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Distinguishing Distinct Neural Systems for Proximal vs Distal Upper Extremity Motor Control After Acute Stroke
David J Lin1, Richard Hardstone2, Julie A DiCarlo2
1From the Center for Neurotechnology and Neurorecovery (D.J.L., R.H., J.A.D., S.M., H.J., K.S.E., K.R., L.R.H.), Department of Neurology, Massachusetts General Hospital, Harvard Medical School; Division of Neurocritical Care (D.J.L., L.R.H.), Department of Neurology; Stroke Service (D.J.L., S.P.F., L.H.S., L.R.H.), Department of Neurology, Massachusetts General Hospital, Boston; VA RR&D Center for Neurorestoration and Neurotechnology (D.J.L., L.R.H.), Rehabilitation R&D Service, Department of VA Medical Center, Providence, RI; Division of Neurocritical Care (S.B.S.), Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Department of Occupational Therapy (H.J., K.S.E.), MGH Institute of Health Professions, Boston, MA; Department of Rehabilitation (P.B.), Exercise and Nutrition Sciences, University of Cincinnati College of Allied Health Sciences, OH; Department of Biostatistics (J.G.), Columbia University Mailman School of Public Health, New York, NY; Department of Occupational Therapy (J.R.), Massachusetts General Hospital, Boston; School of Engineering (L.R.H.), Brown University, Providence, RI; and Department of Neurology (S.C.C.), University of California, Los Angeles, California Rehabilitation Hospital. dlin7@mgh.harvard.edu.
Stroke can selectively impair proximal or distal arm control, impacting recovery. Preserved distal motor function after stroke predicts better functional outcomes and is linked to specific brain injuries.
Area of Science:
- Neuroscience
- Neurology
- Rehabilitation Medicine
Background:
- The traditional view of post-stroke upper extremity deficits doesn't fully explain distinct proximal and distal motor control organization.
- The central nervous system (CNS) has separate neural circuits for proximal and distal motor control.
Purpose of the Study:
- To distinguish separate proximal and distal upper extremity clinical syndromes after acute stroke.
- To correlate neuroanatomical injury patterns with these distinct motor syndromes.
Main Methods:
- Assessed proximal and distal motor impairment and strength in 141 acute stroke patients within 7 days of onset.
- Used partial correlation and voxel-based lesion-symptom mapping to analyze motor deficits and brain injury locations.
- Examined functional outcomes (Box and Blocks Test, Barthel Index, modified Rankin scale) in relation to motor patterns.
Main Results:
- Distinct proximal and distal upper extremity motor components were identifiable post-stroke (p = 0.002).
- Proximal-dominant weakness occurred in 23% of patients, predicting better functional outcomes (p < 0.001 for all).
- Proximal deficits linked to widespread subcortical injury; distal deficits linked to posterior precentral gyrus injury.
Conclusions:
- Acute stroke can selectively injure proximal and distal upper extremity motor systems.
- Dissociable deficits and functional consequences arise from injury to these distinct motor systems.
- Understanding these distinct systems clarifies components of post-stroke hemiparesis.
