Abstracts

Rationale:
To an untrained observer, dissociative seizures (DS) may appear similar to epileptic seizures. While some other factors can increase the certainty of diagnosis, ictal video-electroencephalography (vEEG) is the gold standard for the diagnosis of DS, otherwise known as functional or psychogenic nonepileptic seizures. Delay in accurate diagnosis has been associated with worse treatment prognosis regarding seizure frequency, quality of life, healthcare utilization, and iatrogenic harm from antiseizure medications (ASMs) including treatment of prolonged DS as status epilepticus. To target interventions that could shorten this delay, we evaluated which factors were associated with time to vEEG (TtV).
Method:
Based on data from 193 consecutive patients with video-electroencephalography (vEEG)-documented dissociative seizures for which TtV was known, we used univariate tests and multivariate log-normal regression with multiple imputation of some missing data to evaluate which of 76 clinical factors were associated with time from first dissociative seizure to vEEG. After this full model, we used recursive feature elimination to sequentially limit the multivariate model to factors with p< 10%.
Results:
The average and median TtV were 8.1 years and 3 years, respectively (min 1 day, max 52 years); and robust log-average of 2.8 years. In the selected multivariate model, the factors associated with longer TtV were more ASMs stopped due to side effects (p=0.04), more medications for other medical conditions (p=0.05), more seizure types (p=0.0003), a comorbidity of hypertension (p=0.01), and seizures that were triggered by sleep deprivation (p=0.0006). Factors associated with shorter TtV were older age of onset (p=4x10-12), active employment or student status (p=0.001), higher seizure frequency (p=0.002), comorbidity of migraines (p=0.0008). Sex, psychiatric history, and specific ictal behaviors did not contribute to the selected multivariate model.
Conclusion:
This analysis of factors suggests that patients with potentially higher impact of seizures on their life had a shorter time to Video-EEG (TtV). Further, patients with canonical features associated with dissociative seizures reduced TtV. Conversely; patients with more complex medical history, multiple seizure types, and adverse response to ASMs had longer TtV. Each of these factors suggests that the selecting the patient’s treatment may be more complex. Instead of these complexities shortening time to referral to a comprehensive epilepsy center, they had the reverse effect. Therefore, our analysis provides actionable information that complex cases may benefit from earlier referral to a comprehensive epilepsy center, because vEEG may identify DS. If vEEG does not identify DS, these cases may benefit from more specialized care of epilepsy.
Funding:
:NIH R25NS065723