Abstracts

Hypothalamic hamartoma (HH) is associated with refractory epilepsy with multiple seizure types. Few studies have addressed the ictal findings in non-gelastic seizures. Adult patients with MRI diagnosed HH and epilepsy underwent continuous video-eeg monitoring to document all seizure types and ictal SPECT. Seizures were classified acccording to clinical and ictal EEG findings. Data were correlated with MRI and ictal SPECT. Six patients (ages 18-39 years; 4 men) with sessile HHs, measuring 0.178 to 9.952cm³. Four were right lateralized and two left. Four had posterior, one middle HHs. The remaining HH was unclassifiable. Three seizure types were seen: gelastic (GS), complex partial (CPS) and asymmetric tonic postural (ATPS). GS were associated with other seizure types. An individual patient could present either CPS or ATPS. GS were present in five patients. Ictal EEG in GS showed no or nonspecific changes . Four patients had ATPS. In three, ATPS were associated with GS. The other patient had isolated ATPS; ictal EEG showed diffuse attenuation or paroxysmal fast activity, followed by right frontal ictal activity in one patient. The remaing two patients had CPS with automatisms; ictal EEG showed unilateral temporal activity. In both, CPS were associated with GS. A generalized tonic-clonic seizure was seen in four patients, always preceded by another seizure type. The two smallest HH were associated with CPS and not to ATPS. The HH[apos]s side correlated with EEG lateralization during CPS. We found no correlation between the middle/posterior HH location and seizure type. Ictal SPECT was performed in five patients and showed increased flow in two (increased right temporal flow in one CPS and increased left frontal and HH flow in one GS/ATPS, concordant with hamartoma lateralization). Accepting HH intrinsic epileptogenicity, we propose that seizure progression from GS to other seizure types is due to seizure activity spread from the HH to other brain areas. Electroclinical differences between CPS and ATPS suggest a different ictal spread. CPS could result from temporal lobe involvement ([quot]horizontal spread[quot]) and ATPS from midline structures ([quot]vertical spread[quot]). Horizontal spread correlated with HH lateralization and only occured in the smallest HHs. Vertical spread was seen in the larger HH with features of frontal/midline involvement. There was no association between HH/mamillary body relationship and seizure spread pattern. Seizure types in HH were limited to three specific seizure types. The pattern of clinical seizure types in each patient, ictal EEG and SPECT findings suggest ictal onset in the HH, with horizontal spread in CPS (in smaller HHs) or vertical spread in ATPS (in the larger HHs). Seizure and HH lateralization was seen in both seizure types. (Supported by FAPESP (The State of S[atilde]o Paulo Research Foundation).)