Cognitive performance in functional seizures compared with epilepsy and healthy controls: a systematic review and meta analysis.

BACKGROUND

Cognition is a core component of functional seizures, but the literature on cognition in this disorder has been heterogeneous, with no clear unifying profile emerging from individual studies. The aim of this study was to do a systematic review and meta-analysis of cognitive performance in adults with functional seizures compared with epilepsy (including left temporal lobe epilepsy) and compared with healthy non-seizure cohorts.

METHODS

In this systematic review and meta-analysis, starting Feb 6, 2023, replicated and updated on Oct 31, 2023, a medical librarian searched MEDLINE, Embase, PsycINFO, and Web of Science. Inclusion criteria were full reports documenting raw or standardised cognitive test data in adults with functional seizures compared with adults with epilepsy, prospectively recruited healthy comparisons, or published norms. Grey literature was retained and there were no language or date restrictions. We excluded studies only reporting on mixed functional seizures and epilepsy, or mixed functional neurological samples, with no pure functional seizures group. Risk of bias was evaluated using a modified version of the Newcastle-Ottawa Scale. People with lived experiences were not involved in the design or execution of this study. This study is registered as CRD42023392385 in PROSPERO.

FINDINGS

Of 3834 records initially identified, 84 articles were retained, including 8654 participants (functional seizures 4193, epilepsy 3638, and healthy comparisons 823). Mean age was 36 years (SD 12) for functional seizures, 36 years (12) for epilepsy, and 34 years (10) for healthy comparisons, and the proportion of women per group was 72% (range 18-100) for functional seizures, 59% (range 15-100) for epilepsy, and 69% (range 34-100) for healthy comparisons. Data on race or ethnicity were rarely reported in the individual studies. Risk of bias was moderate. Cognitive performance was better in people with functional seizures than those with epilepsy (Hedges' g=0·17 [95% CI 0·10-0·25)], p<0·0001), with moderate-to-high heterogeneity (Q[56]=128·91, p=0·0001, I

INTERPRETATION

Patients with functional seizures have widespread cognitive impairments that are likely to be clinically meaningful on the basis of moderate effect sizes in multiple domains. These deficits might be slightly less severe than those seen in many patients with epilepsy but nevertheless argue for consideration of clinical assessment and treatment.

FUNDING

Department of Veterans Affairs, Veterans Health Administration.

Informations de copyright

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Déclaration de conflit d'intérêts

Declaration of interests RVP receives funding from VA Providence, RR&D Center for Neurorestoration and Neurotechnology; engages in profit sharing with the International Neuropsychological Society for Continuing Education proceeds from the Navigating Neuropsychology podcast; receives royalties from publication of the book, Becoming a Neuropsychologist: Advice and Guidance for Students and Trainees (Springer, 2021); receives travel support from Brown University Department of Psychiatry and Human Behavior; is a member of the advisory board for the New2Neuropsychology organisation; and the research reported or outlined here was supported by the Department of Veterans Affairs, Veterans Health Administration, VISN 1 Career Development Award to R Van Patten. TAA is supported by a Career Development Award (1IK2RX004764) from the VA Rehabilitation Research and Development Service. EC receives grant funding from the Women's Board of Northwestern University, and is on the Medical Advisory Board for the Epilepsy Foundation of Chicago. JAB engages in profit sharing with the International Neuropsychological Society for Continuing Education proceeds from the Navigating Neuropsychology podcast; receives royalties from publication of the book, Becoming a Neuropsychologist: Advice and Guidance for Students and Trainees (Springer, 2021); and is a member of the Advisory Board for the New2Neuropsychology organisation. HA has received research funding from National Institutes of Health, Department of Defense Congressionally Directed Medical Research Program Epilepsy Research Program, The Epilepsy Consortium, Eisai, UCB, and Cerevel. SC is a co-investigator for the National Institute of Mental Health U01 MH 123427 study, “Low intensity focused ultrasound: A new paradigm for depression and anxiety”. EWT gratefully acknowledges the support of a VA Rehabilitation Research and Development Research Career Scientist Award. WCL has served on the editorial boards of Epilepsia, Epilepsy & Behavior, Journal of Neurology, Neurosurgery and Psychiatry, and Journal of Neuropsychiatry and Clinical Neurosciences; receives funding from the DoD CDMRP Epilepsy Research Program (W81XWH-17-0169, PI), co-editor royalties for Gates and Rowan's Nonepileptic Seizures, and co-author royalties from Oxford University Press for Taking Control of Your Seizures: Workbook and for Treating Nonepileptic Seizures: Therapist Guide; serves on the Epilepsy Foundation New England Professional Advisory Board; received honoraria for the American Academy of Neurology Meeting Annual Course; served as a clinic development consultant at University of Colorado Denver, Cleveland Clinic, SpectrumHealth, Emory University, Oregon Health Sciences University, and Vanderbilt University; and provided medicolegal expert witness testimony. All other authors declare no competing interests.