Get access

Dementia in Parkinson's disease: Usefulness of the pill questionnaire


  • Pablo Martinez-Martin MD, PhD

    Corresponding author
    1. Research Unit, Alzheimer Centre Reina Sofia Foundation, and CIBERNED, CIEN Foundation. Carlos III Institute of Health, Madrid, Spain
    • Correspondence to: Dr. Pablo Martinez-Martin, Alzheimer Centre Reina Sofia Foundation, C/Valderrebollo, 5, 28031 Madrid, Spain;

    Search for more papers by this author

  • Funding agencies: Logistics of the current study were supported by an unrestricted grant from UCB Pharma, Madrid, Spain.

  • Relevant conflicts of interest/financial disclosures: Nothing to report.

  • Full financial disclosures may be found in the online version of this article.


The Level I algorithm for the diagnosis of dementia associated with Parkinson's disease (PD-D) recommended by the Movement Disorder Society task force includes a Pill Questionnaire to determine the impact of cognitive decline on daily activities. The objective of this study was to test the performance of the Pill Questionnaire as a screening tool for the detection of dementia (all-cause) in patients with PD and to test the performance of another functional scale substituting the Pill Questionnaire for the diagnosis of “probable PD-D” (pPD-D). Data were collected from 529 patients who had PD in Hoehn and Yahr stages 1 through 5. The measures used include the Scales for Outcomes in PD-Motor (SCOPA-Motor), scales for psychiatric complications, the Mini Mental State Examination, the Clinical Impression of Severity Index, and the Pill Questionnaire. The SCOPA-Motor functional subscale score was categorized as “impact” or “no impact” of PD on daily activities. According to clinical judgment, 13.3% of patients had dementia. For detecting dementia, the Pill Questionnaire had 89% accuracy, although its positive predictive value was 55%. Performance was worse with the categorized SCOPA-Motor subscale. According to the Movement Disorder Society task force criterion, 85 patients (16.1%) had pPD-D. When the Pill Questionnaire was substituted by the categorized SCOPA-Motor subscale, the modified algorithm showed sensitivity, specificity, and accuracy indexes over 90% but had positive predictive value of 66% for pPD-D diagnosis. Although the Pill Questionnaire demonstrated acceptable basic properties as a screening tool for dementia, its positive predictive value was low. The SCOPA-Motor subscale cannot be proposed as a substitute for the Pill Questionnaire. © 2013 International Parkinson and Movement Disorder Society