Abstracts

Rationale: Video-EEG monitoring is the gold standard in making the correct diagnosis in patients with paroxysmal spells concerning for seizures. Up to 30% of patients admitted to the long-term video-EEG monitoring unit suffer from PNEA. Furthermore, the patients with PNEA are suggestible, and an outpatient video-EEG with activation can diagnose PNEA in 70% of patients and may be sufficient in making the correct diagnosis. Methods: We set out to design a simple questionnaire that can be administered by non-physicians. Based on the results of this questionnaire, the scheduling personnel can determine if the patient will benefit from outpatient 2 hour video-EEG with activation or prolonged admission to the long-term video-EEG monitoring unit. Several features are commonly observed in PNEA such as multiple psychiatric comorbidities, a “seizure” in the physician’s office, unusual triggers, fibromyalgia and multiple drug allergies. Some of these features are well-documented and some are based on personal observations. Conversely, young age of onset and injuries are more common in patients with ES. Based on how strongly these findings are associated with PNEA or ES, we assigned positive and negative numerical points to each, and added the assigned points for the total score of each patient (refer to table 1). Results: We retrospectively reviewed 45 consecutive patients admitted to the long-term video-EEG monitoring unit. Only patients older than 18 years were included. We obtained the answers to the questionnaire from the patient’s chart and compared it to their final diagnosis based on the video-EEG findings. Patients without recorded habitual episodes were excluded, regardless of the interictal EEG findings. Patients with both PNEA and ES were also excluded. A Receiver Operating Curve was used to determine the best cut-point for the questionnaire to accurately differentiate between psychogenic and epileptic seizures. A score of greater than or equal to “1” on our scale resulted in 89.5% sensitivity and 88.5% specificity in predicting PNEA. Conversely, using the ROC, a score of “0” or less has a specificity of 92.3% and a sensitivity of 78.9% in diagnosing ES. Conclusions: Using a simple questionnaire, we were able to accurately predict PNEA in up to 90% of patients admitted to the long-term video-EEG monitoring unit. A score of greater than “1” on our scale had a sensitivity and specificity of almost 90% in predicting PNEA. In the prospective portion of our study, we plan to use this scale prior to admission to the video-EEG monitoring unit and compare the scores obtained pre-admission to the patient’s final diagnosis after video-EEG. By predicting PNEA, patients with scores highly suggestive of PNEA can undergo 2-hour video-EEG with activation, which can be especially important in areas with limited resources.