Principal Investigator: Carolynn Patten, PhD, PT Project Staff: Kevin C. McGill, PhD and Felix E. Zajac, PhD Project Category: Stroke - 2004 Objective: This project is a continuation of the Career Development and Advanced Career Development Awards for Carolynn Patten, Ph.D., PT, which were officially completed in February 2004. The continuation phase is established to maintain an open IRB protocol and access to data to allow preparation and submission of publications. The scientific objectives of this project are to elucidate neuromuscular mechanisms responsible for functional weakness in persons with post-stroke hemiparesis. The initial target professional goal of these Career Development Awards were for Dr. Patten to secure peer reviewed funding in the form of an RR&D Merit Review grant as co-principal investigator. This Advanced Career Development Award provided her salary support through February of 2004. By the end of the Career Development Award period it was expected that Dr. Patten would be prepared to compete successfully for peer reviewed funds as a fully independent researcher. This objective was met. Research Plan and Methods: In this cross-sectional design, 14 persons with post-stroke hemiparesis and 7 control subjects were studied while performing three types of muscular contractions: isometric force production, contralateral limb effects on isometric force production, and cyclic dynamic force production involving both eccentric and concentric conditions. Force production and motor unit activity were studied concurrently in the lower extremities while subjects performed motor tasks on an instrumented bicycle ergometer. Motor unit signals were recorded from the vastus medialis muscle using needle and/or fine wire electrodes. EMG signals were decomposed into their constituent parts using advanced decomposition software, the discharge patterns of individual motor unit action potential trains identified and the control properties of groups of concurrently active motor units compared between subject groups and across task conditions. Clinical Relevance to the VA: Impaired movement control, including weakness and undue fatigue, are frequent complaints of hemiparetic persons. This research is important for its role in identifying physiologic mechanisms associated with functional weakness in hemiparetic persons, for its potential to provide a sensitive, scientifically-based means for assessment of rehabilitation potential in the hemiparetic patient population, and to determine the efficacy of therapeutic interventions used in rehabilitation. Research Plan for the Next Year: The funded portion of this project was completed in Feburary of 2004. We continue to analyze data and submit manuscripts. Preliminary data obtained from this project were used in the successful VA Merit Review proposal, Therapeutic Effects on Neuromuscular Function in Post-stroke Hemiparesis, which is currently in its second year of funding. Additional follow up proposals are planned including a collaborative NIH proposal led by Kevin McGill to pursue development of advanced decomposition techniques for analysis of motor unit signals. Funding Source: Advanced Career Development Award Funding Status: Completed |
