PHOENIX, Ariz. - A simple but reliable way to distinguish psychogenic nonepileptic seizures from epilepsy is to look at the patient's eyes, researchers here reported.
PHOENIX, Ariz., June 15 - A simple but reliable way to distinguish psychogenic nonepileptic seizures from epilepsy is to determine whether the patient's eyes are closed or open, researchers here reported.
In nearly every one of more than 200 patients studied, the eyes of those with psychogenic nonepileptic seizures closed during seizures, while the eyes of those with epilepsy remained open, said neurologist Steve S. Chung, M.D., and colleagues, at the St. Joseph's Medical Center here in the June 13 issue of Neurology.
In an editorial, W. Curt LaFrance, Jr., M.D., of Brown Medical School in Providence, R.I., and Selim R. Benbadis, M.D., of the University of South Florida in Tampa said a quick and accurate way to distinguish psychogenic nonepileptic seizures from epilepsy is crucial.
"There is an average of seven years delay between the onset of seizures and the correct diagnosis of psychogenic nonepileptic seizures, the editorialists wrote. "During that time, while they are being treated for epileptic seizures, patients are prescribed antiepileptic drugs that do not treat their disorder. When their seizures do not abate, they are prescribed more antiepileptic drugs, sometimes to the point of toxicity."
Dr. Chung and colleagues retrospectively reviewed videos of seizures of 208 patients with either psychogenic nonepileptic seizures or epilepsy. Of the 52 patients with psychogenic nonepileptic seizures, 50 closed their eyes during the seizure, the investigators reported.
"Most of them closed their eyes for the entire duration of the seizure, and a few closed their eyes forcefully with facial frowning," the authors said. Some even covered their eyes with their hands at times.
In contrast, 152 of the 156 patients with epilepsy had their eyes open, at least during the onset of the seizure. "During tonic-clonic activity, rhythmic eye blinking was typically seen followed by postictal confusion and eye closure, even though their eyes were open at the onset," the authors said.
"Even when epileptic seizures occurred during sleep, many patients opened their eyes at the onset of seizures," they added.
Ictal eye closure was 96% sensitive and 98% specific for diagnosing psychogenic nonepileptic seizures, the investigators found. Similarly, ictal eye opening was 98% sensitive and 96% specific for indicating true epileptic seizures, they said.
"In our clinical experience, many observers (e.g., family members) can accurately describe whether a patient's eyes were open or closed during a seizure," the authors said. "Thus, careful history taking of seizure semiology in an outpatient setting may help to discern between epileptic seizures or psychogenic nonepileptic seizures. If possible, a home video clip of a seizure can also help to make a diagnosis without long-term monitoring."
Two other studies, published in the same issue of Neurology, also provided information to help clinicians distinguish psychogenic nonepileptic seizures from epilepsy:
A study in Scotland compared 26 patients whose psychogenic nonepileptic seizures began when they were 55 or older to 241 people whose psychogenic nonepileptic seizures started when they were younger than 55. The researchers found that those with late-onset psychogenic nonepileptic seizures were more likely to be male (42% compared with 23%; P=.029) and have severe health problems (42% versus 8%; P<.001). The late onset group was also more likely to report health-related traumatic experiences (47% compared with 4%; P<.0001) and less likely to report a history of sexual abuse (4% versus 32%; P=.008).
"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 in a subset of patients," said Roderick Duncan, Ph.D., of the West of Scotland Regional Epilepsy Service in Glasgow, and colleagues.
A small, German study examined 18 patients 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 psychogenic nonepileptic seizures were more likely to be less than 30 years old, to have a port system implanted for administration of IV drugs (likely because of repeated emergency presentations with psychogenic nonepileptic seizures), and to have lower blood levels of the enzyme creatine kinase, which normally rise after epileptic seizures, the study found.
These characteristics can help guide the emergency doctor to the correct diagnosis, said Martin Holtkamp, M.D., of Charite-University Medicine Berlin, and colleagues.
"Patients pay a price physically, socially, and financially as long as their psychogenic nonepileptic seizures remain undiagnosed and improperly treated," Dr. LaFrance and Dr. Benbadis said. "The gold standard diagnostic test is video EEG. With it and a thorough history and physical, aided by the above red flags, we make the diagnosis of psychogenic nonepileptic seizures with a high degree of certainty."
"Yet the persistent seven- to 10-year delay in diagnosis of psychogenic nonepileptic seizures clearly indicates that the index of suspicion is not high enough when treating refractory seizures," they said. "The three studies in this issue make a major contribution to helping raise the clinicians' suspicion and thereby to recognize psychogenic nonepileptic seizures."
Among those diagnosed with epilepsy in the United States, 5% to 20% may actually have psychogenic nonepileptic seizures, they noted.