RT Journal Article SR Electronic T1 Addendum JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 980 OP 980 DO 10.1136/jnnp.46.11.980 VO 46 IS 11 YR 1983 UL http://jnnp.bmj.com/content/46/11/980.abstract AB