caa a22 4500 445354364 CHVBK 20180317142855.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s00221-010-2504-z doi (NATIONALLICENCE)springer-10.1007/s00221-010-2504-z Perturbations of ground support alter posture and locomotion coupling during step initiation in Parkinson's disease [Elektronische Daten] [Mark Rogers, Marjorie Hilliard, Katherine Martinez, Yunhui Zhang, Tanya Simuni, Marie-Laure Mille] 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 1.5cm 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. Springer-Verlag, 2010 Parkinson's disease nationallicence Posture nationallicence Step initiation nationallicence Limb load nationallicence Rogers Mark Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Hilliard Marjorie Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Martinez Katherine Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Zhang Yunhui Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Simuni Tanya Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Mille Marie-Laure Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut Experimental Brain Research Springer-Verlag 208/4(2011-02-01), 557-567 0014-4819 208:4<557 2011 208 221 https://doi.org/10.1007/s00221-010-2504-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00221-010-2504-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rogers Mark Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 700 1- Hilliard Marjorie Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 700 1- Martinez Katherine Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 700 1- Zhang Yunhui Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 700 1- Simuni Tanya Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 700 1- Mille Marie-Laure Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA aut NATIONALLICENCE 773 0- Experimental Brain Research Springer-Verlag 208/4(2011-02-01), 557-567 0014-4819 208:4<557 2011 208 221 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer