“…In the first one, the signal features extraction, producing the most valuable data that can be further processed in the second stage. This stage can be carried out by methods such as common spatial pattern (CSP), extreme energy ratio (ERR), autoregressive (AR) parameters, wavelet packet transform (WPT) (Sun and Zhou, 2014)(Lipiński, 2011), principal component analysis (PCA) (Agarwal et al , 2015)(Staniucha and Wojciechowski, 2016) or hidden Markov model (HMM) (Nasehi and Pourghassem, 2013). Methods of this stage are subject to further improvement but, in our work, we do not focus on this area; thus, we interpret raw signal, appropriately divided into time windows, without additional preprocessing.…”