Neuromyelitis optica spectrum disorders associated with other autoimmune diseases

Associations between neuromyelitis optica spectrum disorder, Sjögren's syndrome, and conditions with electrolyte disturbances

OBJECTIVE

Electrolyte disorders are among the important conditions negatively affecting the disease course of neuromyelitis optica spectrum disorder (NMOSD). Possible mechanisms may include renal tubular acidosis (RTA) accompanying Sjögren's syndrome (SS), syndrome of inappropriate antidiuretic hormone secretion (SIADH), and central diabetes insipidus (DI). Currently, the overlap profiles between these conditions remain uncertain.

METHODS

This cross-sectional study collected data from the nationwide administrative Diagnosis Procedure Combination (DPC) database and evaluated the overlap profiles.

RESULTS

Among the 28,285,908 individuals from 1203 DPC-covered hospitals, 8477 had NMOSD, 174108 had SS, 4977 had RTA, 7640 had SIADH, and 24,789 had central DI. Of those with NMOSD, 986 (12%) had SS. The odds ratio (OR) for a diagnosis of NMOSD in those with SS compared with those without was 21 [95% confidence interval (CI), 20-23]. Overlap between NMOSD and SS was seen both in males (OR, 28 [95% CI, 23-33]) and females (OR, 16 [15-17]) and was more prominent in the younger population. Among patients with SS, the prevalence of RTA was lower in patients with NMOSD compared with those without NMOSD. Patients with NMOSD showed a higher prevalence of SIADH (OR, 11 [7.5-17]; p < 0.0001) and DI (OR, 3.7 [2.4-5.3]; p < 0.0001). Comorbid SS in NMOSD was associated with a higher prevalence of DI.

CONCLUSIONS

Patients with NMOSD are likely to have SS, SIADH, and central DI. RTA in SS does not facilitate the overlap between NMOSD and SS. SS in NMOSD may predispose patients to DI.

Predictors of overlapping autoimmune disease in Neuromyelitis Optica Spectrum disorder (NMOSD): A retrospective analysis in two inner-city hospitals

BACKGROUND

The coexistence of Neuromyelitis Optica spectrum disorder (NMOSD) with other autoimmune diseases (AD-NMOSD) presents worse clinical outcomes and healthcare costs than NMOSD alone (NMOSD-only). NMOSD and other autoimmune diseases also have a higher prevalence and morbidity in Black. We aim to compare clinical features and treatment responses in NMOSD patients with and without overlapping autoimmunity in a predominantly Black cohort. We further identify predictors associated with each clinical subtype.

METHODS

AD-NMOSD (n = 14) and NMOSD-only (n = 27) patients were identified retrospectively. Demographic, clinical, laboratory, imaging, and response to treatment data were examined.

RESULTS

Our cohort was predominately Black (82.9%). The prevalence of grouped-comorbidities, history of infections, sensory symptoms, Expanded Disability Status Scale (EDSS) before treatment, double-stranded DNA, antinuclear, ribonucleoprotein, and antiphospholipid antibodies, spinal-cord edema, white matter occipital lesions, and the levels of C-reactive protein, urine protein/creatinine, white blood cell count in cerebrospinal fluid (CSF), were higher in AD-NMOSD patients (p < 0.05 and/or Cramer's V > 30, Cohen's d > 50), whereas the age of males, visual symptoms, serum albumin, platelet count, and optic nerve enhancement were lower. EDSS after treatment improved in both groups being more evident in NMOSD-only patients (p = 0.003, SE = 0.58 vs p = 0.075, SE = 0.51). Other variables had a close to moderate SE, and others did not differ between NMOSD subtypes. A higher frequency of grouped-comorbidities, lower serum albumin, and platelet count were independently associated with a higher risk for AD-NMOSD.

CONCLUSIONS

Some clinical features between AD-NMOSD and NMOSD-only patients were similar, while others differed. Comorbidities, serum albumin, and platelet count may be independent predictors of AD-NMOSD.

