University of Twente Student Theses


Benefits of high-density electromyography for spinal moment estimation via musculoskeletal modeling

Ghasem Zadeh Khoei, Ali (2022) Benefits of high-density electromyography for spinal moment estimation via musculoskeletal modeling.

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Abstract:Bipolar electrodes that record the electrical signals of the muscles have been the most common approach of surface muscle activity measurement in the past. In recent years, high-density electromyography (HDEMG) has shown to have its advantages in recording EMG signals of the muscles with considerably large areas. Previous EMG-driven models have been used to analyze lumbosacral joint moments; however, none of them was driven by HD-EMG, and therefore, it is unclear to what extent HD-EMG technology can benefit the analysis of joint moments. In the current study, we assessed effect of bipolar EMG (BP-EMG), HD-EMG and a new method of processing HD-EMG based on watershed algorithm for each muscle in driving a large-scale HD-EMG-driven model of trunk muscles to estimate the L5-S1 joint moments during different symmetric lifting tasks. We also compared the differences at EMG levels of BP-EMG and HD-EMG. Moreover, we provided a highly accurate map of thoracolumbar muscle activity during these movements using 512 HD-EMG channels (256 electrodes on each side of the spine). During our experiment, subject’s kinematics, ground reaction forces, HD-EMGs of thoracolumbar muscles and BP-EMGs of abdominal muscles were used in estimation of L5-S1 joint moment through inverse dynamics and HD-EMG driven modelling. One healthy male subject performed symmetric box lifting tasks with 5 and 15 kg weight using squat and stoop techniques. We found 0,88 average correlation coefficient (R2) between the reference moments from ID and estimated joint moments using HD-EMG recordings and the root mean squared errors (RMSE) ranging from 19.23 to 25.07 Nm. This study represents the first step for developing a framework that allows estimating thoracolumbar joint moments which has the potential to be used together with emerging embedded textile electrodes, eliminating the need for palpation of spine to locate the precise sites of bipolar electrode placements.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Programme:Biomedical Engineering MSc (66226)
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