title: Kinematic analysis in patients with Parkinson's disease and SWEDD.
abstract: OBJECTIVE
  The differential diagnosis between mild Parkinson's disease (PD) and Scan Without Evidence of Dopaminergic Deficit(SWEDD) is challenging. Progressive reduction in amplitude and speed of finger tapping (sequence effect) has been considered as the most useful sign for discriminating PD from SWEDD. However, a video analysis reported that sequence effect is a major confounding factor for the misdiagnosis of PD. Our objective was to perform a kinematic analysis of finger tapping to explore parameters for distinguishing between patients with PD and SWEDD.
  
  
  METHODS
  We enrolled 14 patients with PD, 17 patients with SWEDD and 18 age- and sex-matched healthy controls. Amplitude, speed and frequency of finger tapping were measured using gyroscopes, and the means, decrement and variability in kinematic parameters for specific tapping duration were calculated.
  
  
  RESULTS
  Compared to SWEDD group, PD group showed more decrement in amplitude and speed of the first 20 taps, more decrement in frequency after 20 taps and more variability in speed of 15 seconds of taps. However, none of parameters was a practically useful indicator distinguishing individual patients with PD from those with SWEDD.
  
  
  CONCLUSIONS
  Analysis of finger tapping, even using an apparatus, is not useful for distinguishing mild PD and SWEDD.
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Myung Jun
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sha Lom
authors.initials: SL
authors.lastname: Kim
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chul Hyoung
authors.initials: CH
authors.lastname: Lyoo
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Myung Sik
authors.initials: MS
authors.lastname: Lee
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D003937:Diagnosis, Differential; D005260:Female; D005385:Fingers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D049268:Positron-Emission Tomography
keywords: Parkinson's disease; SWEDD; finger tapping; kinematic analysis