Approximately 25-30% of children with Autism Spectrum Disorder (ASD) will develop epilepsy, as many as 50-60% of children with ASD have some changes in the brain waves found on the EEG
Epilepsy is defined as having two or more seizures which are unprovoked (not caused by illness, head injury, low blood sugar, etc.). Approximately 25-30% of children with autism spectrum disorders (ASD) will develop epilepsy. Epilepsy is more common in children whose ASD is due to a genetic or metabolic disorder (symptomatic ASD) as compared to those with no clear cause for ASD (idiopathic). While epilepsy can begin at any age, the two most common times for seizures to start are early childhood (approximately 1-5 years of age) and adolescence (approximately 11-18 years of age). Individuals with symptomatic ASD are more likely to begin having seizures in early childhood and individuals with idiopathic ASD are more likely to begin having seizures as teenagers. Seizures can begin in adulthood but this is much less common. As children grow older and go through puberty, seizure types can change. Many children will outgrow their seizures as they move into adulthood.
Children with ASD can have many different types of seizures. The easiest type of seizure to recognize is a generalized tonic-clonic seizure (formerly called “grand mal”) consisting of shaking of arms and legs with eyes rolled back and loss of consciousness. Other types of seizures commonly seen are absence seizures (staring spells) and myoclonic seizures (very quick jerks of the arms or legs) and focal seizures. Focal seizures (also known as partial seizures) start in just one part of the brain and usually consist of decreased awareness, often with some unusual movements of the face or arms. More severe forms of epilepsy (most commonly seen in symptomatic ASD) can also include atonic seizures (sudden drops of the head or whole body) and tonic seizures (stiffening of the whole body).
Although approximately 25-30% of children with ASD will develop epilepsy, as many as 50-60% of children with ASD have some changes in the brain waves found on the EEG( the electroencephalogram or the procedure to measure brain waves). EEGs are not recommended for all children with ASD. They should be obtained for children with behaviors that are suspicious for seizures or for children who have experienced loss of skills occurring after age three. A typical EEG lasts about an hour, however, sometimes a 24-hour EEG is needed to help decide if a certain behavior is a seizure. EEGs can also be used to find abnormal brain wave activity during a night of sleep.
There are many other events or behaviors that can be mistaken for seizures and need to be considered in children with ASD. An example is esophageal or acid reflux that can cause children to have behaviors such as full body stiffening or decreased awareness. Sleep problems such as nightmares or night terrors can also look like seizures. Some children, especially those who are non-verbal, can develop random episodes of rage that can be mistaken for seizures but are often due to discomfort such as gastrointestinal pain or headaches.