Rationale:
GOFE is a rare, relatively new recognized pattern in generalized epilepsy described as evolving focal activity from generalized onset seizure. Although focal features of generalized epilepsy are well established concept in the literature, there is only a handful of case reports describing GOFE. Hereby, we describe two distinct ictal patterns of both focal and generalized onset in one patient.
Methods:
A 32-year-old female with history of seizures started age of 4-year-old. Has family history of epilepsy. Semiology reported as behavioral arrest with staring or absence, later, developed generalized tonic clonic seizures (GTCs). Routine EEG showed 2.5-4 Hz of generalizes spike-polyspike waves (GSWs). After initial diagnosis of generalized epilepsy, seizures were controlled for 10 years with antiseizure medication (ASMs). Later, seizures became refractory to treatment. Multiple broad spectrum ASMs were tried including ZNS, LTG, LE, TPM, VPA, CLB. No combination of ASMs granted seizure freedom. She also, had VNS placed without significant improvement. EMU evaluation revealed of interictals of 2.5-4 Hz of GSWs and intermittent left temporal slowing. Multiple seizures recorded included type-1 staring spells with gestural and oral automatisms. Type-2 GTC: onset with starring, mouth and left-hand automatism, right head version then GTCs. Also, nonspecific auras recorded without EEG correlates. EEG ictal onsets for all seizures show similar 2.5-4 Hz of GSWs lasting for 3-5 seconds followed by focal evolution in the left temporal head region (Figure.1). Focal semiological features occurred during the focal evolution. MRI brain revealed bitemporal encephaloceles. PET scan showed hypometabolism in the left inferior temporal gyrus. Due to refractory nature, focal features and MRI findings, it was decided to explore with SEEG to confirm diagnosis and evaluate for neuromodulation options. Bilateral SEEG implantation was performed with a focus on temporal and frontal regions. SEEG revealed interictal of GSWs and diffuse left temporal and orbitofrontal spikes. Two ictal patterns seen (figure.2) 1) Focal onset seizures from lateral temporal region associated with staring, oral and gestural automatism. 2) Generalized onset seizures associated with staring and subtle oral automatism followed by GTC seizure.
Results:
Our patient exhibits both focal and generalized onset seizures. These findings are similar to these reported by Linane et al. (2016) as one of their patient’s series had focal (temporal) onset seizures in addition to generalized onset seizures while the rest of studies only reported generalized onset on scalp EEG. Our findings may suggest a spectrum in genetic generalized epilepsy syndrome, coexisting focal epilepsy or less favored possibility of secondary bilateral synchrony.
Conclusions:
We report SEEG proven focal onset seizure in generalized epilepsy with GOFE. The mechanisms behind GOFE remain unclear but may involve brain network synchronization dynamics, neuroplasticity and excitability threshold, in addition to thalamocrotical circuitry. Clinically, GOFE seizures present challenges in terms of diagnosis, classification, and treatment.
Funding: No funding