Comparison of the effects of kilohertz- and low-frequency electric stimulations: A systematic review with meta-analysis

Enhanced nerve function recovery in radial nerve palsy patients with humerus shaft fracture: a randomized study of low-frequency pulse electrical stimulation combined with exercise therapy

Objective

To evaluate the effect of low-frequency pulse electrical stimulation plus exercise therapy on nerve function recovery in patients with radial nerve palsy after humerus shaft fracture.

Methods

A total of 110 patients with humerus shaft fracture and radial nerve injury admitted to our hospital from January 2017 to December 2021 were recruited. They were randomized to receive either conventional exercise therapy (control group) or conventional exercise therapy plus low-frequency pulse electrical stimulation (study group) according to the random number table method, with 55 cases in each. Clinical efficacy, muscle strength recovery, nerve conduction velocity (MCV), amplitude, wrist joint, and elbow joint activities of patients were analyzed and compared.

Results

Patients with low frequency stimulation (LFS) showed significantly higher treatment effectiveness (89.09%) than those with exercise therapy only (69.09%). The incorporation of LFS with exercise therapy provided more enhancement in the muscle strength of wrist extensor and total finger extensor in patients when compared with a mere exercise intervention, suggesting better muscle function recovery of patients produced by LFS. Moreover, a significant increase in MCV and its amplitude was observed in all included patients, among which those receiving LFS showed a greater escalation of MCV and its amplitude. Following a treatment duration of 6 months, more patients in the LFS cohort were reported to achieve a wrist extension and elbow extension with an angle over 45° than the controls. There was no notable variance in adverse responses noted between the two patient groups.

Conclusion

In patients afflicted with humerus shaft fracture and radial nerve injury, the amalgamation of exercise therapy with low-frequency pulse electrical stimulation can significantly improve clinical efficacy, promote nerve function, and muscle strength recovery, and features a high safety profile.

Relevance to clinical practice

The combination of exercise therapy and low-frequency pulsed electrical stimulation can notably improve the promotion of neurologic function and muscle strength recovery in patients with humerus shaft fractures and radial nerve injuries with a high degree of safety.Clinical trial registration:https://www.researchregistry.com, identifier researchregistry9461.

KiloHertz currents on aspects of muscle function: A scoping review

BACKGROUND

Neuromuscular electrical stimulation (NMES) with kiloHertz currents (kHz) is a resource used in rehabilitation for producing muscle contractions with functional objectives, resulting from the optimization of the performance of aspects of muscle function (AOMF). However, parameters such as inadequate frequency, phase duration, amplitude, and therapy time may limit the effectiveness of NMES by the absence of adequate stimuli to generate positive adaptations in the AOMF. This study aimed to present an overview of the effectiveness and dosimetry of NMES by kHz on AOMF, such as torque and hypertrophy, in healthy people.

METHODS

The study was outlined as a scoping review. From the search, 3892 studies were found of which were incorporated into Rayyan software for exclusion of duplicates and further selection by titles and abstracts, which resulted in 33 articles for this review.

RESULTS

According to the included studies, kHz can increase torque and generate hypertrophy. Only the studies with Russian current showed hypertrophy gains. Dosimetry was not always detailed in the studies, which hinders stipulating optimal parameters for kHz.

CONCLUSION

From this review, it is concluded that NMSC by kHz is a valid resource to optimize AOMF, although the dosimetric parameters are still inconsistent.

The response of the neuronal activity in the somatosensory cortex after high-intensity intermediate-frequency magnetic field exposure to the spinal cord in rats under anesthesia and waking states

Novel technologies using the intermediate-frequency magnetic field (IF-MF) in living environments are becoming popular with the advance in electricity utilization. However, the biological effects induced by the high-intensity and burst-type IF-MF exposure used in the wireless power transfer technologies for electric vehicles or medical devices, such as the magnetic stimulation techniques, are not well understood. Here, we developed an experimental platform using rats, that combined an 18 kHz, high-intensity (Max. 88 mT), Gaussian-shaped burst IF-MF exposure system with an in vivo extracellular recording system. In this paper, we aimed to report the qualitative differences in stimulus responses in the regions of the somatosensory cortex and peripheral nerve fibers that were induced by the IF-MF exposure to the rat spinal cord. We also report the modulation of the stimulus responses in the somatosensory cortex under anesthesia or waking states. Using this experimental platform, we succeeded in the detection of the motor evoked potentials or the neuronal activity in the somatosensory cortex that was induced by the IF-MF exposure to the spinal cord in rats. Compared to the state of anesthesia, the neuronal activities in the somatosensory cortex was enhanced during the waking state. On the other hand, these neuronal responses could not be confirmed by the IF-MF exposure-related coil sound only. Our experimental results indicated the basic knowledge of the biological responses and excitation mechanisms of the spinal cord stimulation by the IF-MF exposure.