We have previously reported that the use of a 32-symptom Wearing-off Questionnaire (WOQ-32) identified wearing off more frequently than a clinician's evaluation or the complications subscale of the Unified Parkinson Disease Rating Scale (UPDRS). However, this prototype tool was not designed for clinical practice and required simplification for daily use. Although wearing off is a commonly understood concept among neurologists caring for Parkinson disease patients, there are a number of definitions in the literature. For the purpose of this study and to include both motor and nonmotor parkinsonian symptoms, wearing off was defined as a generally predictable recurrence of motor and nonmotor symptoms that precedes scheduled doses of anti-parkinsonian medication and usually improves after those doses. Using this definition, retrospective analysis and expert opinion were used to identify the 9 most predictive and relevant of the symptoms previously identified as part of the WOQ-32. The resulting 9-symptom questionnaire (WOQ-9) identified 158 (95.8%) of the 165 subjects captured by the 32-Symptom Wearing-off Questionnaire as having wearing off, excluding 7 subjects reporting only balance difficulty (n = 3), numbness (n = 2), difficulty standing (n = 1), and abdominal discomfort (n = 1). Subjects reporting wearing off with the WOQ-9 were significantly younger, had been longer diagnosed with Parkinson disease, experienced a longer duration of levodopa therapy, exhibited a higher UPDRS total score, had higher levodopa equivalent dosages, and increased dyskinesia compared with patients not identified as wearing off with the WOQ-9. No statistical differences were noted with respect to sex, UPDRS subsection scores, Schwab & England Scale, or Hoehn & Yahr Scale.
*Division of Neurology, Duke University Medical School, Durham, North Carolina, USA; †Parkinson's Disease and Movement Disorders Center, University of South Florida College of Medicine, Tampa, Florida, USA; ‡Department of Neurology, Philipps-University, Marburg, Germany; §Department of Clinical Neurosciences, Royal Free & University College Medical School, London, UK; ∥Movement Disorders Program, Department of Neurology, Medical College of Georgia, Augusta, Georgia, USA; ¶Department of Neurology, IRCCS San Raffaele Pisana Roma, Italy; and the **Neurology Service, Institut Clinic de Neurociencies, Hospital Clinic, Universitat de Barcelona and Institut d' Investigació Biomèdica August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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