LGI1 and viral encephalitis: However, further characteristic clinical signs are usually present - for instance, characteristic eye movement abnormalities in opsoclonus-myoclonus syndrome (OMS); hyperekplexia and prominent brainstem and autonomic involvement in progressive encephalomyelitis with rigidity and myoclonus (PERM); and clinical signs for limbic encephalitis (seizures, memory impairment) in LGI1- and CASPR2-encephalitis [40].