Should Aquaporin-4 Antibody Test Be Performed in all Patients With Isolated Optic Neuritis?

BACKGROUND

Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients.

METHODS

We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients.

RESULTS

Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up.

CONCLUSION

Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.

Burden and cost of comorbidities in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is associated with various comorbidities, including non-autoimmune and autoimmune conditions. The burden and cost of illness for NMOSD are unclear, particularly in the context of comorbidities.

METHODS

Claims data from IBM MarketScan Commercial and Medicare Supplemental Databases between 2014 and 2018 were analyzed. Patients with NMOSD were specified as having inpatient or outpatient claims for NMOSD diagnosis or specific NMOSD symptoms claims and no subsequent claims for multiple sclerosis (MS) or use of MS disease-modifying therapy (DMT). Continuous enrollment ≥ 6 months before and ≥ 1 year after the first claim (index date) was required for study inclusion. Total costs stratified by comorbidities within 12 months post-index date were calculated per patient and compared 1:5 with matched non-NMOSD controls.

RESULTS

A total of 162 patients with NMOSD and 810 non-NMOSD controls were evaluated. A significantly higher proportion of NMOSD patients had comorbidities than non-NMOSD controls (66.7% vs 41.5%; P < 0.001). Concomitant autoimmune disease occurred in 19.1% vs 4.9% (P < 0.001) of patients with NMOSD vs non-NMOSD controls. NMOSD patients incurred significantly higher total median (interquartile range) healthcare costs per patient ($68,386.48 [$23,373.54-$160,862.70]) than matched non-NMOSD controls with autoimmune disease ($17,215.13 [$6715.48-$31,441.93]; P < 0.001) or patients with NMOSD without autoimmune comorbidity ($23,905.42 [$8632.82-$67,251.54]; P = 0.022). Similarly, patients with NMOSD and non-autoimmune comorbidities incurred higher median healthcare costs than matched controls.

CONCLUSIONS

Patients with NMOSD experience significant disease burden and cost that are amplified by comorbidities. Effective therapies are needed, particularly for patients with concomitant autoimmune disease.

Recurrent optic neuritis in a patient with Sjogren syndrome and neuromyelitis optica spectrum disorder: A case report

RATIONALE

Neuromyelitis optica spectrum disorder (NMOSD) patients, especially those with anti-aquaporin-4 antibody positivity, a water channel expressed on astrocytes, is often accompanied by autoimmune diseases (ADs) including Sjogren syndrome (SS). Here, we report a case of a young Chinese woman with recurrent optic neuritis who was diagnosed with asymptomatic SS and NMOSD.

PATIENT CONCERNS

A 22-year-old Chinese woman suffered from optic neuritis for 3 years. The main manifestation was recurrent loss of vision. The anti-aquaporin-4 antibody was positive in the cerebrospinal fluid, and she was diagnosed with NMOSD. Other laboratory tests revealed positive anti-SSA and anti-SSB antibodies, and labial gland biopsy showed lymphocytic infiltration. She also fulfilled the international criteria for SS.

DIAGNOSIS

On the basis of recurrent vision loss and laboratory examination, we defined the patient with SS accompanied by NMOSD.

INTERVENTIONS

When the patient first experienced vision loss, the corticosteroid treatment in the external hospital was effective, and her visual acuity improved significantly. However, in several later attacks, such treatment was no longer obviously effective. Considering the patient's condition, she was treated with corticosteroids, cyclophosphamide, and immunoglobulin therapy on admission.

OUTCOMES

The patient's visual acuity was increased to the right eye 20/800 and left eye finger counting when she was discharged from the hospital.

LESSONS

SS accompanied with NMOSD is common in clinical practice, and always with the positive Anti-AQP4 antibody as a potential biomarker. Patients with SS and NMOSD showed significant neurological symptoms and had a worse prognosis than SS patients with negative anti-AQP4 antibody because of cross-immunity between anti-SSA antibody and anti-AQP4 antibody. Rheumatologists and ophthalmologists should pay attention to this and perform appropriate tests.

