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Infantile Spasms (IS) are a type of epilepsy. They may also be called Epileptic Spasms or West Syndrome.  An Infantile Spasm is when there is a sudden stiffening of the body and the arms, legs and head bend backwards and forwards. This is called a seizure. Children with IS may also have Developmental Delay, Autism (ASD) or go on to develop other types of epilepsy.

What is it like for siblings who have a brother or sister with Infantile Spasms?

Lots of siblings have really good relationships with their brothers and sisters who have IS.  They enjoy playing with them and spending time with them.  However, siblings also say that their brothers and sisters with IS can need lots of extra attention and help with everyday things from a parent, which can make them feel left out. Siblings might also feel sad that they can’t play with their brothers and sisters in the same way that other children can.

What causes Infantile Spasms?

Some babies get IS because of the way their brain has formed, or an infection or injury early in their life, or a problem with their genes (the instructions for how your body develops). For some children the doctors don’t find a reason why it happens.  IS usually start when a baby is between 3 and 8 months old. They cannot be caught like a cold.

What does it mean?

Babies can have seizures or spasms which are a sudden stiffening of the body. This is when the arms are flung out as the knees pull up and the body bends forward. Sometimes the head can be thrown back as the body and legs stiffen in a straight-out position. Babies may cry during or after the seizure although each seizure lasts only a second or two, but they usually happen close together in a series.  They happen most often just after waking up and hardly ever happen when a baby is asleep.


Babies with IS often seem to stop developing and may stop being able to sit, roll over, or babble when they could do these things before. Babies with IS may also stop being interested in what is going on around them and not be interested in playing.


Each baby with IS is different. But they may also go on to have problems with things like walking and balancing, riding a bike or playing with toys. They may also struggle with talking, drawing and writing, using a spoon or fork, or getting dressed by themselves. They may have difficulty understanding words or ideas, explaining how they feel or understanding other people’s feelings.


IS might not look as like there is much happening which can be different to other types of epilepsy, but they still might affect how the brain works on the inside.

What treatment is there?

Most babies and infants who have IS have to be given medicine every day. They might need to be given more than one type of medicine. This may help to prevent seizures. Sometimes it can stop the seizures altogether.

Other babies with IS may have Dietary Treatment. This is when only eating some type of foods can help to reduce the number of seizures which they have.

Sometimes, when these treatments don’t work, they may need to have an operation.

As they get older babies and infants with IS may need:

  • physiotherapy to help their arms and legs to work better
  • occupational therapy to help them with doing tasks and looking after themselves
  • speech and language therapy to help them with talking and understanding


This has been read and approved for publication by the UK Infantile Spasms Trust in July 2022 and will be reviewed and updated every 2 years