Pearls & Oy-sters: Two Cases of Stereotactic EEG-Proven Insular Epilepsy With Nonlocalizing Scalp EEG and Interesting Semiologies.

Insular epilepsy is a great mimicker and can be mistaken for seizures originating from other areas of the brain or as nonepileptic spells. The semiology of insular epilepsy can include, but is not limited to, auditory illusions, paresthesias, gastric rising, laryngeal constriction, and hyperkinetic movements. These arise from both the functions of the insula itself and its extensive connections with other regions of the brain. Noninvasive workup can be negative or nonlocalizing because of the insula's location deep within the lateral sulcus. Stereotactic EEG can therefore be an important tool in cases of insular epilepsy so that patients may be appropriately diagnosed and evaluated for potential surgical treatment. We present 2 cases of epilepsy with nonlocalizing scalp EEG and challenging semiologies, the workup undertaken to identify them as cases of insular epilepsy, and subsequent surgical treatments and outcomes.