June 06, 2006
Up to 30 percent of those diagnosed with epilepsy don't actually have the disorder. They have psychological nonepileptic seizures, or psychogenic seizures, that are caused by psychological conditions, not by the abnormal electrical activity in the brain that causes epileptic seizures.
Because these nonepileptic seizures are similar to epileptic seizures, they can be difficult to diagnose. Three new studies published in the June 13, 2006, issue of Neurology, the scientific journal of the American Academy of Neurology, may help make that diagnosis easier.
"The need for an accurate diagnosis early on is crucial," said neurologist Selim Bendadis, MD, of the University of South Florida in Tampa, who wrote an editorial accompanying the studies. "Right now there is an average of seven to nine years from the time someone first has these seizures and when they are correctly diagnosed with psychological nonepileptic seizures. During that time, they are given drugs for epilepsy that do not treat their problem and they undergo repeated testing – they pay a price physically, socially and financially."
In the simplest of the three studies, researchers reviewed videos of 208 people whose seizures were monitored at Barrow Neurological Institute in Phoenix, AZ. They found that 50 out of 52 people with psychological nonepileptic seizures closed their eyes during seizures, while 152 out of 156 people with epileptic seizures opened their eyes during seizures.
"We need to confirm these results, but these findings could help guide us toward the appropriate diagnosis early on," said the study author, neurologist Steve S. Chung, MD. "In our experience, family members can accurately describe whether a patient's eyes were open or closed during a seizure."
The second study compared 26 people whose psychological nonepileptic seizures began when they were 55 or older to 241 people whose nonepileptic seizures started when they were younger than 55. The researchers found that those with late onset nonepileptic seizures were more likely to be male (42 percent compared to 23 percent) and have severe health problems (42 percent and eight percent). The late onset group was more likely to report health-related traumatic experiences (47 percent compared to four percent) and less likely to report a history of sexual abuse (four percent and 32 percent).
"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 nonepileptic seizures in a subset of patients," said study author Rod Duncan, PhD, of the West of Scotland Regional Epilepsy Service in Glasgow.
The third study examined 18 people seen in the emergency room for continuous seizures, or status epilepticus, that did not respond to epilepsy medication. Compared to those with epileptic seizures, those with nonepileptic seizures were more likely to be less than 30 years old, were more likely to have a port system implanted for administration of IV drugs and had lower blood levels of the enzyme creatine kinase, which normally rise after epileptic seizures.
"These characteristics can help guide the emergency doctor to the correct diagnosis, which is so critical in these cases, because the drugs can result in severe complications if it is in fact not epilepsy," said study author and neurologist Martin Holtkamp, MD, of Charité – University Medicine Berlin in Germany. "Yet an immediate diagnosis is required, even though there is often no time to access EEG recordings and the patient's detailed history."
Benbadis said, "The 'red flags' raised by these studies make a major contribution in helping raise awareness about making the diagnosis of psychological nonepileptic seizures when dealing with seizures that do not respond to medications."