A major advance over the past decade in the nosology of CNS inflammatory demyelinating diseases has been the distinction between classic MS (CMS) and neuromyelitis optica (NMO). Japanese investigators were first to recognize the optic-spinal form of MS (OSMS) in which, like NMO, clinical attacks of transverse myelitis and optic neuritis predominate. However, despite diagnostic advances that have facilitated the distinction between CMS and NMO, the relationship of Asian OSMS to MS and NMO as diagnosed in Western countries is still controversial. In both OSMS and NMO, the occurrence of aquaporin-4 autoantibodies and longitudinally extensive spinal cord lesions and less common but highly specific symptoms such as intractable vomiting and hiccough in both OSMS and NMO suggest that they are identical.1-3 However, some Japanese and Asian investigators argue that no characteristic is specific and that OSMS and classic MS represent a continuum.
Read More: Japanese optic-spinal MS: is it MS or neuromyelitis optica and does the answer dictate treatment?