Epileptogenic networks in two patients with hypothalamic hamartoma

Hypothalamic hamartomas (HH) are typically associated with gelastic seizures but also implicated in the genesis of other seizure types. In order to identify networks involved in seizure generation, we performed EEG-fMRI in two adult patients with HH, the first with predominantly gelastic seizures and the second with complex partial and no typical gelastic seizures. The ictal and interictal analysis of the patient with gelastic seizures revealed the involvement of the HH, the cingulate gyrus, the precuneus and the prefrontal cortex. The interictal analysis of the patient with complex partial seizures, showed changes in blood oxygenlevel dependent signal over the temporal lobes, the base of the frontal lobe, the cingulate, the precuneus and the prefrontal cortex, but not the HH. The differences in the neural networks implicated may account for differences in clinical manifestation of seizures owing to HH.