June 12, 2006 -- A surprisingly large percentage of epilepsy patients who do not respond to drug treatment don't really have epilepsy at all. It often takes a decade or longer for these patients to get a correct diagnosis -- but new research finds there are simple clues that can make a correct diagnosis easier.
A patient's eye movements during a seizure can help distinguish seizurescaused by epilepsy from those psychological in nature.
That is the finding from one of three new studies examining the diagnosis of non-epileptic seizures published in the June issue of the journal Neurology.
Videos of Seizures
Researchers from the Barrow Neurological Institute in Phoenix, Ariz. reviewed videos of 221 people having seizures. They found that 50 of the 52 people having non-epileptic seizures closed their eyes during the event, while 152 of 156 having epileptic seizures kept their eyes open or blinked until the seizure was over.
Researcher and neurologist Steve S. Chung, MD, says that observation could potentially shorten the time to an accurate diagnosis for many patients.
"We need to confirm these results, but these findings could help guide us toward the appropriate diagnosis early on," he says. "In our experience, family members can accurately describe whether a patient's eyes were open or closed during a seizure."
Getting a Correct Diagnosis
Roughly one in three patients with a diagnosis of epilepsy is not helped by anti-seizure drugs. It is believed that as many as a third of these patients don't have epilepsy at all.
Instead of being caused by abnormal electrical activity in the brain, as is the case with epilepsy, the non-epileptic seizures are psychological in origin.
University of South Florida neurologist Selim R. Benbadis, MD, tells WebMD that it takes an average of seven to nine years for patients with psychological non-epileptic seizures to get a correct diagnosis.
Recording Electrical Signals
This can usually be done with a video-electroencephalogram (EEG), but that test is not performed as often as it should be, Benbadis says. An EEG records electrical signals in the brain through sensors placed on the scalp. In the video-electroencephalogram, patients are videotaped while their EEG is recorded, usually over the course of several days.
"Neurologists don't tend to suspect non-epileptic seizures early on, even when the patient is not responding to drugs," Benbadis says. "They often try different drugs for years without success."
Understanding the difference between epileptic and non-epileptic seizures could help raise suspicion earlier and help a large number of patients avoid years of unnecessary drug treatment, Benbadis says.
Health Trauma May Trigger Seizures
In a second study, researchers compared 26 people whose non-epileptic seizures began when they were aged 55 or older with 241 people whose non-epileptic seizures started at a younger age.
Compared with the younger seizure patients, patients with non-epileptic, psychological seizures beginning later in life were roughly twice as likely to be male, and eight times as likely to have other severe health problems.
The older group was more likely to report health-related traumatic experiences (47% compared to 4%) and less likely to report a history of sexual abuse (4% vs. 32%).
"Our findings suggest that the development of physical ill health, especially when it has been frightening to the patient, may be an important triggering factor for non-epileptic seizures," says researcher Roderick Duncan, MD, PhD, of the West of Scotland Regional Epilepsy Service in Glasgow.
The third study involved 18 people treated in emergency rooms for seizures that did not respond to drugs. Compared to patients with epileptic seizures, those with non-epileptic seizures were more likely to be younger -- with an average age of 25 vs. 42 -- and have lower blood levels of the muscle enzyme creatine kinase, which normally rises after epileptic seizures.
Benbadis says the three studies should help raise awareness about psychologically-based non-epileptic seizures among patients and their doctors.
"When a patient has seizures but doesn't respond to treatment, it is appropriate to try different medications for a few months or even a year or two," he says. "After that, there are just two possibilities. Either it is not epilepsy, or it is epilepsy that is not responsive to drugs. In both cases, these patients need to be monitored at an epilepsy center to determine where to go from there."