title: Evaluation of spinal and bulbar muscular atrophy by the clustering index method.
abstract: BACKGROUND
  A reliable electrophysiological marker for clinical trials is increasingly needed in spinal and bulbar muscular atrophy (SBMA). We previously developed a quantitative analysis method for surface electromyography (SEMG), the clustering index (CI) method. Our purpose was to test the utility of the CI method for evaluating lower motor neuron involvement in SBMA patients.
  
  
  METHODS
  Subjects included 29 SBMA patients and 27 healthy controls. The recording electrode was placed over the abductor digiti minimi (ADM) muscle with a proximal reference. The Z-score, based on the CI method, was compared with compound muscle action potential (CMAP) amplitude and motor unit number estimation (MUNE), with regard to sensitivity.
  
  
  RESULTS
  The Z-scores of the CI method, CMAP amplitude, and MUNE were abnormal in 100%, 72%, and 93% of the patients, respectively. Interrater reliability of the CI method was sufficiently high.
  
  
  CONCLUSIONS
  The CI method is promising as a non-invasive electrophysiological marker in SBMA.
authors.affiliation: Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Mana
authors.initials: M
authors.lastname: Higashihara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sonoo
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Yu
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Haruo
authors.initials: H
authors.lastname: Uesugi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
authors.forename: Erik
authors.initials: E
authors.lastname: Stålberg
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuji
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009134:Muscular Atrophy, Spinal / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity