Does anybody know any good source of statistics on PPMS or can give a reference to any medical papers on progression rates? The only info I have found in the public domain is the statement “One such study published by Canadian researchers found that although 25% of their study group needed assistance to walk seven and a half years after their symptoms began, 25% were still able to walk unaided after living for 25 years with the condition.” which is from the MS TRUST PPMS exposed document. I would like to be able to read the source paper for this and any other related info on progression rate statistics.