Transitional objects and objective clinical signs in functional/dissociative seizures and epileptic seizures: A comparative study

OBJECTIVE: Functional/Dissociative Seizures (FDS), formerly known as psychogenic nonepileptic seizures, are common in tertiary epilepsy centers and remain challenging to distinguish from epileptic seizures. Beyond semiological features, additional behavioral markers such as the presence of transitional objects have been proposed as potential diagnostic clues. This study aimed to assess whether transitional objects and selected clinical semiological features could help differentiate FDS from epileptic seizures during video-electroencephalographic (vEEG) monitoring. METHODS: We conducted a retrospective cross-sectional study at the Epilepsy Monitoring Unit of the Centre Hospitalier de l'Université de Montréal (CHUM). Adult patients who underwent vEEG monitoring between April 2018 and April 2025 were included. The FDS group comprised patients with at least one recorded FDS, while age- and sex-matched controls consisted of patients with confirmed epileptic seizures and no recorded FDS. Video recordings were systematically reviewed by an epileptologist to assess the presence of transitional objects (e.g., stuffed animals, blankets, pillows, slippers) and predefined semiological features, including pelvic thrusting, ictal eye closure, back arching (opisthotonos), and ictal crying. RESULTS: A total of 101 patients with FDS (383 events) and 101 patients with epileptic seizures (371 events) were analyzed. Transitional objects were observed in 18 patients with FDS and 16 controls (unadjusted p = 0.177; Holm-Bonferroni-adjusted p = 0.849), with no significant differences between groups. In contrast, pelvic thrusting, ictal eye closure, back arching, and ictal crying were significantly more frequent in the FDS group. Psychiatric comorbidities were also more prevalent among patients with FDS (41 vs. 18, unadjusted p < 0.001; Holm-Bonferroni-adjusted p = 0.003), particularly depression and bipolar disorder. SIGNIFICANCE: Transitional objects, including stuffed animals, do not appear to be discriminative markers between FDS and epileptic seizures. However, specific semiological features remain useful for positive diagnosis of FDS, in line with current International League Against Epilepsy recommendations. These findings support a clinically driven diagnostic approach based on seizure semiology rather than transitional objects alone.