Rates of Autism and Epilepsy
Rates of autism have increased considerably over the last 50 years. The high concurrence of autism and epilepsy conditions has led to a considerable increase in epilepsy conditions as well. According to the Autism Speaks website, an estimated one third of people suffering from autism will develop epilepsy in the coming years.
As a neurological condition, autism disorder exists on a spectrum, with varying degrees or symptoms experienced by different people. Likewise, people affected by epilepsy experience this condition in different degrees. Data collected by Autism Speaks shows epilepsy rates among people with autism range from 20 to 40 percent compared to a one percent occurrence within the general population. Interestingly enough, it's estimated that five percent of children affected by epilepsy will go on to develop autism disorder.
Similarities Between Autism and Epilepsy
Abnormalities in brain neuron or brain cell activity are characteristic of both autism and epilepsy. Brain neuron activity has to do with how brain cells communicate with one another. For people with autism, these activities have a significant impact on their ability to concentrate, learn and communicate with others. With epilepsy, abnormal neuron activity is almost like a short-circuiting that takes place in the brain, which accounts for the recurring seizures a person may experience.
As brain neuron activity plays a central role for both disorders, some of the brain abnormalities present in autism may very well contribute to the likelihood of a person developing seizures. In effect, any overloads or disturbances in neuron activity found in autism may predispose a person to epilepsy.
Effects of Illness
For some children affected by autism, the first seizure episode may be triggered by an illness. Some seizures may actually be triggered by the onset of a fever in a child. Also known as febrile seizures, these events are not uncommon in children with high fevers, regardless of whether autism is present or not.
The occurrence of fever, in and of itself, represents the immune system kicking into gear. Part of the immune system's response involves creating inflammation as a means to isolate the threat, or germ or virus. According to the Autism Key website, the antibodies released in the process can disrupt neuron activity in the brain of autistic children. When this happens, there's an increased risk of seizure since the brain's neural network has been disrupted.
According to the Journal of Neuroinflammation, 25 percent of children suffering from autism also have some form of allergic condition. In a nutshell, an allergic reaction is an immune system response where the body, in many cases attacks itself in attempt to protect the body from a perceived threat. This response in turn produces inflammation in the affected areas.
Based on the chemicals released in the body and brain during an allergic reaction, environmental triggers, such as allergies and stress may play a role in the connection between seizures and autism. In the case of stress reactions, the chemicals secreted by the brain in response to a stressor can also have disruptive effects on neuron activity.
Effects on the Blood-Brain Barrier
The brain's cells have a protective coating that prevents certain materials from crossing over from the bloodstream into the brain. This coating acts as the blood-brain barrier. For people affected by autism and/or epilepsy, allergies, fevers and stress may affect the blood-brain barrier's ability to properly protect brain cells.
A research study cited in the Journal of Neuroinflammation describes how certain conditions, such as stress, fever and allergic reactions tend to weaken the blood-brain barrier in people affected by autism and seizures. The study also goes onto speculate whether treatment for neuro-inflammation may be more effective in treating epilepsy when anti-seizure medications fail.