Ali Falaki1, Xuemei Huang2, Mechelle M Lewis3, Mark L Latash4. 1. Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA. 2. Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA; Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA; Department of Radiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA; Department of Neurosurgery, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA. 3. Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA; Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, USA. 4. Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA. Electronic address: mll11@psu.edu.
Abstract
BACKGROUND: Postural instability is one of most disabling motor symptoms in Parkinson's disease. Indices of multi-muscle synergies are new measurements of movement and postural stability. OBJECTIVES: Multi-muscle synergies stabilizing vertical posture were studied in Parkinson's disease patients without clinical symptoms of postural instability (Hoehn-Yahr ≤ II) and age-matched controls. We tested the hypothesis that both synergy indices during quiet standing and synergy adjustments to self-triggered postural perturbations would be reduced in patients. METHODS: Eleven Parkinson's disease patients and 11 controls performed whole-body tasks while standing. Surface electromyography was used to quantify synergy indices stabilizing center of pressure shifts in the anterior-posterior direction during a load-release task. RESULTS: Parkinson's disease patients showed a significantly lower percentage of variance in the muscle activation space accounted for by the first four principal components, significantly reduced synergy indices during steady state, and significantly reduced anticipatory synergy adjustments (a drop in the synergy index prior to the self-triggered unloading). CONCLUSIONS: The study demonstrates for the first time that impaired synergic control in Parkinson's disease can be quantified in postural tasks, even in patients without clinical manifestations of postural instability. Synergy measurements may provide a biomarker sensitive for early problems with postural stability in Parkinson's disease.
BACKGROUND: Postural instability is one of most disabling motor symptoms in Parkinson's disease. Indices of multi-muscle synergies are new measurements of movement and postural stability. OBJECTIVES: Multi-muscle synergies stabilizing vertical posture were studied in Parkinson's diseasepatients without clinical symptoms of postural instability (Hoehn-Yahr ≤ II) and age-matched controls. We tested the hypothesis that both synergy indices during quiet standing and synergy adjustments to self-triggered postural perturbations would be reduced in patients. METHODS: Eleven Parkinson's diseasepatients and 11 controls performed whole-body tasks while standing. Surface electromyography was used to quantify synergy indices stabilizing center of pressure shifts in the anterior-posterior direction during a load-release task. RESULTS:Parkinson's diseasepatients showed a significantly lower percentage of variance in the muscle activation space accounted for by the first four principal components, significantly reduced synergy indices during steady state, and significantly reduced anticipatory synergy adjustments (a drop in the synergy index prior to the self-triggered unloading). CONCLUSIONS: The study demonstrates for the first time that impaired synergic control in Parkinson's disease can be quantified in postural tasks, even in patients without clinical manifestations of postural instability. Synergy measurements may provide a biomarker sensitive for early problems with postural stability in Parkinson's disease.
Authors: Stanislaw Solnik; Nemanja Pazin; Chase J Coelho; David A Rosenbaum; John P Scholz; Vladimir M Zatsiorsky; Mark L Latash Journal: Exp Brain Res Date: 2013-01-04 Impact factor: 1.972
Authors: Alessander Danna-Dos-Santos; Kajetan Slomka; Vladimir M Zatsiorsky; Mark L Latash Journal: Exp Brain Res Date: 2007-01-13 Impact factor: 2.064
Authors: Mariusz P Furmanek; Stanisław Solnik; Daniele Piscitelli; Omid Rasouli; Ali Falaki; Mark L Latash Journal: J Mot Behav Date: 2017-09-15 Impact factor: 1.328
Authors: Sandra M S F Freitas; Paulo B de Freitas; Ali Falaki; Tyler Corson; Mechelle M Lewis; Xuemei Huang; Mark L Latash Journal: Exp Brain Res Date: 2020-10-17 Impact factor: 1.972
Authors: Ali Falaki; Hang Jin Jo; Mechelle M Lewis; Barbara O'Connell; Sol De Jesus; James McInerney; Xuemei Huang; Mark L Latash Journal: Clin Neurophysiol Date: 2018-03-09 Impact factor: 3.708