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Partial (focal) seizure - Overview

Alternative Names

Focal seizure; Jacksonian seizure; Seizure - partial (focal)

Definition of Partial (focal) seizure:

A partial seizure is an episode of abnormal electrical activity in one specific part of the brain.

Causes, incidence, and risk factors:

All seizures are caused by abnormal electrical disturbances in the brain. Partial (focal) seizures occur when this electrical activity remains in a limited area of the brain. The seizures may sometimes turn into generalized seizures, which affect the whole brain. This is called secondary generalization.

Partial seizures can be further characterized as:

Simple -- not affecting awareness or memory
Complex -- affecting awareness or memory of events before, during, and immediately after the seizure, and affecting behavior

The abnormal electrical activity is due to an area of abnormal brain tissue. The abnormal tissue may have been present since birth or earlier (congenital), or may develop after a head injury, infection, stroke, or certain other conditions. In many patients, no obvious cause can be determined.

A partial seizure may occur at any age, as a single episode or as a repeated, chronic seizure disorder (epilepsy). They are seen less frequently in children than in adults.

Risk factors include any injury to the brain. This includes trauma, stroke, brain tumors, infections (such as meningitis), or prior brain surgery. A family history of these types of seizures may also increase your risk.

Central nervous system

Reviewed last on: 6/19/2008
Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

References

Foldvary-Schaefer N, Wyllie E. Epilepsy. In: Goetz, CG. Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 52.

Krumholz A, Wiebe S, Gronseth G, et al. Practice parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007;69(21):1991-2007.

Pollack CV Jr. Seizures. In: Marx, JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, PA: Mosby Elsevier; 2006: chap 100.

Spenser SS. Seizures and Epilepsy. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 426.

Tomson T, Hiilesmaa V. Epilepsy in pregnancy. BMJ. 2007 Oct 13;335(7623):769-73.

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