Abstract Details

Title Anti LGI1 Encephalitis, Beyond the Limbic System - Persistent Executive Dysfunction in Long-term Follow-up

Topic Autoimmune Neurology

Presentation(s) P9 - Poster Session 9 (5:00 PM-6:00 PM)

Poster/Presentation
Number 1-005

Objective To investigate long-term cognitive trajectories in LGI1-AE, with a particular focus on executive function and its persistence over time.

Background

Leucine-rich glioma-inactivated 1 (LGI1) antibody-associated autoimmune encephalitis (AE) often presents with faciobrachial dystonic seizures (FBDS), memory impairment, and behavioral disturbances. Although most patients improve following immunotherapy, long-term cognitive trajectories and the persistence of domain-specific deficits remain poorly defined. Executive deficits are often considered transient, but their persistence has not been systematically examined.

Design/Methods

We conducted a retrospective cohort study of 18 patients with LGI1-AE followed at a single tertiary center between 2015 and 2025. Cognitive function was assessed longitudinally using domain-specific subscales from the Montreal Cognitive Assessment (MoCA), including a broad Executive Index Score (EIS), a narrow executive composite, and delayed recall. Statistical comparisons were performed to evaluate changes over time and differences by age.

Results Over a median [IQR] follow-up of 41.2 [24.8-50.5] months, global cognition, memory, and executive function improved significantly; MoCA scores increased from 20 [16–24] at baseline to 24 [19–27] at last follow-up (p=0.001), EIS rising from 9 [7–12] to 10.5 [9–13] (p=0.001) and the narrow executive composite from 2 [1–3] to 3 [2–4] (p=0.001). Delayed recall increased from 1 [0–2] to 2.5 [0–4] (p=0.024). However, executive function remained the most persistently impaired domain, particularly among older patients (>65 years). At last follow-up, despite similar treatment timing, older patients exhibited more severe and persistent deficits than younger patients in total MoCA (19 [15.8-24] vs. 26 [24-27.8], p=0.016) and EIS (9.5 [7.5-10.2] vs. 12.5 [11.2-13.0], p=0.009).

Conclusions Executive dysfunction is a prominent and persistent long-term cognitive deficit in LGI1-AE, challenging previous assumptions that it is predominantly transient. Patients over 65 have worse cognitive outcomes than younger patients. These findings underscore the need for domain-specific cognitive monitoring and targeted rehabilitation, particularly for older adults.

Authors/Disclosures
Dror Shir, MD (Mayo Clinic) PRESENTER	Dr. Shir has nothing to disclose.
Yael Paran (Ichilov)	Yael Paran has nothing to disclose.
Yifat Alcalay (Tel Aviv Medical Center)	Yifat Alcalay has nothing to disclose.
Avi Gadoth, MD (Tel-Aviv Medical Center)	Dr. Gadoth has received intellectual property interests from a discovery or technology relating to health care.

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