Beyond video-EEG: identifying functional/dissociative seizures through clinical assessment

This study compared the clinical features of functional/dissociative seizures (FDS) and epileptic seizures using video-EEG.

Early identification of functional/dissociative seizures based on clinical semiology.

Seizure semiology was retrospectively analyzed in 51 FDS and 51 age- and sex-matched epilepsy patients. All diagnoses were confirmed by video-EEG. Evaluated features included sustained eye closure, side-to-side head movements, pelvic thrusting, opisthotonus, side-to-side body movements, grimacing, fluctuating course, limb tremors, vocalization, awareness, and seizure duration.

Functional/dissociative seizures patients more frequently exhibited sustained eye closure (90.2% vs. 31.4%), pelvic thrusting (43.1% vs. 5.9%), opisthotonus (27.5% vs. 0%), fluctuating course (66.7% vs. 21.6%), and limb tremors (76.5% vs. 39.2%) compared with epilepsy patients (all p < 0.001). FDS episodes were longer (median 180 s vs. 66 s, p < 0.001). Logistic regression identified sustained eye closure (OR: 56.9), pelvic thrusting (OR: 8.1), and seizure duration (OR: 1.011 per second) as independent predictors of FDS. Significant co-occurrences included opisthotonus with pelvic thrusting and grimacing, fluctuating course with tremor, and side-to-side body movement with head movement and pelvic thrusting.

Sustained eye closure, pelvic thrusting, and prolonged duration are key indicators of FDS. Recognizing these signs can improve diagnostic accuracy when video-EEG is unavailable, prevent unnecessary antiseizure treatment, and facilitate timely psychological care, enhancing overall patient management.