Electrical Stimulation Parameters Influence in Muscle Activity Inhibition: Experimental Study

Ana Rita Antunes de Campos

Key information

Authors:

Ana Rita Antunes de Campos (Ana Rita Antunes de Campos)

Supervisors:

João Pedro Grilo Gouveia; Rui Miguel de Moura Antunes e Valejo Coelho (Rui Miguel de Moura Antunes e Valejo Coelho)

Published in

November 27, 2024

Abstract

Stroke survivors often face long-term disabilities, particularly gait impairments, making gait rehabilitation crucial. Functional electrical stimulation-based orthoses are effective for movement disorders, but their efficacy may be limited in cases of muscle overactivity, such as spastic paresis, common among stroke and neurological condition survivors. This study examines the impact of electrical stimulation (ES) parameters on muscle activity inhibition, focusing on reciprocal inhibition between the tibialis anterior (TA), receiving ES via the common peroneal nerve, and the soleus (SOL), where inhibition will be assessed. The study involved eight healthy participants aged 23 to 56 years. ES parameters included pulse widths of 0.01ms, 0.2ms, and 0.3ms, with amplitudes set at 50% of the sensory threshold (ST), the ST, twice the ST, the motor threshold, and the maximum comfortable value. Surface electromyographic (sEMG) electrodes monitored TA and SOL muscle activity. Following a familiarisation phase with the ES technique, the impact of ES on SOL contraction was recorded through continuous sEMG monitoring, maintaining contraction at 20% of maximal voluntary isometric contraction. The study concludes that a personalised approach is crucial for addressing individual differences, particularly regarding age and sex. While the reciprocal inhibition reflex can be modulated, its sole reliance is challenging due to other influencing mechanisms. Therefore, being essential to prevent these mechanisms from disrupting intended actions. The study’s findings indicate that higher intensities of ES are more effective in eliciting heteronymous inhibition, while lower intensities show negligible effects, warranting further investigation in spastic paresis patients.