In some BCI designs, ‘signal enhancement’ or some of form of ‘pre-processing’ is performed to increase the signal-to-noise ratio of the brain signal(s) prior to extracting the features. To reduce the dimensionality of the problem, it is desired to reduce the number of features and/or the number of EEG channels. ‘Feature selection’ could be performed after or at the feature extraction stage to reduce the number of features and/or EEG channels used. Ideally, the features that are meaningful or useful in the classification stage are identified and chosen, while others are omitted.