An e-Delphi approach to develop a patient-reported outcome measure to assess functional/dissociative seizures...

Functional / dissociative seizures (FDS) are a debilitating condition for which there are no validated, reliable, or co-produced condition-specific severity measures. Such a measure would be of value for clinical and research applications. Here, we conduct a three-round electronic-Delphi survey with the aim of achieving consensus on questions that could be used to assess FDS severity as part of a patient reported outcome measure.

e-Delphi members consisted of individuals living with FND, professional experts in the condition (e.g., healthcare providers, researchers), and nonprofessional caregivers. Participants were recruited via international organisations linked with FND. The purpose and tasks of each round were iteratively developed and based on participants' responses to the previous round.

In total, 90 people participated in round one (54 individuals with FDS, 32 professionals and 4 nonprofessional cares). This reduced to 67 and 55 in rounds two and three, respectively. Overall, 136 candidate items proposed by the current authors or participants were initially considered for inclusion. The final measure consisted of three sections with 29 items assessing severity of FDS, six exploring frequency and duration of seizures, and a checklist of symptoms commonly associated with FDS. 90% of those in round three were "happy" with the proposed measure.

Notwithstanding the challenges of operationalising severity and the inter- and intra-individual variability of the condition, consensus on items to include was achieved by experts by experience or training. Future scale development will evaluate the proposed measure prior to its implementation in clinical and research practice.