title: Diagnostic accuracy of the clapping test in Parkinsonian disorders.
abstract: BACKGROUND
  To determine the diagnostic value of the clapping test, which has been proposed as a reliable measure to differentiate between progressive supranuclear palsy (where performance is impaired) and Parkinson's disease (where performance should be normal).
  
  
  METHODS
  Our study group included a large cohort of consecutive outpatients including 44 patients with Parkinson's disease, 48 patients with various forms of atypical parkinsonism and 149 control subjects. All subjects performed the clapping test according to a standardized protocol.
  
  
  RESULTS
  Clapping test performance was normal in all control subjects, and impaired in 63% of the patients with atypical parkinsonism. Unexpectedly, we also found an impaired clapping test in 29% of the patients with Parkinson's disease.
  
  
  CONCLUSIONS
  Although the proportion with an abnormal clapping test was significantly higher in atypical parkinsonism, the clapping test did not discriminate well between Parkinson's disease and atypical parkinsonism.
authors.affiliation: Parkinson Centre Nijmegen (ParC), Institute of Neurology (935), Radboud University Nijmegen Medical Centre, 9101, 6500, HB Nijmegen, The Netherlands.
authors.forename: W F
authors.initials: WF
authors.lastname: Abdo
authors.forename: A G W
authors.initials: AG
authors.lastname: van Norden
authors.forename: K F
authors.initials: KF
authors.lastname: de Laat
authors.forename: F-E
authors.initials: FE
authors.lastname: de Leeuw
authors.forename: G F
authors.initials: GF
authors.lastname: Borm
authors.forename: M M
authors.initials: MM
authors.lastname: Verbeek
authors.forename: P H P
authors.initials: PH
authors.lastname: Kremer
authors.forename: B R
authors.initials: BR
authors.lastname: Bloem
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007100:Imitative Behavior / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis