What do infantile spasms look like?

Short answer: infantile spasms look like a sudden bend forward, stiffening backward, or a mix of both, of a baby's neck, body, arms or legs. Each spasm lasts 1 to 2 seconds, and they usually come in a cluster, one after another, often just after the baby wakes up.¹

If you think your baby is having them, film the movements on your phone and see a doctor urgently. Infantile spasms are a serious type of epilepsy, and fast diagnosis and treatment matter.^2,3

Signs of infantile spasms

Doctors describe a spasm as a sudden flexion (bending), extension (stiffening and straightening), or mixed flexion-extension of the muscles of the trunk, neck and upper arms and legs.¹ Reviews describe three main types:^4,5

• A flexor spasm: a sudden bend forward of the trunk and neck, with the arms drawn in. This is the classic form.⁵
• An extensor spasm: a sudden stiffening and straightening of the trunk, neck, arms or legs.¹
• A mixed spasm: some bending and some stiffening in the same spasm.¹

The ILAE notes that spasms can be on one side or both.¹ The exact look varies from baby to baby, which is one reason a video helps.

They come in clusters

One spasm on its own is less typical. Spasms usually come in a series, often on waking from sleep.¹ If a movement only ever happens once at a time, doctors consider other types of seizure or other causes.¹ A cluster can be a few spasms or more than 100, and can last from under a minute to more than 10 minutes.⁶

Subtle signs

Some spasms are small. They can be only a chin movement, a grimace or a head nod.¹ Spasms can also be uneven, stronger on one side, or only on one side.¹

Changes in development

Development may slow or go backward when spasms begin, so a baby may stop doing things they could do before. Some babies keep developing normally at first, so normal development does not rule spasms out.⁷

When do infantile spasms start?

Spasms start between 1 and 24 months of age, most often between 3 and 12 months.⁷

Symptoms of infantile spasms at 2 months

Babies can have spasms from 1 month old, so a 2-month-old can have them.⁷ At this age, the normal startle (Moro) reflex is still present, which can make spasms harder to tell apart. The Moro reflex normally goes away after 3 or 4 months.⁸ Clusters of movements on waking are a reason to get checked at any age.

Infantile spasms or normal movement?

Many harmless movements in babies can look like spasms. Spasms are also easy to dismiss. In a survey of 100 families, parents often said their sense that "something is wrong" was discounted, and many reported that the doctors they first saw did not know infantile spasms well.⁹

These are the most common look-alikes. Only a doctor can sort them out, often with an EEG.

Startle (Moro) reflex

The Moro reflex is a normal newborn reflex. It is set off by a sudden change in head position: the baby looks startled, the arms fling out with the palms up, and the baby may cry.⁸ It normally goes away after 3 or 4 months.⁸ A startle has a trigger. Spasms usually come in a series, often on waking.¹

Reflux and Sandifer syndrome

In Sandifer syndrome, reflux causes arching of the back, twisting of the limbs, and turning or tilting of the head. These events often happen with or after feeding.¹⁰

Benign myoclonus of infancy and shuddering

Benign myoclonus of infancy and shuddering attacks usually start from 4 months. They are a brief jerk or a shiver-like shudder of the head and body lasting a few seconds. They happen while the baby is awake, often during feeding or in a high chair or car seat, and do not distress the baby.¹⁰ The ILAE lists these as conditions to rule out before diagnosing infantile spasms.¹⁰

Jerks only in sleep

Benign neonatal sleep myoclonus is brief flurries of jerks that happen only during sleep. Waking the baby stops them.¹⁰

Head drops

Non-epileptic head drops begin at 3 to 6 months and go away by 12 months. Babies with them develop normally.¹⁰ Because a head nod can also be a subtle spasm, head drops still need a doctor's review.¹

Infantile spasms vs seizures

Infantile spasms are one of several seizure types in babies. Doctors tell seizure types apart partly by how long each movement lasts:¹

• Epileptic spasm: 1 to 2 seconds.
• Myoclonic jerk: shorter than a spasm.
• Tonic seizure: stiffening lasting from 3 seconds to minutes.

The condition is now called infantile epileptic spasms syndrome (IESS). West syndrome is the form with spasms, an EEG pattern called hypsarrhythmia, and a stall or loss of development.⁷

Infantile spasms video: how to record a useful one

A video is one of the most useful things a parent can bring. In a US study of 80 babies, those whose parents brought a smartphone video had their first EEG 16 days sooner, and were diagnosed and started treatment about 17 days sooner, than babies without one.² The authors urge pediatricians to ask parents for smartphone videos.² In a study of 180 clinicians watching smartphone videos of spasms and look-alikes, clinicians were right about two times in three (64%), rising to 72% after brief training and a standard clinical history.¹¹

Tips, based on what doctors look for:

• Be ready after naps and in the morning. Spasms usually come on waking.¹
• Keep filming through the whole cluster. Spasms come in a series, and the pattern is part of what doctors look for.¹
• Show the whole body and the face. Spasms involve the trunk, arms and legs, and subtle ones may be only a head nod, chin movement or grimace.¹
• Write down what happened. Note the time, whether the baby had just woken, how many movements there were, how long the cluster lasted, and any change in skills. In the video study, accuracy rose after brief training and a standard clinical history.^7,11
• Do not wait for a perfect video. Filming should never delay getting care.

This site does not host videos. Ask your baby's doctor or a family group such as the Infantile Spasms Action Network where to see examples.

When to seek care

See a doctor the same day or as soon as possible if your baby has clusters of sudden bends, stiffening or head nods, especially on waking, or seems to be losing skills. Bring your video and ask directly: "Could these be infantile spasms, and does my baby need an EEG?" Experts advise seeing a pediatric neurologist as early as possible if the events on video look suspicious, and a prolonged video-EEG awake and asleep if spasms are suspected.⁶

Speed matters. A longer delay before effective treatment is linked to lower development scores.^12,13 If you are told the movements are nothing but they keep happening, ask for a referral to a pediatric neurologist.

What happens next

The doctor will usually arrange an EEG, which records brain waves and is best done to include sleep.¹⁴ If infantile spasms are confirmed, treatment usually starts quickly with hormonal treatment (ACTH or prednisolone) or vigabatrin. Vigabatrin is the usual first choice when tuberous sclerosis is the cause.¹⁵

If vigabatrin is prescribed for spasms, it is given as a measured liquid dose twice a day.¹⁶ Every vigabatrin form is the same medicine.¹⁶ The ready-to-use liquid (labeled for infantile spasms from 1 month to 2 years, like the powder) needs no mixing; in one small study funded by its maker, doses prepared from it were more accurate than doses mixed from powder.^16,17