Supplementary Material for: Eyelid Tremor in a Patient with Anti-Caspr2 Antibody-Related Encephalitis

We describe the first case of a patient with eyelid tremor probably associated with anti-contactin-associated protein-like 2 (Caspr2) antibody. Encephalitis associated with anti-voltage-gated potassium channel antibody is now attributed to autoantibodies against leucine-rich glioma inactivated 1 (Lgi1) and less frequently against Caspr2. Eyelid tremor or blepharoclonus is a rare or underdiagnosed involuntary movement that has been found in patients with infarction in the thalamus or drug-induced or idiopathic parkinsonism. Since patients with anti-Caspr2 antibody-related encephalitis occasionally have extrapyramidal signs, we speculate that the eyelid tremor was also caused by anti-Caspr2 antibody in our patient. Partial resolution of his symptoms by plasmapheresis also supported the involvement in immunological processes.