Non-invasive treatment of patients with upper extremity spasticity following stroke using paired trans-spinal and peripheral direct current stimulation

Alexandra Paget-Blanc,Johanna L Chang,Zaghloul Ahmed,Regina Lin,Bruce T Volpe,Maira Saul

doi:10.1186/s42234-019-0028-9

Abstract

BackgroundMuscle spasticity is a common impediment to motor recovery in patients with chronic stroke. Standard-of-care treatments such as botulinum toxin injections can temporarily relieve muscle stiffness and pain associated with spasticity, but often at the expense of increased muscle weakness. Recent preclinical investigations of a non-invasive treatment that pairs trans-spinal direct current stimulation and peripheral nerve direct current stimulation (tsDCS+pDCS) provided promising data for a novel approach based on bioelectronic medicine for the treatment of patients with post-stroke spasticity.MethodsTwenty-six patients with upper limb hemiparesis and wrist spasticity at least 6 months after their initial stroke participated in this single-blind crossover design study to test whether tsDCS+pDCS reduces chronic upper-extremity spasticity. Subjects received five consecutive daily sessions (20 min of stimulation or sham) of anodal tsDCS+pDCS, separated by a one-week washout period. The sham condition always preceded the active condition. Clinical and objective measures of spasticity and motor function were collected before and after each condition, and for five weeks after the completion of the active intervention.ResultsSubjects treated with active tsDCS+pDCS demonstrated significant reductions in both Modified Tardieu Scale scores (summed across the upper limb, P < 0.05), and in objective torque measures (Nm) of the spastic catch response at the wrist flexor (P < 0.05), compared to the sham condition. Motor function also improved significantly (measured by the Fugl-Meyer and Wolf Motor Function Test; P < 0.05 for both tests) after active treatment.ConclusionstsDCS+pDCS intervention alone significantly reduced upper limb spasticity in participants with stroke. Decreased spasticity was persistent for five weeks after treatment, and was accompanied by improved motor function even though patients were unsupervised and there was no prescribed activity or training during that interval.Trial registrationNCT03080454, March 15, 2017.

Highlights

Muscle spasticity is a common impediment to motor recovery in patients with chronic stroke
Spasticity is a motor disorder that occurs in 20–43% of individuals after stroke, and is defined as a velocity dependent increase in the tonic stretch reflex resulting from simultaneous co-contraction of agonist and antagonist muscles that often leads to increased stiffness and permanent contracture
For MTSflexor, pairedsample Wilcoxon Signed Rank revealed no significant difference in scores after sham and active treatment

Summary

Introduction

Muscle spasticity is a common impediment to motor recovery in patients with chronic stroke. Standard-of-care treatments such as botulinum toxin injections can temporarily relieve muscle stiffness and pain associated with spasticity, but often at the expense of increased muscle weakness. Spasticity is a motor disorder that occurs in 20–43% of individuals after stroke, and is defined as a velocity dependent increase in the tonic stretch reflex resulting from simultaneous co-contraction of agonist and antagonist muscles that often leads to increased stiffness and permanent contracture. Spasticity occurs more frequently in the upper rather than the lower limbs, and this regional propensity contributes to less recovery of upper limb independence, often resulting in near permanent impairment of the wrist and hand (Sommerfeld et al, 2012). When the spasticity continues to worsen and becomes severe or causes pain, the standard-of-care is botulinum toxin injection (Levy et al, 2018)

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