Design of an Advanced Portable System for High Density Surface EMG Recording with Wireless Control of Signal Quality

High density surface EMG (HD-sEMG) is a technique for evaluating and recording the electrical activity produced by muscles by placing a 2-dimensional (2D) grid (comprising many closely spaced electrodes with 3~10 mm center-to-center), instead of just a few electrodes, on the muscles. The advantage of HD-sEMG over intramuscular (needle) EMG, apart from the non-invasiveness and the relative ease of obtaining spatial distributions of electrical muscle activity, is its high reproducibility in follow up studies. Despite the importance of HD-sEMG in many fields (such as a valuable aid in discovering and diagnosing abnormalities not only in the muscles but also in the motor system as a whole), the development of HD-sEMG detecting and recording system is considered to be quite behind technology nowadays. It is necessary to develop a new generation HD-sEMG detecting and recording device in order to meet the requirements in more channels, higher resolution and portable, which is why the design of an advanced portable system for high density surface EMG recording with wireless control of signal quality (HD-sEMG RSWC) is proposed. In this thesis, the design of a portable system for high density surface EMG recording with wireless control of signal quality (HD-sEMG RSWC) is going to be proposed. A prototype (including hardware, firmware and control panel) is going to be implemented and its performances are going to be tested. Physiological applications using this prototype to acquire EMG signals from biceps brachii muscle and dorsal forearm muscles during contractions are going to be studied. The HD-sEMG prototype satisfied the design criteria defined in the thesis and has advantage of 64-channel cable-free signal quality control (The existing commercial available product is only 32-channel wirelessly). In first application (EMG signals acquired from biceps brachii muscle), motor unit action potentials (MUAPs) produced by motor units of biceps brachii were detected . Information concerning the innervation zone (IZ) and conduction velocity of the MUAP can be obtained from all columns showing the MUAP. Location of the IZ can be estimated, by visual inspection. Conduction velocity (CNV) can be estimated as the ratio between the distance D travelled by the MUAP in the time interval T. The second physiological application (EMG signals acquired from dorsal forearm muscles ) shows that the spatial properties of the monopolar EMG amplitude distribution (RMS) over the proximal portion of dorsal forearm can be used to discriminate different contractions. Active areas by different contractions of different subjects can be the same, such as subject3 (wrist extension) and subject1 (middle finger extension).