Erratum to: J Neurol DOI 10.1007/s00415-009-5419-5

Unfortunately, in the second paragraph of the discussion, there is a typing error in references. The text should read “...in contrast with others [11, 19, 26, 31, 33, 34]” and not “...in contrast with others [1, 7, 8, 10, 11, 17, 19, 21, 22, 26, 27, 30–34]”.