with DLB pathology vs Alzheimer disease (AD) and AD+DLB pathologies.
  
  
  RESULTS
  Mini-Mental State Examination (MMSE) scores showed that persons with pure DLB had cognitive impairment of relatively moderate severity (final MMSE score 15.6 +/- 8.7) compared to patients with pure AD and AD+DLB (final MMSE score 10.7 +/- 8.6 and 10.6 +/- 8.6). Persons with pure DLB pathology from both data sets had more years of formal education and were more likely to be male. Differences in final MMSE scores were significant (p < 0.01) between pure DLB and both AD+DLB and pure AD even after correction for education level, gender, and MMSE-death interval. Even in cases with extensive neocortical LBs, the degree of cognitive impairment was most strongly related to the amount of concomitant AD-type neurofibrillary pathology.
  
  
  CONCLUSIONS
  Dementia with Lewy bodies can constitute a debilitating disease with associated psychiatric, motoric, and autonomic dysfunction. However, neocortical Lewy bodies are not a substrate for severe global cognitive impairment as assessed by the Mini-Mental State Examination. Instead, neocortical Lewy bodies appear to constitute or reflect an additive disease process, requiring Alzheimer disease or other concomitant brain diseases to induce severe global cognitive deterioration.
authors.affiliation: Department of Pathology, Division of Neuropathology, University of Kentucky Medical Center, 800 S. Limestone, University of Kentucky, Lexington, KY 40536-0230, USA. pnels2@email.uky.edu
authors.forename: P T
authors.initials: PT
authors.lastname: Nelson
authors.forename: R J
authors.initials: RJ
authors.lastname: Kryscio
authors.forename: G A
authors.initials: GA
authors.lastname: Jicha
authors.forename: E L
authors.initials: EL
authors.lastname: Abner
authors.forename: F A
authors.initials: FA
authors.lastname: Schmitt
authors.forename: L O
authors.initials: LO
authors.lastname: Xu
authors.forename: G
authors.initials: G
authors.lastname: Cooper
authors.forename: C D
authors.initials: CD
authors.lastname: Smith
authors.forename: W R
authors.initials: WR
authors.lastname: Markesbery
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D004522:Educational Status; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000503:physiopathology / Q000523:psychology*; D008297:Male; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance; D012042:Registries; D012720:Severity of Illness Index; D017678:Sex Distribution; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology