System for the measurement of semg and angular displacement of the ankle-foot joint complex for muscle co-activation detection in the diagnosis of foot drop pathology




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Lecture notes in electrical engineering, 1876-1119, Vol. 685, 2021, p. 626-638

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Springer Nature

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The measurement of physiological variables for the assessment of pathologies is gaining a lot of strength and attention, even more so when it comes to wearable embedded systems able to offer comfort and precision in measurements. This work aimed to develop an electronic wearable sensing and wireless system that could measure the electrical activity of the Tibialis Anterior and Peroneus Longus muscles through bipolar surface electromyography; the system also identifies the muscle activations of antagonistic muscles, a phenomenon known as muscle co-activations. Sensing the angular displacement of the joint complex of the ankle in the sagittal and frontal planes through an Inertial Measurement Unit sensor system. A system with modular and smart architecture was designed and develop. It is based around five stages in charge of sensing, processing, and transmitting the data registers to a PC or a mobile device. The surface electromyography module is built around a two-channel amplifier sampling at 1 ksps/ch with a resolution of 10 bits; the angular displacement stage is based around an IMU sensor sampling at 1 ksps and 16 bits of resolution. Both data registers are transmitted wirelessly. A prototype with the architecture previously described was developed and tested. A statistical analysis of the data collected compared with commercial instruments was deployed, showing a Mean Square Error of ≤±5.5% for the sEMG and an average error of ≤±1.5∘ in the angular displacement measurements. The measurements made and the data verification protocol show that the equipment fully complies with all the technical and functional requirements of the project. Additionally, a record of muscle co-activation is presented, which can provide additional information, not only of the physiological state of the muscles but also the status of the pathology. By reducing the size of the device, improving the experimental setup and making small improvements to the hardware, the developed system opens a new panorama in the assessment and characterization of pathological conditions in real patients and therefore in the rehabilitation field.

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Foot drop, Rehabilitation, Modular systems, sEMG amplifier, Smart sensing system