A neurologist is a medical doctor who specializes in treating diseases and disorders of the nervous system including the brain, spinal cord, and nerves. They diagnose and treat conditions like epilepsy, multiple sclerosis, Alzheimer's disease, stroke, migraines, and other neurological problems. Neurologists must complete medical school, an internal medicine residency, and an additional 3 year residency in neurology to be board certified in this specialty.