Erratum to: J Neurol (2014) 261:2101–2111 DOI 10.1007/s00415-014-7446-0

The original version of this article unfortunately contained a mistake. The affiliation of the fifth author (João Correia de Sá) is incorrect. The correct affiliation should be:

J. Correia de Sá

Hospital de Santa Maria, Lisbon, Portugal