Abstracts

Hippocampal formation (HF) abnormalities have been reported in patients with epilepsy. The purpose of this study was to evaluate the shape, orientation and positioning of the HF in healthy controls and in patients with partial epilepsy due to malformations of cortical development (MCD), mesial temporal lobe epilepsy (MTLE) and in those with HF dimorphism (HFD) but without hippocampal sclerosis. In addition, we analyzed the clinical and neurophysiological aspects of patients with HF abnormalities, comparing to those with MLTE., We analyzed the MRIs of 30 healthy adult controls, 34 patients with MCD, 68 patients with MTLE and 12 patients with HFD, focusing on the HF shape (round or pyramidal instead of ovoid), orientation (vertically instead of transversely oriented) and positioning (medial positioning with respect to temporal horn). Patients with HF abnormalities were compared to patients with MLTE, regarding clinical and neurophysiological data., HF abnormalities were not found in any healthy control, but in 30 patients: 5 with MTLE (MTLE/HFD, 7.35%), 13 with MCD (MCD/HFD, 38.23%) ([italic]p[/italic][lt]0.003) and in all patients with HFD. Mean ages were 31, 11.15 and 18.92 years, respectively. For clinical evaluation, they were compared with patients with MTLE without HFD (MTLE/HFD[ndash] :[italic]n[/italic]=63). The age of the first seizure was 10.70, 15.00, 4.59 and 15.91 for the patients with MTLE/HFD[ndash], MTLE/HFD+, MDC/HFD+ [italic](p[/italic][lt]0.010) and HFD, respectively. Twenty-one (33.33%) of the MTLE/HFD[ndash] patients had febrile seizure, in contrast to no patient in the other groups ([italic]p[/italic][lt]0.005). All TLE/HFD[ndash] patients were pharmacoresistant ([italic]p[/italic][lt]0.0001), while four MCD/HFD+ (30.77%) and three HFD patients (17.65%) had their seizures controlled. Interictal analysis revealed the following data: in MTLE/HFD+ patients, one (20%) had no IED and the other four presented temporal IEDs; in HFD patients, two (16.67%) had no IED, six (50%) had temporal IEDs, and four (33.33%) had extratemporal discharges. MCD/HFD+ patients had heterogeneous distribution of IEDs. Seizures were recorded in 15 patients: three with MTLE/HFD+ (two with ipisilateral temporal onset and one with extratemporal onset); six patients with HFD (two with onset in the temporal region at the side of the lesion and four with extratemporal seizures); and six MCD/HFD+ patients (all with extratemporal onset)., In our study, HF abnormalities were not observed in healthy controls, and were found more often in patients with MCD than in MTLE patients. HFD did not correlate to clinical and neurophysiological data. Further studies, with larger series and histopathological examination, will be necessary to elucidate if HFD might be a marker of more extensive brain malformation., (Supported by Fapesp
CNPq.)