Extraction of ocular artefacts from EEG using independent component analysis

Eye activity is one of the main sources of artefacts in EEG and MEG recordings. A new approach to the correction of these disturbances is presented using the statistical technique of independent component analysis. This technique separates components by the kurtosis of their amplitude distribution over time, thereby distinguishing between strictly periodical signals, regularly occurring signals and irregularly occurring signals. The latter category is usually formed by artefacts. Through this approach, it is possible to isolate pure eye activity in the EEG recordings (including EOG channels), and so reduce the amount of brain activity that is subtracted from the measurements, when extracting portions of the EOG signals. (C) 1997 Elsevier Science Ireland Ltd.