Neuromyelitis optica spectrum standstill in rheumatic systemic autoimmune diseases

Background

Neuromyelitis optica spectrum disorders (NMOSD) are considered as an autoantibody-mediated disorder that targets aquaporin-4 (AQP4); other autoantibodies could be detected in such spectrum of diseases, including anti-nuclear antibody and antibodies to extractable nuclear antigens. Systemic autoimmune diseases such as systemic lupus erythematosus (SLE), Sjogren’s syndrome (SS), and other autoimmune diseases can overlap with NMOSD. We aimed in this review to address the current evidence describing the relation of NMOSD to systemic autoimmunity diseases, its controversy of being co-association or the same etiology, and its practical implications.

Main body

The current review was done using a search for related articles or case reports on PubMed until 2019. The keywords included neuromyelitis optica spectrum disorders in combination with autoimmune disease nomenclature. We described the literature background of this controversy, to summarize the evidence of NMOSD relationship to systemic autoimmune diseases.

Conclusion

NMOSD associated with systemic autoimmune diseases is more common in SLE and Sjogren’s syndrome rather than other autoimmune diseases, frequently affects females more than males; AQP4 antibodies should be tested for all NMOSD like manifestations associated with an autoimmune disorder; however, the clinical diagnosis of NMOSD regardless of the cord lesion length and the presence of positive AQP4 antibody can occur in systemic autoimmune diseases.

Neuromyelitis optica spectrum disorders in the Arabian Gulf: challenges and growing experience

Neuromyelitis optica spectrum disorders (NMOSD) have been studied in different ethnic groups, including Asians, African-Americans, and Caucasians. Demonstrating the clinical features among diverse communities is important to understand the variable disease phenotypes, which will lead to further classification and better clinical management. Testing for antibody against aquaporin-4 (AQP4), the most common target antigen in NMOSD, is not available in many countries and tests use different methods, with variable sensitivity. With negative antibody results, the diagnosis of NMOSD becomes challenging and may affect the outcomes of patients with NMOSD. There are no adequate studies that assess NMOSD cohorts in the Arabian Gulf region, despite the increasing number of diagnosed cases. It is worth assessing NMOSD cohorts in the Arabian Gulf population to study the natural history of disease and to establish an epidemiological background for future perspectives. Various challenges to implement such a mission are outlined, including disease rarity, overlapping presenting symptoms and signs, which posed the issue of mimickers in the differential diagnosis, lack of specialized clinics, absence of highly sensitive testing methods for diagnosis, and the indefinite agreement on the negative AQP4 NMOSD criteria. Collaborative efforts started to take a place among many experts in the region to establish a registry of NMOSD patients for better perception of the disease pattern.

Demyelinating syndrome in systemic sclerosis and neuromyelitis optica

Background

This article reports a case diagnosis of a 44-year-old female who presented with intractable hiccups and vomit complicated with an acute onset of paraplegia. Transverse myelitis was evident on MRI and serological studies were consistent with Neuromyelitis Optica (NMO) based on NMO-IgG sero-positivity. Further studies revealed positive ANA, anti-RNA polymerase III autoantibodies, and Scl-70, leading to a concurrent diagnosis of systemic sclerosis (SSc). The coexistence of these two disease processes and their underlying clinical manifestations and therapeutic interventions are seldom reported in literature and are worth reporting.

Case presentation

The patient was treated with high dose steroids, and subsequently developed malignant hypertension and acute renal failure, later identified on biopsy as steroids-induced scleroderma renal crisis. Although Neuromyelitis Optica spectrum disorder (NMOSD) has often been associated with various collagen and autoimmune diseases, the coexistence of NMOSD and SSc presented a challenge where the patient underwent aggressive physical therapy and necessitated an intervention with Rituximab to achieve an appropriate clinical response.

We have received a written consent forms from the participant in our study, and we have them on file in case they are requested. We have also received the patient’s written consent for the data and images presented in this article.

