Clinical expression and EEG features of patients with juvenile myoclonic epilepsy (JME) from North India.

We aimed to characterize the clinical profile, EEG features and response to treatment of juvenile myoclonic epilepsy (JME) patients. We studied 103 JME probands with a standard protocol recording age of onset, type, frequency of seizures, EEG data, detailed family history and response to treatment in a superspeciality university hospital in New Delhi. The mean age of onset of disease was 14.01 +/- 3.14 years with a male to female ratio of 1.19 : 1. The myoclonic jerks were present in all the probands, generalized tonic-clonic seizures (GTCS) were present in 75.72% and 11.65% probands had absence seizures. The incidence of febrile convulsion (FC) was higher (9.7%) in our JME probands reflecting some ethnic variation or ascertainment bias. There was a considerable delay (of approximately 5.26 +/- 4.61 years) in the diagnosis of JME in our probands because most of the patients were referred from private physicians who were possibly not familiar with this epileptic syndrome in this part of the world or thought it was a milder variety of GTCS. The family history was positive in 25.24% JME probands among first- and second-degree relatives. An interictal EEG was found to be abnormal in 81 (78.64%) patients with the predominant abnormality being generalized polyspike and wave (PSW) discharges (39.80% probands). The majority of patients (80.58%) showed a good response to treatment with valproate alone. There was a subset of patients (11.65%) who required the addition of other antiepileptic drugs (AEDs) for control of GTCS: 7.76% of JME patients were diagnosed as cases of GTCS by private practitioners before they were registered in our study and their seizures were well controlled on other AEDs (without valproate) prescribed by the referring physicians (carbamazepine-4, phenytoin-2, clobazam-2). It is concluded that the clinical features and EEG data of JME probands were comparable to reports from other parts of the world except for the fact that the incidence of FC was higher in our JME patients. There was a delay in the diagnosis of JME due to unfamiliarity with the epileptic syndrome among private practitioners in this part of the world. There was a subset of JME patients who had complete seizure control on other AEDs besides valproate.