Non-paretic arm force does not over-inhibit the paretic arm in chronic post-stroke hemiparesis

No idea what this means, but if it can reduce spasticity your doctor can decipher it and produce a stroke protocol.
http://www.sciencedirect.com/science/article/pii/S0003999314000082

• Michael A. Dimyan, MD^{, ∗,} ,
• Monica A. Perez, PhD^∗,
• Sungyoung Auh, PhD^∗,
• Erick Tarula, MD^∗,
• Matthew Wilson, MD^∗,
• Leonardo G. Cohen, MD

• Human Cortical Physiology and Stroke Neurorehabilitation Section (MAD, MAP, ET, MW, LGC), and Clinical Neurosciences Program (SA) Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD

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Abstract

Objective

To determine whether non-paretic arm force over-inhibits the paretic arm in patients with chronic unilateral post-stroke hemiparesis. We hypothesized that interhemispheric inhibition would increase more in healthy controls than in hemiparetic patients.

Design

Case-control neurophysiologic and behavioral study of patients with chronic stroke.

Setting

Federal research institution, outpatient clinical research setting

Participants

Eighty-six referred patients were screened to enroll 9 participants with greater than 6 month history of one unilateral ischemic infarct that resulted in arm hemiparesis, with residual ability to produce 1Nm of wrist flexion torque, without contraindication to transcranial magnetic stimulation. 8 age- and handedness-matched healthy volunteers without neurologic diagnosis were studied for comparison.

Interventions

Not Applicable

Main Outcome Measures

Change in interhemispheric inhibition targeting the ipsilesional primary-motor-cortex (M1) during non-paretic arm force.

Results

Healthy age-matched controls had significantly greater increases in inhibition from their active to resting M1 than did stroke patients from their active contralesional to resting ipsilesional M1 in the same scenario (20% ±7 vs. -1% ±4, F_1,12=6.61, p=0.0245). Patients with greater increases in contralesional to ipsilesional inhibition were better performers on the nine-hole-peg-test of paretic arm function.

Conclusions

Our findings reveal that producing force with the non-paretic arm does not necessarily over-inhibit the paretic arm. Though limited in generalizability by the small sample size, we found that greater active contralesional to resting ipsilesional M1 inhibition was related to better recovery in this subset of chronic post-stroke patients.