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Therapeutic Effects on Neuromuscular
Function in Post-stroke Hemiparesis
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Principal Investigator: Carolynn Patten, PhD, PT
Project Staff: Kevin C. McGill, PhD; Garry E. Gold, MD; David C.
Tong, MD; Heather E. Brown, MSPT; Dhara Kothari, MS PT; Sara M. Northrop, MPT;
and C. Maria Kim, MSc, PT
Project Category: Stroke - 2003
Objective: The overriding objective of the proposed research is to
determine the mechanisms through which therapeutically induced adaptations in
neuromuscular activation affect weakness and locomotor disability in persons
with post-stroke hemiparesis. Clinical assessments, strength measurement, motor
unit firing patterns, magnetic resonance imaging, and gait analysis will be
used to better understand the relationship between impaired neuromuscular
function and motor disability.
Clinically-based Questions:
What is the relationship between impairment (strength), disability
(gait velocity), and clinical outcome? Can clinically important change in
disability be predicted on the basis of changes in motor impairment following
therapeutic intervention?
How significantly are key gait parameters (self-selected walking speed,
fastest walking speed, single limb support, step length, cadence) affected by
therapeutic intervention targeted at reducing neuromuscular impairment?
Experimentally-based Questions:
What is the extent of activation impairment in the lower extremity of
persons with post-stroke hemiparesis? Is therapeutic intervention effective at
reducing activation impairment?
What is the relationship between functional weakness and disruptions in
the motor unit recruitment-rate coding relationship in hemiparesis?
What are the prominent adaptations in neuromuscular activation patterns
(MU recruitment and secondary firing characteristics) which mediate improved
functional strength in hemiparetics?
Project Milestones to Date:
Due to the protracted continuing resolution in 2003, the start date for
the project (originally October 1, 2002) did not occur until April 1, 2003.
Project development and infrastructure placement were accomplished by
July 1, 2003.
The first class of subjects was enrolled on July 1, 2003 and completed
treatment on or around September 1, 2003. All subjects are retained for follow
up evaluations at 6 and 12 months post-intervention and thus remain in some
stage of project participation.
Fourteen subjects have been enrolled to date. An overall sample size of
38 subjects was projected. We anticipate reaching enrollment of 17 subjects by
April 1 and 23 subjects by June 1, thus believe we are on target with regard to
recruitment.
Preliminary data from this project were discussed in conjunction with
other data from the PI's research program in an invited colloquiam at Smith
College in November, 2003.
Mr. Henrik Baare Olsen visited Dr. Patten's lab in September, 2003 to
provide new motor unit analysis software.
New Project Goals: We project a manuscript reporting activation
impairment in the lower extremity from the cross-sectional data of this cohort
by December, 2004.
Funding Source: VA RR&D Merit Review
Funding Status: Funded
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