Abstracts

Rationale: Temporal lobe seizures commonly exhibit clinical features that overlap with panic disorders. Ictal panic has been associated with focal dyscognitive seizures of temporal lobe origin. The feeling of pre-ictal fear is typically brief, lasting from seconds to a few minutes. The pathway for pre-ictal and ictal fear is complex and can involve the temporal, limbic, orbitofrontal and anterior cingulate cortices. The onset zone for panic sensation is typically mesial temporal lobe and has been shown to involve the orbitofrontal cortex. We are reporting a case of prolonged panic attack associated with simple-partial status epilepticus captured by stereotactic depth electrodes (SEEG). Methods: A 44 year-old woman with intractable focal dyscognitive seizures since early childhood was shown to have a right anterior temporal seizure onset on non-invasive video-EEG monitoring but had normal imaging studies. The semiology of her typical seizures began with an aura of a "hot flash", strange smell, or weird feeling, followed by head turning to the right, vocalization and bicycling movement of her legs. She underwent SEEG monitoring with electrodes placed in bilateral amygdalae, hippocampi, orbitofrontal regions, supplementary motor areas, and anterior cingulate gyri. Fourteen seizures consistent with her typical ictal events were captured. Results: The patient reported a feeling of intense fear on the seventh day of monitoring while she was on two-thirds of her usual dose of carbamazepine. The onset of fear was preceded three hours earlier by continuous spike-and-wave discharges in the right posterior orbital gyrus (POG) of the orbitofrontal cortex. Occasional spike-and-wave discharges were seen in the right lateral amygdala. During this three-hour period, she was awake, following all commands and was intact to cognitive testing. The patient continued to have a continual episode of fear, panic and anxiety for the next two hours, during which time her SEEG recorded continuous spike-and-wave discharges in right POG. Five hours and 26 minutes after the onset of these SEEG changes and panic attack, she had her typical ictal event of vocalization, head turning to the right, followed by bicycling movement of her legs. Electrographically, this event was preceded by attenuation in the right medial amygdala and hippocampus, followed by high frequency discharge in the same areas. These discharges spread to the left lateral amygdala within 14 seconds and then to the entire left hemisphere. Conclusions: Our patient had a prolonged event of simple partial status epilepticus associated with feelings of intense fear and anxiety. SEEG showed initial involvement of the right POG only, with a much delayed spread to the right temporal regions. To date, this is the first reported case of a prolonged episode of panic and fear captured on SEEG showing initial involvement in POG, supporting the view that it and insular region are critical regions for the generation of fear. Stimulation data in additional subjects may be useful to confirm or extend this observation.