Repetitive peripheral magnetic stimulation for improving everyday activities in people after stroke

Review question
Is repetitive peripheral magnetic stimulation (rPMS) effective for improving daily activities in people after stroke?

Background
Stroke, the most common cause of disability, occurs when the blood supply to part of the brain is interrupted or reduced. Two types of stroke are known: ischaemic (due to lack of blood flow) and haemorrhagic (due to bleeding). Paralysis of the arm or leg after stroke causes problems with daily activities and functions, including eating, showering, dressing, and walking. People after stroke with hemiparesis require physical rehabilitation, that is, training of upper and lower limbs, exercise focused on activities of daily living, and fitting of appropriate walking aids (e.g. cane). However, effective treatments are currently limited. rPMS is a painless method of stimulation that has been used to try to improve movement in people with brain or nerve disorders.

Search date
The search is current to 7 January 2019.

Study characteristics
This is an update of the review published in 2017. We examined the evidence from four trials of rPMS (three individual RCTs and one cross-over trial) involving a total of 139 participants. Two studies compared rPMS against 'sham' stimulation (a very weak stimulation or a sound only). Two studies compared rPMS plus rehabilitation versus sham plus rehabilitation.

Key results
We found little evidence for the use of rPMS to improve activities of daily living, muscle strength, upper limb function, and spasticity (unusual stiffness of muscles) in people after stroke. Although one trial reported that rPMS reduced spasticity of the upper limb, the effect was small and remains unclear.

Quality of the evidence
We classified the quality of the evidence as low for improving activities of daily living, mainly because one study had a small sample size.

Authors' conclusions
It remains unclear whether use of rPMS is useful for improving activities of daily living and functional ability in people after stroke. More trials involving larger numbers of participants are needed to determine the effects of rPMS.

Authors' conclusions: 

Available trials provided insufficient evidence to permit any conclusions about routine use of rPMS for people after stroke. Additional trials with large sample sizes are needed to provide robust evidence for rPMS after stroke.

Read the full abstract...
Background: 

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive treatment method that can penetrate to deeper structures with painless stimulation to improve motor function in people with physical impairment due to brain or nerve disorders. rPMS for people after stroke has proved to be a feasible approach to improving activities of daily living and functional ability. However, the effectiveness and safety of this intervention for people after stroke currently remain uncertain. This is an update of the review published in 2017.

Objectives: 

To assess the effects of rPMS in improving activities of daily living and functional ability in people after stroke.

Search strategy: 

On 7 January 2019, we searched the Cochrane Stroke Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); PsycINFO; the Allied and Complementary Medicine Database (AMED); Occupational Therapy Systematic Evaluation of Evidence (OTseeker); the Physiotherapy Evidence Database (PEDro); ICHUSHI Web; and six ongoing trial registries. We screened reference lists, and we contacted experts in the field. We placed no restrictions on the language or date of publication when searching electronic databases.

Selection criteria: 

We included randomised controlled trials (RCTs) conducted to assess the therapeutic effect of rPMS for people after stroke. Comparisons eligible for inclusion were (1) active rPMS only compared with 'sham' rPMS (a very weak form of stimulation or a sound only); (2) active rPMS only compared with no intervention; (3) active rPMS plus rehabilitation compared with sham rPMS plus rehabilitation; and (4) active rPMS plus rehabilitation compared with rehabilitation only.

Data collection and analysis: 

Two review authors independently assessed studies for inclusion. The same review authors assessed methods and risk of bias, undertook data extraction, and used the GRADE approach to assess the quality of evidence. We contacted trial authors to request unpublished information if necessary. We resolved all disagreements through discussion.

Main results: 

We included four trials (three RCTs and one cross-over trial) involving 139 participants. Blinding of participants and physicians was well reported within all trials. We judged the overall risk of bias across trials as low. Only two trials (with 63 and 18 participants, respectively) provided sufficient information to be included in the meta-analysis. We found no clear effect of rPMS on activities of daily living at the end of treatment (mean difference (MD) -3.00, 95% confidence interval (CI) -16.35 to 10.35; P = 0.66; 1 trial; 63 participants; low-quality evidence) and at the end of follow-up (MD -2.00, 95% CI -14.86 to 10.86; P = 0.76; 1 trial; 63 participants; low-quality evidence) when comparing rPMS plus rehabilitation versus sham plus rehabilitation. We found no statistical difference in improvement of upper limb function at the end of treatment (MD 2.00, 95% CI -4.91 to 8.91; P = 0.57; 1 trial; 63 participants; low-quality evidence) and at the end of follow-up (MD 4.00, 95% CI -2.92 to 10.92; P = 0.26; 1 trial; 63 participants; low-quality evidence) when comparing rPMS plus rehabilitation versus sham plus rehabilitation. We observed a significant decrease in spasticity of the elbow at the end of follow-up (MD -0.48, 95% CI -0.93 to -0.03; P = 0.03; 1 trial; 63 participants; low-quality evidence) when comparing rPMS plus rehabilitation versus sham plus rehabilitation. In terms of muscle strength, rPMS treatment was not associated with improved muscle strength of the ankle dorsiflexors at the end of treatment (MD 3.00, 95% CI -2.44 to 8.44; P = 0.28; 1 trial; 18 participants; low-quality evidence) when compared with sham rPMS. No studies provided information on lower limb function or adverse events, including death. Based on the GRADE approach, we judged the quality of evidence related to the primary outcome as low, owing to the small sample size of the studies.

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