What are the clinical features (semiology) EEG patterns and common causes of seizures from different areas of the brain
Localization Features and Common Causes of Seizures
| Region | Typical Semiology | EEG | Etiology |
|---|---|---|---|
| Frontal | Often nocturnal, occur in clusters, often brief <30 seconds. Other symptoms relate to subregion of frontal lobes (versive turning). Complex motor automatisms such as bicycling, pelvic thrusting, or other sexual gestures. Vocalizations common, minimal postictal symptoms. | Frontal or anterior vertex epileptiform discharges. Occasionally frontal bisynchronous discharges. Often no obvious change or obscured by muscle artifact. | Trauma, malformations such as cortical dysplasia or cavernous angiomas, strokes, tumors, infections, anoxia. Some genetic syndromes. |
| Mesial temporal | Auras common: olfactory, gustatory, rising epigastric sensation, déjà vu, “indescribable” feeling. Behavioral arrest, lip-smacking/swallowing (oroalimentary) and ipsilateral hand (manual). Semipurposeful or repetitive stereotypical movements. Contralateral dystonic posturing. Significant postictal confusion. Often ipsilateral postictal nose wipe. | Temporal epileptiform discharges localized to anterior temporal region or sphenoidal electrodes, if used. Rhythmic theta activity within 30 seconds of seizure onset. | Mesial temporal sclerosis, postinfectious, trauma. |
| Lateral temporal | Auras more likely to be auditory, vertiginous, visual distortions, early aphasia symptoms. Frequent secondary generalization. | Lateral temporal epileptiform discharges and rhythmic theta activity. | Lateral cortical lesions and dysplasias. Cavernous angiomas. Genetic. |
| Parietal | Rare. May reflect activity of association cortex activity and include elementary or unusual formed sensory phenomena, nausea/abdominal, dysphasia, or speech arrest. | Parietal epileptiform discharges. | Usually due to cortical lesions such as infarcts, cortical dysplasia, malignancies. |
| Occipital | Usually consist of unformed visual phenomena. May be negative visual symptoms. | Occipital epileptiform discharges, unilateral or bisynchronous. | Cortical lesions such as infarcts, dysplasia, or malignancies, but also as an idiopathic epilepsy syndrome (benign epilepsy with occipital paroxysms). |