Conclusion

This article expands on NMOSD associated autoimmune diseases. Systemic Sclerosis is an insidious disease that is often diagnosed late as not all patients often report skin manifestation. The finding suggests that patients presenting with acute neurological manifestations get tested for NMO-IgG/AQP-4 antibodies and other immunological studies based on clinical findings.

Comprehensive review of neuromyelitis optica and clinical characteristics of neuromyelitis optica patients in Puerto Rico

Neuromyelitis optica (NMO) is an immune-mediated inflammatory disorder of the central nervous system. It is characterized by concurrent inflammation and demyelination of the optic nerve (optic neuritis [ON]) and the spinal cord (myelitis). Multiple studies show variations in prevalence, clinical, and demographic features of NMO among different populations. In addition, ethnicity and race are known as important factors on disease phenotype and clinical outcomes. There are little data on information about NMO patients in underserved groups, including Puerto Rico (PR). In this research, we will provide a comprehensive overview of all aspects of NMO, including epidemiology, environmental risk factors, genetic factors, molecular mechanism, symptoms, comorbidities and clinical differentiation, diagnosis, treatment, its management, and prognosis. We will also evaluate the demographic features and clinical phenotype of NMO patients in PR. This will provide a better understanding of NMO and establish a basis of knowledge that can be used to improve care. Furthermore, this type of population-based study can distinguish the clinical features variation among NMO patients and will provide insight into the potential mechanisms that cause these variations.

Clinical characteristics of 153 Brazilian patients with neuromyelitis optica spectrum disorder (NMOSD)

BACKGROUND

The 2015 criteria for diagnosing neuromyelitis optica spectrum disorder (NMOSD) have encouraged several groups across the world to report on their patients using these criteria. The disease typically manifests with severe relapses of optic neuritis, longitudinally extensive myelitis and/or brainstem syndromes, often leading to severe disability. Some patients are seropositive for antibodies against aquaporin-4 (AQP4), others are positive for anti-myelin oligodendrocyte glycoprotein (MOG), while a few are negative for both biomarkers. The disease is complex, and only now are specific therapeutic clinical trials being carried out. The present study adds to the literature through detailed clinical data from 153 medical records of Brazilian patients.

METHODS

Retrospective assessment of medical records from nine specialized units in Brazil.

RESULTS

NMOSD was more prevalent in females (4.1:1), who had significantly fewer relapses than males (p = 0.007) but presented similar levels of disability over time. African ancestry was associated with higher levels of disability throughout the disease course (p < 0.001), although the number of relapses was similar to that observed in white patients. Concomitant autoimmune diseases were relatively rare in this population (6.5%). Positivity for anti-AQP4 antibodies was identified in 62% of the patients tested, while 3% presented anti-MOG antibodies. Anti-AQP4 antibodies were not associated to worse disease course. The last medical record showed that six patients had died and 13 were wheelchair-bound. Seventy percent of the patients did not respond to first-line therapy (azathioprine and/or corticosteroids), and five patients continued to relapse even after four different courses of treatment.

CONCLUSION

The present study adds to the reports from other countries presenting original data on Brazilian patients diagnosed with NMOSD according to the 2015 criteria.

Autoimmune diseases associated with Neuromyelitis Optica Spectrum Disorders: A literature review

INTRODUCTION

Neuromyelitis Optica (NMO) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS) which predominantly involves optic nerves and spinal cord. Since the introduction of Neuromyelitis Optica Spectrum Disorders (NMOSD) as a separate entity, there have been many reports on its association with other disorders including systemic and organ-specific autoimmune diseases. Here, we reviewed other immune-mediated diseases associated with NMOSD and tried to categorize them.

METHODS

The present review was conducted using the PUBMED database based on papers from 1976 (i.e., since the first NMO comorbidity with SLE was reported) to 2017. We included all articles published in English. The keywords utilized included Neuromyelitis optica, Neuromyelitis Optica Spectrum Disorders, Devic's disease, in combination with comorbidity or comorbidities.

