[Article] Effect of Spatial Filtering on Crosstalk Reduction in Surface EMG Recordings

Porto, the institutional repository of the Politecnico di Torino, is provided by the University Library and the IT-Services. The aim is to enable open access to all the world. Please share with us how this access benefits you. Your story matters. ABSTRACT Increasing the selectivity of the detection system in surface electromyography (EMG) is beneficial in the collection of information of a specific portion of the investigated muscle and to reduce the contribution of undesired components, such as non-propagating components (due to generation or end-of-fibre effects) or crosstalk from nearby muscles. A comparison of the ability of different spatial filters to reduce the amount of crosstalk in surface EMG measurements was conducted in this paper using simulated signals. It focused on the influence of different properties of the muscle anatomy (changing subcutaneous layer thickness, skin conductivity, fibre length) and detection system (single, double and normal double differential, with two interelectrode distances-IED) on the amount of crosstalk present in the measurements. A cylindrical multilayer (skin, subcutaneous tissue, muscle, bone) analytical model was used to simulate single fibre action potentials (SFAPs). Fibres were grouped together in motor units (MU) and motor unit action potentials (MUAP) were obtained by adding the SFAPs of the corresponding fibres. Interference surface electromyogram (EMG) signals were obtained, modelling the recruitment of MUs and rate coding. The average rectified value (ARV) and mean frequency content (MNF) of the EMG signals were studied and used as a basis for determining the selectivity of