Paroxysmal choreoathetosis.

Paroxysmal choreoathetosis is the essential symptomatology in the following 4 syndromes: (a) paroxysmal kinesogenic choreoathetosis; (b) paroxysmal nonkinesogenic choreoathetosis; (c) supplementary sensorimotor seizures, and (d) paroxysmal nocturnal dystonia. All these syndromes are characterized by similar clinical symptomatology of the paroxysmal events. However, the pathophysiology of the choreoathetotic episodes differs considerably. In the first two syndromes the paroxysms are most probably generated by nonepileptogenic abnormal discharges in the basal ganglia whereas in the third syndrome (supplementary sensorimotor seizures) there is convincing evidence indicating that the pathogenesis is an epileptic process in the cortex. Finally, in the last syndrome (paroxysmal nocturnal dystonia) there is still controversy whether the paroxysms are of an epileptic or nonepileptic nature.