Clinical and EEG features of patients with EEG wicket rhythms misdiagnosed with epilepsy

Background: EEG wicket rhythms are 6- to 11-Hz medium-to-high voltage bursts that are sometimes misidentified as epileptogenic activity. The authors determined the clinical and EEG features of patients with wicket rhythms who had been incorrectly diagnosed with epilepsy. Methods: Electroencephalographers at an epilepsy center re-read EEGs for patients referred for epilepsy management and identified patients with wicket rhythms. On further evaluation, the majority (54 %; 25/46) of these patients were found not to have epilepsy. The authors compared the clinical and EEG features for the 25 patients with wickets and nonepileptic episodes with those of age- and sex- matched patients with partial-onset epilepsy using univariate and multivariate analysis. Results: Several features distinguished patients with EEG wicket patterns and nonepileptic episodes (n = 25) from age- and sex- matched patients with epilepsy (n = 25): mid-adult age at onset of episodes (mean 38.4 years vs 19.8 years), prolonged clinical episodes (mean 155 minutes vs 2.3 minutes), and long duration of EEG wicket patterns (mean 0.66 seconds vs 0.11 second spikes). After controlling for other factors, patients without major confusion during episodes were unlikely to have epilepsy. Conclusion: Wicket patterns are often interpreted as epileptogenic. This distinctive EEG pattern should be considered in patients with clinical episodes atypical for epilepsy.