“…These set of techniques either compute several statistical measurements on input data (e.g., average, variance, skewness) or extract more complex gait characteristics, which may include stride length, joint angles, and other related features. In the context of machine learning, handcrafted features refer to manually designed features that are extracted from raw data and used as input to a classifier [ 8 , 28 , 29 , 30 ]. For instance, the technique proposed in [ 31 ] extracted several statistical quantities on input data (e.g., mean, median, mode, standard deviation, skewness, and kurtosis) to show the gait fluctuation in a patient with Parkinson’s.…”