Parameter mapping of hemiplegic shoulder electrical stimulation for motor function: A scoping review

Electrical stimulation (ES) of the shoulder is effective in treating subluxation and shoulder pain. However, few studies have reported on ES of the hemiplegic shoulder with motor function as an outcome; thus, the method remains unclear.We aimed to map the existing evidence and identify the parameters for ES of the hemiplegic shoulder for motor function in stroke patients.A literature search was performed through PubMed and Scopus to retrieve original articles from 1975 to March 2023 using the terms "stroke", "shoulder", and "electricity". We selected studies in which ES was performed on hemiplegic shoulders after stroke, parameters were described, and upper extremity motor functional assessment was included as an outcome. The extracted data included study design, phase, sample size, electrode position, parameters, intervention period, evaluation frequency, outcomes, and results.Of the 449 titles identified, 25 fulfilled the inclusion and exclusion criteria. Nineteen were randomized controlled trials. The most common electrode positions and parameters (frequency and pulse width) were over the posterior deltoid and the supraspinatus (upper trapezius) muscles, 30 Hz, and 250μs, respectively. The intervention period was 30-60 minutes per day, 5-7 days per week, for 4-5 weeks in over half of the studies.Stimulation positions and parameters for electrical stimulation of the hemiplegic shoulder are inconsistent. Whether ES represents a significant treatment option remains unclear. Establishing universal ES methods is necessary to improve the motor function of hemiplegic shoulders.