Developmental and epileptic encephalopathy in patients with epilepsy due to hypothalamic hamartomas.

OBJECTIVE

What factors influence cognition and behavior in patients with epilepsy caused by hypothalamic hamartoma (HH)?

METHODS

We conducted a retrospective study of 103 patients referred to the Epilepsy Center in Freiburg, Germany, over the past 24 years. Analyzed parameters included development/intellectual functioning, behavior, seizure types and frequency, as well as electroencephalography (EEG) and magnetic resonance imaging (MRI) analyses.

RESULTS

Half of the patients showed signs of global developmental delay (GDD) or intellectual disability (ID). Patients with GDD/ID were younger at epilepsy onset (p < .05) and at first referral (p < .001), had shorter disease durations (p < .01), experienced more frequent seizures (p < .001), and were prescribed more antiseizure medication (ASM; p < .01). They also had larger HH volumes (hamartoma types Delalande III and IV, both p < .001) and more frequent pathological EEG background activity (p < .001), as well as more extended interictal epileptiform discharges (IEDs; p < .05, the rate of IED and seizure types were comparable, p > .05). Of interest, pathological EEG background activity and HH type were the only predictors of GDD/ID resulting in a highly predictive model (R = 0.75, p < .001). Patients with GDD/ID also experienced more externalized behavioral problems, particularly aggression, which was predicted only by EEG background activity (R = 0.36, p < .001). None of the epilepsy-specific parameters, such as duration and seizure type or frequency, were significant predictors.

SIGNIFICANCE

Our findings support the idea that patients with epilepsy due to HH and GDD/ID may have a more severe underlying condition with a likely genetic etiology, characterized by developmental and epileptic encephalopathy.