Non-epileptic seizures resemble epileptic seizures, but are not accompanied by abnormal electrical discharges. Rather, these seizures are believed to be brought on by psychological stresses.

Dr. Diane Thomas reported that 15.7 percent of hospital patients who experienced non-epileptic seizures also had epileptic seizures during the same hospital stay. Previous studies found the percentage of such patients experiencing both types of seizures was less than 10 percent.

Thomas reported the findings Dec. 2 at a meeting of the American Epilepsy Society. The finding is significant because epileptic and non-epileptic seizures are treated differently. Non-epileptic seizures do not respond to epilepsy medications, and typically are treated with psychotherapy, anti-depressants, or both, Thomas said.

Non-epileptic seizures used to be called pseudoseizures. But they are quite real, and the preferred term now is psychogenic non-epileptic seizure. A non-epileptic seizure can resemble the convulsions characteristic of a grand mal epileptic seizure, or the staring-into-space characteristic of a petit mal epileptic seizure. But unlike an epileptic seizure, the brain waves during a non-epileptic seizure are normal.

Non-epileptic seizures can be triggered by stresses such as physical or sexual abuse, incest, job loss, divorce or death of a loved one. In some cases, the traumatic event may be blocked from the patient's conscious memory.

Non-epileptic seizures often are mistaken for epileptic seizures. While some patients who have both types can distinguish between the two, others find it difficult to distinguish when they are having non-epileptic seizures.

The only way to make a definitive seizure diagnosis is to monitor a patient with an electroencephalogram (EEG) and a video camera. (The EEG can detect abnormal electrical discharges that indicate an epileptic seizure.) The patient is monitored with the camera until a seizure occurs, and the EEG recordings from the event are then analyzed.

Thomas conducted her study at the University of Maryland Medical Center, where she did a fellowship in epilepsy before recently joining Loyola. Thomas and colleagues reviewed 256 patients who had come to the hospital to have their seizures monitored. Seventy of the patients had documented non-epileptic seizures. Of these, 11 patients (15.7 percent) also experienced epileptic seizures during their hospital stays.

Thomas is an assistant professor in the Department of Neurology of Loyola University Chicago Stritch School of Medicine. In addition to epilepsy, her special interests include HIV neurology.