Clinical and EEG characteristics of Juvenile Myoclonic Epilepsy

Objective: To determine the clinical and electroencephalographic characteristics of patients with Juvenile Myoclonic Epilepsy (JME).

Methods: In this descriptive case series study, 60 patients of Juvenile myoclonic epilepsy (JME) were included. After detailed history clinical examination, Electroencephalography (EEG) with standard protocol was performed in all patients and was analyzed by a neurologist.

Results: Out of 60 patients, 26 (43.3%) were males and 34 (56.6%) were females. Mean age at the onset of myoclonic jerks (MJ) and generalized tonic clonic seizures (GTCS) was 13.7 ± 2.12 years and 14.15 ± 1.79 years respectively. Average delay in the diagnosis was 5.2 years. Myoclonic jerks (MJ) were present in all patients, GTCS in 52 (86.6%), and absence seizures in 8 (13.33%) patients. 6 (10%) had only Myoclonic Jerks. First seizure type was MJ in 52 (86.6%) and absence in 8 (13.3%). Most common precipitating factors were sleep deprivation in 80% and fatigue in 66.6%. Family history for epilepsy was positive in 20%. Diagnosis by referring physicians was JME in only 6 (10%) patients. EEG was abnormal in 42 patients (70%) showing generalized , 4- to 6-Hz polyspike and wave in 27 (45%), generalized single spike/ sharp waves in 7 patients (11.6%), 8 (13.3%) patients had 3-Hz spike-and-wave (SW) activity in addition to the polyspike-and-wave (PSW) pattern. Independent focal EEG abnormalities were noted in 12 patients (20%).

Conclusion: Many of our patients were misdiagnosed by the referring physicians and were prescribed inappropriate antiepileptic drugs. Factors causing misdiagnosis were failure to elicit history of myoclonic jerks, misinterpreting myoclonic jerks as partial seizures and misinterpretation of EEG abnormalities.