1EMIL PASZTOR Department of Neurosurgical Studies, The Institute of Neurology, Queen Square, London, England
2LINDSAY SYMON Department of Neurosurgical Studies, The Institute of Neurology, Queen Square, London, England
3N. W. C. DORSCH Department of Neurosurgical Studies, The Institute of Neurology, Queen Square, London, England
4NEIL M. BRANSTON Department of Neurosurgical Studies, The Institute of Neurology, Queen Square, London, England