A minority of patients with functional seizures have abnormalities on neuroimaging

Wesley T Kerr; John K Lee; Amir H Karimi; Hiroyuki Tatekawa; L Brian Hickman; Michael Connerney; Siddhika S Sreenivasan; Ishita Dubey; Corinne H Allas; Jena M Smith; Ivanka Savic; Daniel H S Silverman; Lubomir M Hadjiiski; Nicholas J Beimer; William C Stacey; Mark S Cohen; Jerome Engel Jr; Jamie D Feusner; Noriko Salamon; John M Stern

doi:10.1016/j.jns.2021.117548

A minority of patients with functional seizures have abnormalities on neuroimaging

J Neurol Sci. 2021 Aug 15:427:117548. doi: 10.1016/j.jns.2021.117548. Epub 2021 Jun 18.

Authors

Wesley T Kerr¹, John K Lee², Amir H Karimi², Hiroyuki Tatekawa³, L Brian Hickman⁴, Michael Connerney², Siddhika S Sreenivasan², Ishita Dubey², Corinne H Allas², Jena M Smith², Ivanka Savic⁵, Daniel H S Silverman⁶, Lubomir M Hadjiiski⁷, Nicholas J Beimer⁸, William C Stacey⁹, Mark S Cohen¹⁰, Jerome Engel Jr¹¹, Jamie D Feusner¹², Noriko Salamon¹³, John M Stern²

Affiliations

¹ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA. Electronic address: WesleyTK@g.UCLA.edu.
² Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
³ Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
⁴ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Internal Medicine, University of California at Irvine, Irvine, CA, USA.
⁵ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Women's and Children's Health, Karolinska Institute and Neurology Clinic, Karolinksa University Hospital, Karolinska Universitetssjukhuset, Stockholm, Sweden.
⁶ Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
⁷ Department of Radiology, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
⁸ Department of Neurology, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA; Department of Psychiatry, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
⁹ Department of Neurology, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
¹⁰ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA; Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Departments of Bioengineering, Psychology and Biomedical Physics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
¹¹ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Brain Research Institute, University of California Los Angeles, Los Angeles, CA, USA.
¹² Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA; Department of Women's and Children's Health, Karolinska Institute and Neurology Clinic, Karolinksa University Hospital, Karolinska Universitetssjukhuset, Stockholm, Sweden; Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada; Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
¹³ Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

PMID: 34216975
DOI: 10.1016/j.jns.2021.117548

Abstract

Objective: Functional seizures often are managed incorrectly as a diagnosis of exclusion. However, a significant minority of patients with functional seizures may have abnormalities on neuroimaging that typically are associated with epilepsy, leading to diagnostic confusion. We evaluated the rate of epilepsy-associated findings on MRI, FDG-PET, and CT in patients with functional seizures.

Methods: We studied radiologists' reports from neuroimages at our comprehensive epilepsy center from a consecutive series of patients diagnosed with functional seizures without comorbid epilepsy from 2006 to 2019. We summarized the MRI, FDG-PET, and CT results as follows: within normal limits, incidental findings, unrelated findings, non-specific abnormalities, post-operative study, epilepsy risk factors (ERF), borderline epilepsy-associated findings (EAF), and definitive EAF.

Results: Of the 256 MRIs, 23% demonstrated ERF (5%), borderline EAF (8%), or definitive EAF (10%). The most common EAF was hippocampal sclerosis, with the majority of borderline EAF comprising hippocampal atrophy without T2 hyperintensity or vice versa. Of the 87 FDG-PETs, 26% demonstrated borderline EAF (17%) or definitive EAF (8%). Epilepsy-associated findings primarily included focal hypometabolism, especially of the temporal lobes, with borderline findings including subtle or questionable hypometabolism. Of the 51 CTs, only 2% had definitive EAF.

Significance: This large case series provides further evidence that, while uncommon, EAF are seen in patients with functional seizures. A significant portion of these abnormal findings are borderline. The moderately high rate of these abnormalities may represent framing bias from the indication of the study being "seizures," the relative subtlety of EAF, or effects of antiseizure medications.

Keywords: Clinical diagnostics; Conversion disorder; Decision analysis; Dissociative seizures; Psychogenic non-epileptic seizures.

MeSH terms

Electroencephalography
Epilepsy*
Humans
Magnetic Resonance Imaging
Neuroimaging
Positron-Emission Tomography
Seizures* / complications
Seizures* / diagnostic imaging