Updates are available Erratum dated 2015-03-24

Article History

First Online: 17 February 2015

Change Date: 24 March 2015

Change Type: Correction

Change Date: 19 February 2015

Change Type: Correction

Change Details: In the version of this article initially published online, the Competing interests section was incomplete. The error has been corrected for the PDF and HTML versions of the article.

Change Details: In the version of this article initially published online, the Acknowledgements section was incomplete. The error has been corrected for the print, PDF and HTML versions of the article.

Competing interests

: R.M.R. is a full-time employee of Biogen. However, this article was written and submitted while he worked at the Cleveland Clinic. D.A.H. has consulted for Allergan Pharmaceuticals, Bristol-Myers Squibb, EMD Serono, Genzyme Sanofi-Aventis, MedImmune, Mylan Pharmaceuticals, Novartis Pharmaceuticals, Questcor and Teva Neuroscience. C.F.L. declares no competing interests.