Title: Dopaminergic modulation of multi-muscle synergies in postural tasks performed by patients with Parkinson's disease.
Authors: Falaki, Ali; Huang, Xuemei; Lewis, Mechelle M; Latash, Mark L
Published In J Electromyogr Kinesiol, (2017 Apr)
Abstract: BACKGROUND: Postural instability is one of most disabling motor symptoms in Parkinson's disease. Indices of multi-muscle synergies are new measurements of postural stability. OBJECTIVES: We explored the effects of dopamine-replacement drugs on multi-muscle synergies stabilizing center of pressure coordinate and their adjustments prior to a self-triggered perturbation in patients with Parkinson's disease. We hypothesized that both synergy indices and synergy adjustments would be improved on dopaminergic drugs. METHODS: Patients at Hoehn-Yahr stages II and III performed whole-body tasks both off- and on-drugs while standing. Muscle modes were identified as factors in the muscle activation space. Synergy indices stabilizing center of pressure in the anterior-posterior direction were quantified in the muscle mode space during a load-release task. RESULTS: Dopamine-replacement drugs led to more consistent organization of muscles in stable groups (muscle modes). On-drugs patients showed larger indices of synergies and anticipatory synergy adjustments. In contrast, no medication effects were seen on anticipatory postural adjustments or other performance indices. CONCLUSIONS: Dopamine-replacement drugs lead to significant changes in characteristics of multi-muscle synergies in Parkinson's disease. Studies of synergies may provide a biomarker sensitive to problems with postural stability and agility and to efficacy of dopamine-replacement therapy.
PubMed ID:
28110044
MeSH Terms: Adult; Aged; Dopamine Agents/pharmacology*; Dopamine Agents/therapeutic use; Female; Humans; Levodopa/pharmacology*; Levodopa/therapeutic use; Male; Muscle Contraction; Muscle, Skeletal/physiology*; Parkinson Disease/drug therapy; Parkinson Disease/physiopathology*; Postural Balance/drug effects*; Posture