A NEW MICROCOMPUTER-BASED ONLINE OCULAR ARTIFACT REMOVAL (OAR) SYSTEM

In many clinical and psychological situations it is often helpful to remove ocular artefacts (OAs) from the EEG signals so that the true EEG can be analysed. These artefacts are associated with movements in the ocular system (eyelids, eyeball etc. ). Although satisfactory OA removal is now possible offline, online OA removal has been unsatisfactory. Previously reported online methods required the cooperation of subjects which cannot always be guaranteed, involved time-consuming manual calibration, and can only deal with one type of OA as they assume a constant correction factor. A new online system for removing OAs from the EEG signals is described which overcomes these disadvantages and offers additional advantages, such as flexibility. The system is based on the Motorola 68000 microprocessor and uses the numerically stable UD factorisation algorithm which allows continuous adaptive OA removal.