Epilepsy, Jacksonian:A brief alteration in movement, sensation or nerve function caused by abnormal electrical activity in a localized area of the brain. Seizures of this type typically cause no change in awareness or alertness. They are transient, fleeting, ephemeral.
Jacksonian seizures are extremely varied and may involve, for example, apparently purposeful movements such as turning the head, eye movements, smacking the lips, mouth movements, drooling, rhythmic muscle contractions in a part of the body, abnormal numbness, tingling, and a crawling sensation over the skin. Jacksonian seizures are a form of epilepsy.
These seizures are named for the pioneering English neurologist, John Hughlings Jackson, who studied speech defects in brain disorders and confirmed the location in the brain of the speech center ("Broca's center"). He described what are today called Jacksonian seizures in 1863 and in 1875 found the areas in the brain that caused them. Jackson was among the towering figures of 19th-century medicine, one of "the great men of medicine." (There were few, if any, women in medicine in the 19th century.)