Jacksonian seizure

Alternative names
Simple seizure; Complex seizure; Partial (focal) seizure; Seizure - partial (focal)


A partial seizure is an episode of abnormal activity in a localized (specific) part of the brain which causes changes in attention, movement, and/or behavior.

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 confined to a limited area of the brain; they may sometimes progress to generalized seizures, which affect the whole brain.

Partial seizures can be further characterized as simple (not affecting awareness and memory) or complex (affecting awareness and memory of events before, during, and immediately after the seizure, and affecting behavior).

The abnormal electrical activity results from localized areas of abnormal brain tissue. These areas may have been present since birth or earlier (congenital), or they may develop following head trauma, infections, stroke, and certain other conditions. In many patients, no obvious cause can be determined. Partial seizures are more likely to be caused by a definable lesion in adults than in children.

A partial (focal) 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, but still account for about 45% of pediatric seizure disorders.

Risk factors include any injury to the brain. This includes trauma, stroke, brain tumors, infections (such as meningitis), or prior brain surgery.


Patients with focal seizures can have any of the symptoms below. Patients with simple focal seizures do not lose consciousness and will be aware and remember the events that occur at the time. Patients with complex partial seizures will have abnormal consciousness and may or may not remember any or all of the symptoms or events surrounding the seizure.

  • abnormal motor control       o rhythmic muscle contraction/relaxation (clonic activity) - common       o affecting one side of the body (leg, part of the face, or other isolated area)       o abnormal head movements       o forced turning of the head  
  • automatisms - purposeless, complex movement (such as picking at clothes)       o abnormal mouth behaviors       o lip smacking       o chewing/swallowing without cause       o automatisms usually indicate the seizure is complex  
  • forced turning of the eyes  
  • abnormal sensations       o numbness, tingling, crawling sensation, etc.       o may occur in only one part of the body or may spread       o may occur with or without motor symptoms  
  • hallucinations (visual, hearing, touch, smells, etc.)  
  • abdominal pain or discomfort  
  • nausea  
  • sweating  
  • flushed face  
  • dilated pupils  
  • rapid heart rate/pulse

Other symptoms:

  • black out spells - periods of time lost from memory  
  • changes in vision  
  • sensation of deja vu  
  • changes in mood or emotion

Signs and tests

The diagnosis is based on the symptoms, taking into consideration the patient’s other history. It is extremely difficult to diagnose a single focal seizure. However, the diagnosis is easier to make in patients who have recurrent, stereotyped episodes -especially if there are risk factors such as a history of Head injury.

Some of the tests that may be performed include:

  • EEG - this can show characteristic changes confirming partial (focal) seizures, and may show the focus (the location of the cause). A normal EEG does not rule out seizures.  
  • EEG monitoring over several days may be necessary in order to record an event while it is occurring.  
  • Head CT or head MRI scan - these may show the location and extent of the lesion causing the symptom.


Whenever someone has a seizure for the first time, he or she should be taken to an emergency room, as there may be a serious underlying medical condition which needs to be treated. First-aid measures should be performed as appropriate, including protecting the person from injury during the seizure, preventing him or her from inhaling vomit or mucus into the lungs, keeping the airway clear, and assistance with breathing.

Treatment of the causes may stop the seizures. This may include medication, surgical repair of tumors or brain lesions, and other treatments.

An isolated seizure with an obvious avoidable trigger, such as fever or toxic reactions, is treated by removing or treating the precipitating factor.

An isolated seizure may not require treatment. Findings on MRI or EEG may determine how likely recurrent seizures are and may help determine the need for ongoing treatment, such as anticonvulsants (anti-seizure medications). The response to these drugs varies, and medication and dosage may have to be adjusted repeatedly.

Multiple, repeated seizures are usually treated with anti-seizure drugs such as phenytoin or carbamazepine for preventive, long-term use. Follow-up includes review of the need for drugs and monitoring for side effects. Drugs may need to be continued indefinitely.

Some patients with seizures that are difficult to treat may respond to a vagal nerve stimulator - a device that stimulates a nerve in the chest and reduces the number of seizures. Other patients may respond to surgery that removes the abnormal brain cells responsible for causing seizures.

Patients who have seizures that could result in loss of motor control or consciousness should be advised not to drive, swim alone, or engage in other activities during which a seizure could endanger themselves or others.

The patient might need to wear informational jewelry or cards (such as Medic-Alert) to aid in obtaining prompt medical treatment if a seizure occurs.

Expectations (prognosis)

The outlook is largely determined by the underlying cause of the focal seizures. Patients who have recurrent seizures that are not due to a temporary condition (e.g., a drug side effect or infection) have a chronic condition called epilepsy.

Seizures that occur singly or in a closely associated group are commonly triggered by an acute condition such as brain injury and may occur as an isolated incident, or they may develop into a chronic seizure disorder. Seizures within the first 2 weeks of a brain injury do not necessarily mean that a chronic seizure disorder will develop. EEG and MRI findings may help determine whether the condition is likely to become chronic.

Death or permanent brain damage from seizures is rare, but either can occur if the seizure is prolonged or if many seizures occur in close proximity (status epilepticus).

Serious injury can occur if the seizure happens while the person is driving or operating dangerous equipment. These activities may be restricted for people with poorly controlled seizure disorders.

Infrequent seizures, however, need not severely restrict lifestyle. Work, school, and recreation do not necessarily need to be restricted, but precautions should be taken to reduce risks if a seizure should occur.


  • progression to generalized seizures  
  • epilepsy (recurrent seizures)  
  • prolonged or closely occurring seizures (status epilepticus)  
  • injury from falls, bumps, biting self  
  • injury caused by a seizure during driving/operating machinery  
  • aspiration pneumonia  
  • permanent brain damage (stroke or other damage)  
  • side effects of medications (with or without observable symptoms)  
  • complications of surgery  
  • women who choose to get pregnant should inform their doctor in advance for appropriate adjustments in medications (many of the anti-epileptic medications can cause birth defects)

Calling your health care provider

Call your local emergency number (911) if this the first time a person has had a seizure or a seizure is occuring in someone without a medical ID bracelet (instructions explaining what to do). In the case of someone who has had seizures before, call the ambulance for any of these emergency situations:

  • This is a longer seizure than the person normally has, or an unusual number of seizures for the person  
  • Repeated seizures over a few minutes  
  • Repeated seizures where consciousness or normal behavior is not regained between them (status epilepticus)

Call your health care provider if any new symptoms occur (including possible side effects of medications):

  • Drowsiness, restlessness, confusion, sedation  
  • Nausea/vomiting  
  • Rash  
  • Loss of hair  
  • Tremors or abnormal movements  
  • Problems with coordination  
  • Fevers, infections


Treating the underlying disorders may reduce the risk of further seizures. In most cases, the seizures may not be preventable.

Avoid Head injury by wearing helmets during risky activities, and avoid illegal drug use or excessive alcohol intake.

Johns Hopkins patient information

Last revised: December 5, 2012
by Potos A. Aagen, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.