RT Journal Article SR Electronic T1 Correction JF Practical Neurology JO Pract Neurol FD BMJ Publishing Group Ltd SP 279 OP 279 DO 10.1136/practneurol-2012-000244corr1 VO 12 IS 4 YR 2012 UL http://pn.bmj.com/content/12/4/279.2.abstract AB