For the estimated 65 million people around the world suffering from epilepsy, most worry about when they will experience their next seizure and if they will be prepared. These seizures are caused by disturbances in the electrical activity of the brain, but doctors rarely know what causes the disturbances. A study published in the medical journal of the American Academy of Neurology found that epilepsy patients who sleep on their stomachs have a higher risk for suffering a fatal seizure.

"Sudden unexpected death is the main cause of death in uncontrolled epilepsy and usually occurs unwitnessed during sleep," Dr. James Tao, from the University of Chicago in Illinois and a member of the American Academy of Neurology, said in a statement.

Tao and his colleagues gathered data from 25 studies based on 254 sudden expected death cases where investigators recorded body position. Researchers focused their study on tonic clonic seizures. Formerly known as grand mal seizures, tonic clonic seizures carry a higher risk of dying suddenly due to the affect they have on the entire brain compared to partial seizures which only affect a certain area of the brain.

Findings revealed that in 73 percent of sudden unexpected death cases tied to a tonic clonic seizure the person was in the prone sleeping position, while in the remaining 27 percent of cases they were sleeping in a different position. The research team also pointed out 11 reported sudden death cases that occurred while the patients were being monitored with an EEG. In all of those cases, the patient died in the prone sleeping position.

It also appears that younger people are, on average, four times more likely to suffer a fatal tonic clonic seizure while sleeping on their stomach compared to older people. A subgroup of 88 people revealed that 86 percent of people under the age of 40 died suddenly while sleeping on their stomach compared to 60 percent of people over the age of 40.

"We're not sure why this was more common in younger people," Tao explained. "It may be that they are more likely to be single and not have anyone with them during a seizure while sleeping." Currently around 326,000 American children under the age of 15 have been diagnosed with epilepsy.

According to the Epilepsy Foundation, epileptics who suffer a tonic clonic seizure often lose consciousness, experience muscle stiffness, and jerking movements. This type of seizure generally lasts one to three minutes and has a much longer recovery period. Tonic clonic seizures are what people envision when they think of a “convulsive seizure.”

"Similar to infant SIDS cases, adults often have an impaired ability to wake up after a seizure, especially a general seizure," Tao added. "Our findings highlight an important strategy for preventing sudden unexpected death in epilepsy--that 'back is best.’ Using wrist watches and bed alarms designed to detect seizures during sleep may also help prevent these deaths."

Source: Liebenthal J, Wu S, Rose S, Ebersole J, Tao J. Association of prone position with sudden unexpected death in epilepsy. Neurology. 2015.