The effects of electromyography-triggered electrical stimulation on shoulder subluxation, muscle activation, pain, and function in persons with stroke: A pilot study

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

BACKGROUND

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.

OBJECTIVE

We aimed to map the existing evidence and identify the parameters for ES of the hemiplegic shoulder for motor function in stroke patients.

METHODS

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.

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.

CONCLUSION

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.

Effects of position-triggered electrical stimulation on post-stroke hemiparetic shoulder subluxation

BACKGROUND

Shoulder subluxation is a frequent complication after stroke causing joint instability, shoulder pain, decreased activities of daily living, and impedance to rehabilitation progress. Electrical stimulation (ES) is considered an effective modality to reduce shoulder subluxation in acute stroke. However, few studies have investigated the effect of position-triggered ES, which induces active muscle contraction though accurate motion detection.

AIM

To investigate whether position-triggered ES was more effective in reducing acute hemiplegic shoulder subluxation after stroke than passive ES.

DESIGN

Single-blind, randomized controlled trial.

SETTING

University hospital rehabilitation center.

POPULATION

Fifty post-stroke subacute hemiparetic patients with shoulder subluxation.

METHODS

Patients were randomly assigned into two groups. The position-triggered ES group received 30-minute ES sessions, 5 days per week for 3 weeks with specially modified Novastim® CU-FS1 for motion triggering. The passive ES group received the same protocol without motion triggering. The vertical distance (VD) and the joint distance (JD), relative VD and JD (rVD, rJD), upper extremity component of Fugl-Meyer Motor Assessment (FMAupper), Motricity Index (MI), Manual Function Test (MFT), and peak torque of affected shoulder abductor (PT) were assessed at baseline (T0), end of electrical stimulation session (T1), and 3 weeks (T2) after treatment.

RESULTS

Repeated-measures analysis of variance revealed significant interaction between TIME and INTERVENTION on JD and rJD, indicating that shoulder subluxation was significantly more reduced in position-triggered ES than in passive ES (p<0.05). However, FMAupper, MI, MFT, and PT did not show this significance. The change of (Δ)JD , ΔrVD, and ΔrJD in the motion-triggered ES group improved significantly more at T1 than in the passive ES group (p<0.05). This significant improvement was not seen at T2.

CONCLUSIONS

Position-triggered ES may be more effective than passive ES in improving post-stroke shoulder subluxation; however, this effect was not maintained after the withdrawal of stimulation.

CLINICAL REHABILITATION IMPACT

Position-triggered ES may be useful to reducing post-stroke shoulder subluxation.

Shoulder-Pacemaker Treatment Concept for Posterior Positional Functional Shoulder Instability: A Prospective Clinical Trial

BACKGROUND

Pathological muscle activation patterns of the external rotators and periscapular muscles can result in posterior positional functional shoulder instability (PP-FSI). In several patients, physical therapy and surgical treatment are not successful.

PURPOSE

The shoulder-pacemaker treatment concept was evaluated prospectively in patients with PP-FSI and previously failed conventional therapy attempt.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A negative selection of 24 consecutive cases of noncontrollable PP-FSI in 16 patients with previously failed conventional therapy were included in this prospective study. The shoulder-pacemaker treatment consisted of an electrical muscle stimulation-based therapy protocol with 9 to 18 one-hour treatment sessions. Two patients were excluded because of nonadherence to the training schedule, leaving a final study cohort of 21 cases in 14 patients. Follow-up included assessment of clinical function, impairment during daily activities and sports, satisfaction, Western Ontario Shoulder Instability Index (WOSI), Rowe score, and Subjective Shoulder Value at 0 weeks, 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months after intervention.

RESULTS

WOSI, Subjective Shoulder Value, and Rowe score showed a highly significant improvement at all time points of follow-up (P < .001). Young age (P = .005), low weight (P = .019), shoulder activity level (P = .003), unilateral affliction (P = .046), and higher baseline WOSI score (P = .04) were associated with a better treatment effect. Cases with increased glenoid retroversion, posterior scapulohumeral decentering, and dysplastic bony glenoid shape showed a trend toward shorter treatment effect duration. No complications during the intervention or follow-up period were observed.

CONCLUSION

The shoulder-pacemaker therapy concept is an effective treatment with rapid improvement and sustained outcome over the course of 2 years in patients with noncontrollable PP-FSI with previously failed conventional treatment. Young and more athletic patients with lower weight and unilateral pathology respond best to the treatment.