Infantile Spasms


Here you’ll find answers to some of the questions that parents often have about this condition. Additional resources are listed at the bottom of the page. Diagnosis and management information can be found in the Infantile Spasms module, which is written for primary care clinicians but also may be of help to parents and family members.

What is an infantile spasm and what causes it?

An infantile spasm (IS) is a specific type of seizure seen in an epilepsy syndrome of infancy and childhood known as West syndrome. West syndrome is characterized by infantile spasms, developmental regression, and a specific pattern on electroencephalography (EEG) testing called hypsarrhythmia (chaotic brain waves). The onset of infantile spasms is usually in the first year of life, typically between 4-8 months. Infantile spasms usually stop by age 5, but may be replaced by other seizure types. Many underlying disorders, such as birth injury, metabolic disorders, and genetic disorders can give rise to spasms, making it important to identify the underlying cause. In some children, no cause can be found. Infantile Spasms (NINDS)

What are the symptoms of infantile spasms?

The seizures primarily consist of a sudden bending forward of the body with stiffening of the arms and legs; some children arch their backs as they extend their arms and legs. Spasms tend to occur upon awakening or after feeding, and often occur in clusters of up to 100 spasms at a time. Infants may have dozens of clusters and several hundred spasms per day.

How are they diagnosed?

Spasms are usually diagnosed by evaluating the clinical circumstances, the presence of developmental delay or regression, and an abnormal EEG—one that shows a particular pattern called "hypsarrhthymia." Additional testing may be performed to look for the underlying cause of the infantile spasms.

What is the prognosis?

The prognosis for children with IS is dependent on the underlying causes of the seizures. The intellectual prognosis for children with IS is generally poor because many babies with IS have neurological impairment prior to the onset of spasms. Spasms usually resolve by mid-childhood, but more than half of the children with IS will develop other types of seizures. IS will sometimes gradually turn into Lennox-Gastaut syndrome, an epileptic disorder of later childhood.

What is the risk for other family members or future babies?

The risk to your family and future babies will depend on the underlying cause for the spasms. Some spasms may have a genetic component and may be possible or likely in future pregnancies. Other spasms may be caused by brain damage; e.g., prenatal stroke.

What treatments/therapies/medications are recommended or available?

Treatment with corticosteroids such as prednisone is standard, although serious side effects can occur. Several newer antiepileptic medications, such as topiramate, may ease some symptoms. Some children have spasms as the result of brain lesions and surgical removal of these lesions may result in improvement.

Is it safer to use vigabatrin or steroids?

The choice of one therapy over another should be made only after a full discussion of benefits and risks with your child's physician. Although both of these treatments have potentially dangerous side effects, the consequences of untreated infantile spasms are often devastating. You might consider joining a support group of parents who have made a similar choice to get a parent perspective. See Support Groups (Epilepsy Association of Utah).


Information & Support

Where can I go for further information?

For Parents and Patients


Epilepsy Foundation
A national organization that provides information about epilepsy; programs to improve epilepsy treatment; materials to assist in helping people with epilepsy find jobs; activities in schools to educate the public; activities to educate policymakers; funds for research; and news about conferences and other items of interest.

Epilepsy Association of Utah
For individuals with epilepsy, families, and friends, this site offers newsletters, events, links, local and youth support groups, activities for kids, first aid for seizures, and more.


Infantile Spasms (NINDS)
Information from the National Institute of Neurological Disease and Stroke including diagnosis, treatment, and clinical trials in progress.

Infantile Spasms (
Several frequently asked questions and answers about infantile spasms.

Services in Montana

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Early Intervention for Children with Disabilities/Delays

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Authors & Reviewers

Initial Publication: March 2012; Last Update: September 2016
Current Authors and Reviewers (click on name for bio):
Author: Lynne M. Kerr, MD, PhD
Contributing Author: URLEND Trainees, 2011-2012
Funding: The Medical Home Portal thanks the 2011-2012 URLEND Medical Home Portal trainees group for their contribution to this page.