Simple partial seizures result from epileptic activity which is localized in one part of the brain, usually the cortex or limbic system.
Consciousness is not impaired: people experiencing a simple partial seizure can talk and answer questions. They will remember what went on during the seizure.
Simple partial seizures take different forms in different people. They are further classified according to their symptoms:
- Autonomic Seizures These seizures are accompanied by autonomic symptoms or signs, such as abdominal discomfort or nausea which may rise into the throat (epigastric rising), stomach pain, the rumbling sounds of gas moving in the intestines (borborygmi), belching, flatulence and vomiting. This has sometimes been referred to as abdominal epilepsy. Other symptoms may include pallor, flushing, sweating, hair standing on end (piloerection), dilation of the pupils, alterations in heart rate and respiration, and urination. A few people may experience sexual arousal, penile erection, and orgasm.
- Emotional and Other Simple partial seizures which arise in or near the temporal lobes often take the form of an odd experience. One may see or hear things that are not there. One feels emotions, often fear, but sometimes sadness, anger, or joy. There may be a bad smell or a bad taste, a funny feeling in the pit of the stomach or a choking sensation. These seizures are sometimes called simple partial seizures of temporal lobe origin or temporal lobe auras.
- Motor Other simple partial seizures include (clonic, jerking) convulsive movements. Jerking typically begins in one area of the body, the face, arm, leg, or trunk and may spread to other parts of the body. These seizures are sometimes called Jacksonian motor seizures; their spread is called a Jacksonian march. It cannot be stopped.
- Sensory Seizures Some simple partial seizures consist of a sensory experience. The person may see lights, hear a buzzing sound, or feel tingling or numbness in a part of the body. These seizures are sometimes called Jacksonian sensory seizures.
Simple partial seizures usually last just a few seconds, although they may be longer. If there are no convulsions, they may not be obvious to the onlooker.
In some children, simple partial seizures lead to complex partial seizures, or to tonic-clonic convulsions.