People with parkinson's disease and normal MMSE score have a broad range of cognitive performance

Daniel J. Burdick, Brenna Cholerton, G. S. Watson, Andrew Siderowf, John Q. Trojanowski, Daniel Weintraub, Beate Ritz, Shannon L. Rhodes, Renecca Rausch, Stewart A. Factor, Cathy Wood-Siverio, Joseph F. Quinn, Kathryn A. Chung, Sindhu Srivatsal, Karen L. Edwards, Thomas J. Montine, Cyrus P. Zabetian, James B. Leverenz

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Cognitive impairment, including dementia, is common in Parkinson's disease (PD). TheMini-Mental State Examination (MMSE) has been recommended as a screening tool for Parkinson's disease dementia (PDD), with values below 26 indicative of possible dementia. Using a detailed neuropsychological battery, we examined the range of cognitive impairment in PD patients with an MMSE score of 26 or higher. In this multicenter, cross-sectional, observational study, we performed neuropsychological testing in a sample of 788 PD patients with MMSE scores of 26 or higher. Evaluation included tests of global cognition, executive function, language, memory, and visuospatial skills. A consensus panel reviewed results for 342 subjects and assigned a diagnosis of no cognitive impairment, mild cognitive impairment, or dementia. Sixty-seven percent of the 788 subjects performed 1.5 standard deviations below the normative mean on at least one test. On eight of the 15 tests, more than 20% of subjects scored 1.5 standard deviations or more below the normative mean. Greatest impairments were found on Hopkins Verbal Learning and Digit Symbol Coding tests. The sensitivity of the MMSE to detect dementia was 45% in a subset of participants who underwent clinical diagnostic procedures. A remarkably wide range of cognitive impairment can be found in PD patients with a relatively high score on the MMSE, including a level of cognitive impairment consistent with dementia. Given these findings, clinicians must be aware of the limitations of the MMSE in detecting cognitive impairment, including dementia, in PD.

Original languageEnglish (US)
Pages (from-to)1258-1264
Number of pages7
JournalMovement Disorders
Issue number10
StatePublished - Sep 2014


  • Assessment of cognitive disorders/dementia
  • Mild cognitive impairment
  • Parkinson's disease
  • Parkinson's disease with dementia
  • cognition

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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