The motivation of this presentation is to disseminate the scope and application of Brain-Computer Interfaces (BCI) in the early diagnosis of perceptual, learning and motor disorders. Special emphasis will be given to the diagnosis of olfactory perception, learning and memory disorder, and neuro-motor rehabilitation by BCI means. A brief overview of sensory-motor coordination in the context of cognitive failure detection in car-driving will also be addressed. The scope of type-2 fuzzy sets in handling uncertainty in the decoding of brain signals will be highlighted. Design issues of Vertical Slice-based General Type-2 Fuzzy Classification in the context of Short-Term Memory modeling and diagnosis will be briefly introduced. The presentation would come to an end with a discussion on early detection of the Alzheimer’s and Parkinson diseases by olfactory perceptual-ability measurement using BCI means, and the degree of Short-Term memory degradation in patients with memory disorder.