Advances of the pathological mechanism and related factors of cognitive impairment in neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSDs) are recurrent autoimmune inflammatory disorders of the central nervous system, with uni- or bilateral optic neuritis, transverse myelitis and brainstem syndromes as clinical hallmarks. Aquaporin-4 immunoglobulin G antibody (AQP4-IgG) is a specific pathogenic antibody to NMOSD. Numerous studies have demonstrated the presence of cognitive impairment in multiple sclerosis (MS) and the problem of cognitive impairment in NMOSD has previously been ignored because of its more prominent neurophysiological disability. In recent years, with the development of neuroimaging and measurement of cognitive scales, a series of studies has demonstrated that cognitive impairment may be present in NMOSD with or without brain lesions, thus revealing possible occult brain pathology damage in the disease process. Considering the high incidence rates of recurrence and disability, NMOSD insidiously progressing to comorbid cognitive impairment could bring serious economic and mental burdens to patients and families. The problem of cognitive impairment in NMOSD is gradually attracting the attention of clinical and scientific researchers and making progress, including neuroimaging predictors of cognitive impairment, neuropathological changes and molecular indicators of blood. In this article, the major studies on cognitive impairment in NMOSD are reviewed. The current status of research, pathological mechanisms, cognitive scales, neuroimaging advances and the effects of other factors of cognition in NMOSD is also systematically described, providing clinicians with a basis of assessing cognitive changes, disease progression and treatment prognosis in NMOSD in their clinical work.