Why was this study needed?
More than 1.2 million people in the UK are living with the effects of stroke. About two-thirds of stroke survivors leave hospital with residual disability and one quarter experience spasticity.
Electrical stimulation is sometimes used as treatment after a stroke. It includes functional electrical stimulation and neuromuscular electrical stimulation, which both focus on muscle contraction. Transcutaneous electrical stimulation (TENS) targets the sensory nerves in a different way.
Transcutaneous electrical stimulation has been suggested as an adjunct to other rehabilitation therapy to try and reduce spasticity. The device is portable and can be self-administered at home, so its potential for managing spasticity is appealing.
There have been a number of small studies of TENS with conflicting results. This review aimed to combine the results to see if there was evidence for its use to treat spasticity after stroke.
What did this study do?
This systematic review identified 15 studies (10 randomised controlled trials) reporting the effectiveness of TENS on spasticity after stroke.
Studies compared TENS, used alone or alongside other therapies such as functional exercises, with placebo, no treatment or other treatments. Thirteen studies assessed lower limb spasticity, with 11 targeting the ability to flex the foot. Most assessed use in the chronic rather than acute phase of stroke.
Transcutaneous electrical stimulation regimen varied widely. Intervention periods ranged from one day to 12 weeks, the number of TENS sessions from one to seven per week, and the duration of sessions ranged from less than 20 minutes up to 60 minutes.
Trials were small with maximum participant size 80. The quality of randomised controlled trials was good overall, with lack of participant blinding being the most likely source of bias. Seven trials were pooled in meta-analysis.
What did it find?
- Transcutaneous electrical stimulation used alongside other physical therapies was moderately effective in reducing spasticity in the lower limbs compared with placebo (standard mean difference [SMD] -0.64, 95% confidence interval [CI] -0.98 to -0.31). This was from meta-analysis of five trials (221 adults) with broadly similar results.
- Pooled results of two trials (60 adults) also found that TENS alongside other physical therapies was more effective at reducing spasticity than no TENS (SMD -0.83, 95% CI -1.51 to -0.15).
- Five studies assessed longer-term effects on spasticity. Three studies found the effects were maintained for a period of two to five weeks whilst two studies found the effects lasted for less than a day and that spasticity returned to baseline levels immediately following the intervention.
- None of the studies reported any adverse effects of TENS.
What does current guidance say on this issue?
The NICE guideline on stroke rehabilitation (2013) does not currently include recommendations for use of TENS. NICE advises against the routine use of electrical stimulation for the hand and arm but suggests a trial of treatment may be considered if there is sign of muscle contraction, and the person cannot move their arm against resistance.
NICE guidance from 2009 advises that there is sufficient evidence that functional electrical stimulation can improve walking in people with drop foot following a stroke, provided the normal arrangements are in place for clinical governance, consent and audit.
What are the implications?
This review suggests that TENS, when delivered alongside other physical therapies, could be considered for lower limb spasticity as part of a stroke rehabilitation programme.
The findings are similar to a 2015 systematic review which found that electrical stimulation gave small but significant improvements in spasticity following stroke. Again this earlier review was limited by small sample sizes, varied treatment regimens and few studies that could be pooled in meta-analysis.
There was insufficient evidence to support use for upper limbs.
Cost was not assessed, but TENS is a non-invasive therapy and devices are widely available and could easily be used at home.
Citation and Funding
Mahmood A, Veluswamy SK, Hombali A, et al. Effect of transcutaneous electrical nerve stimulation on spasticity in adults with stroke: a systematic review and meta-analysis. Arch Phys Med Rehabil. 2018; 16 November. doi: 10.1016/j.apmr.2018.10.016. [Epub ahead of print].
No funding information was provided for this study.
NICE. Functional electrical stimulation for drop foot of central neurological origin. IPG278. London: National Institute for Health and Care Excellence; 2009.
NICE. Stroke rehabilitation in adults. CG162. London: National Institute for Health and Care Excellence; 2013.
NICE. Spasticity (after stroke) – botulinum toxin type A. ID768. London: National Institute for Health and Care Excellence; in development.
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Stroke Association. State of the nation: stroke statistics. London: Stroke Association; 2018.