Clinical studies have shown that sensory input improves motor function when added to active training after neurological injuries in the spinal cord.

We aimed to determine the effect on motor function of extremities of adding an electrical sensory modality without motor recruitment before or with routine rehabilitation for hemiparesis after stroke by a comprehensive systematic review and meta-analysis.

We searched databases including MEDLINE via PubMed and the Cochrane Central Register of Controlled Trials from 1978 to the end of November 2017 for reports of randomized controlled trials or controlled studies of patients with a clinical diagnosis of stroke who underwent 1) transcutaneous electrical nerve stimulation (TENS) or peripheral electromyography-triggered sensory stimulation over a peripheral nerve and associated muscles or 2) acupuncture to areas that produced sensory effects, without motor recruitment, along with routine rehabilitation. Outcome measures were motor impairment, activity, and participation outcomes defined by the International Classification of Functioning, Disability and Health.

The search yielded 11studies with data that could be included in a meta-analysis. Electrical sensory inputs, when paired with routine therapy, improved peak torque dorsiflexion (mean difference [MD] 2.44 Nm, 95% confidence interval [CI] 0.26–4.63). On subgroup analysis, the combined therapy yielded a significant difference in terms of sensory stimulation without motor recruitment only on the Timed Up and Go test in the chronic phase of stroke (MD 3.51sec, 95% CI 3.05–3.98). The spasticity score was reduced but not significantly (MD−0.83 points, 95% CI -1.77−0.10).

Electrical sensory input can contribute to routine rehabilitation to improve early post-stroke lower-extremity impairment and late motor function, with no change in spasticity. Prolonged periods of sensory stimulation such as TENS combined with activity can have beneficial effects on impairment and function after stroke.