Researchers at Sichuan University in China investigated the utility of 24-hour video-EEG (VEEG) in evaluating the risk of recurrence following an initial unprovoked seizure in 134 patients aged 3 to 77 years (66.4% male). Their results were reported in Seizure.1
The lifetime risk of experiencing at least one seizure is as high as 10% in the general population, and an estimated 3% of individuals will develop epilepsy.2 Based on the practical clinical definition of epilepsy established by International League Against Epilepsy (ILAE), a “first seizure with an abnormal EEG or brain imaging cannot be diagnosed as epilepsy unless there is sufficient evidence to substantiate a recurrence risk of more than 60%…,” the study authors wrote.3 However, previous findings regarding the value of EEG in predicting recurrence risk have been inconclusive.
In the current study, participants were screened for inclusion by 2 epileptologists. Patients whose first seizures were categorized as generalized, partial, or status epilepticus, as well as those who had experienced clusters of 2 or more seizures within 24 hours, were included in the study. Those with other types of seizures, non-epileptic seizures, and seizures resulting from acute factors were excluded. Participants underwent 24-hour VEEG within 7 days of the initial unprovoked seizure, and 2 blinded experts interpreted the results. Follow-up sessions took place at 3, 6, 12, and 24 months following the first seizure, unless patients experienced a recurrence, in which case follow-up was discontinued and treatment with AEDs was initiated.
According to their findings, the overall risk of recurrence for the total sample was 51.5%. VEEG abnormalities were detected in 56.7% of patients, and these were a statistically significant predictor of recurring seizure, according to multivariate analysis using Cox regression [RR 2.84, 95% confidence interval (CI) 1.67-4.82, P < .001]. The recurrence risk was especially high (73.2%) in patients showing epileptiform discharge abnormalities. In this group, the risk was greater among patients with epileptiform discharges vs those with normal results or nonsignificant abnormalities on VEEG (RR 2.76, 95% CI 1.83-5.34, P < .001 and RR 2.05, 95% CI 1.14-3.82, P < .001, respectively). There was no significant difference in recurrence rates between patients with generalized and focal epileptiform discharge abnormalities (RR 1.09, 95% CI 0.44-2.69, P = .85).
The observed risk of recurrence “would meet the diagnostic criteria for the patients with a first unprovoked seizure and a VEEG with epileptiform discharge abnormality and could be used to diagnose epilepsy according to the practical clinical definition of epilepsy published by ILAE in 2014,” the authors concluded.
References
- Chen T, Si Y, Chen D, et al. The value of 24-hour video-EEG in evaluating recurrence risk following a first unprovoked seizure: A prospective study. Seizure. 2016; 40:46-51.
- Pohlmann-Eden B, Beghi E, Camfield C, Camfield P. The first seizure and its management in adults and children. BMJ. 2006; 332(7537): 339–342.
- Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia. 2014; 55(4):475-82.
