Abstracts

RATIONALE: Non-epileptic seizures (NES) account for approximately 20% of all cases of intractable epilepsy. In the absence of early and definitive diagnosis, patients with non-epileptic seizures may be treated, often for an extended period of time, without benefit with expensive antiepileptic drugs (AEDs) with potentially serious adverse effects. We reviewed our experience to identify features that would be useful in differentiating NES from epileptic seizures based mainly on semiology and clinical characteristics.
METHODS: All admissions to the Video-EEG Monitoring Unit at the Medical College of Ohio between 1997-2001 were reviewed after IRB approval of the protocol. All patients with NES underwent extensive chart review to identify clinical features, semiology, co-morbidity and treatment. Data was analyzed utilizing independent samples t test and chi square analysis.
RESULTS: One hundred and thirteen patients with NES were identified, fifty six were excluded because of inadequate clinical data. Data from fifty seven patients with NES was analyzed and compared to twenty-four patients randomly selected patients with complex partial seizures. In NES group the mean age was 33.61 years (range 12-71), 31% of these were males. Mean duration of seizures in the NES group prior to the diagnosis was 9.7 years (range 1 month to 40 years). Mean number of AEDs used was 1.82 (range 0-5), 61% of the patients with NES had been exposed to two or more AEDs prior to their diagnosis.
Aura was more likely in patients with complex partial seizures (70.8 %) compared to the NES group (28 %, p [lt] 0.0001). Clinical features seen only in patients with NES included crying (15.7%), thrashing (15.7%) and pelvic thrusting (21%), while orofacial (50%) and limb automatisms (29%) as well as focal dystonia (13%) were seen only in patients with complex partial seizures. The mean seizure duration in the NES group was 419.6 seconds versus 61.2 seconds in the complex partial seizure group, which was a statistically significant difference (p [lt] 0.0001). Routine EEG was not very helpful in discriminating between patients with NES from epileptic seizures as EEG was abnormal in 55% of the patients with NES. The most common abnormality was either generalized (45%) or focal slowing (45%). Interictal epileptiform discharges were noted in only 5% with NES. In patients with complex partial seizures, routine EEG was abnormal in 88% of patients. The presence of epileptiform activity was more likely in the epilepsy (66%) cohort compared to the NES group (5%, p [lt] 0.001). Head trauma was reported by 35.08%. Psychiatric comorbidity was noted in 47% of patients with NES, including depression (29.8%), anxiety (8.8%) or personality disorder (8.8%).
CONCLUSIONS: Patients with NES are frequently misdiagnosed and receive prolonged AED therapy often with multiple agents. Although non-epileptic seizures may be more common in women, a third of the patients with NES in our series were men. Clinical features suggestive of non-epileptic seizures include prolonged duration of episodes often associated with crying, thrashing, pelvic thrusting and absence of aura, orofacial or limb automatisms.These clinical features if elicited during initial evaluation should alert physicians to consider early diagnositic video-EEG monitoring in these patients.