All seizures are caused by abnormal electrical disturbances in the brain. Focal seizures occur when this electrical activity is in a limited area of the brain. Sometimes the seizures stay only in one part of the brain, while at other times, the seizures can turn into bilateral tonic clonic seizures, which affect the whole brain. This is called secondary generalization.
Focal seizures can be divided into whether they affect awareness or not:
- Focal, aware
- Focal, awareness impaired
Focal seizures are also classified by whether they are motor (movements with the seizures) or not.
Partial seizures are the most common type of seizure in people 1 year and older. In people older than 65 who have blood vessel disease of the brain or brain tumors, partial seizures are very common.
People with focal, awareness impaired seizures may or may not remember any or all of the symptoms or events during the seizure.
Depending on where in the brain the seizure starts, symptoms can include:
- Abnormal muscle contraction, such as abnormal head or limb movements
- Staring spells, sometimes with repetitive movements such as picking at clothes or lip smacking
- Eyes moving from side to side
- Abnormal sensations, such as numbness, tingling, crawling sensation (like ants crawling on the skin)
- Hallucinations, seeing, smelling, or sometimes hearing things that are not there
- Abdominal pain or discomfort
- Flushed face
- Dilated pupils
- Rapid heart rate/pulse
Other symptoms may include:
Exams and Tests
The doctor will perform a physical exam. This will include a detailed look at the brain and nervous system.
An EEG (electroencephalogram) will be done to check the electrical activity in the brain. People with seizures often have abnormal electrical activity seen on this test. In some cases, the test shows the area in the brain where the seizures start. The brain may appear normal after a seizure or between seizures.
Blood and urine tests may also be ordered to check for other health problems that may be causing the seizures.
Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures; Partial (focal) seizure
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Kanner AM, Ashman E, Gloss D, et al. Practice guideline update summary: efficacy and tolerability of the new antiepileptic drugs I: treatment of new-onset epilepsy: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2018;91(2):74-81. PMID: 29898971 pubmed.ncbi.nlm.nih.gov/29898971/.
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Review Date 1/23/2022
Updated by: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.