title: Enhancement of parkinsonian rigidity with contralateral hand activation.
abstract: OBJECTIVE
  Quantify the enhancement of parkinsonian rigidity associated with a contralateral activation maneuver.
  
  
  METHODS
  Twelve subjects with PD and eight controls participated in the study protocol. Subjects' tested hand was displaced by a servo-motor throughout wrist flexion and extension motions of 60° without and with a concurrent gripping activation in the contralateral hand, referred to as Passive and Active conditions, respectively. Subjects with PD were tested in both OFF-MED and ON-MED states. Rigidity was quantified by integrating torque with position during both flexion and extension (torque resistance). ANOVA was performed to assess the effect of contralateral activation on rigidity.
  
  
  RESULTS
  PD patients had significantly (0.038) enhanced torque resistance in OFF-MED compared to healthy controls and ON-MED. In the Active condition, differences in torque resistance were magnified (p=0.002). Medication substantially reduced differences in torque resistance between controls and PD patients in the Passive and Active conditions.
  
  
  CONCLUSIONS
  A contralateral activation maneuver substantially increases rigidity in patients with PD, specifically the OFF-MED state. Rigidity is reduced with the application of dopaminergic medication, even with the presence of a contralateral activation maneuver.
  
  
  CONCLUSIONS
  These data support the use of a contralateral activation maneuver as a tool in the diagnosis of PD.
authors.affiliation: Rehabilitation Science Research Laboratory, Department of Physical Therapy, Creighton University, Omaha, NE 68178, USA. douglaspowell@creighton.edu
authors.forename: Douglas
authors.initials: D
authors.lastname: Powell
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hanson
authors.forename: A Joseph
authors.initials: AJ
authors.lastname: Threlkeld
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.forename: Ruiping
authors.initials: R
authors.lastname: Xia
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000627:therapeutic use; D004185:Disability Evaluation; D004576:Electromyography; D005260:Female; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology*; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009127:Muscle Rigidity / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy; D012720:Severity of Illness Index; D014955:Wrist Joint / Q000294:innervation
chemical_list: D000978:Antiparkinson Agents