Evoked EMG-based torque prediction under muscle fatigue in implanted neural stimulation - LIRMM - Laboratoire d’Informatique, de Robotique et de Microélectronique de Montpellier
Journal Articles Journal of Neural Engineering Year : 2011

Evoked EMG-based torque prediction under muscle fatigue in implanted neural stimulation

Abstract

In patients with complete spinal cord injury, fatigue occurs rapidly and there is no proprioceptive feedback regarding the current muscle condition. Therefore, it is essential to monitor the muscle state and assess the expected muscle response to improve the current FES system toward adaptive force/torque control in the presence of muscle fatigue. Our team implanted neural and epimysial electrodes in a complete paraplegic patient in 1999. We carried out a case study, in the specific case of implanted stimulation, in order to verify the corresponding torque prediction based on stimulus evoked EMG (eEMG) when muscle fatigue is occurring during electrical stimulation. Indeed, in implanted stimulation, the relationship between stimulation parameters and output torques is more stable than external stimulation in which the electrode location strongly affects the quality of the recruitment. Thus, the assumption that changes in the stimulation-torque relationship would be mainly due to muscle fatigue can be made reasonably. The eEMG was proved to be correlated to the generated torque during the continuous stimulation while the frequency of eEMG also decreased during fatigue. The median frequency showed a similar variation trend to the mean absolute value of eEMG. Torque prediction during fatigue-inducing tests was performed based on eEMG in model cross-validation where the model was identified using recruitment test data. The torque prediction, apart from the potentiation period, showed acceptable tracking performances that would enable us to perform adaptive closed-loop control through implanted neural stimulation in the future.

Dates and versions

lirmm-00630237 , version 1 (07-10-2011)

Identifiers

Cite

Mitsuhiro Hayashibe, Qin Zhang, David Guiraud, Charles Fattal. Evoked EMG-based torque prediction under muscle fatigue in implanted neural stimulation. Journal of Neural Engineering, 2011, 8 (6), pp.7. ⟨10.1088/1741-2560/8/6/064001⟩. ⟨lirmm-00630237⟩
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