Abstracts

Comorbidity (CO) of both epileptic (ES) and psychogenic nonepileptic (PNES) seizures in the same patient is well documented. Less well studied is the effort required to reach this diagnosis, and the yield from additional days of monitoring., We identified 36 adult patients (64% female) with video-EEG confirmed ES and PNES events, from all long term monitorings performed at the UW Regional Epilepsy Center from mid-1999 to 2006. ES was defined as having definite ictal EEG abnormalities, while PNES was defined as episodes of unresponsiveness or abnormal motor activity in the absence of an electrographic seizure. For a diagnosis of CO, both types of events had to be captured during one or more video-EEG monitorings. Mean age at time of final diagnosis was 33 years (SD=11)., The mean number of monitorings required to diagnose CO was 1.6 (SD=0.9; median=1.0; range=1-5). Average number of required monitoring days (across one or more admissions) was 6.0 (SD=4.0; range=2-21). The mean number of discrete unequivocal events recorded before reaching a diagnosis of CO was 6.2 (SD=6.9; median=4.0; range=2-35). Elapsed time between a patient[apos]s first recorded event and a diagnosis of CO averaged 3.8 days (SD=4.0; range=0-20). For the 50% of patients whose initial event was a PNES spell, elapsed time to an epileptic seizure averaged 2.6 days of additional monitoring (SD=1.7; range=0-5). In contrast, patients who initially experienced an epileptic seizure required nearly twice this time to convert from an exclusive diagnosis of ES to CO (M=5.1 days; SD=5.2; range=1-20). Twelve of the 36 patients underwent surgery for intractable ES, with 42% experiencing their first PNES event after surgery., Most patients with verified comorbid diagnoses of ES and PNES events require relatively few monitorings to document both. In the current data, a comorbid diagnosis was reached in 90% of the sample in two or fewer monitoring admissions cumulatively totaling eight days or less. A full 64% of the sample was diagnosed with CO in only one monitoring admission. Perhaps of greatest clinical utility is the observation that 83% of patients who initially presented with a PNES event went on to have an unequivocal epileptic seizure within four monitoring days of their initial spell. Thus, when a diagnosis of epilepsy is strongly suspected in a patient who initially presents with a PNES event, evidence suggests that allowing several more monitoring days in selected patients can yield clinically useful data critical to appropriate patient care. Additionally, there was a subgroup of patients who developed PNES following surgical resection of an epileptic focus. Prediction of which patients warrant additional admissions or monitoring days remains to be determined, but is critical to efforts to reduce length of stay, without compromising quality of care.,