title: Higher muscle passive stiffness in Parkinson's disease patients than in controls measured by myotonometry.
abstract: OBJECTIVE
  To assess muscle passive stiffness in medicated Parkinson's disease patients using myotonometry.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Kinesiology laboratory.
  
  
  METHODS
  Women with Parkinson's disease (PD) (n=8) and healthy matched elderly women (controls) (n=10) (mean age: PD, 77+/-3y; controls, 77+/-4y).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Passive stiffness of relaxed biceps brachii (BB) muscle was measured using myotonometry. Additionally, surface electromyographic and mechanomyographic signals were recorded from the muscle at rest, and amplitude of those signals was analyzed offline.
  
  
  RESULTS
  The values of BB muscle passive stiffness were significantly (P=.004) higher in PD than in the controls, with a statistically significant influence of parkinsonian rigidity score (Unified Parkinson's Disease Rating Scale) on intergroup differences (P<.001). The Spearman correlation coefficient rho value showed a significant (P=.005) positive relationship (rho=.866) between the parkinsonian rigidity score and passive stiffness values of BB in PD. The groups did not differ significantly in the electromyogram amplitude (P=.631) and mechanomyogram amplitude (P=.593) of the BB muscle, and values of these parameters did not correlate significantly with rigidity score (P=.555, P=.745, respectively) in the patients.
  
  
  CONCLUSIONS
  Myotonometer is a sensitive enough tool to show that PD patients have higher muscle passive stiffness than healthy controls.
authors.affiliation: Department of Kinesiology, Faculty of Physiotherapy, University School of Physical Education, Wroclaw, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Marusiak
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kisiel-Sajewicz
authors.forename: Anna
authors.initials: A
authors.lastname: Jaskólska
authors.forename: Artur
authors.initials: A
authors.lastname: Jaskólski
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004185:Disability Evaluation; D004576:Electromyography; D005260:Female; D006801:Humans; D009127:Muscle Rigidity / Q000175:diagnosis*; D010300:Parkinson Disease / Q000503:physiopathology*; D026741:Physical Therapy Modalities; D034941:Upper Extremity