RESULTS

Diseases with immune-based pathogenesis are the most frequently reported co-morbidities associated with NMOSD, most of which are antibody-mediated diseases. According to literature, Sjogren's Syndrome (SS) and Systemic Lupus Erythematosus (SLE) are the most frequently reported diseases associated with NMOSD among systemic autoimmune diseases. Further, myasthenia gravis in neurological and autoimmune thyroid diseases in non-neurological organ-specific autoimmune diseases are the most reported comorbidities associated with NMOSD in the literature.

CONCLUSIONS

NMOSD may be associated with a variety of different types of autoimmune diseases. Therefore, systemic or laboratory signs which are not typical for NMOSD should be properly investigated to exclude other associated comorbidities. These comorbidities may affect the treatment strategy and may improve the patients' care and management.

Neuromyelitis Optica: Review and Utility of Testing Aquaporin-4 Antibody in Typical Optic Neuritis

Neuromyelitis optica (NMO) is an autoimmune, inflammatory demyelinating disorder often leading to severe vision impairment and disability. The discovery of a diagnostic biomarker, the aquaporin-4 antibody (AQP4-IgG), transformed the clinical diagnosis and treatment of NMO and broadened the spectrum of disease [NMO spectrum disorders (NMOSD)]. Though the antibody is highly sensitive and specific to NMOSD, routine testing in patients with typical optic neuritis is considered controversial. This article will provide a brief review of NMOSD and highlight the pros and cons of routine testing in typical optic neuritis.

Frequency of autoimmune disorders and autoantibodies in patients with neuromyelitis optica

OBJECTIVE

The aim of this study was to report the frequency of autoimmune disorders and autoantibodies in 22 patients with neuromyelitis optica (NMO), as well as whether the seropositivity for autoantibodies differs between anti-aquaporin 4 (AQP4) positive and AQP4 negative NMO patients.

METHODS

Demographic, medical records, and a profile of autoantibodies were evaluated in 22 NMO patients, including AQP4, anti-thyroid-stimulating hormone receptor, antinuclear antibodies (ANA), anti-thyroperoxidase (anti-TPO), anti-thyroglobulin (anti-Tg), anti-double-stranded DNA, anti-neutrophil cytoplasmic, anti-cyclic citrullinate peptide, rheumatoid factor, anti-SSA/Ro, anti-SSB/La, anti-Smith antibodies (anti-Sm), anti-ribonucleoprotein, anti-nucleosome, and anti-Scl70. Thyroid-stimulating hormone and free thyroxin were measured.

RESULTS

The frequency of women was higher than men (95.5% vs. 4.5%) and 68.2% were Afro-Brazilians. Six (27.3%) patients presented other autoimmune disorders, such as Hashimoto thyroiditis (n=2), Graves' disease (n=1), juvenile idiopathic arthritis (n=1), systemic lupus erythematosus and systemic sclerosis (n=1), and Raynaud's phenomenon (n=1). The most frequent autoantibodies were anti-AQP4 (54.5%), anti-nucleosome (31.8%), ANA (27.3%), anti-TPO (22.7%), and anti-Tg (22.7%). Difference was not observed in the frequency of autoimmune disorders when the patients were compared according to their anti-AQP4 status.

CONCLUSION

The results of the present study underscored that the NMO patients present high frequency of autoantibodies against cellular antigens and the presence of autoimmune disorders. Further studies with large number of NMO patients may contribute to advances in the understanding of NMO disease mechanisms.

Aquaporin-4 positive neuromyelitis optica spectrum disorders secondary to thrombopenic purpura: A case report

RATIONALE

Neuromyelitis optica spectrum disorders (NMOSD) is considered as an immune-mediated disorder in the central nervous system (CNS). Numerous autoimmune diseases are frequently complicated with NMOSD and distinct clinical characteristics are noted in NMOSD patients with other autoimmune diseases. However, to our best knowledge, co-occurrence of NMOSD and thrombopenic purpura is rarely identified.

