Event detection in single trial EEG during attention and memory related task

P300 is an endogenous event related potential (ERP) elicited by a rare or significant visual stimulus and is widely preferred in brain computer interface (BCI) to assess the cognition level of the subject. Many researchers contribute to P300 estimation as this signal is of very low strength in background electroencephalogram (EEG) activity. This paper proposes a novel signal processing algorithm to detect the P300 event in a single trial EEG acquired from midline electrode sites in oddball paradigm to evaluate attention and memory related tasks of subjects. The algorithm incorporates wavelet combined adaptive noise canceller followed by ensemble and moving averager. Time domain analysis shows the localisation of ERP around 300 ms for target stimuli attended by the subjects. The short-time Fourier transform (STFT) analysis shows strong theta activity associated to memory related task. Thus, the proposed algorithm is efficient in detecting the P300 with higher correlation coefficient of 0.82 (average) compared to other existing methods.