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Lookup NU author(s): Dr Izzy Williams
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology. Background and purpose: Cognitive complaints are common in functional neurological disorder (FND), but it is unclear whether objective neurocognitive deficits are present. This systematic review summarized validated/standardized cognitive test performance in FND samples across cognitive domains. Methods: Embase, PsycInfo and MEDLINE were searched from inception to 15 May 2023, combining terms for FND and cognitive domains (e.g., attention, memory, executive functioning). Studies included a range of FND phenotypes (seizures, motor, cognitive disorder, mixed), compared to healthy or clinical controls. Risk of bias was assessed with the modified Newcastle–Ottawa Scale and a qualitative synthesis/narrative review of cognitive performance in FND was conducted. Test performance scores were extracted, and random effects meta-analyses were run where appropriate. This review was registered on PROSPERO, CRD42023423139. Results: Fifty-six studies including 2260 individuals with FND were eligible. Although evidence for some impairments emerged across domains of executive functioning, attention, memory and psychomotor/processing speed, this was inconsistent across studies and FND phenotypes. Common confounds included group differences in demographics, medication and intellectual functioning. Only 24% of studies objectively assessed performance validity. Meta-analyses revealed higher scores on tests of naming (g = 0.67, 95% confidence interval [CI] 0.50, 0.84) and long-term memory (g = 0.43, 95% CI 0.13, 0.74) in functional seizures versus epilepsy, but no significant differences in working (g = −0.08, 95% CI −0.44, 0.29) or immediate (g = 0.25, 95% CI −0.02, 0.53) memory and cognitive flexibility (g = −0.01, 95% CI −0.29, 0.28). Conclusions: There is mixed evidence for objective cognitive deficits in FND. Future research should control for confounds, include tests of performance validity, and assess relationships between objective and subjective neurocognitive functioning.
Author(s): Millman LSM, Williams IA, Jungilligens J, Pick S
Publication type: Review
Publication status: Published
Journal: European Journal of Neurology
Year: 2024
Pages: ePub ahead of Print
Online publication date: 02/07/2024
Acceptance date: 30/05/2024
ISSN (print): 1351-5101
ISSN (electronic): 1468-1331
Publisher: John Wiley and Sons Inc
URL: https://doi.org/10.1111/ene.16386
DOI: 10.1111/ene.16386
Data Access Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
