[1] Univ Glasgow, Western Infirm, Gardiner Inst, Div Cardiovasc & Med Sci, Glasgow G11 6NT, Lanark, Scotland
[2] Univ Glasgow, Robertson Ctr Biostat, Glasgow, Lanark, Scotland
[3] Univ Essen Gesamthsch, Dept Neurol, Essen, Germany
[4] Univ Helsinki, Cent Hosp, Dept Neurol, Helsinki, Finland