“…The non-linearity, the ceiling and floor effects and the inter-observation variability of clinical rating scales makes them highly subjective and with a low level of reliability [ 8 ]. For this reason, several research centers and companies have been recently working in body motion tracking with wearable devices of patients suffering from Parkinson’s Disease (PD) [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], Epilepsy [ 11 , 15 , 16 ], Stroke [ 11 , 17 ], Multiple Sclerosis [ 15 , 18 ], among others. However, these body motion tracking systems oriented-development for a specific disease or symptom(s) reveals limitation in their user, such as the ones discussed in the two next sub-sections.…”