An introduction to neuroepidemiology.

Neuroepidemiology is the application of the methods of epidemiology to the problems of clinical neurology. After diagnosis, the most basic characterization of a disease is its frequency. This characterization requires ascertainment of case (numerator) within their population at risk (denominator) to provide incidence, prevalence, and mortality rates. Mortality rates come from government publications, and morbidity rates (incidence and prevalence) from specific field surveys. Definition of the course of illness and identification of risk factors for occurrence or course require specific studies and appropriate statistical testing.