Effect of Transcutaneous Electrical Nerve Stimulation on Spasticity in Adults With Stroke: A Systematic Review and Meta-analysis.

Objectives: (1) To determine the effect of transcutaneous electrical nerve stimulation (TENS) on poststroke spasticity. (2) To determine the effect of different parameters (intensity, frequency, duration) of TENS on spasticity reduction in adults with stroke. (3) To determine the influence of time since stroke on the effectiveness of TENS on spasticity.

Data Sources: PubMed, PEDro, CINAHL, Web of Science, CENTRAL, and EMBASE databases were searched from inception to March 2017.

Study Selection: Randomized controlled trial (RCT), quasi-RCT, and non-RCT were included if (1) they evaluated the effects of TENS for the management of spasticity in participants with acute or subacute or chronic stroke using clinical and neurophysiological tools; and (2) TENS was delivered either alone or as an adjunct to other treatments.

Data Extraction: Two authors independently screened and extracted data from 15 of the 829 studies retrieved through the search using a pilot tested pro forma. Disagreements were resolved through discussion with other authors. Quality of studies was assessed using Cochrane risk of bias criteria.

Data Synthesis: Meta-analysis was performed using a random-effects model that showed (1) TENS along with other physical therapy treatments was more effective in reducing spasticity in the lower limbs compared to placebo TENS (SMD -0.64; 95% confidence interval [95% CI], -0.98 to -0.31; P=.0001; I=17%); and (2) TENS, when administered along with other physical therapy treatments, was effective in reducing spasticity when compared to other physical therapy interventions alone (SMD -0.83; 95% CI, -1.51 to -0.15; P=.02; I=27%). There were limited studies to evaluate the effectiveness of TENS for upper limb spasticity.

Conclusion: There is strong evidence that TENS as an adjunct is effective in reducing lower limb spasticity when applied for more than 30 minutes over nerve or muscle belly in chronic stroke survivors (review protocol registered at PROSPERO: CRD42015020151).