Abstract Details

Title Video Head Impulse Test Characteristics of Anti-Glutamic Acid Decarboxylase (GAD)–Associated Neurologic Disorders

Topic Autoimmune Neurology

Presentation(s) P2 - Poster Session 2 (8:00 AM-9:00 AM)

Poster/Presentation
Number 8-009

Objective To investigate vestibular characteristics in patients with anti-glutamic acid decarboxylase 65 (anti-GAD65)-associated neurologic disorders using video head-impulse testing (vHIT) and examine its relationship with cerebellar radiologic markers.

Background Anti-GAD65-associated neurologic disorders may present with prominent vestibular and oculomotor (VOM) dysfunction, likely due to involvement of the vestibulocerebellum. vHIT allows for objective assessment of the vestibular system. vHIT patterns in anti-GAD65-associated neurologic disorders have never been reported before.

Design/Methods Retrospective review of medical records from 1997 to 2024 identified patients with diagnosis of anti-GAD65-associated neurologic disorders who also completed vHIT. Phenotypes included stiff-person syndrome spectrum disorders (SPSD) and GAD65-positive pure cerebellar ataxia (CA). vHIT parameters included vestibulo-ocular reflex (VOR) gain, and presence of catch-up saccades. A VOR gain <0.7 was considered decreased, and >1.0 increased or hyperactive. Available Brain MRI and FDG-PET scans were analyzed for measurement of cerebellar volume and uptake analysis, respectively.

Results A total of 33 out of 228 patients were identified. The majority of patients reported vestibular symptoms (67%) and most common phenotypes were SPS-plus (51%), followed by classic SPS (27%). Median (IQR) titer of GAD65-antibody in serum was 118,939 IU/mL (22,975 - 312,361IU/mL). Eye movement findings localizing to the cerebellum were present in 82% of patients. Mean VOR gain was 1.05±0.19 in classic SPS, 1.13±0.13 in progressive encephalomyelitis with rigidity and myoclonus (PERM), 1.05±0.23 in SPS-plus, and 0.85±0.21 in CA. One-way ANOVA revealed significant difference in mean VOR gain among the various phenotypes;F(3,64)= 3.11, p= .032. VOR gain was increased in 58% of patients, mostly bilaterally. The majority of vHITs did not have presence of catch-up saccades, although two showed a hyperactive VOR with back-up saccades. Brain and PET scan findings are currently being analyzed.

Conclusions The vHIT pattern in patients with anti-GAD65-associated neurologic disorders suggest vestibulocerebellar dysfunction. Together with video-oculography findings, it may provide diagnostic clues for these rare disorders.

Authors/Disclosures
Ruth Andrea Salazar Camelo, MD (Johns Hopkins School of Medicine) PRESENTER	Dr. Salazar Camelo has nothing to disclose.
Norman Beauchamp III, MD	Dr. Beauchamp has nothing to disclose.
Yujie Wang, MD (UW Northwest)	Dr. Wang has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TG Therapeutics. The institution of Dr. Wang has received research support from Genentech. The institution of Dr. Wang has received research support from uniQure. The institution of Dr. Wang has received research support from NIH/NINDS.
Kemar E. Green, DO (John's Hopkins Medicine)	Dr. Green has nothing to disclose.
Scott D. Newsome, DO, FAAN (Johns Hopkins Hospital)	Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Newsome 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. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for TG Therapeutics. The institution of Dr. Newsome has received research support from Biogen. The institution of Dr. Newsome has received research support from Genentech/Roche. The institution of Dr. Newsome has received research support from Department of Defense. The institution of Dr. Newsome has received research support from Patient Centered Outcomes Research Institute. The institution of Dr. Newsome has received research support from National MS Society. The institution of Dr. Newsome has received research support from Lundbeck. The institution of Dr. Newsome has received research support from Sanofi. The institution of Dr. Newsome has received research support from Kyverna Therapeutics. Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving as a Lead PI for Clinical Trial with Roche.

��ɫ��

��ɫ��