title: Receiver operating characteristic analysis of sphincter electromyography for parkinsonian syndrome.
abstract: OBJECTIVE
  We performed receiver operating characteristic (ROC) analysis to determine the ability of sphincter electromyography (EMG) to distinguish multiple system atrophy (MSA) from other parkinsonisms. The following was determined: (1) the appropriate motor unit potential (MUP) parameter among duration, phase, and amplitude; (2) the desirable parameter of our duration criteria; that is, more than 20% MUPs having >10 ms duration (criteria a) or mean duration >10 ms (criteria b).
  
  
  METHODS
  We retrospectively reviewed 441 case records where sphincter EMG were performed in patients with parkinsonian syndromes: MSA, n = 263; Parkinson's disease, n = 129; dementia with Lewy bodies, n = 25; and progressive supranuclear palsy, n = 24. We performed ROC analysis of the data sets.
  
  
  RESULTS
  The area under the curve used to differentiate MSA from other parkinsonian syndromes was 0.68 in duration, 0.57 in phase, and 0.51 in amplitude, respectively; these values were statistically significant. With regard to our duration criteria, area under the curve was 0.69 for the average duration of MUPs (criteria b) and 0.67 for percentage of MUPs of duration >10 ms (criteria a); these values were also statistically significant.
  
  
  CONCLUSIONS
  This study suggests that duration is appropriate parameter for the differentiation of MSA. However, the area under the curve of the mean duration was insufficient to confirm the diagnosis; sphincter EMG should be used as a supportive diagnostic tool for the diagnosis of MSA.
authors.affiliation: Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan. tatsuya-yamamoto@mbc.nifty.com
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Ryuji
authors.initials: R
authors.lastname: Sakakibara
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Uchiyama
authors.forename: Chiharu
authors.initials: C
authors.lastname: Yamaguchi
authors.forename: Fumio
authors.initials: F
authors.lastname: Nomura
authors.forename: Takashi
authors.initials: T
authors.lastname: Ito
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: Masashi
authors.initials: M
authors.lastname: Yano
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Awa
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yamanishi
authors.forename: Takamichi
authors.initials: T
authors.lastname: Hattori
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuwabara
mesh_terms: D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000503:physiopathology*; D019540:Area Under Curve; D003704:Dementia / Q000175:diagnosis / Q000503:physiopathology; D003937:Diagnosis, Differential; D004576:Electromyography; D005260:Female; D006801:Humans; D007564:Japan; D016631:Lewy Bodies; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis / Q000503:physiopathology; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology; D020734:Parkinsonian Disorders / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors