Pediatric epilepsy: EEGs may not fully predict seizure status
by Bianca Quijano, Reviewed by Dr. Salah Almubarak
Assistant Editor, The Chronicle
Electroencephalograph findings may not be completely sufficient for prediction of seizure re-occurrence in children with epilepsy. After starting anti-epileptic drug treatments, seizure freedom was experienced by patients despite having abnormal electroencephalograph (EEG) results, according to findings published in the Canadian Journal of Neurological Sciences (June 2017 44(S2):S32).
“Hopefully [these findings] encourage physicians to have a more holistic view of patients, instead of just ordering test results and basing all of their treatment options on the results of those tests,” said co-author Afsoun Amiraslany, a physiology and pharmacology student at the University of Saskatchewan in Saskatoon.
The retrospective study focused on 151 pediatric patients with epilepsy at the Royal University Hospital in Saskatoon. An EEG scan was conducted on 75 of the patients before starting on an anti-epileptic drug (AED). Among the 75 participants, 54 (72%), initially had abnormal EEG results.
After the introduction of AEDs, 38 (70.3%) of the participants developed normal EEG scans while 16 (29.7%) continued to have abnormal scans.
Among those with normal EEGs on follow-up, 81.5% had seizure freedom. In comparison, seizure freedom was seen in 43.7% of participants with abnormal EEGs.
AVOIDING UNNECESSARY TREATMENTS AND SIDE-EFFECTS
The researchers emphasized that EEGs provide important clinical information, but they should be used in conjunction with other diagnostic factors, such as patient history, brain imaging, neurological exam, and reaction to medication.
“We should avoid treating EEGs unnecessarily, in order to avoid side-effects from unnecessary medication,” said co-author Dr. Salah Almubarak, chairperson of the Pediatric Epilepsy Program of Saskatchewan and professor of neurology at the University of Saskatchewan.
Dr. Almubarak added that patients with abnormal EEGs before undergoing AED therapy may be at a higher risk for seizure re-occurrence, compared to those who developed normal EEGs.
PAUSING AED THERAPY: FACTORS TO CONSIDER
Furthermore, stopping AED treatment should be based on an agreement between patient and physician.
“In specific conditions, it might be reasonable to consider weaning off medication [even] if the EEGs are not specifically abnormal, the patient has no seizures for more than three to four years, and if there are no other significant factors suggesting that [patients] have a tendency for seizures,” said Dr. Almubarak. “But whether the EEG is normal or not, after the patient has no seizures for more than three to four years, we educate patients that there is still a chance of seizure re-occurrence after we wean off the medication.”
The influence of EEG findings on treatment options is also determined by the type of epilepsy that patients have.
“For example, in patients with benign Rolandic epilepsy, there is a consensus that abnormal EEG spikes will resolve on their own as the child grows older,” said Dr. Almubarak. “[However,] in patients with Juvenile myoclonic epilepsy, abnormal EEGs will be lifelong and may not improve. In such conditions, we will not wean off medication.”
NEED FOR FURTHER INVESTIGATION
Participants in the study were prescribed a variety of AEDs such as valproic acid, levetiracetam, clobazam, and phenobarbital. Amiraslany said that future studies should focus on how specific drugs affect EEG results and seizure freedom.
Furthermore, abnormal EEG results in participants with seizure freedom included photoparoxysmal responses, as well as single spike-waves, brief spike-wave bursts, epileptiform spike-wave discharges, and generalized spike-wave discharges. Dr. Almubarak noted that future studies should investigate how these abnormal EEGs affect long-term outcomes, after patients stop medication. It is still unknown why patients can live without seizures despite having these abnormal EEGs in specific conditions.
