Dr Roberto Tuchman, co-author of the article on epilepsy and autism in the Winter 2015 issue of Your Autism Magazine, goes into more depth on what seizures are, explains the relationship between epilepsy, autism and intellectual disability (ID), and a little bit about how treatments are prescribed.
What exactly is a seizure?
The term 'seizure' is used to describe paroxysmal, stereotyped, relatively brief interruptions of ongoing behaviour, associated with electrographic seizure patterns. 'Electrographic' means when seizures are evident on an EEG monitor.
Seizures can be divided into two types.
- those that are provoked by an acute event such as fever, infection, trauma, or metabolic illness.
- those that are unprovoked (ie, seizures that are likely to be genetic)
For practical purposes, epilepsy is defined as two unprovoked seizures.
When we see electrographic patterns in the brain without clinically recognizable cognitive, behavioural, or motor functions or any apparent impairment of consciousness, these are called 'sub-clinical' or 'nonconvulsive' seizures.
When an electroencephalogram (EEG) shows spikes and spike and wave discharges which are different to normal, these are called 'epileptiform abnormalities'.
Just because someone has abnormal electrical activity on the EEG, it doesn't mean they have seizures or epilepsy.
When making a diagnosis of seizures, we take into account the person's clinical history and the EEG findings.
The diagnosis of seizures sometimes requires prolonged EEG monitoring with time-locked video recording (also called video telemetry) to help us find out whether what an individual with autism is experiencing is, in fact, a seizure.
What is the link between ID, autism and epilepsy?
Although ID is not a defining feature of autism, it does change socio-cognitive function, communication, and behaviour, negatively impacting neurodevelopmental outcomes in people with autism and in those with epilepsy.
Because of this strong association between epilepsy, ID, and autism, some people think the risk of developing autism in children with epilepsy is dependent on ID, and that in the absence of ID, there is little evidence for a significantly increased risk of autism in children with epilepsy.
Recent research has found common genetic abnormities that put an individual at risk of developing autism, seizures, ID, or all three disorders.
For this reason, when we see someone with autism and epilepsy, especially with ID, we will order genetic testing.
How do you work out the right treatment?
In general, the treatment of seizures in a person with autism follows the same guidelines as those used for people with epilepsy who don’t have autism.
The first thing is always to look at the cause, which will include using an EEG with sleep, an MRI to rule out anything unusual in the structure of the brain which could be causing the seizures, and in some situations, genetic testing. The type of seizure that person is having will determine what medication is used.
For someone with autism who has an abnormal EEG that shows epileptiform activity who has not had a seizure, there is no evidence that treating it improves the outcomes for that person.
In very rare cases, the EEG shows nearly continuous abnormal electrical activity during sleep. This is called 'electrical status epilepticus during slow wave sleep' (ESES) and may suggest a need for treatment with medications.
There is also a rare syndrome known as 'epileptic aphasia' or 'Landau-Kleffner syndrome' in which a child develops normally until the age of two or three years, then loses their language and may develop behaviours which appear to be autistic. In these children, you would probably use a prolonged sleep (usually overnight) EEG to look for ESES.
However it is important to point out that in the vast majority of children with autism who have an abnormal EEG without seizures, you wouldn’t look at treatment unless there is a clear link between the abnormal electrical activity and a slowing down or stalling of that child's development.
If someone with autism is diagnosed with seizures, the neurologist and family should then discuss appropriate further steps together. This might be an MRI, genetic testing and medications.
Dr Roberto Tuchman is Director of the Brain Development Network at Nicklaus Children’s Hospital in Florida, USA. He is also Clinical Professor of Neurology and Psychiatry at the Herbert Wertheim College of Medicine at Florida International University.
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