A form of epilepsy involving brief alteration in movement, sensation or nerve function caused by abnormal electrical activity in a localized area of the brain. Jacksonian seizures is a form of simple complex seizures in which the abnormal electrical activity is localized to one region in the brain. Seizures of this type typically cause no change in awareness or alertness. They are transient, fleeting, and 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.
These seizures are named for the 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.)
- Jadassohn-Lewandowski Syndrome
“The nail plates of all the fingers and toes are extremely thickened, and so hard that they cannot be cut with a scissors; the father has to trim them with a hammer and chisel.”
Or Jak3. An enzyme found only in cells in the immune system that is critical for the cell signaling process resulting in the development of white blood cells. Mutation of the gene encoding JAK3 is responsible for a form of severe combined immunodeficiency (SCID). JAK stands for Janus kinase or Just Another Kinase.
- JAK3 inhibitor
A drug that inhibits the enzyme JAK3 (which is found only in immune cells) and acts as an immunosuppressant.
- Jakob's disease
Better known as Creutzfeldt-Jakob disease (CJD), a dementing disease of the brain. It is believed due to an unconventional, transmissible agent (a prion). Symptoms of CJD include forgetfulness, nervousness, jerky trembling hand movements, unsteady gait, muscle spasms, chronic dementia, balance disorder, and loss of facial expression. CJD is classified as a spongiform encephalopathy. Most cases […]
- Jakob-Creutzfeldt disease
A degenerative disease of the brain that causes dementia and, eventually, death. It is believed to be caused by an unconventional microbe called a prion, rather than by bacteria or a virus. Abbreviated CJD. Symptoms of CJD include forgetfulness, nervousness, trembling hand movements, unsteady gait, muscle spasms, chronic dementia, balance disorder, and loss of facial […]