Impaired hand function is a major cause of chronic disability among stroke survivors. Although a number of treatment approaches have been developed to facilitate the recovery of hand function, most target mildly impaired individuals. Efforts to rehabilitate individuals with severe impairment often treat the hand/wrist in isolation without consideration of the deleterious effects of proximal joint demands, like those experienced when lifting the arm against gravity to reach and retrieve a glass from a cabinet. Our long-term goal is to bring effective therapeutic strategies to those with moderate to severe hand impairment. To do this we have focused on the role of abnormal joint coupling in arm functioning. Following the loss of corticospinal tract fibers, movement in individuals with stroke s impaired by stereotypic multi-joint movement patterns (synergies) that result in the loss of independent joint control. For instance in the paretic arm, shoulder abduction is abnormally coupled with elbow flexion (flexor-synergy). As part of the first cycle of this R01 (years 1-5), we quantified torque-coupling patterns, and associated muscle activations, isometrically by using a 6 Degree-of-Freedom load cell. We also discovered that multi-joint isometric efforts were constrained to these abnormal coupling patterns. As part of the second cycle of this R01 (years 6-10), we progressed the work into dynamics, utilizing robotic devices to establish that reaching work area is reduced as a function of increasing abduction loading, and conducting robotic joint perturbation studies to demonstrate the integrated nature of the loss of independent joint control and vibration reflexes. Finally, recent work using the asymmetric tonic reflex and transcranial magnetic stimulation to probe brainstem excitability has provided evidence of increase reliance on the ipsilateral reticular formation, presumably through the reticulospinal tract, as the source of loss of independent joint control. The overall goal of the current renewal (years 11-15) is to further our understanding of the effects of the flexion synergy on wrist/hand function and the underlying neurophysiology. To do this we will determine the extent to which isometric shoulder abduction effort (Aim 1) and functional arm reaching (Aim 2) alter muscle activation during isometric hand muscle activations. These studies will inform our third approach to detect the intention behind actual hand movements and ultimately determine the impact of the flexion synergy on dynamic wrist/finger movement (Aim 3). Detecting wrist/hand movement intent within the context of a quantitatively controlled whole-limb movement in individuals with moderate to severe impairment is innovative and has the potential to propel the field vertically. We will use the results from Aims 1-3 to develop an effective algorithm for detecting hand opening, closing, and relaxation, a key component in restoring function to the paretic hand in individuals with moderate to severe impairment following stroke. Thus, the outcome of this study is expected to have a crucial impact on future rehabilitation approaches even for the most severely impaired stroke survivors.

Public Health Relevance

The proposed research is relevant to public health because it seeks to quantify wrist and finger activity in the paretic upper limb of chronic hemiparetic stroke survivors while lifting up the arm and during functional movements. This is relevant to the NIH's mission because it will not only lead to a better understanding of how arm movements may impact the control of wrist and fingers following a stroke but it will also seek to determine hand movement intent by picking up weak signals from paretic wrist and finger muscles. This requires the use of sophisticated signal analysis techniques. The accurate determination of movement intent is expected to lead to the development of new clinical devices that facilitate the return of basic hand function (i.e., grasping and releasing objects) even in the more impaired stroke survivors.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD039343-11A1
Application #
8579570
Study Section
Musculoskeletal Rehabilitation Sciences Study Section (MRS)
Program Officer
Nitkin, Ralph M
Project Start
2000-09-15
Project End
2018-05-31
Budget Start
2013-08-01
Budget End
2014-05-31
Support Year
11
Fiscal Year
2013
Total Cost
$318,215
Indirect Cost
$103,253
Name
Northwestern University at Chicago
Department
Physical Medicine & Rehab
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Perlmutter, Sam; Lin, Fang; Dewald, Julius P A (2014) Development of a device for measurement of multi-directional isometric trunk kinetics in a seated position. IEEE Trans Neural Syst Rehabil Eng 22:344-51
Miller, Laura C; Dewald, Julius P A (2012) Involuntary paretic wrist/finger flexion forces and EMG increase with shoulder abduction load in individuals with chronic stroke. Clin Neurophysiol 123:1216-25
Schwerin, Susan C; Yao, Jun; Dewald, Julius P A (2011) Using paired pulse TMS to facilitate contralateral and ipsilateral MEPs in upper extremity muscles of chronic hemiparetic stroke patients. J Neurosci Methods 195:151-60
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Acosta, Ana Maria; Dewald, Hendrik A; Dewald, Jules P A (2011) Pilot study to test effectiveness of video game on reaching performance in stroke. J Rehabil Res Dev 48:431-44
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Yao, Jun; Dewald, Julius P A (2009) Impact of time-frequency representation to the generalization ability of synthesized time-frequency spatial patterns algorithm in Brain Computer Interface. Conf Proc IEEE Eng Med Biol Soc 2009:6473-6
Zhou, Jie; Yao, Jun; Deng, Jie et al. (2009) EEG-based classification for elbow versus shoulder torque intentions involving stroke subjects. Comput Biol Med 39:443-52
Ellis, Michael D; Sukal-Moulton, Theresa; Dewald, Julius P A (2009) Progressive shoulder abduction loading is a crucial element of arm rehabilitation in chronic stroke. Neurorehabil Neural Repair 23:862-9
Miller, Laura C; Ruiz-Torres, Ricardo; Stienen, Arno H A et al. (2009) A wrist and finger force sensor module for use during movements of the upper limb in chronic hemiparetic stroke. IEEE Trans Biomed Eng 56:2312-7

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