Neuromuscular Electrical Stimulation with Kilohertz Frequency Alternating Current to Enhance Sensorimotor Cortical Excitability

Strategies for precision vagus neuromodulation

The vagus nerve is involved in the autonomic regulation of physiological homeostasis, through vast innervation of cervical, thoracic and abdominal visceral organs. Stimulation of the vagus with bioelectronic devices represents a therapeutic opportunity for several disorders implicating the autonomic nervous system and affecting different organs. During clinical translation, vagus stimulation therapies may benefit from a precision medicine approach, in which stimulation accommodates individual variability due to nerve anatomy, nerve-electrode interface or disease state and aims at eliciting therapeutic effects in targeted organs, while minimally affecting non-targeted organs. In this review, we discuss the anatomical and physiological basis for precision neuromodulation of the vagus at the level of nerve fibers, fascicles, branches and innervated organs. We then discuss different strategies for precision vagus neuromodulation, including fascicle- or fiber-selective cervical vagus nerve stimulation, stimulation of vagal branches near the end-organs, and ultrasound stimulation of vagus terminals at the end-organs themselves. Finally, we summarize targets for vagus neuromodulation in neurological, cardiovascular and gastrointestinal disorders and suggest potential precision neuromodulation strategies that could form the basis for effective and safe therapies.

Comparison between Russian and Aussie currents in the grip strength and thickness muscles of the non-dominant hand: A double-blind, prospective, randomized-controlled study

Objectives

This study aims to compare the Russian and Aussie currents in the force gain and hypertrophy of the forearm muscles responsible for the grip.

Patients and methods

This double-blind, prospective, randomized-controlled study included a total of 30 healthy women (mean age: 20.2±1.7 years; range, 18 to 25 years) between May 2018 and July 2018. The participants were randomly divided into three groups: control group (CG, n=10), Aussie current group (ACG, n=10), and Russian current group (RCG, n=10). All three groups underwent a force test with a gripping dynamometer and the collection of images of the superficial and deep flexor muscles of the fingers with diagnostic ultrasound. The CG received a fictious current stimulus, while the other two groups received the designated stimuli from their currents. Further evaluations were performed after 24 h of the 12th application of the current.

Results

For grip, there were no significant differences in the moment of evaluation and interaction, while the effect size yielded certain points to advantages of force gain for the group using the RCG. The thickness of the superficial muscles showed a significant difference for the first evaluation between CG and RCG (p=0.014) and between RCG and ACG (p=0.010), indicating a larger effect size for RCG.

Conclusion

Our study results show that the Russian current is proven to be the mode which yields the most optimal results.