Infantile Spasms: How Early Diagnosis Protects Brain Development

What looks like a simple startle reflex may actually be a neurological emergency.

Infantile spasms are a serious type of seizure that typically begins during infancy. The movements can be extremely brief and subtle, which means parents may initially mistake them for normal infant behavior, reflux, colic, or a startle response.

Recognizing the difference matters because infantile spasms can interfere with a baby’s developing brain. Rapid diagnosis and appropriate treatment are important for controlling seizures and protecting developmental progress.

For parents who notice unusual repetitive movements, clusters of sudden body contractions, or a loss of previously acquired developmental skills, prompt evaluation by a pediatric neurologist is important.

Neurology Center for Epilepsy & Seizures (NCES) provides specialized pediatric neurology care for children with suspected seizures, epilepsy, and other neurological conditions throughout New Jersey.

What Are Infantile Spasms?

Infantile spasms are a type of epileptic seizure that occurs in babies. They are sometimes referred to as epileptic spasms.

An individual spasm may last only a second or two. During that brief event, a baby’s body may suddenly stiffen, bend forward, or extend.

The movements can involve:

• Sudden bending of the head or body
• Arms extending outward
• Arms and legs pulling inward
• Brief stiffening
• Repeated head drops
• A quick crunching motion of the body

What makes infantile spasms particularly recognizable is their tendency to occur in clusters.

Instead of one isolated movement, a baby may have a series of spasms separated by several seconds. The cluster can continue for several minutes.

Spasms frequently occur around transitions between sleep and wakefulness, especially after the baby wakes.

Because each movement can be so brief, parents may initially wonder if they are seeing a normal startle.

What Age Do Infantile Spasms Usually Start?

Infantile spasms typically begin during the first year of life, often between approximately 3 and 12 months of age, with many cases beginning around 4 to 8 months.

This period coincides with rapid stages of brain development.

During infancy, the brain is forming and strengthening neural connections involved in movement, communication, learning, vision, social interaction, and other abilities.

That rapid development is one reason infantile spasms require urgent attention.

Parents shouldn’t wait for the movements to become more dramatic before contacting a healthcare professional.

Infantile Spasms vs. a Normal Startle Reflex

Babies make many sudden movements, and not every unusual movement is a seizure.

The Moro reflex, commonly called the startle reflex, can cause an infant to suddenly extend the arms and legs in response to a sensation such as unexpected movement or noise.

Infantile spasms can sometimes resemble these normal movements.

There are important differences to watch for.

A normal startle usually occurs in response to a recognizable stimulus. Infantile spasms may appear without an obvious trigger and frequently repeat in a cluster.

Parents should be particularly attentive to:

• Repeated identical movements
• Several spasms occurring close together
• Episodes after waking
• Sudden head drops
• Repeated body crunching
• Changes in alertness or interaction
• Loss of developmental abilities

If you’re unsure what you’re seeing, record the episode on your phone if it is safe to do so.

A video can provide valuable information to the child’s pediatrician or neurologist. Do not delay seeking medical care while trying to capture a perfect recording.

How Infantile Spasms Can Affect Brain Development

A baby’s brain undergoes extraordinary development during the first years of life.

Neural networks are rapidly developing to support abilities such as:

• Visual attention
• Movement
• Language
• Memory
• Learning
• Social interaction
• Problem-solving

Infantile spasms are concerning not simply because a baby is having seizures. The abnormal electrical activity associated with the condition can disrupt healthy brain function during a critical developmental period.

Some children with infantile spasms experience developmental delays or developmental regression.

Regression means a child loses a skill that had already been acquired.

For example, a baby who has been smiling socially or interacting with caregivers may become less engaged. A child who has developed better head control or other motor abilities may stop progressing or appear to lose some of those skills.

This connection between seizures and development is why infantile spasms require rapid neurological evaluation.

Developmental Regression Can Be an Important Warning Sign

Parents usually know their baby’s behavior better than anyone else.

Changes in interaction or development can therefore be an important clue, even when the movements themselves are difficult to identify.

Contact your child’s healthcare provider promptly if unusual movements occur alongside changes such as:

• Less smiling
• Reduced eye contact
• Decreased interaction
• Loss of previously acquired skills
• Reduced visual attention
• Changes in muscle control
• Slower developmental progress

Developmental regression has many possible causes and does not automatically mean a child has infantile spasms.

When regression occurs alongside suspicious repetitive movements, however, neurological assessment becomes particularly important.

Warning Signs of Infantile Spasms Parents Should Know

Infantile spasms do not usually resemble the prolonged convulsive seizure many people picture when they hear the word “seizure.”

They can be much subtler.

Sudden Jerking or Body Crunching

The baby’s head and torso may suddenly bend forward while the arms move outward or inward.

Repeated Head Drops

Some spasms appear primarily as brief head movements.

Clusters of Similar Movements

A series of nearly identical movements occurring several seconds apart is an important pattern to recognize.

Spasms After Waking

Clusters commonly occur shortly after a baby wakes from sleep.

Developmental Regression

A baby may stop making developmental progress or lose abilities that had previously emerged.

Changes in Alertness

Parents may notice that their baby seems less engaged or visually attentive than before.

These signs warrant prompt medical attention.

What Should I Do If I Think My Baby Is Having Infantile Spasms?

If you suspect infantile spasms, contact your child’s healthcare provider promptly and explain exactly what you are seeing.

If possible and safe, record a video of an episode.

Videos can help clinicians see the movement pattern rather than relying solely on a verbal description.

