Abstract Details

Title Frontal cognitive-behavioural deficits in patients with anti-leucine-rich glioma-inactivated protein 1 antibody encephalitis

Topic Autoimmune Neurology

Presentation(s) S22 - Autoimmune Neurology: Autoimmune Encephalitis and Other Antibody-associated Syndromes (4:06 PM-4:18 PM)

Poster/Presentation
Number 004

Background Cognitive impairment is a common manifestation of anti-LGI1 encephalitis and is typically defined as prominent memory deficits. We frequently encounter frontal cognitive-behavioural deficits when evaluating these patients, but this has yet to be well described in the literature.

Objective To determine the prevalence of a frontal cognitive-behavioural phenotype in patients with anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis.

Design/Methods We retrospectively identified patients from three tertiary centres in Toronto, Ontario who were diagnosed with anti-LGI1 encephalitis between October 2013 and September 2022. Patient electronic medical records were evaluated for cognitive features and frontal features were categorized based on the diagnostic criteria for behavioural variant frontotemporal dementia (bvFTD).

Results Fifteen patients were identified (median age 65 years [range 18–84]; 8 [53.3%] male). Fourteen (93.3%) patients had cognitive symptoms that localized to the frontal lobe. Two developed these symptoms during treatment with steroids and were therefore excluded from further analysis. The remaining 12 patients presented with behavioural disinhibition (n=11), apathy or inertia (n=5), perseverative, stereotyped or compulsive/ritualistic behaviours (n=4), hyperorality and dietary changes (n=4), a neuropsychological profile with predominant deficits in executive tasks (n=4), and loss of sympathy or empathy (n=1). Seven (46.7%) met diagnostic criteria for possible bvFTD. Of these, 3 had significant functional decline and none had neuroimaging findings consistent with bvFTD. Anterograde memory impairment was common (n=11), and patients also presented with language deficits (n=3) and difficulties with spatial navigation (n=3). Of the 12 patients with frontal symptoms, only 5 had faciobrachial dystonic seizures.

Conclusions Patients with anti-LGI1 encephalitis can exhibit frontal cognitive-behavioural symptoms in addition to memory impairment, and screening for these features on clinical assessment may help to identify the diagnosis. Clinicians should also consider anti-LGI1 encephalitis in the differential diagnosis of bvFTD.

Authors/Disclosures
Sydney Lee, MD (Adult Neurology Program, University of Toronto) PRESENTER	Dr. Lee has nothing to disclose.
Seth A. Climans, MD (London Health Sciences Centre)	Dr. Climans has nothing to disclose.
Gregory S. Day, MD, MSc, FAAN (Mayo Clinic)	Dr. Day has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Parabon Nanolabs. The institution of Dr. Day has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Eli Lilly. Dr. Day has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Arialys Therapeutics. Dr. Day has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ionis. Dr. Day has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for DynaMed (EBSCO Health). Dr. Day has stock in ANI Pharmaceuticals. The institution of Dr. Day has received research support from National Institutes of Health / NIA. The institution of Dr. Day has received research support from Chan Zuckerberg Initiative. The institution of Dr. Day has received research support from Alzheimer's Association. The institution of Dr. Day has received research support from National Institutes of Health / NINDS. The institution of Dr. Day has received research support from Horizon Therapeutics. The institution of Dr. Day has received research support from AVID Radiopharmaceuticals. Dr. Day has received personal compensation in the range of $500-$4,999 for serving as a Presenter at Annual Meeting (CME) with American Academy of Neurology. Dr. Day has received personal compensation in the range of $500-$4,999 for serving as a Content Development (CME) with PeerView, Inc. Dr. Day has received personal compensation in the range of $5,000-$9,999 for serving as a Content Development (CME) with Continuing Education, Inc. Dr. Day has a non-compensated relationship as a Clinical Director with AntiNMDA Receptor Encephalitis Foundation that is relevant to AAN interests or activities.
Julien Hebert, MD (Toronto Western Hospital (University Health Network))	Dr. Hebert has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Paladin Labs.
Sarah Lapointe, MD (CHUM)	Dr. Lapointe has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion.
Ronald C. Ramos, MD (Juravinski Hospital and Cancer Centre)	Dr. Ramos has nothing to disclose.
Claude Steriade, MD (NYU)	The institution of Dr. Steriade has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for The Epilepsy Study Consortium. Dr. Steriade has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Dynamed. Dr. Steriade has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for DOJ. The institution of Dr. Steriade has received research support from NIH. Dr. Steriade has received personal compensation in the range of $500-$4,999 for serving as a Consultant with Epitel. Dr. Steriade has received personal compensation in the range of $500-$4,999 for serving as a Consultant with Jazz Pharmaceuticals.
	No disclosure on file
Alexandra Muccilli, MD (Saint Michael's Hospital - Multiple Sclerosis Clinic)	Dr. Muccilli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Muccilli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Muccilli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for EMD Serono. Dr. Muccilli has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion.
David F. Tang-Wai, MD, FRCPC (Toronto Western Hospital/University Health Network)	Dr. Tang-Wai has nothing to disclose.