Poser criteria are diagnostic criteria for multiple sclerosis (MS). They replaced the older Schumacher criteria, and now they are considered obsolete as McDonald criteria have superseded them. Nevertheless, some of the concepts introduced have remained in MS research, like CDMS (clinical definite MS), and newer criteria are often calibrated against them. The criteria were unveiled in the Annals of Neurology in 1983 by a team lead by Dr. Charles M. Poser.