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1 – 2 of 2Michela Goffredo, Maurizio Schmid, Silvia Conforto, Filiberto Bilotti, Claudio Palma, Lucio Vegni and Tommaso D’Alessio
A novel model of the upper arm under transcutaneous electrical stimulation with multi-pad electrodes is presented and experimentally validated. The model aims at simulating and…
Abstract
Purpose
A novel model of the upper arm under transcutaneous electrical stimulation with multi-pad electrodes is presented and experimentally validated. The model aims at simulating and analysing the effects of surface electrical stimulation on biceps brachii. The paper aims to discuss these issues.
Design/methodology/approach
Both the passive properties of tissues surrounding nerve bundles and the active characteristics of the nervous system are included. The output of the proposed model is nerve recruitment and muscle contraction.
Findings
Simulations and experimental tests on six healthy young adults have been conducted and results show that the proposed model gives information on electrically elicited muscle contraction in accordance with in-vivo tests and literature on motor unit recruitment order. Tests with different electrodes configurations show that the spatial distribution of active electrodes is a critical factor in electrically elicited muscle contractions, and that multi-pad electrodes can optimise the stimulation effectiveness and patient comfort with sequences of biphasic pulses of 350 μs at 30 pulses/s and threshold values of 2 mA.
Originality/value
Results encourage the use of the proposed model of the upper arm as a valid and viable solution for predicting the behaviour of the neuromuscular system when surface electrical stimulation is applied, thus optimising the design of neuroprosthetics.
Details
Keywords
Mary Grace Cassar, Cristiana Sebu, Michael Pidcock, Shubham Chandak and Brian Andrews
The purpose of this paper is to investigate the design of skin surface electrodes for functional electrical stimulation using an isotropic single layered model of the skin and…
Abstract
Purpose
The purpose of this paper is to investigate the design of skin surface electrodes for functional electrical stimulation using an isotropic single layered model of the skin and underlying tissue. A concentric ring electrode geometry was analysed and compared with a conventional configuration, specifically to localise and maximise the activation at depth and minimise the peak current density at the skin surface.
Design/methodology/approach
The mathematical formulation determines the spatial electric potential distribution in the tissue, using the solution to the Laplace equation in the lower half space subject to boundary conditions given by the complete electrode model and appropriate asymptotic decay. Hence, it is shown that the electric potential satisfies a weakly singular Fredholm integral equation of the second kind which is then solved numerically in MATLAB for a novel concentric ring electrode configuration and the conventional two disk side-by-side electrode configuration.
Findings
In both models, the electrode geometry can be optimised to obtain a higher activation and lower maximum current density. The concentric ring electrode configuration, however, provides improved performance over the traditional two disk side-by-side electrode configuration.
Research limitations/implications
In this study, only a single layer of medium was investigated. A comparison with multilayer tissue models and in vivo validation of numerical simulations are required.
Originality/value
The developed mathematical approaches and simulations revealed the parameters that influence nerve activation and facilitated the theoretical comparison of the two electrode configurations. The concentric ring configuration potentially may have significant clinical advantages.
Details