Seizure imitators monitored using video-EEG in children with intellectual disabilities

Diagnosis of seizure imitators in children is often challenging, and individuals with intellectual disability (ID) could be at additional risk of seizure imitator misdiagnosis. We aimed to elucidate distinct features of clinical semiology among children of different intellectual levels, which may help in distinguishing seizure imitators from epilepsy in such individuals. We retrospectively compared semiological features of seizure imitators in children with and without ID captured using video-electroencephalography (video-EEG). Seizure imitators were classified based on the definition of the International League Against Epilepsy (ILAE). A total of 67 individuals (mean age: 8.4 years, SD: 4.2 years) with seizure imitators documented using long-term video-EEG were identified, in which 27 patients had normal IQ/DQ, 20 had moderate ID, and 20 had severe ID. There was no statistically significant difference in the semiological features of seizure imitators between individuals with ID and those without ID; similarly, no difference was found between those with moderate ID and severe ID compared with individuals with normal IQ/DQ. Among all the patients, altered responsiveness mimicking cognitive or absence seizures was most frequently observed (36%), followed by jerks mimicking myoclonic seizures (22%). The most common seizure imitators among all the patients were unclassifiable nonepileptic seizures per the ILAE definition (28 cases, 42%), followed by day dreaming (24 cases, 36%) and physiological myoclonus (14 cases, 21%). In summary, the present study found no marked difference in semiological features of seizure imitators between patients with ID and those without ID regardless of ID severity, suggesting the necessity of early video-EEG for correct diagnosis.