Department of Neurosurgery, Oulu University Hospital, PL 22, 90220 Oulu, Finland Correspondence to: Dr A Niemelä, Department of Neurosurgery, Oulu University Hospital, PL 22, 90220 Oulu, Finland; asko ...

Sobell Department of Motor Neuroscience, Institute of Neurology, London, UK Dr S Tisch, Unit of Functional Neurosurgery, Sobell Department, Institute of Neurology, University College London, Box 146, ...