Electrical stimulation for preventing and treating post-stroke shoulder pain

Electrical stimulation of muscles improves shoulder stiffness after a stroke but there is not enough evidence to prove whether it reduces shoulder pain. Patients who have a stroke (a sudden catastrophe in the brain either because an artery to the brain blocks, or because an artery in or on the brain ruptures and bleeds) often develop shoulder pain. This adds to the difficulties caused by the stroke. Pain in the shoulder can cause weakness, loss of muscle tone and loss of feeling. Electrical neuromuscular stimulation (ES) is done by applying an electrical current to the skin. This stimulates nerves and muscle fibres and may improve muscle tone, muscle strength, and reduce pain. The review found that shoulder stiffness improved after ES. No adverse effects were noted. The review also found there was not enough evidence to decide if ES can reduce shoulder pain or not. More research is needed.

Authors' conclusions: 

The evidence from randomised controlled trials so far does not confirm or refute that ES around the shoulder after stroke influences reports of pain, but there do appear to be benefits for passive humeral lateral rotation. A possible mechanism is through the reduction of glenohumeral subluxation. Further studies are required.

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Background: 

Shoulder pain after stroke is common and disabling. The optimal management is uncertain, but electrical stimulation (ES) is often used to treat and prevent pain.

Objectives: 

To determine the efficacy of any form of surface ES in the prevention and/or treatment of pain around the shoulder at any time after stroke.

Search strategy: 

We searched the Cochrane Stroke Review Group trials register and undertook further searches of MEDLINE, EMBASE and CINAHL. Contact was established with equipment manufacturers and centres that have published on the topic of ES.

Selection criteria: 

We considered all randomised trials that assessed any surface ES technique (functional electrical stimulation (FES), transcutaneous electrical nerve stimulation (TENS) or other), applied at any time since stroke for the purpose of prevention or treatment of shoulder pain.

Data collection and analysis: 

Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data.

Main results: 

Four trials (a total of 170 subjects) fitted the inclusion criteria. Study design and ES technique varied considerably, often precluding the combination of studies. Population numbers were small. There was no significant change in pain incidence (Odds Ratio (OR) 0.64; 95% CI 0.19 to 2.14) or change in pain intensity (Standardised Mean Difference (SMD) 0.13; 95% CI -1.0 to 1.25) after ES treatment compared to control. There was a significant treatment effect in favour of ES for improvement in pain-free range of passive humeral lateral rotation (Weighted Mean Difference (WMD) 9.17; 95% CI 1.43 to 16.91). In these studies ES reduced the severity of glenohumeral subluxation (SMD -1.13; 95% CI -1.66 to -0.60), but there was no significant effect on upper limb motor recovery (SMD 0.24; 95% CI -0.14 to 0.62) or upper limb spasticity (WMD 0.05; 95% CI -0.28 to 0.37). There did not appear to be any negative effects of electrical stimulation at the shoulder.

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