Jan F A Hendrickx1, Andre M De Wolf2, Stanley Skinner3. 1. Department of Anesthesiology, Intensive Care and Pain Therapy, OLV Hospital, Moorselbaan 164, 9300, Aalst, Belgium. jcnwahendrickx@yahoo.com. 2. Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. 3. Department of Neurophysiology, Abbott Northwestern Hospital, Minneapolis, MN, USA.