West Syndrome

West Syndrome and Infantile Spasms

Hands applying electrodes to baby for electroencephalography
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West syndrome is a form of seizure disorder (epilepsy) that begins in infancy. A specific type of seizure called infantile spasm is part of this syndrome, as are abnormal brain wave patterns called hypsarrhythmia, and mental retardation. Almost any condition that can cause brain damage can cause West syndrome. The two most common causes are tuberous sclerosis and lack of oxygen during birth. Sometimes a cause is suspected but can’t be confirmed; in this case, it is called “cryptogenic West syndrome.”

West syndrome accounts for 2 percent of epilepsies in childhood, but 25 percent of epilepsy that begins in the first year of life. The rate of infantile spasm is estimated between 2.5 to 6.0 per 10,000 live births.

Symptoms of West Syndrome

West syndrome most commonly begins between ages 3-6 months.Symptoms include:

  • Infantile spasms – Most often in this type of seizure the infant suddenly bends forward at the waist and the body, arms, and legs stiffen. This is sometimes called a “jackknife” seizure. Some infants may instead arch their backs, or bob their heads, or cross their arms across the body like they are hugging themselves. These spasms last a few seconds and occur in clusters of anywhere from 2 to 100 spasms at a time. Some infants have dozens of these clusters of spasms in a day. The spasms most commonly occur after an infant wakes up in the morning or after a nap.
  • Hypsarrhythmia – An electroencephalogram (EEG) records electrical activity in the brain in the form of brain waves. An infant with West syndrome will have abnormal, chaotic brain wave patterns called hypsarrhythmia.
  • Mental retardation – this is due to the brain injury that has caused West syndrome.

Other symptoms may be present because of the underlying disorder causing West syndrome. Other neurological disorders such as cerebral palsy may also be present.

Diagnosing West Syndrome

West syndrome will be suggested by the presence of infantile spasms.

A thorough neurological examination will be done to look for possible causes. This may include laboratory tests and a brain scan using computed tomography (CT) or magnetic resonance imaging (MRI). An EEG will be done to look for the hypsarrhythmia usually present in West syndrome.

Treatment of West Syndrome

Most often West syndrome is treated with adrenocorticotropic hormone (ACTH) or prednisone. These treatments may be very effective in stopping or slowing the infantile spasms. Some infants may respond to antiseizure medications such as Felbatol (felbamate), Lamictal (lamotrigine), Topamax (topiramate), or Depakote (valproic acid). Infants with tuberous sclerosis may be treated with vigabatrin (not currently approved for use in the U.S.). Sometimes, removal of damaged brain tissue through brain surgery may be effective.

Infantile spasms usually resolve by about age 5, but more than half of children affected will develop other types of seizures, including Lennox-Gastaut syndrome. Many infants with West syndrome have long-term cognitive and learning impairment, most likely due to the brain damage that caused the infantile spasms.


"NINDS Infantile Spasms Information Page." Disorders A-Z. 9 Dec 2008. National Institute of Neurological Disorders and Stroke.

"Infantile Spasms/West Syndrome." Epilepsy Syndromes. Epilepsy Foundation.​