“…Our investigation revealed that FFT, PCA, WT, and AR were the most widely used and effective methods for feature extraction among the reviewed articles in this domain; these methods were reported as superior 31%, 19%, 15%, and 15% of the time, respectively. For example, FFT has been implemented by researchers in several published studies [ 81 , 196 , 211 , 239 , 240 , 241 , 242 ] to extract features on the basis of the frequency of the EEG signals; however, another study has confirmed AR as one of the most reliable methods [ 243 ]. We also identified several essential feature extraction techniques that were less frequently applied in MWL tasks, including entropy and HHT, which elicited features of both nonlinear and non-stationary signals.…”