Video-polygraphic analyses of 302 myoclonic seizures (MS) in 5 patients with juvenile myoclonic epilepsy (JME) are reported from the Department of Pediatrics, Tokyo Women’s Medical College, Japan. MS occurred singly or repetitively and corresponded to generalized bilaterally synchronous single or multispike-and-wave complexes at 3-5 Hz. Either distal or proximal muscles were involved, and facial jerks were infrequent. MS were asymmetrical in 4 of 5 patients and 9 to 38% of all seizures. Contraction and postmyoclonic inhibition of proximal muscles with atonia alternated with a flapping tremor during analysis of EMG in outstretched arms; myoclonic EMG potentials were suddenly disrupted when the arms dropped. Four patients fell when MS were intense. [1]

COMMENT. A total of eight articles on juvenile myoclonic epilepsy were published in the March/April 1994 issue of Epilepsia. Panayiotopoulos CP et al reported a 5-year prospective study of 66 patents with JME seen at the King Khalid University Hospital, Riyadh, Saudi Arabia [2]. Prevalence was 10.2% among 672 patients with epilepsies. Inheritance was autosomal recessive with siblings involved in 13 of 41 families. Diagnosis had been missed before referral in 63 and even after the initial visit in one-third. Age at onset was 10 years (range 5-16 years). Absence seizures (in 33%) predated myoclonic jerks (in 97%) by 4 years, and generalized tonic-clonic seizures (in 79%) by 4.4 years. Myoclonic and GTC seizures occurred mainly on awakening. One-third had an essential type tremor. A combination of valproate and clonazepam was the most effective treatment. Relapse occurred in 9 of 11 patients after drug withrawal.

Clinical and EEG asymmetries were reported in 26 of 85 (31%) patients with JME seen at the Department of Neurology, Bowman Gray School of Medicine, Winston-Salem, NC. Fourteen (54%) were initially misdiagnosed as having partial seizures. [3]