Specific characteristic presentations include Severe bilateral optic neuritis that involves the optic chiasm, causing loss of vision in the horizontal half (upper or lower) of the visual field (altitudinal visual field defect) or loss of acuity (20/200 or worse) A complete spinal cord syndrome, particularly with paroxysmal tonic spasms An area postrema syndrome, causing intractable hiccups or nausea and vomiting (the area postrema is a structure that controls vomiting and is located on the floor of the 4th ventricle) Acute transverse myelitis extending over ≥ 3 contiguous spinal cord segments Diagnosis of NMOSD Brain and spinal cord MRI Visual evoked potentials Diagnosis of neuromyelitis optica spectrum disorder usually includes brain and spinal cord MRI and visual evoked potentials (1).