The features of autism are often subtle and difficult to define.
But roughly one-third of individuals with the disorder have one symptom that’s almost impossible to miss: seizures.
The CDC estimates on the average, one in 110 U.S. children are affected by autism spectrum disorders, (which is four times more likely to develop in boys than in girls).
And medical evidence suggests that the prevalence of epilepsy in autism ranges from 7% to 46%.
Although the prevalence of seizures by age is not well studied, recent studies suggest the risk of seizure remains high into adulthood.
In fact, seizures are the most prevalent neurological disorder associated with ASD (Autism Spectrum Disorder).
New research suggests that “treatment-resistant epilepsy (TRE) is common among patients with autism, and more than one-third of patients in our study group had treatment-resistant epilepsy,” said Dr. Orrin Devinsky, director of the NYU Comprehensive Epilepsy Center, who led the study.
“Among patients for whom we had complete AED and seizure control data, 55% had TRE.”
Futhermore, in patients with TRE, researchers found that seizure onset was at an earlier age than in patients who were seizure-free.
TRE patients also had more developmental regression, as well as motor and language delays, than seizure-free participants.
Three patients had surgical resection and one underwent anterior callosotomy.
These surgical treatments provided little or no improvement in seizure status.
In nine patients with vagus nerve stimulator (VNS) implantation, limited improvement of seizures was noted in two patients and no improvement in seven patients.
“In patients with autism, we found that surgical and VNS outcomes were less favorable, providing a lower rate of seizure freedom, than in other TRE populations,” concluded Dr. Devinsky.
Different forms of autism are often genetic in origin. The reason for this combination is unknown.
A new theory is that the synapsin gene (SYN1) predisposes people to both autism and epilepsy.
And it strengthens the hypothesis that a mutation of the gene could be the cause of both conditions.
A growing number of candidate genes are implicated in both autism and in epilepsy, and many of them are involved in shoring up synapses, the connections between neurons.
The synaps in genes play a crucial role in the development of the membrane surrounding neurotransmitters.
These neurotransmitters ensure communication between neurons.
Although mutations in other genes involved in the development of synapses (the functional junction between two neurons) have previously been identified, this mechanism has never been proved in epilepsy in humans until this new study.
Also, the role of the electroencephalogram (EEG) has become paramount in diagnosing epilepsy and autism.
These EEG studies can reveal hints of the biological roots of autism and epilepsy, and also help clinicians explore new ways of diagnosing and treating both conditions.
“There’s been a lot of interest in using EEG as a biomarker that may tell us a little bit about what is going on in the brain,” says Dr. Tuchman, Clinical Professor of Neurology and Psychiatry at Florida International University Herbert Wertheim College of Medicine.
As many as 40% of an experimental group with autism had epilepsy, which was symptomatic in most children.
Half of the children who had convulsions, had abnormal electroencephalograms, and were diagnosed with epilepsy.
All children with convulsions as the referring symptom had an epileptiform electroencephalogram and were diagnosed with epilepsy.
Furthermore, this study is in agreement with other studies showing that nearly all autistic children with seizures also exhibit epileptiform activity on electroencephalograms.
“Anecdotally, people attest that if you suppress spikes, it can help other areas of development and behavior,” says Shafali Spurling Jeste, assistant professor of psychiatry and neurology at the University of California, Los Angeles.
People with autism are at a higher risk for seizures if they have certain specific neurologic conditions, such as tuberous sclerosis, neurofibromatosis or untreated phenylketonuria.
Seizures are associated with increased mortality and morbidity in individuals with ASD and are the leading cause of mortality in adults with ASD.
Certain subgroups of individuals with ASD have a higher risk for developing seizures and epilepsy.
These subgroups include individuals with intellectual disabilities, genetic abnormalities and/or brain malformations.
A study published in the Journal of Child Neurology found that 39% of those with autism who’d donated brain tissue had epilepsy.
“There seems to be increased mortality in people with autism and epilepsy as compared to those with autism alone,” said Clara Lajonchere, Vice President of Clinical Programs for Autism Speaks, and senior author of the study.
“People with autism are more likely than those in the general population to experience sudden, unexplained death,” she said, adding that some of those deaths are likely from seizures.
“It’s not fully understood why seizures can be deadly”, Doctor Devinksy said.
But it’s believed that seizures can interfere with breathing, brain function and heart rhythms.
Other forms of epilepsy, such as complex partial epilepsy, generalized tonic-clonic epilepsy and absence seizures, may also occur in children with autism.
Often, the seizures can be controlled by anti-consultants,
Four anti-epileptic drugs: Depakene, Depakote, Eilim, (valproic acid), Lamictal, (lamotrigine), Keppra, (levetiracetam) and Zarotin (ethosuximide), were reported to most often reduce the number or lessen the severity of seizures.
But on average, they had little positive or negative effect on the other symptoms of autism.
Certain traditional non-antiepileptic drug treatments — particularly the Ketogenic Diet and the Modified Atkins Diet (M.A.D.) — were perceived to both lessen the number and reduce the severity of seizures and other symptoms, but had the same outcome as anti-epileptic drugs.
However, there is new hope that epilepsy-autism could be reversible with an existing drug already shown to be safe in children, and that could help prevent autism from developing in newborns who have seizures.
Led by Frances Jensen, MD, in the Department of Neurology and the F.M. Kirby Neurobiology Center at Boston Children’s Hospital, the study demonstrated that a group of signaling molecules, known collectively as the mTOR pathway, shows increased activation after a seizure.
This increased signaling — above and beyond the surge that normally occurs early in life — disrupted the normal balance of synapse and circuit development to produce epilepsy and altered social behavior.
The drug Rapamycin (taken before and after seizures), prevented development of abnormal patterns of connections (synapses) between brain cells, reduced later-life seizures and eased autistic-like symptoms.
“Our findings show one of probably many pathways that are involved in this overlap — importantly, one that is already a therapeutic target and where treatment — can reverse the later outcome,” said Jensen.
Both experts agree that much more needs to be learned about epilepsy and autism, including possibly screening children diagnosed with autism for epilepsy.
“They are already dealing with cognitive, social and emotional problems,” said Devinksy. “And now you add to it epilepsy. It adds to the overall problem of autism.”
The key to a solution begins with increasing our understanding of the shared brain networks, genes and other biological mechanisms that underlie these two conditions.
Think of what a world of difference that would make!
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About the author
Phylis Feiner Johnson has been a professional copywriter for 30 years. She also spent 20 years with epilepsy. She writes from the heart to increase education, awareness and funding for epilepsy research. For further information, contact The Epilepsy Foundation of Eastern Pennsylvania at http://www.efepa.org/ and please make a contribution to become an advocate, too.