Task-oriented arm training in standing improves both anticipatory postural control and upper extremity functional outcomes in stroke patients.

Research Report
Population: Adult

Sandy McCombe Waller, PT, PhD, NCS, Director of Educational Affairs, Associate Professor, University of Maryland Baltimore, School of Medicine smccombewaller@som.umaryland.edu

Toye Jenkins, MS, PT, Research specialist, University of Maryland Baltimore County tojenkins@som.umaryland.edu

Cheih-ling Yang, MS, OT, PhD Student, University of Maryland Baltimore cyang@som.umaryland.edu

Mark Rogers, PT, PhD, Chair and Professor, University of Maryland Baltimore mrogers@som.umaryland.edu

Keywords: Plasticity, Postural Control, Upper Extremity Function, Stroke

Objective: Physical disability resulting from stroke is multifaceted, impacting both upper extremity (UE) and postural control, leaving patients at risk for immobility and falls.  In current rehabilitation practice, training is often segmented and targets quite narrowly on one area of disability. As a result, carryover of isolated gains in physical abilities to meaningful context-specific functional performance is limited. To function in an upright world, training should prepare individuals to perform tasks in standing. Moving an arm to reach forward in standing involves anticipatory postural adjustments (APAs) of the legs that precede and accompany the goal directed arm movement, and reactive responses that stabilize balance and prevent falling. This integrated motor task requires the interaction of both corticospinal and subcortical systems. In previous work we identified delayed and reduced magnitude of APAs preceding a functional reach in standing using a cued reaching task using the neural probe of acoustic startle. We hypothesized training the arm in standing without explicit cues for postural adjustments would engage subcortical pathways that contribute to APAs while also improving UE function. We report in this paper the changes in neural response to acoustic startle, effects on anticipatory postural control as well as UE functional outcomes after 6 weeks of arm training in standing. Subjects: Ten participants with chronic stroke.  Methods: Neural response to acoustic startle was measured by the presence of startle induced movements during movement preparation and planning. Anticipatory postural control and reaching were evaluated with a cued reaching task in standing. APAs were characterized by onset and maximal displacement of the center of pressure (COP), and onset/offset of EMG from tibialis anterior, soleus. Paretic reach onset/offset and duration were measured. UE functional tests included the Fugl-Meyer UE Test (FM), Wolf Motor Function Test (WMFT), Box and Blocks and the University of Maryland Arm Questionnaire for Stroke (UMAQS). Training consisted of 6-weeks task oriented training with the paretic arm, in standing, with no explicit cues for postural weight shift. Results: After training subjects demonstrated an increase in startle induced movement responses, significant improvements in APAs as measured by onset and displacement of the COP. EMG timing improved post training to resemble timing characteristics of controls previously collected. Both the onset and timing of reaching improved significantly. UE functional gains were seen in FM scores and WMFT (time and weight). Gains in UMAQS scores indicated increased daily use of the arm after training. Discussion/Conclusion: Results indicate gains in subcortical neural responses, anticipatory postural responses and paretic reaching in stroke as well as functional UE outcomes. Clinical Relevance: Arm training in the functional context of standing may better engage subcortical and corticospinal systems which can lead to gains in both postural control and function of the arm after stroke.

McCombe Waller, Sandy , PT, PhD, NCS; Jenkins, Toye , MS, PT; Yang, Cheih-ling , MS, OT; Rogers, Mark W, PT, PhD. Task-oriented arm training in standing improves both anticipatory postural control and upper extremity functional outcomes in stroke patients.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online. https://u.osu.edu/ivstep/poster/abstracts/050_mccombe-waller-et-al/