Example of how it may be overfit: Waterfalls are loud, audio regions of our brain may activate in response to waterfalls. Classifier reads that to predict waterfalls.
Great example! Similar thing probably holds for moving main limbs. A good EEG should be able to pick up when you think about moving your hand or leg. I doubt a good EEG could distinguish more than a few dozen patterns. Most experiments have trouble with even a handful of patterns. Still could be useful, but just very limited.
