The Patient Determined Disease Steps (PDDS) is a PRO developed with the Patient Registry of the North American Research Committee on MS (NARCOMS). Its clinical counterpart is the Disease Steps, a ClinRO developed by Hohol in 1995.
Hohol MJ; Orav EJ; Weiner HL
Hohol MJ, Orav EJ, Weiner HL. Disease Steps in multiple sclerosis: A simple approach to evaluate disease progression. Neurology 1995; 45: 251–55 (PubMed abstract)