Abstracts

Rationale: Patients with frontal lobe epilepsy (FLE) are prone to misdiagnosis due to their atypical appearance or bizarre behavior, sudden onset and termination and tendency to rapid secondary generalization due to high connectivity of epileptic networks spread with minimal post-ictal confusion. It may be confused with sleep disorders, psychogenic non-epileptic seizures, generalized epilepsy or Lennox Gastaut Syndrome (LGS). Detailed seizure semiology and the underlying epileptic networks arising from the superior frontal gyrus (SFG) is diverse and could be divided in different regions. The purpose of this study is to illustrate some of the clinical features of SFG epilepsy and demonstrate how it may also mimic generalized epilepsy.

Methods: We present five patients with intractable focal epilepsy who underwent surgical resection of different areas of the superior frontal gyrus achieving seizure freedom. Data includes: semiology, video EEG evaluation, MRI brain and ancillary testing for the presurgical evaluation (MEG, PET, SPECT and VBM).

Results: The mean age at evaluation was 34 years old (19 - 55) and three are female. Patients had multiple predominantly sleep related seizures per day. Semiologies and findings in scalp EEG varied as detailed in Table 1. Interictal epileptiform generalized discharges were present in 3/5 (patients 1, 3, 4). MRI identified a superior frontal lesion in 3/5 (patients 3-5), PET showed hypometabolism in SFS in patient 4 and 5, but patient 1 showed hypermetabolism in the same region. SPECT showed epileptic networks involving the SFS and fronto-central regions in all except patient 3. MEG clusters involving the SFS/SFG were seen in patients 1, 3 and 5. SEEG was completed in 3/5 cases. All patients underwent resective surgery, reaching favorable outcomes (Engle I) with follow up from 7 to 34 months.

Conclusions: SFG epilepsy can present with different semiologies including complex motor, asymmetric tonic, dialeptic, axial tonic, myoclonic and GTC seizures, which depends on the network involved. Semiology can be divided in posterior with more prominent, less elaborated, motor manifestations (tonic, myoclonic, asymmetric tonic) and anterior with more complex motor movements and autonomic symptoms including the mesial and lateral aspects of the SFG. The nextworks involved are insula, anterior cingulate, frontal operculum and parietal lobe. Finally, semiology and scalp EEG findings may mislead the treatment and outcomes since at times it can resemble generalized epilepsy. Therefore, we would like to emphasize the importance of surgical evaluation at a tertiary care center in patients with focal intractable epilepsy and generalized features.

Funding: Please list any funding that was received in support of this abstract.: None.