Document Detail

Perturbations of ground support alter posture and locomotion coupling during step initiation in Parkinson's disease.
MedLine Citation:
PMID:  21153725     Owner:  NLM     Status:  MEDLINE    
During the initiation of stepping, anticipatory postural adjustments (APAs) for lateral weight transfer and propulsion normally precede the onset of locomotion. In Parkinson's disease (PD), impaired step initiation typically involves altered APA ground force production with delayed step onset and deficits in stepping performance. If, as in stance and gait, sensory information about lower limb load is important for the control of stepping, then perturbations influencing loading conditions could affect the step initiation process. This study investigated the influence of changes in lower limb loading during step initiation in patients with PD and healthy control subjects. Participants performed rapid self-triggered step initiation with the impending single stance limb positioned over a pneumatically actuated platform. In perturbation trials, the stance limb ground support surface was either moved vertically downward (DROP) or upward (ELEVATE) by 1.5 cm shortly after the onset of the APA phase. Overall, PD patients demonstrated a longer APA duration, longer time to first step onset, and slower step speed than controls. In both groups, the DROP perturbation reinforced the intended APA kinetic changes for lateral weight transfer and resulted in a significant reduction in APA duration, increase in peak amplitude, and earlier time to first step onset compared with other conditions. During ELEVATE trials that opposed the intended weight transfer forces both groups rapidly adapted their stepping to preserve standing stability by decreasing step length and duration, and increasing step height and foot placement laterally. The findings suggested that sensory information associated with limb load and/or foot pressure modulates the spatial and temporal parameters of posture and locomotion components of step initiation in interaction with a centrally generated feedforward mode of neural control. Moreover, impaired step initiation in PD may at least acutely be enhanced by augmenting the coupling between posture and locomotion.
Mark W Rogers; Marjorie Johnson Hilliard; Katherine M Martinez; Yunhui Zhang; Tanya Simuni; Marie-Laure Mille
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Publication Detail:
Type:  Journal Article     Date:  2010-12-12
Journal Detail:
Title:  Experimental brain research     Volume:  208     ISSN:  1432-1106     ISO Abbreviation:  Exp Brain Res     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-25     Completed Date:  2011-05-04     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  557-67     Citation Subset:  IM    
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MeSH Terms
Aged, 80 and over
Antiparkinson Agents / therapeutic use
Biomechanical Phenomena
Data Interpretation, Statistical
Extremities / physiology
Locomotion / physiology*
Middle Aged
Parkinson Disease / physiopathology*
Posture / physiology*
Walking / physiology*
Reg. No./Substance:
0/Antiparkinson Agents

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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