[ARTICLE] Effects of transcutaneous electrical acupoint stimulation on upper-limb impairment after stroke: A randomized, controlled, single-blind trial – Full Text

Abstract

Objective

To evaluate the effects of transcutaneous electrical acupoint stimulation (TEAS) on upper limb motor recovery during post-stroke rehabilitation.

Design

Single-blind, randomized controlled trial.

Setting

Four inpatient rehabilitation facilities.

Subjects

A total of 204 stroke patients with unilateral upper limb motor impairment were randomly 1:1 allocated to TEAS or sham TEAS group. Baseline demographic and clinical characteristics were comparable between the two groups.

Interventions

Both groups received conventional physical and occupational therapies. TEAS and sham TEAS therapy were administered to two acupoints (LI10 and TE5) with a pulse duration of 300 µs at 2 Hz on the affected forearm for 30 times over 6 weeks.

Outcome measures

The upper-extremity Fugl-Meyer score (primary outcome), manual muscle testing, modified Ashworth scale, Lindmark hand function score, and Barthel index were evaluated by blinded assessors at baseline, 2, 4, 6, 10, and 18 weeks.

Results

The number of patients who completed the treatment was 99 and 97 in the TEAS and the sham group. No significant between-group difference was found in the Upper-Extremity Fugl-Meyer score, Modified Ashworth Scale, Lindmark hand function score, and Barthel Index after intervention and during follow-up. However, the TEAS group exhibited 0.29 (95% CI 0.02 to 0.55) greater improvements in Manual Muscle Testing of wrist extension than the sham group (p  =  0.037) at 18 weeks.

Conclusions

Administration of TEAS therapy to hemiplegic forearm could not improve the upper extremity motor recovery. However, TEAS on the forearm might provide potential benefits for strength improvement of the wrist

Introduction

Globally, stroke is one of the most common causes of death and long-term adult disability,¹ with nearly 2.5 million annual new cases in China.² Persistent disability after stroke is associated with serious upper extremity and hand impairment, as more than half of stroke survivors are not able to regain proper arm function even 6 months after stroke.³

Many studies have aimed at developing treatment methods for upper limb and hand rehabilitation after stroke and some treatments have demonstrated clear effectiveness with ample evidence such as constrained-induced movement therapy and robotic therapy.⁴ However, constrained-induced movement therapy is not applicable in patients with moderate to severe impairment.⁵ Robotic therapy can be a feasible alternative intervention for patients with severe arm paresis, but robotic devices are usually expensive.⁶ The efficacies of other treatment techniques like mirror therapy, mental practice, and virtual reality have not been proven with high-quality evidence.^4,7 Therefore, novel rehabilitation approaches should be developed to improve upper limb motor outcomes after stroke.

Transcutaneous electrical acupoint stimulation (TEAS), a combination of transcutaneous electrical nerve stimulation technique and Chinese traditional acupuncture theory, is a potentially efficient, safe, and low-cost therapeutic option for stroke rehabilitation.^8–12 Transcutaneous electrical nerve stimulation uses low-voltage electrical currents to provoke nerves or muscles over the skin, generating various therapeutic effects.^13,14 In contrast, TEAS therapy is usually with lower frequency (2–4 Hz), higher intensity (to tolerance threshold), and longer pulse width (100–400 ms).^15,16 During TEAS treatment, electrical stimulation is administered to selected acupoints, eliciting an “acupuncture point sensation.”¹⁷

Currently, reported clinical evaluations of TEAS therapy in stroke rehabilitation so far have mostly found at least some evidence to suggest therapeutic benefits in walking performance^9,10 and overall function.⁸ Currently, two studies focused on the effectiveness of TEAS on the affected upper extremity motor performance in stroke patients, and both studies did not find that TEAS was better than the placebo-TEAS when combined with active training.^11,12 In addition to promoting motor recovery, TEAS also demonstrated certain effects on relieving muscle spasticity following brain injury.¹⁸ We also found a review article showing the positive effects of TEAS on upper limb functional recovery in stroke patients.¹⁹ However, all included articles were published in Chinese, so the positive finding in this review article suffers from possible language bias. Also, most included RCTs did not accurately describe the stages of stroke, and the duration and treatment protocols of included trials varied significantly.¹⁹

Given these conflicting results about the clinical effects of TEAS in motor recovery in patients with brain damage, the exact therapeutic effects of TEAS on post-stroke upper limb motor recovery remain unclear. Therefore, this single-blind, randomized controlled trial aimed to investigate whether a combination of TEAS therapy and conventional rehabilitation methods could produce additional benefits to stroke patients with arm and hand motor impairments. We hypothesized that TEAS might be effective in improving motor function, spasticity, muscle strength, or activities of daily living during stroke recovery. […]

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Figure 1. Forearm acupoints used in this study.