RT Journal Article SR Electronic T1 Correction JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 1559 OP 1559 DO 10.1136/jnnp.50.11.1559 VO 50 IS 11 YR 1987 UL http://jnnp.bmj.com/content/50/11/1559.abstract AB