Only having seizures while asleep is a recognised pattern with epilepsy. Sleeping changes the hormonal and chemical state in the brain, which can allow seizures to happen more easily in some people. If a person with epilepsy has this established pattern (allowing them to drive after three years like this) how likely is this to change?

Drs Fernandez and Salas-Puig, from the University Hospital in Oviedo, Spain, conducted a long follow-up study to investigate. They followed fifty-five adults (average age 50 years) over a period of at least 10 years. All had been diagnosed with pure sleep epilepsy, having had no seizures while awake for an average of 22 years.

During the 10-year follow-up period, 31% of patients experienced one or more seizures when awake. These episodes were more common in people who were taking more than one anti-epileptic drug, and were also associated with occasions when a drug was withdrawn quickly.

The likelihood of having a seizure when awake did not depend on the age of the patient, their type of epilepsy (generalised or focal), the frequency of their seizures, or which anti-epileptic drug they were taking. Generally speaking these patients had few seizures, with only 9% having more than one per month.

This study, published in the journal Epileptic Disorders in February 2007, followed a small number of carefully selected patients, so these results may not be applicable to everybody with nocturnal seizures. In this study, a patient with nocturnal seizures had a 2 in 3 chance of having no seizures while awake over a ten year period, an encouraging result.

Please note: if you notice a change in your normal seizure pattern, standard medical advice is that you see a doctor about it.