Frontal cognitive-behavioural deficits in patients with anti-leucine-rich glioma-inactivated protein 1 antibody encephalitis (S22.004)

Abstract

<h3>Objective:</h3> To determine the prevalence of a frontal cognitive-behavioural phenotype in patients with anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis. <h3>Background:</h3> 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. <h3>Design/Methods:</h3> 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). <h3>Results:</h3> 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. <h3>Conclusions:</h3> 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. <b>Disclosure:</b> Dr. Lee has nothing to disclose. Dr. Climans has nothing to disclose. 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 an Editor, Associate Editor, or Editorial Advisory Board Member for DynaMed (EBSCO Health). Dr. Day has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Barrow Law. 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. 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. Dr. Hebert has nothing to disclose. 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. Dr. Ramos has nothing to disclose. The institution of Dr. Steriade has received research support from NIH. The institution of Dr. Steriade has received research support from Dorris Duke Fund to Retain Clinician Scientists. Dr. Wennberg has nothing to disclose. 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. Tang-Wai has nothing to disclose.