[1] Turku Univ Hosp, Dept Clin Neurophysiol, Postal Box 52, FIN-20521 Turku, Finland
[2] Turku Univ Hosp, Div Med Imaging, Turku, Finland
[3] Univ Turku, Dept Clin Neurophysiol, Turku, Finland
[4] Univ Tubingen, Dept Neurol & Stroke, Tubingen, Germany
[5] Univ Tubingen, Hertie Inst Clin Brain Res, Tubingen, Germany