EEG and video-EEG seizure monitoring has limited utility in patients with hypothalamic hamartoma and epilepsy

Hypothalamic hamartomas (HHs) are a malformation of the ventral hypothalamus and tuber cinereum, associated with gelastic seizures and epilepsy. We sought to determine the spectrum of electroencephalography (EEG) abnormalities in a large cohort of HH patients.Data was collected for HH patients undergoing evaluation between 2003 and 2007. Data included seizure history, prior treatment, and results of diagnostic studies. After informed consent, data were entered into a database.We reviewed 133 HH patients. Mean age at time of data analysis was 15.7 years (59.4% male). Most patients had gelastic (77%) and/or complex partial seizures (58%). Records for 102 EEG studies on 73 patients were reviewed. Interictal epileptiform abnormalities were seen in 77%, localizing predominately to the temporal and frontal regions. Records for 104 video-EEG (VEEG) studies on 65 patients were reviewed. Of 584 gelastic seizures (GS) captured, no ictal EEG change was noted in 438 (75%). Of GS with localizing features, 89% suggested onset from the temporal and/or frontal regions. There were 160 complex partial seizures (CPS). For those with localizing features, 100% localized to the temporal and/or frontal head regions. EEG and VEEG findings correlated with the side of HH attachment. VEEG did not influence outcome.EEG features in HH patients are diverse. The majority of gelastic seizures fail to demonstrate change in the EEG. The lack of EEG changes with many clinical seizures, and the false localization seen in those events with an ictal change suggest the utility of EEG is limited in the evaluation of these patients.