Pertussis vaccine immunizations each year in the United States), and the risk of death from the disease was high (pertussis killed thousands of Americans each year before the vaccine was introduced). No studies showed a causal connection, and later studies showed no connection of any type between the DPT vaccine and permanent brain injury. The alleged vaccine-induced brain damage proved to be an unrelated condition, infantile epilepsy. In 1990, the "Journal of the American Medical Association" called the connection a "myth" and "nonsense". However, negative publicity and fear-mongering caused the immunization rate to fall in several countries, including the UK, Sweden, and
Unverricht–Lundborg disease ULD, MRIs taken once the disease has progressed show characteristic damage, which may help to correct a misdiagnosis. While ULD is a rare disease, the lack of well defined cases to study and the difficulty in confirming diagnosis provide strong evidence that this disease is likely under diagnosed. Unverricht–Lundborg disease is also known as EPM1, as it is a form of progressive myoclonic epilepsy (PME). Other progressive myoclonic epilepsies include myoclonus epilepsy and ragged red fibers (MERRF syndrome), Lafora disease (EPM2a or EMP2b), Neuronal ceroid lipofuscinosis (NCL) and sialidosis. Progressive myoclonic epilepsies generally constitute only a small percentage of epilepsy