EMG activity of finger flexor muscles and grip force following low-dose transcutaneous electrical nerve stimulation in healthy adult subjects

Abstract

Somatosensory stimulation modulates cortical and corticospinal excitability and consequently affects motor output. Therefore, low-amplitude transcutaneous electrical nerve stimulation (TENS) has the potential to elicit favorable motor responses. The purpose of the two presented pilot studies was to shed light on TENS parameters that are relevant for the enhancement of two desirable motor outcomes, namely, electromyographic (EMG) activity and contraction strength of the finger flexors and wrist muscles. In 5 and 10 healthy young adults (in Study I and Study II, respectively) TENS was delivered to the volar aspect of the forearm. We manipulated TENS frequency (150 Hz vs. 5 Hz), length of application (10, 20, and 60 min), and side of application (unilateral, right forearm vs. bilateral forearms). EMG amplitude and grip force were measured before (Pre), immediately after (Post), and following 15 min of no stimulation (Study I only). The results indicated that low-frequency bursts of TENS applied to the skin overlying the finger flexor muscles enhance the EMG activity of the finger flexors and grip force. The increase in EMG activity of the flexor muscles was observed after 20 min of stimulation, while grip force was increased only after 1 h. The effects of uni- and bilateral TENS were comparable. These observations allude to a modulatory effect of TENS on the tested motor responses; however, unequivocal conclusions of the findings are hampered by individual differences that affect motor outcomes, such as in level of attention.

Ulnar Nerve Conduction Block Using Surface Kilohertz Frequency Alternating Current: A Feasibility Study

“…Klaiput and Kitisomprayoonkul delivered low frequency stimulation (burst of alternating current at 1 Hz consisting of 5 pulses of 1‐millisecond duration, at 10 Hz, for 500 milliseconds with 50% duty cycle) over the median and ulnar nerves at the wrist in chronic and subacute stroke patients and reported increased pinch strength. Kafri et al reported that the effect of 150 Hz frequency TENS, applied to the skin overlying the finger flexor muscles, on EMG output was not significant, whereas low frequency bursts of TENS enhanced EMG activity and grip force. No previous study reported reduced of myoelectrical activity or hand muscle force post surface stimulation.…”

A multimodal assessment of balance in elderly and young adults

“…Postural sway, or horizontal movement from the center of gravity, is another component of balance impairment, as it reflects the postural control system's ability to stabilize the moving center of mass. A large body of work has demonstrated age effects on sway, including age-related increases in sway amplitude [ 12 - 16 ]. While there are central factors that contribute to age-related changes in sway, peripheral effects such as sarcopenia, coupled with larger proportions of Type I and the loss of the more powerful Type II muscle fibers in older adults, is also important in the development of age-related sway patterns [ 17 ].…”

Headache due to spinothalamic tract injury in patients with mild traumatic brain injury

“…Diffusion tensor tractography (DTT), derived from diffusion tensor imaging (DTI), enables three-dimensional reconstruction, and evaluation of the spinothalamic tract (STT). [6] Several studies using DTT have demonstrated that injury of the STT is a pathogenetic mechanism of central pain following TBI. [7–10] However, no study of headache due to injury of the STT has been reported.…”