Abstracts

Rationale: There remains hesitancy in pursuing epilepsy surgery in children with features of both focal and generalized epilepsy, epileptic and developmental encephalopathy, moderate to severe intellectual disability, in the context of normal brain MRI.

Methods: Case of a 16-year-old male, with drug resistant, non-lesional epileptic encephalopathy was reviewed retrospectively chart review was performed to obtain the clinical information.

Results: He presented with daily focal non motor impaired seizures since age 4 years. Also had weekly nocturnal hyperkinetic seizures with grunting noise, fearful face, whole body rocking and bicycling. Electroencephalogram (EEG) showed frequent generalized spike and polyspike discharges with rare left temporal spike waves, generalized paroxysmal fast activity, loss of normal sleep transients and diffuse slowing of the background, suggesting an epileptic encephalopathy. Ictal EEG showed diffuse bilateral synchronous onset. Seizures were refractory to nine anti-seizure medications and vagal nerve stimulation. Genetic testing was unremarkable. MRI brain, 1.5 T and 3T were normal except minimal T2 signal abnormality in bilateral hippocampi without associated volume loss. Ictal single photon emission spectograph was nonlocalizing. Positron emission tomography scan at age 5 was normal but at age 15 showed focal hypometabolism at depth of sulcus at left parietotemporal junction. Neuropsychology testing was significant for moderate intellectual disability and was non lateralizing. Nocturnal hyperkinetic seizures was suggestive of possible parietofrontal epileptogenic network, with rapid generalization. Bilateral intracranial recording with stereo-EEG (SEEG) was pursued. Hyperkinetic seizures were localized to the left posterior cingulate and precuneus regions with rapid spread to right anterior cingulate region. Based on aggregate findings, a recommendation of focal resection of left precuneus extending up to left posterior cingulate was made. Seizure frequency decreased by greater than 50% post operatively. Additionally, the patient’s behavior and quality of life improved significantly.

Conclusions: SEEG has expanded our ability to uncover distinctive epileptogenic networks debunking conventional theories. A thorough clinical and diagnostic investigation is warranted in cases where epilepsy can have mixed focal and generalized features. Our case demonstrates focal onset epilepsy with a scalp EEG suggesting a generalized epilepsy disorder or an epileptic encephalopathy.

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