Often, no underlying cause can be found for absence seizures. Many children appear to have a genetic predisposition to them. Sometimes hyperventilation can trigger an absence seizure.

In general, seizures are caused by abnormal nerve cell (neuron) activity in the brain. The brain's nerve cells normally communicate with each other by sending electrical and chemical signals across the synapses that connect the cells. In people who have seizures, the brain's usual electrical activity is altered. During an absence seizure, these electrical signals repeat themselves over and over in a three-second pattern.

People who have seizures may also have altered levels of neurotransmitters, which are the chemical messengers that help the nerve cells communicate with one another.

This type of seizure may be more prevalent in children. Many children gradually outgrow absence seizures over months to years.

Jun. 23, 2011