A seizure threshold is the level of stimulation at which your brain will have a seizure. People with epilepsy may be considered to have a lower-than-normal seizure threshold. This means that only slightly increased brain stimulation may induce a seizure for someone with epilepsy. One’s seizure threshold is mostly determined by genetics, but other factors can lower your threshold. Fever and illness may lower one’s threshold. This may be most important in pediatric patients with a genetic predisposition to febrile seizures in childhood.