Older Children’s Spasms Often Missed But Surgery Helps

What was studied

This study looked at late-onset epileptic spasms, which means epileptic spasms starting after 12 months of age. The researchers reviewed records from 62 children diagnosed between 2011 and 2021. All children had spasms confirmed on video, had epileptiform activity on EEG, and none had hypsarrhythmia. The median age when spasms started was 23 months, with a range from 1 year to 15 years.

The team examined how these children first presented, what caused the spasms, how often the diagnosis was delayed or mistaken, which treatments were tried, and how the children were doing over time. They used modern brain imaging and genetic testing to look for causes.

What they found

Diagnosis was often delayed. The median delay was 8 months, and only 24% of children were correctly diagnosed at first presentation. Common misdiagnoses were myoclonic epilepsies and non-epileptic phenomena.

A cause was identified in 95% of children. Most causes were structural-malformative brain abnormalities, especially focal cortical dysplasia and mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy. Smaller groups had structural-acquired causes such as postnatal stroke or central nervous system infection, genetic causes, or oncological causes.

Children with structural aetiologies often had normal development before spasms began, a later median age at spasm onset, and were more likely to have asymmetric or subtle spasms and additional seizures before the spasms.

Prednisolone was associated with cessation of spasms in 29% of treated children, and vigabatrin in 35%. Clobazam was effective in 17%. Other antiseizure medications, vagus nerve stimulation, and ketogenic diet therapy were ineffective in this group. Epilepsy surgery was associated with cessation of spasms in 86% (18/21) of the children who had surgery.

At a median follow-up of 10.3 years, 76% were free of spasms and 53% were free of all seizures. More children with unilateral structural-malformative aetiologies became seizure-free than children with other aetiologies, most commonly after surgery but occasionally after vigabatrin or clobazam. Impairment of cognitive function or adaptive behaviour was more common in children with genetic than structural aetiologies, and in children with ongoing seizures than in those with seizure freedom. Among children who underwent epilepsy surgery, 62% achieved average or low-average adaptive functioning or normal intellectual capacity.

Limits of the evidence

This was a retrospective study, meaning the researchers looked back at past records rather than assigning treatments in a controlled way. Because of that, the study cannot show with certainty that one treatment led to better outcomes than another.

The study included 62 children, and some treatment groups were likely small, which makes treatment estimates less certain. The abstract also does not give full details on how treatment choices were made or how children were selected for surgery.

For families and caregivers

For families, this study shows that epileptic spasms can start after infancy and are often missed at first. Earlier recognition may be important, because diagnosis was often delayed.

The study also found that many children with late-onset spasms had an identifiable cause, especially a structural brain abnormality, and that children with unilateral structural-malformative causes were more likely to become seizure-free, often after surgery. Still, outcomes varied, and not every child became seizure-free or had typical cognitive or adaptive functioning.

What to watch next

Future studies could compare treatments more directly and help clarify which children are most likely to benefit from medicines versus surgery.

Terms in this summary

epileptic spasms

A type of seizure that causes sudden brief body stiffening or jerking, often happening in clusters.

EEG

A test that records the brain's electrical activity.

hypsarrhythmia

A very disorganized EEG pattern often seen in infantile spasms.

structural-malformative

Caused by a brain structure that formed differently during development.

focal cortical dysplasia

A brain malformation where part of the brain's outer layer did not develop normally and can cause seizures.

vigabatrin

A seizure medicine often used for epileptic spasms.

prednisolone

A steroid medicine sometimes used to treat epileptic spasms.

epilepsy surgery

An operation to remove or disconnect the part of the brain causing seizures.