Parkinson disease with dementia: Comparing patients with and without alzheimer pathology

Marwan N. Sabbagh, Charles H. Adler, Tyson J. Lahti, Donald J. Connor, Linda Vedders, Lars K. Peterson, John N. Caviness, Holly A. Shill, Lucia I. Sue, Iryna Ziabreva, Elaine Perry, Clive G. Ballard, Dag Aarsland, Douglas G. Walker, Thomas G. Beach

Research output: Contribution to journalArticlepeer-review

125 Scopus citations


Subjects with Parkinson disease (PD) frequently develop dementia with greater than one-third meeting neuropathologic diagnostic criteria for Alzheimer disease (AD). The objective is to identify clinical and neuropathologic differences between Parkinson disease with dementia (PDD) subjects, with and without coexistent AD pathology. Neuropathologic examination was available on subjects diagnosed by clinicopathologic criteria with PDD-AD (N=23) and PDD+AD (N=28). A small subset of subjects with PDD-AD and PDD+AD had received at least 1 standardized neuropsychologic assessment. PDD+AD subjects were significantly older at age of PD onset and death, progressed to onset of dementia in less time, and had a shorter duration of PD symptoms before the onset of dementia. Education, responsiveness of L-dopa and dopaminergic medications, presence of cognitive fluctuations and hallucinations, and mean Mini-Mental State Examination, Global Deterioration Scale, Functional Assessment Staging, and Unified Parkinson Disease Rating Scale scores did not differ significantly between the 2 groups. The PDD+AD group had significantly greater total plaques, neuritic plaques, total tangles, and Braak stages compared with PDD-AD. This study suggests that it is difficult to distinguish PDD+AD and PDD-AD on the basis of movement, clinical, and neuropsychologic assessment. PDD-AD and PDD+AD have similar degrees of dementia and approximately half of PDD subjects have enough AD pathology to attain a neuropathologic diagnosis of AD. PDD can develop in the absence of significant Alzheimer pathology.

Original languageEnglish (US)
Pages (from-to)295-297
Number of pages3
JournalAlzheimer disease and associated disorders
Issue number3
StatePublished - Jul 2009


  • Alzheimer disease
  • Assessment of dementia
  • Dementia
  • Dementia with Lewy bodies
  • Neurofibrillary tangles
  • Parkinson disease
  • Parkinson disease with dementia
  • Senile plaques

ASJC Scopus subject areas

  • Clinical Psychology
  • Gerontology
  • Geriatrics and Gerontology
  • Psychiatry and Mental health


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