Terminology for psychogenic nonepileptic seizures: making the case for "functional seizures"

PURPOSE: The purpose of the study was to review the literature on the terminologies for psychogenic nonepileptic seizures (PNES) and make a proposal on the terminology of this condition. This proposal reflects the authors' own opinions. METHODS: We systematically searched MEDLINE (accessed from PubMed) and EMBASE from inception to October 10, 2019 for articles written in English with a main focus on PNES (with or without discussion of other functional neurological disorders) and which either proposed or discussed the accuracy or appropriateness of PNES terminologies. RESULTS: The search strategy reported above yielded 757 articles; 30 articles were eventually included, which were generally of low quality. "Functional seizures" (FS) appeared to be an acceptable terminology to name this condition from the perspective of patients. In addition, FS is a term that is relatively popular with clinicians. CONCLUSION: From the available evidence, FS meets more of the criteria proposed for an acceptable label than other popular terms in the field. While the term FS is neutral with regard to etiology and pathology (particularly regarding whether psychological or not), other terms such as "dissociative", "conversion", or "psychogenic" seizures are not. In addition, FS can potentially facilitate multidisciplinary (physical and psychological) management more than other terms. Adopting a universally accepted terminology to describe this disorder could standardize our approach to the illness and facilitate communication between healthcare professionals, patients, their families, carers, and the wider public.