Validation of patient determined disease steps (PDDS) scale scores in persons with multiple sclerosis. Learmonth YC, Motl RW, Sandroff BM, Pula JH, Cadavid D BMC Neurol. 2013 Apr 25; 13(1):37. Epub 2013 Apr 25. PMID: 23617555. Abstract CommentRecommendBookmarkWatch