Abstract Details

Title “Obvious” indications for Neural antibody testing in Epilepsy or Seizures: The ONES checklist

Topic Autoimmune Neurology

Presentation(s) P1 - Poster Session 1 (9:00 AM-5:00 PM)

Poster/Presentation
Number 025

Objective

To develop a checklist that identifies patients who have “obvious” indications for neural antibody testing, and compare its diagnostic performance to predictive scores.

Background Numerous predictive scores have been developed to help determine which patients with epilepsy or seizures of unknown etiology should undergo neural antibody testing. However, their diagnostic advantage compared to only performing testing in patients with “obvious” indications (e.g. broader features of autoimmune encephalitis) requires further study.

Design/Methods

We developed the “Obvious” indications for Neural antibody testing in Epilepsy or Seizures (ONES) checklist through literature review. We then retrospectively reviewed patients who underwent neural antibody testing for epilepsy or seizures at our center between March 2019 and January 2021, to determine and compare the sensitivity and specificity of the ONES checklist to the recently-proposed Antibody Prevalence in Epilepsy and Encephalopathy (APE2)/Antibodies Contributing to Focal Epilepsy Signs and Symptoms (ACES) reflex score.

Results One-hundred-seventy patients who underwent neural antibody testing for epilepsy or seizures were identified. Seventy-four of 170 (43.5%) with a known etiology were excluded from sensitivity/specificity analyses; none had a true-positive neural antibody. Of the 96 patients with an unknown etiology, fourteen (15%) had a true-positive neural antibody. The proportion of false-positives was significantly higher among patients with a known etiology (3/3, 100%) compared to an unknown etiology (2/16, 13%) (P = .01). There was no significant difference of the APE2/ACES reflex score compared to the ONES checklist with regard to sensitivity (93% for both, P > .99) or specificity (71% versus 78%, P = .18) for true-positive neural antibodies.

Conclusions Compared to only performing neural antibody testing in patients with epilepsy or seizures of unknown etiology who have “obvious” indications, predictive scores confer no clear diagnostic advantage. Pre-specified definitions of what constitutes a true-positive neural antibody is required in future studies to avoid false-positives that can confound results.

Authors/Disclosures
Yiu-Chia Chang, MD (London Health Science Centre) PRESENTER	Dr. Chang has nothing to disclose.
	No disclosure on file
Seyed M. Mirsattari, MD, PhD, FRCPC (Mayo Clinic)	Dr. Mirsattari has nothing to disclose.
Jorge G. Burneo, MD, MSPH, FAAN (University of Western Ontario)	Dr. Burneo has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier, Clinical Neurology and Neurosurgery Journal. Dr. Burneo has received research support from The Jack Cowin Endowed Chair in Epilepsy Research. Dr. Burneo has received publishing royalties from a publication relating to health care. Dr. Burneo has received personal compensation in the range of $500-$4,999 for serving as a Speaker with Jazz Pharmaceuticals.
Adrian Budhram, MD (London Health Sciences Centre)	Dr. Budhram has nothing to disclose.

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