Diagnosis of juvenile bilateral jerking at awakening: A study of 18 cases

Eighteen patients presenting with juvenile (11 to 21 yrs) onset of bilateral jerks of the arms at awakening were studied. Fifteen had clinical (normal interictal neurological examination, frequent association with generalized tonic-clonic fits; good response to monotherapy with phenobarbital, sodium valproate or acetazolamide) and EEGraphic (interictal spike-wave or polyskike-wave complexes at 3-6 c/s) features of the juvenile myoclonic epilepsy of Janz (JME). In the remaining 3 patients, clinical, EEGraphic or neuroradiological data made the diagnosis of JME questionable: bradykinesia (1 patient), calcification of the left lenticular nucleus (1 patient), normal EEG activity during polygraphic recordings of 'jerks' at awakening (1 patient). Juvenile onset of jerks at awakening may occur in myoclonic epilepsies phenocopies of JME as well as in nonepileptic patients suffering from pseudoseizures.