Periodic Spatial Filter for Single Trial Classification of Event Related Brain Activity
Foad Ghaderi, Elsa Andrea Kirchner
In Proceedings of the 10th International Conference on Biomedical Engineering, (BioMed-2013), 13.2.-15.2.2013, Innsbruck, o.A., Feb/2013.
Because of the small amplitudes of event related potentials (ERPs), they are usually hidden in electroencephalogram (EEG) recordings. This is particularly a problem when analyzing single-trial data. A spatial filtering method for P300 detection in oddball paradigm is proposed in this paper which is based on the assumption that brain responses to the same stimulus look the same (or at least do not change significantly over trials). Therefore, the sequence generated by concatenating all the responses to the same type of stimulus has a hidden periodicity. Enhancing the periodic structure of this sequence, a transformation is found to project the data into a lower dimensional subspace. Experiments show that even with a small subspace of the projected data, the classification performance in single-trial P300 detection is still high.