Unverricht-Lundborg disease (ULD) is a rare progressive myoclonic epilepsy disorder characterized by action- and stimulus-sensitive myoclonus, and tonic-clonic seizures with ataxia, but with only a mild cognitive decline over time.

A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior.