Infantile spasms (IS), also known as West Syndrome, are subtle seizures that occur in a baby’s first year of life – a time when brain development is most critical. The neurological effects of this rare epilepsy syndrome can be severe, often causing large developmental delays and cognitive and physical deterioration.

Not all children with IS will respond to treatment. There is no reliable way of predicting who will respond favorably. Learn about CURE Epilepsy’s Infantile Spasms Initiative, established to advance the understanding of the underlying pathology of infantile spasms and lead to the development of a therapy or cure.

What are the signs of Infantile Spasms?

Because these spasms do not look like traditional seizures, primary care physicians and pediatricians can find it challenging to diagnose IS. This often means a delay in effective treatment for affected children during the critical window within the weeks and months after the emergence of symptoms, which can have dire consequences.

Perhaps the most important way to improve infantile spasms outcomes is to recognize the signs and symptoms and get children suspected of having infantile spasms evaluated by a trained medical provider. Consider using the STOP Infantile Spasms mnemonic (right) developed by ISAN as an important starting point.

Infantile spasms are a medical emergency. If you recognize movements in your baby like those in the video below, please reach out to your healthcare provider for help.

Source: Infantile Spasms Awareness Network video, produced by the Child Neurology Foundation

Quick Facts

  • Infantile spasms affect 1 in 2000 children1,2
  • Infantile spasms are also known as West Syndrome, after Dr. W.J. West, who first described the symptoms of “infantile convulsions” in his own son in 1841.
  • Typically begin between 2 and 12 months old and peaks around 4 to 8 months old3
  • Seizures are subtle, often resembling a jerk, reflex, or head bob. Involuntary movements of the trunk and limbs are characteristic of the syndrome, as well developmental delays or the loss of capabilities, and an atypical EEG pattern of large, synchronous disorganized brain waves (hypsarrhythmia).
  • Current standard treatment is a hormone (ACTH, prednisone) or anti-seizure medication (vigabatrin).
  1. Riikonen R. Epidemiological data of West syndrome in Finland. Brain Dev. 2001; 23: 539– 541.
  2. Ludvigsson P, Ólafsson E, Sigurðardóttir S, et al. Epidemiologic features of infantile spasms in Iceland. Epilepsia. 1994; 35: 802– 805.
  3. Hrachovy R. West’s syndrome (infantile spasm). Clinical description and diagnosis. Adv Exp Med Biol. 2002;497:33–50.

What Does the Future Hold?

Infantile Spasms Initiative researcher Chris Dulla, PhD talks about possible directions for treatments and cures for infantile spasms.

Questions about Infantile Spasms?

What are infantile spasms?

Infantile spasms is a rare epilepsy disorder that most often emerges within the first year of life. The first symptoms that are typically noticed are physical spasms, which may look like brief, synchronous movements of the head, trunk, and limbs, or may be subtler ‘head nods’. Children with infantile spasms also typically show developmental delays or developmental deterioration, which may become apparent after the first symptoms appear. Additionally, children with infantile spasms often have an abnormal EEG characterized by hypsarrhythmia, which is a disorganized pattern of brain activity.4

Infantile spasms are also known as West Syndrome, after Dr. W.J. West, who first described the symptoms of “infantile convulsions” in his own son in 1841 (West, Lancet, 1841).

4 Commission on Pediatric Epilepsy of the International League Against Epilepsy, 1992; Lux and Osborne, 2004

What do infantile spasms look like?

Infantile spasms can be subtle or obvious. In the subtlest cases, these seizures may take the form of a slight drop of the head or other type of involuntary movement. They might also look like the classic Moro reflex, in which an infant reaches both arms out at the same time. Other infantile spasms may involve the infant extending or jerking its arms, legs, and neck at the same time. These spasms can occur as a single event, or may occur in clusters of several spasms. They often occur in the morning or after the child wakes from a nap.5

To view videos of children with infantile spasms, please visit the Infantile Spasms Project.

5 Shields, 2006

What causes infantile spasms?

There are many different possible causes for infantile spasms, including malformations in brain structures, genetic abnormalities, infections, trauma, or tumors.6 Infantile spasms are more common in individuals with certain underlying disorders: for example, infantile spasms occur in 30 to 50% of children with tuberous sclerosis,7 a rare genetic disorder. In some case, infantile spasms occur without any identifiable underlying cause (called cryptogenic infantile spasms), while in other cases there is a clear underlying cause for the seizures (called symptomatic infantile spasms).8

6 Pellock et al., 2010; Paciorkowski et al., 2011
7 Ohtsuka et al., 1998; Chu-Shore et al., 2010; Moavero et al., 2010
8 Pellock et al., 2010

How can I tell if my child is having infantile spasms?

If you suspect your child is having infantile spasms, one of the most important things you can do is to videotape one or more of the episodes to show to your child’s doctor. You may wish to compare your child’s behavior to behavior in children diagnosed with infantile spasms, which can be done by watching videos of children with infantile spasms online. Many of these videos can be found by searching “infantile spasms” on YouTube, or by viewing the collection of videos available on the Infantile Spasms Project website.

What should I do if I suspect my child is having infantile spasms?

If you suspect your child is having infantile spasms, take a video to show your child’s pediatrician or a neurologist and have your child evaluated. Infantile spasms can be subtle and are often mistaken for other conditions, but it is important to get a diagnosis as soon as possible – so follow your instincts if you believe something is wrong.

This helpful mnemonic tool developed by the Infantile Spasms Action Network (to which CURE belongs) can help you understand what to do if you suspect infantile spasms:

How are infantile spasms diagnosed?

Diagnosis will typically first consist of a physical examination to determine whether spasms can be seen. Because spasms may not occur while the child is at the doctor’s office or may be very subtle, it is helpful to bring a video of a suspected episode to show the doctor.

Age is also considered in diagnosis, because infantile spasms most often emerge within the first year of life, frequently between ages 4 and 8 months (although they can occur later).

An EEG is an important part of diagnosis. The most common EEG pattern associated with infantile spasms is hypsarrhythmia, which looks like very large, disorganized, and chaotic brain waves.9

9 Shields, 2006; Pellock et al., 2010

What treatments are available for infantile spasms?

Currently, two of the most effective treatments for infantile spasms are adrenocorticotropic hormone (ACTH), a hormone produced by the body, and Vigabatrin, an antiseizure medication.10 There are also a number of other hormonal therapies and drugs that are sometimes used to treat infantile spasms, and in certain cases surgery is recommended.11 The American Academy of Neurology (AAN) and Child Neurology Society created an information sheet that provides more information on infantile spasms treatment options. It is important to weigh the benefits and drawbacks of each treatment method. Your doctor can help you develop a treatment strategy that is right for your child.

10 Tsao, 2009, Nelson, 2015
11 Tsao, 2009, Nelson, 2015

How often does infantile spasms occur?

In most studies, the number of reported infantile spasms cases falls in the range of 2 to 4.2 children per 10,000 live births per year.12 Infantile spasms have been found to occur slightly more often in boys than in girls,13 and most often appear between the ages of 4 and 8 months.14

12 Cowan and Hudson, 1991; Trevathan et al., 1999; Pellock et al., 2010
13 Cowan and Hudson, 1991; Ludvigsson et al., 1994
14 Shields, 2006

Are infantile spasms genetic?

There are some genetic links to infantile spasms. Mutations, deletions, or abnormalities in certain genes have been associated with infantile spasms. These gene abnormalities associated with the presentation of infantile spasms can lead to many different possible changes in the brain depending upon the gene involved – changes such as brain malformations, errors in metabolism, changes in brain excitability, or other genetic disorders (such as tuberous sclerosis).15

Importantly, there is a lot left to learn about the underlying mechanisms of infantile spasms. Therefore, continued research into the underlying causes of infantile spasms is essential.

15 Paciorkowski et al., 2011

Where can I get more information on infantile spasms?

Infantile Spasms Project: A program based at the UCLA intended to guide parents and caregivers of children with infantile spasms as well as practitioners in a straightforward way.

Child Neurology Foundation: An organization that provides support and education for caregivers and children with neurologic conditions, including the promotion of infantile spasms awareness and providing information on the Infantile Spasms Action Network.

Tuberous Sclerosis Alliance: An organization committed to supporting tuberous sclerosis research and providing education and support for individuals and families affected by the disorder.


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