Introduction
Weakened core muscles in hemiplegic stroke patients lead to a decrease in trunk stability and poor sitting balance, which limit the rehabilitation outcomes both in terms of hand function and locomotive ability. For this reason, stimulating the paravertebral muscle using had been tried using neuromuscular electrical stimulation device.
Recently, instead of electrical stimulation, magnetic stimulation is used to improve motor function, which can induce painless deep muscle contraction without direct skin contact. In this pilot study, we investigated whether repetitive peripheral magnetic stimulation (rPMS) can improve the core strength and balance of stroke patients.
Subjects and Methods
This retrospective review was based on chart review of patients hospitalized between January 2019 and May 2019. Inclusion criteria were as follows: 1) subacute stage within 6 months after the onset of the stroke, and 2) who were treated with rPMS in lower paravertebral muscles for at least two weeks. Among these patients, we studied patients who had both initial and follow up back muscle strength measure using pressure biofeedback unit (PBU), as explained below. A total of five patients were included. Medical history including low back pain severity by numeric rating scale (NRS), gender, age, cause of the stroke, duration from the onset, previous history associated with lumbar spine (Table 1).
In order to evaluate low back muscle strength, in a prone position on a hard surface while placing their belly on the PBU (Stabilizer, Chattanooga Group Inc., Hixson, USA), patients contracted their back muscle under examiner’s verbal command. To minimize effect of intrathoracic pressure, full exhalation before back extension was ordered. At end-expiratory cuff pressure was set to 70mmHg, maximal increase of cuff pressure was recorded (△P = maximum cuff pressure – 70 (mmHg)). During each trial, patient was told the cuff pressure, so encouraged to maximize the result by real-time bio-feedback manner.
In lumbar paravertebral muscle rPMS protocol, rPMS coil center was focused at the L3 spinous process. 20-min rPMS session was conducted on a daily basis using electromagnetic stimulation device (Salus Talent Pro, Remed Co., Korea) in biphasic pulse mode of 3-15Hz using pulse duration of 250 μsec. Pain-free maximum intensity stimulation was used.
Results
In all five patients, the mean pressure difference was increased from 24.2 to 25.0 mmHg (p =0.043, by Wilcoxon-signed rank test) and the mean NRS score for low back pain was decreased from 3.8 to 2.2 (p=0.039, Table 2). In addition, no side effect was observed associated with the treatment.
Conclusion
This pilots study suggests that rPMS could be used for core muscle strengthening and pain relief safely. Further research is needed for confirm this finding. |
