Data from: Generalized polyspike train: an EEG biomarker of drug-resistant idiopathic generalized epilepsy

Objective: To identify clinical and EEG biomarkers of drug resistance in
adults with idiopathic generalized epilepsy. Methods: We conducted a
case-control study consisting of a discovery cohort and a replication
cohort independently assessed at two different centres. In each centre
patients with idiopathic generalized epilepsy phenotype and generalized
spike-wave discharges on EEG were classified as drug-resistant or
drug-responsive. EEG changes were classified into pre-defined patterns and
compared between the two groups in the discovery cohort. Factors
associated with drug resistance in multivariable analysis were tested in
the replication cohort. Results: The discovery cohort included 85 patients
(29% drug-resistant and 71% drug-responsive). Their median age at
assessment was 32 years and 50.6% were female. Multivariable analysis
showed that having higher number of seizure types (3 vs. 1: odds ratio
[OR]= 31.1, 95% confidence interval [CI] 4.5-214, p<0.001; 3 vs. 2:
OR=14.6, 95% CI: 2.3-93.1, p=0.004) and generalized polyspike train (burst
of generalized rhythmic spikes lasting less than 1 second) during sleep
were associated with drug resistance (OR=10.8, 95% CI: 2.4-49.4, p=0.002).
When these factors were tested in the replication cohort of 80 patients
(27.5% drug-resistant and 72.5% drug-responsive; 71.3% female; median age
27.5 years), the proportion of patients with generalized polyspike train
during sleep was also higher in the drug-resistant group (OR=4.0, 95% CI:
1.35-11.8, p=0.012). Conclusion: Generalized polyspike train during sleep
may be an EEG biomarker for drug resistance in adults with idiopathic
generalized epilepsy.