Paroxysmal Dyskinesias

Paroxysmal dyskinesias represent a group of uncommon movement disorders that are characterized by episodes of abnormal movements arising from a baseline of normal or nearly normal movement. Recent advances in the genetics of these disorders have helped provide some unification of classification schemes and better understanding. Three major phenotypes constitute the paroxysmal dyskinesias. Paroxysmal kinesigenic dyskinesia is characterized by very brief spells (seconds) that are triggered by sudden movement. Paroxysmal nonkinesigenic dyskinesia (PNKD) is characterized by longer lasting spells (minutes to hours) that may be precipitated by caffeine or alcohol consumption. Paroxysmal exertional dyskinesia is characterized by spells brought on by sustained exertion. The approach to treatment continues to be based on the phenotype more than the genotype.