title: Screening for impaired cognitive domains in a large Parkinson's disease population and its application to the diagnostic procedure for Parkinson's disease dementia.
abstract: BACKGROUND
  Dementia is a new focus of research on improved treatment for Parkinson's disease (PD). In 2007, a screening tool for PD dementia (PD-D) was developed by the Movement Disorder Society (Level I testing), which still requires verification by a large population study.
  
  
  METHODS
  We conducted a cross-sectional and multicenter study including 13 institutions administering the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) to 304 PD patients (mean age: 70.6 ± 8.3 years; mean Hoehn and Yahr stage: 2.7 ± 0.7).
  
  
  RESULTS
  In all, 34.5% of the patients had MMSE scores <26; 94.3% of these patients had impairments in ≥2 cognitive domains and met the criteria for probable PD-D by Level I testing. Executive dysfunction combined with attention and memory impairment was most common (51.4%). In the Level I subtests of executive function, the score for phonemic fluency declined by <50% in patients with high MoCA scores (24-30 points) and lacked specificity for PD-D. No patient had visuospatial impairment (measured by the pentagon copying subtest) alone, and the score for pentagon copying stayed at ≥70% even in patients with low MMSE scores (12-25 points), therefore lacking sensitivity for PD-D.
  
  
  CONCLUSIONS
  Level I testing with administration of the MMSE and MoCA is a practical and efficient screening tool for PD-D. However, the phonemic fluency and pentagon copying tests should be replaced by more specific/sensitive ones when screening for PD-D.
authors.affiliation: Department of Neurology, Tachikawa Hospital, Tachikawa, Shinjuku, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Neurology, Tokyo Metropolitan Neurological Hospital, Fuchu, Shinjuku, Japan.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Neurology, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Shinjuku, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Gotoh
authors.affiliation: Department of Neurology, Mito Red Cross Hospital, Mito, Shinjuku, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Neurology, Keio University School of Medicine, Shinjuku, Japan.
authors.forename: Morinobu
authors.initials: M
authors.lastname: Seki
authors.affiliation: Department of Neurology, Keio University School of Medicine, Shinjuku, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nihei
authors.affiliation: Department of Preventive Medicine and Public Health, Keio University School of Medicine, Shinjuku, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Iwasawa
authors.affiliation: Department of Neurology, Keio University School of Medicine, Shinjuku, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Suzuki
keywords: Cognitive domain; Dementia; Executive function; Mini-Mental State Examination; Montreal Cognitive Assessment; Parkinson's disease