Date	Event	Description
20 January 2016	New search has been performed	New search from 18 January 2016 incorporated
20 January 2016	New citation required but conclusions have not changed	No new trials
30 March 2012	New citation required but conclusions have not changed	Updated searches were run to 14 June 2011. There were no new randomised controlled trials
15 June 2011	New search has been performed	'Risk of bias' tables and 'Summary of findings' tables have been incorporated
14 May 2008	New search has been performed	Updated searches were run to January 2008.
15 April 2008	Amended	Converted to new review format.
17 May 2006	New search has been performed	We updated the searches in 2006. We searched the Cochrane Neuromuscular Disease Group specialised register (March 2006), MEDLINE (to May 2006) and EMBASE (to May 2006). No new relevant references were identified.
12 December 2001	New citation required and conclusions have changed	Substantive amendment