Parkinson's disease-cognitive rating scale: a new cognitive scale specific for Parkinson's disease

Mov Disord. 2008 May 15;23(7):998-1005. doi: 10.1002/mds.22007.

Abstract

Cognitive defects associated with cortical pathology may be a marker of dementia in Parkinson's disease (PD). There is a need to improve the diagnostic criteria of PD dementia (PDD) and to clarify the cognitive impairment patterns associated with PD. Current neuropsychological batteries designed for PD are focused on fronto-subcortical deficits but are not sensitive for cortical dysfunction. We developed a new scale, the Parkinson's Disease-Cognitive Rating Scale (PD-CRS), that was designed to cover the full spectrum of cognitive defects associated with PD. We prospectively studied 92 PD patients [30 cognitively intact (CogInt), 30 mild cognitive impairment (MCI), 32 PDD] and 61 matched controls who completed the PD-CRS and neuropsychological tests assessing the cognitive domains included in the PD-CRS. Acceptability, construct validity, reliability, and the discriminative properties of the PD-CRS were examined. The PD-CRS included items assessing fronto-subcortical defects and items assessing cortical dysfunction. Construct validity, test-retest and inter-rater reliability of PD-CRS total scores showed an intraclass correlation coefficient >0.70. The PD-CRS showed an excellent test accuracy to diagnose PDD (sensitivity 94%, specificity 94%). The PD-CRS total scores and confrontation naming item scores-assessing "cortical" dysfunction-independently differentiated PDD from non-demented PD. Alternating verbal fluency and delayed verbal memory independently differentiated the MCI group from both controls and CogInt. The PD-CRS appeared to be a reliable and valid PD-specific battery that accurately diagnosed PDD and detected subtle fronto-subcortical deficits. Performance on the PD-CRS showed that PDD is characterized by the addition of cortical dysfunction upon a predominant and progressive fronto-subcortical impairment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Aged
  • Brain / physiopathology
  • Cognition Disorders* / diagnosis
  • Cognition Disorders* / etiology
  • Cognition Disorders* / physiopathology
  • Female
  • Frontal Lobe / physiopathology
  • Humans
  • Levodopa / therapeutic use
  • Male
  • Neuropsychological Tests*
  • Parkinson Disease / complications*
  • Parkinson Disease / drug therapy
  • Parkinson Disease / physiopathology
  • Prospective Studies
  • Reproducibility of Results
  • Severity of Illness Index
  • Surveys and Questionnaires*

Substances

  • Levodopa