Editors' Note: Frequency of Asymptomatic Optic Nerve Enhancement in a Large Retrospective Cohort of Patients With Aquaporin-4+ NMOSD

In "Frequency of Asymptomatic Optic Nerve Enhancement in a Large Retrospective Cohort of Patients With Aquaporin-4+ NMOSD," Shah et al. reported that 17% of patients with Aquaporin-4+ NMOSD have asymptomatic optic nerve enhancement, predominantly at the site of prior optic neuritis. They suggested that this could represent intermittent blood-brain barrier breakdown or subclinical optic neuritis. Cao et al. noted that it is unclear whether asymptomatic enhancement is associated with an increased risk of relapse, given silent lesions have both diagnostic and prognostic value in multiple sclerosis. Chen and Shah responded that the number of recurrent attacks was the same for both patients with and without asymptomatic optic nerve enhancement, suggesting this is not a risk factor for relapse. They speculated that the varying prognostic value of enhancement of the optic nerve, as compared with the brain and spinal cord, may be attributed to blood-brain barrier differences, but noted additional studies that include imaging of all 3 parts of the neuroaxis are needed to explore this further. The findings of this study suggest that NMOSD may be a more continuous inflammatory disorder than previously thought. In "Frequency of Asymptomatic Optic Nerve Enhancement in a Large Retrospective Cohort of Patients With Aquaporin-4+ NMOSD," Shah et al. reported that 17% of patients with Aquaporin-4+ NMOSD have asymptomatic optic nerve enhancement, predominantly at the site of prior optic neuritis. They suggested that this could represent intermittent blood-brain barrier breakdown or subclinical optic neuritis. Cao et al. noted that it is unclear whether asymptomatic enhancement is associated with an increased risk of relapse, given silent lesions have both diagnostic and prognostic value in multiple sclerosis. Chen and Shah responded that the number of recurrent attacks was the same for both patients with and without asymptomatic optic nerve enhancement, suggesting this is not a risk factor for relapse. They speculated that the varying prognostic value of enhancement of the optic nerve, as compared with the brain and spinal cord, may be attributed to blood-brain barrier differences, but noted additional studies that include imaging of all 3 parts of the neuroaxis are needed to explore this further. The findings of this study suggest that NMOSD may be a more continuous inflammatory disorder than previously thought.