PATIENT CONCERNS

We presented a rare case of a 72-year-old female with 6-year history of thrombopenic purpura, and 1-month history of blurred vision as well as chest zonethesia. Anti-aquaporin-4 (AQP4) antibodies was positive in the serum of the patient.

DIAGNOSES

With the addition of laboratory findings, iconography findings and physical examination results, the diagnosis of NMOSD was established according to the most recent diagnostic criteria.

INTERVENTIONS AND OUTCOMES

With the treatment of intravenous immunoglobulin (IVIg), the patient felt better at discharge without changing of expanded disability status scale (EDSS) score.

LESSONS

The case indicates that NMOSD could co-occur with thrombopenic purpura. The disturbance of immune system balance may explain this overlap. Further studies are warranted to reveal the mechanism and to explore whether patients with NMOSD with and without thrombopenic purpura have distinct clinical feature, drug responsiveness or prognosis.

Injectable Hydrogels for Spinal Cord Repair: A Focus on Swelling and Intraspinal Pressure

Spinal cord injury (SCI) is a devastating condition that leaves patients with limited motor and sensory function at and below the injury site, with little to no hope of a meaningful recovery. Because of their ability to mimic multiple features of central nervous system (CNS) tissues, injectable hydrogels are being developed that can participate as therapeutic agents in reducing secondary injury and in the regeneration of spinal cord tissue. Injectable biomaterials can provide a supportive substrate for tissue regeneration, deliver therapeutic factors, and regulate local tissue physiology. Recent reports of increasing intraspinal pressure after SCI suggest that this physiological change can contribute to injury expansion, also known as secondary injury. Hydrogels contain high water content similar to native tissue, and many hydrogels absorb water and swell after formation. In the case of injectable hydrogels for the spinal cord, this process often occurs in or around the spinal cord tissue, and thus may affect intraspinal pressure. In the future, predictable swelling properties of hydrogels may be leveraged to control intraspinal pressure after injury. Here, we review the physiology of SCI, with special attention to the current clinical and experimental literature, underscoring the importance of controlling intraspinal pressure after SCI. We then discuss how hydrogel fabrication, injection, and swelling can impact intraspinal pressure in the context of developing injectable biomaterials for SCI treatment.

Gray Matter Volume Reduction Is Associated with Cognitive Impairment in Neuromyelitis Optica

BACKGROUND AND PURPOSE

Whether gray matter impairment occurs in neuromyelitis optica is a matter of ongoing debate, and the association of gray matter impairment with cognitive deficits remains largely unknown. The purpose of this study was to investigate gray matter volume reductions and their association with cognitive decline in patients with neuromyelitis optica.

MATERIALS AND METHODS

This study included 50 patients with neuromyelitis optica and 50 sex-, age-, handedness-, and education-matched healthy subjects who underwent high-resolution structural MR imaging examinations and a battery of cognitive assessments. Gray matter volume and cognitive differences were compared between the 2 groups. The correlations of the regional gray matter volume with cognitive scores and clinical variables were explored in the patients with neuromyelitis optica.

RESULTS

Compared with healthy controls (635.9 ± 51.18 mL), patients with neuromyelitis optica (602.8 ± 51.03 mL) had a 5.21% decrease in the mean gray matter volume of the whole brain (P < .001). The significant gray matter volume reduction in neuromyelitis optica affected the frontal and temporal cortices and the right thalamus (false discovery rate correction, P < .05). The regional gray matter volumes in the frontal and temporal cortices were negatively correlated with disease severity in patients with neuromyelitis optica (Alphasim correction, P < .05). Patients with neuromyelitis optica had impairments in memory, information processing speed, and verbal fluency (P < .05), which were correlated with gray matter volume reductions in the medial prefrontal cortex and thalamus (Alphasim correction, P < .05).

CONCLUSIONS

Gray matter volume reduction is present in patients with neuromyelitis optica and is associated with cognitive impairment and disease severity in this group.