THE EFFECT OF FOOT PLATE NEUROMUSCULAR ELECTRICAL STIMULATION ON LEG BLOOD FLOW

B. Kumaran¹, T. Watson¹

Background: Electrical stimulation has been used to elicit muscle contraction for centuries. Neuromuscular Electrical Stimulation (NMES) utilises surface electrodes to cause muscle contraction either by activating the muscle itself (direct), or the nerve supplying the muscle (indirect). Electrical Stimulation is widely used in physiotherapy with applications such as strength training, rehabilitation and pain management. In addition, NMES devices have been shown to be effective in improving blood flow in a variety of clinical conditions including those with peripheral arterial and venous diseases. A wide variety of these devices are available in the market claiming such benefits.

Purpose: This study investigated whether the foot plate NMES improved blood flow in the legs of asymptomatic people as well as of those with symptoms of potential peripheral vascular disease (PVD).

Methods: A two-group (experimental and sham) randomised controlled trial was conducted with concealed allocation and participant blinding. Additionally, a separate cohort of 13 asymptomatic adults were randomly recruited and studied as a control group using identical methods as the experimental group. Twenty-six community-dwelling adults aged over 65 years who were suffering from symptoms of potential PVD in their leg(s) such as heaviness, tiredness, swelling or cramps were randomised into experimental and sham groups. Participants in all three groups received the intervention (one session of foot stimulation using patterned pulsed biphasic rectangular pulses) delivered by Revitive Medic devices (Actegy Ltd, UK). Blood flow was recorded from the posterior tibial vessels at the ankle joint using Doppler ultrasound (Esaote MyLab70 XVG, Esaote, Italy) before (baseline) and during (intra) stimulation. Doppler images were computationally analysed using MATLAB (MathWorks, Massachusetts) algorithms to process colour image data into numerical data. The numerical data were compared using mixed model factorial ANOVA. The statistical significance was set at p ≤ 0.05 (0.8 P, 95% CI).

Results: A significant overall increase in both the ‘volume’ [F(1,34)=27.87; p<0.001] and ‘intensity’ [F(1,34)=23.03; p<0.001] of blood flow was demonstrated in the ANOVA. Both the flow volume (134 % increase from baseline; p=0.003) and intensity (176 % increase from baseline; p=0.010) were significantly greater in the experimental group during treatment compared to the sham group, while the sham group did not demonstrate any significant change in blood flow. Both the flow volume (97 % increase from baseline; p=0.003) and intensity (116 % increase from baseline; p=0.011) increased significantly in the asymptomatic control group; however, the volume increase was significantly lower than that in the experimental group (p=0.027).

Conclusion(s): NMES can significantly increase local blood flow in the legs of older adults with potential PVD as well as of asymptomatic adults.

Implications: The study informs clinical practice by highlighting the potential benefits of NMES in improving blood flow in the legs of people with potential PVD. The study also provides baseline data for future research.

Funding, acknowledgements: The study was funded by Actegy Ltd., Bracknell, UK.

Keywords: Electrical stimulation, Blood flow, Circulation

Topic: Electrophysical & isothermal agents

Did this work require ethics approval? Yes

Institution: University of Hertfordshire, Hatfield, Hertfordshire, UK.

Committee: hsetecda, UH

Ethics number: aHSK/SF/UH/03458(3); aHSK/SF/UH/03232(1)