Oculomotor Abnormalities in Anti Glutamic Acid Decarboxylase Positive Stiff Person Syndrome

Background: Anti glutamic acid decarboxylase (Anti-GAD) –associated stiff person syndrome (SPS) is a rare autoimmune disorder characterised by rigidity, spasms, and functional disability. Oculomotor dysfunction is an underrecognised manifestation that may provide insight into central nervous system involvement. Methods: We report two illustrative cases of anti-GAD–associated SPS with distinct oculomotor abnormalities documented by videonystagmography and supplementary videos. Results: Patients demonstrated distinct oculomotor abnormalities, including smooth pursuit deficits, sac-cadic latency prolongation, dysmetria, intrusions, and nystagmus. Partial improvement was observed after immunomodulatory therapy. Conclusion: These cases expand the recognised clinical spectrum of anti-GAD SPS and suggest that quantitative eye-movement analysis may provide a sensitive, non-invasive marker of disease activity. Prospective studies are warranted to define prevalence and therapeutic responsiveness.