1. Danish Ramazzini Centre, Department of Occupational Medicine, Herning Hospital, Gl. Landevej 61, 7400 Herning, Denmark
2. Danish Ramazzini Centre ,Department of Occupational Medicine, Aarhus Hospital, Aarhus University Hospital, Norrebrogade, 8000 Aarhus C, Denmark
3. Department of Neurophysiology, Aarhus Hospital, Aarhus University Hospital, Norrebrogade, 8000 Aarhus C, Denmark