For optimal treatment, clinicians must recognize key subgroups of patients with epilepsy who have distinctive patterns of seizures, causes, and treatment needs. Particularly important subgroups are patients who develop seizures in their late adult or elderly years and patients with medically resistant epilepsy. Currently the largest age group of patients diagnosed with new-onset epilepsy is older adult and elderly patients; these patients have a rapidly increasing incidence of seizures beginning in the late 50s and represent the graying of America and the influence of vascular risk factors on producing seizures.