A Retrospective Study Reviewing Timing to Onset of Habitual Psychogenic Non-Epileptic Seizures in a Home Video Telemetry Cohort

Objectives: This study aimed to investigate the onset time to habitual psychogenic non-epileptic seizures (PNES) in adults referred to Guy’s and St Thomas’ Neurophysiology Department for home video telemetry (HVT) with a clinical question of PNES. The primary objective was to determine the optimal time window for HVT recording for patients with suspected PNES to try to improve the allocation of clinical resources. The secondary objective was to explore any potential association between time to habitual PN ES onset and demographic indexes and other clinical, neuro-radiological and semiological findings. Methods: We performed a retrospective analysis of our XLTEK database between 2019 and 2020. A multifactorial analysis of PNES semiologic subtypes, patient demographics, psychiatric comorbidities and neuroimaging was conducted to explore their impact on time to PNES within an HVT study. People who had at least one typical PNES during their recording were included. The exclusion criteria included people who had the test performed without video recording. The total number of participants was 37. The data were extracted from our local XLTEK database. Statistical analyses using Mann–Whitney U and Fischer exact tests were carried out. Results: The mean time to first habitual PNES onset was seven hours, with a mean recording duration of 46 h. The most commonly occurring event type was blank spells (12, 32%), with the least common presentation being déjà vu (1, 3%). There was a significant association between time to PNES onset and male sex (p = 0.04). There was a significant association between time to PNES onset and abnormal MRI findings (p = 0.02). Particular PNES semiologic subtypes were not significantly linked with PNES onset time. Conclusions: Our study highlights that on average, patients with PNES will rapidly have their first habitual event within an HVT study (mean time to event onset of seven hours), consistent with the current literature. This raises the question of whether HVT study duration could be reduced to release study resources and aid departmental efficiencies. We also observe the novel finding that men presented significantly earlier with their habitual PNES event than women, and that abnormal imaging findings were also significantly associated with an earlier time to event onset, although the reason for this association is yet to be determined.