title: Parkinson's disease and sex-related differences in electromyography during daily life.
abstract: METHODS
  Daily bilateral electromyography (EMG) recordings reveal muscle activation patterns implicated in asymmetric Parkinson's disease (PD)-related functional decline. Also, daily EMG recordings reveal sex-differences in muscle activity that give rise to unique PD presentation in males and females.
  
  
  OBJECTIVE
  Quantify handgrip strength and daily muscle quiescence through analysis of gaps in the EMG signal in males and females with PD. Bilateral daily EMG was recorded and normalized to maximal voluntary exertions (MVE). EMG gap was defined as <1% amplitude of MVE for >0.1s and characterized as number, duration and time occupied by gaps. A dynamometer evaluated maximal grip-strength. Three-way repeated measures ANOVA examined differences in gap characteristics and strength. Gap duration was shorter (p=0.04) and occupied less time (p=0.02) in PD than controls. Females had fewer gaps with shorter duration (p=0.004), occupying less time (p=0.004) compared with males. Gaps were fewer (p=0.04) and occupied less time (p=0.01) on more-affected than less-affected side. PD was weaker than controls (p=0.04), females were weaker than males (p=0.00), and the more-affected PD side was weaker than less-affected (p=0.04).
  
  
  CONCLUSIONS
  Quantification of muscle quiescence through gaps in the EMG signal recorded during daily life provides insight into mechanisms underlying differential change in functional performance in males and females with PD.
authors.affiliation: School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada.
authors.forename: Kaitlyn P
authors.initials: KP
authors.lastname: Roland
authors.forename: Gareth R
authors.initials: GR
authors.lastname: Jones
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Jakobi
mesh_terms: D056044:Actigraphy / Q000379:methods; D000203:Activities of Daily Living; D004576:Electromyography / Q000379:methods*; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors