The contributions of epidemiology to the understanding of childhood seizures and epilepsy.

Up through the 1960s, studies of epilepsy were based on patients seen in tertiary referral centers, many of whom had refractory epilepsy. Based on these early studies, epilepsy was believed to be a chronic, progressive, and incurable disorder. Seizures were thought to cause damage and result in further seizures. Clinical management of children with seizures reflected these beliefs. Over the last 25 to 30 years, epidemiologic studies have demonstrated that, contrary to these earlier beliefs, the prognosis of most childhood seizures and epilepsy is excellent. Prognosis is largely determined by the underlying etiology and not the seizures themselves. The differences in the assessment of the prognosis of seizures derived from the earlier studies versus the later epidemiologic studies are largely due to several biases that occurred in the earlier studies. These biases are explained. Several examples are provided of how the epidemiologic studies have greatly altered the prevailing views regarding the prognosis of seizures, and, by doing so, the management of seizures.