. 2013 Aug 6;81(6):552–558. doi: 10.1212/WNL.0b013e31829e6fbf
© 2013 American Academy of Neurology
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivitives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/3.0.