Transcutaneous electrical nerve stimulation improves walking capacity and reduces spasticity in stroke survivors: a systematic review and meta-analysis

Objective: To evaluate (1) the effectiveness of transcutaneous electrical nerve stimulation (TENS) at improving lower extremity motor recovery in stroke survivors and (2) the optimal stimulation parameters for TENS. Review methods: A systematic search was conducted for studies published up to October 2017 using eight electronic databases (CINAHL, ClinicalTrials.gov, the Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, PEDro, PubMed and Web of Science). Randomized controlled trials that evaluated the effectiveness of the application of TENS at improving lower extremity motor recovery in stroke survivors were assessed for inclusion. Outcomes of interest included plantar flexor spasticity, muscle strength, walking capacity and balance. Results: In all, 11 studies met the inclusion criteria which involved 439 stroke survivors. The meta-analysis showed that TENS improved walking capacity, as measured by either gait speed or the Timed Up and Go Test (Hedges’ g = 0.392; 95% confidence interval (CI) = 0.178 to 0.606) compared to the placebo or no-treatment control groups. TENS also reduced paretic plantar flexor spasticity, as measured using the Modified Ashworth Scale and Composite Spasticity Scale (Hedges’ g = –0.884; 95% CI = –1.140 to −0.625). The effect of TENS on walking capacity in studies involving 60 minutes per sessions was significant (Hedges’ g = 0.468; 95% CI = 0.201–0.734) but not in study with shorter sessions (20 or 30 minutes) (Hedges’ g = 0.254; 95% CI = –0.106–0.614). Conclusion: The results support the use of repeated applications of TENS as an adjunct therapy for improving walking capacity and reducing spasticity in stroke survivors.