Introduction: Juvenile myoclonic epilepsy (JME)—one of the most common childhood/ juvenile epilepsy
syndromes accounting for approximately 5 to 10% of all cases of epilepsy. Typical
EEG findings of diffuse, symmetric, bilateral 4 to 6 Hz, polyspike and wave discharges
with fronto-central dominance especially in sleep and activation procedures including
photic stimulation may be absent in many patients. No significant, consistent outcome
predictors have been established for this very common epilepsy syndrome. Role of EEG,
an easily available and fairly affordable investigation, in determining outcome in
JME patients is uncertain till now. Using EEG as a tool to guide regarding management
in such patients would be really helpful, especially in resource poor countries like
India.
Aims: To study the prognostic significance of EEG features in patients with juvenile myoclonic
epilepsy (JME).
Methods: We reviewed the records of consecutive patients with JME attending outpatient clinics
at three tertiary epilepsy care centers who had a minimum follow-up of 4 years after
the first visit. The diagnosis of JME was confirmed as per the international consensus
criteria. The EEGs of all these patients were reviewed by two epileptologists who
were blinded to clinical data. The presence of focal spikes, generalized paroxysmal
fast activity, and fast rhythmic spikes on EEG were considered as atypical features.
Patients with no seizures during the last 2 years of follow-up were considered seizure-free
and we compared the EEG features in seizure-free and nonseizure-free patients.
Results: We identified 151 patients with JME during the study period from April 2013 to July
2018. Of these, 120 (80%) were seizure-free. A total of 50 (33%) patients had atypical
EEG features, 18 (58%) in nonseizure-free group, and 32 (27%) in the seizure-free
group (p < 0.005). Of the 151 patients, 72 (47%) had interictal epileptiform discharges (IEDs)
during wakefulness. Seizure-free patients were less likely to have IEDs during wakefulness
(41% vs. 71%, p < 0.05). Photo-paroxysmal response was equally present between the two groups.
Conclusion: EEG has a prognostic significance in patients with JME. Patients with atypical EEG
features and awake IEDs are less likely to become seizure-free. Thus EEG study can
help in diagnosing and tailoring the treatment of such patients.