Abstracts

Rationale: Hypothalamic hamartomas (HH) are rare lesions that may cause gelastic seizures. Often time, gelastic seizures are intractable to medical therapy, leaving patients with resective surgery as the only alternative.  More recent MRI-guided Laser Interstitial Thermal Therapy (LITT) offers a minimally invasive surgical option to treat HH. There is limited outcome data on LITT in patients with HH and long-standing gelastic seizures.   Methods: A retrospective, IRB approved, chart review was conducted for adult patients with a radiologically confirmed diagnosis of HH and long-standing epilepsy. We collected demographic details, seizure onset & semiology, EEG findings, type of intervention, and post-intervention seizure outcomes.  Results: 19 patients had HH out of which 13 presented with seizures.  We identified 4 patients with long-standing (mean age of 36 years, range 12-66) gelastic seizures in adulthood. Mean age at seizure onset was 5 years (range 1.5-9) and at diagnosis of HH was 27 years (range 1.5-67). Three patients had left-sided HH. All patients had gelastic seizures consisting of inappropriate laughter/giggling. One patient had no ictal or interictal findings. Three patients had other types of seizures in addition to gelastic seizures. The other types of seizures seen were focal seizures with or without impaired awareness, generalized tonic-clonic seizures and atonic seizures.In these 3 patients, multifocal interictal findings were seen in EEG, with variable prominent epileptic focus at different time periods. All the patients failed 3 or more anti-epileptic medications. Mean age for MRI-guided LITT was 42 years (range-21-67). All patients underwent LITT with resolution of gelastic seizures. Three patients had LITT as the primary surgical intervention with ENGEL class I outcome after 18 months. The fourth patient, with epilepsy duration of 12 years, had gamma-knife radiation with ongoing daily gelastic seizures for 1 year followed by LITT with ENGEL class III outcome after 12 months. Notably, the gelastic seizures resolved after the LITT while other types of seizure continued. Conclusions: LITT is a minimally invasive procedure that is highly effective in treating HH with resolution of long-standing gelastic seizures. Good outcome was observed in 3 out of 4 patients independent of duration of seizure, age of onset or EEG findings.  Funding: Not applicable