Note:

• What time the episode occurred
• Whether the baby had just awakened
• How many movements occurred
• How long the cluster lasted
• What the baby’s body did
• How the baby behaved afterward
• Any recent developmental changes

Because infantile spasms require rapid diagnosis and treatment, suspected episodes should not simply be monitored at home for weeks to see if they disappear.

How Pediatric Neurologists Diagnose Infantile Spasms

Diagnosis usually involves combining the child’s clinical history, examination, developmental history, and neurological testing.

One of the most important tests is an electroencephalogram, or EEG.

EEG Testing for Infantile Spasms

An EEG records electrical activity in the brain through electrodes placed on the scalp.

Children with infantile spasms may have a distinctive abnormal EEG pattern called hypsarrhythmia, although not every child shows the classic pattern.

The EEG may also help capture the electrical changes occurring during an actual spasm.

Depending on the situation, longer video EEG monitoring may be necessary.

NCES provides EEG testing in New Jersey, including neurological testing used in the evaluation of suspected seizures and epilepsy.

Parents who want to understand the process in advance can also read our guide to pediatric EEG testing.

Why Might a Baby Need an MRI?

Once infantile spasms are identified, doctors also need to investigate why they are occurring.

Brain MRI may be recommended to look for structural abnormalities or previous brain injuries that could be associated with the seizures.

Depending on the child’s history and findings, additional evaluation may include:

• Genetic testing
• Blood testing
• Metabolic testing
• Developmental assessment
• Additional neurological testing

Identifying the underlying cause can influence treatment decisions and provide families with more information about prognosis.

What Causes Infantile Spasms?

There isn’t one single cause. Infantile spasms may be associated with structural brain abnormalities, genetic conditions, metabolic disorders, previous brain injury, or other neurological conditions.

Tuberous sclerosis complex is one condition strongly associated with infantile spasms.

In some children, determining the cause requires extensive testing.

The underlying cause can also influence the child’s developmental outlook, making a thorough neurological evaluation important beyond simply confirming that the movements are seizures.

How Are Infantile Spasms Treated?

Infantile spasms require treatments specifically shown to be effective against this seizure type.

First-line treatments may include:

• Adrenocorticotropic hormone, or ACTH
• High-dose corticosteroid therapy
• Vigabatrin

Vigabatrin has a particularly important role when infantile spasms are associated with tuberous sclerosis complex.

Treatment selection depends on factors such as the suspected cause, the child’s health, potential medication risks, and the pediatric neurology team’s clinical assessment.

Other treatment approaches may be considered when initial therapies don’t control the spasms.

Some children with a focal structural brain abnormality may also be evaluated for epilepsy surgery, while other treatment strategies may be considered in difficult-to-control cases.

Medication decisions should always be made by the child’s treating neurological team.

Why Follow-Up EEG Testing Matters

Seeing the spasms disappear is important, but visible seizure control isn’t the only consideration.

A child’s neurologist may use follow-up EEG testing to determine whether the abnormal electrical activity associated with the spasms has also improved.

Parents should continue follow-up care even when the movements appear to have stopped.

Ongoing neurological assessment can help evaluate:

• Seizure control
• EEG improvement
• Medication response
• Developmental progress
• Treatment side effects
• Emergence of other seizure types

This close monitoring is especially important during a period of rapid brain development.

Early Intervention Goes Beyond Seizure Control

Controlling infantile spasms is a major priority, but developmental care may also be needed.

Children who experience developmental delays or regression may benefit from early intervention services based on their individual needs.

These may include:

• Physical therapy
• Occupational therapy
• Speech and language therapy
• Developmental services
• Other supportive therapies

The exact services depend on the child’s age and developmental profile.

Neurological treatment and developmental support often work alongside one another rather than serving as alternatives.

Why Early Diagnosis of Infantile Spasms Matters

With infantile spasms, time matters.

Delayed recognition can mean prolonged exposure to seizures and abnormal electrical brain activity during an important stage of development.

Prompt treatment is associated with a better opportunity to control the spasms and may improve developmental outcomes, although every child’s prognosis depends on multiple factors, including the underlying cause.

Early care allows the medical team to:

• Confirm whether the movements are seizures
• Begin appropriate treatment
• Look for an underlying cause
• Monitor EEG activity
• Evaluate development
• Connect families with supportive services

Parents should never feel that they need to diagnose the condition themselves before asking for help.

Recognizing that something appears unusual is enough reason to contact a healthcare professional.

Pediatric Epilepsy Care in New Jersey

Infantile spasms are one example of how differently seizures can appear in children.

Some seizures involve obvious jerking or stiffening. Others cause brief changes in awareness, unusual movements, staring episodes, or subtle behavioral changes.

NCES provides neurological care for children with suspected and diagnosed epilepsy and seizures.

Parents who are new to pediatric epilepsy may also find our guide on navigating a new epilepsy diagnosis helpful when preparing for the next steps in their child’s care.

Don’t Wait When Your Baby’s Movements Look Unusual

Infantile spasms can be easy to overlook because the individual movements are so brief. The pattern is what often raises concern: repeated spasms, clusters after waking, and changes in development or interaction.

If your baby is experiencing movements that could represent seizures, prompt medical evaluation is important.

NCES provides pediatric neurological and epilepsy care for families throughout New Jersey, including evaluation of unusual movements, suspected seizures, and developmental concerns associated with neurological conditions.

Schedule an Appointment with NCES for pediatric neurological care.

For questions about pediatric epilepsy, seizure evaluation, or EEG testing, Contact Us.

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