Commonly, seizures have a recurrent phenomenology that makes them appear somewhat predictable and consistent. Thus, some patients’ seizures typically start with lip smacking, others’ with a visual aura and yet others’ with right hand shaking. For patients whose seizures have a convulsive component this means that the anatomical areas that convulse are usually the same. This is called semiological consistency. Most epilepsy patients experience some degree of this.

But seizures are much more than what can be perceived by the patient, as they sometimes involve prominent autonomic components mediated by variable levels of systemic epinephrine and norepinephrine .

When a near-SUDEP patient came into the hospital in 2023 with florid signs of a severe sympathetic response, we looked back in her chart to see if she had experienced similar seizures in the past. Her bloodwork suggests that her sympathetic responses were semiologically consistent.