Any measurement in which the number of individuals in a study population that display experimental autoimmune encephalomyelitis (EAE) at a point in time or develop EAE within a determined period of time are compared to the total number of individuals in the study population. Often expressed as a percentage but could be expressed as a ratio. EAE is an animal model of brain inflammation in which inflammation is induced through immunization of the animal with central nervous system antigens or by the passive transfer of autoreactive T cells.