Progressive Myoclonus Epilepsy with Adolescent Onset: Clinical Features and Diagnosis

Many of the progressive epilepsy syndromes with adolescent onset are classified as progressive myoclonus epilepsies. It is a heterogenous group of epilepsy syndromes associated with seizure, myoclonus, and progressive neurologic decline. This review focuses on the different adolescent-onset progressive myoclonus epilepsies including Unverricht–Lundborg disease, Lafora disease, juvenile-onset neuronal ceroid lipofuscinosis, sialidosis (cherry-red spot myoclonus), dentatorubral–pallidoluysian atrophy, and myoclonic epilepsy and ragged-red fibers. Their clinical presentations, neurophysiologic and neuroimaging findings, genetics, pathology, and diagnosis are discussed.