Rhythmic myoclonic jerks of the shoulders and arms with tonic abduction that results in progressive lifting of the arms during the seizure. The myoclonic jerks are typically bilateral but may be unilateral or asymmetric. Perioral myoclonias and rhythmic jerks of the head and legs may occur. Seizures last 10-60 seconds and typically occur daily. Level of awareness varies from complete loss of awareness to retained awareness.