Cognition in patients with neuromyelitis optica spectrum disorders: A prospective multicentre study of 217 patients (CogniNMO-Study)

Cognitive assessment in Neuromyelitis Optica spectrum disorders: A systematic review and meta-analysis

INTRODUCTION

Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune disorder primarily affecting the central nervous system, with cognitive impairments often overlooked in clinical studies. This systematic review and meta-analysis aimed to evaluate cognitive function in individuals with NMOSD, addressing gaps in the literature and informing clinical practice.

METHODS

A comprehensive literature search identified 28 eligible studies involving 1365 patients. Cognitive performance was assessed using validated neuropsychological tools, including the Controlled Oral Word Association Test (COWAT), California Verbal Learning Test (CVLT), Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Paced Auditory Serial Addition Test (PASAT), and Symbol Digit Modalities Test (SDMT).

RESULTS

The analysis revealed significant cognitive deficits across multiple domains. Verbal fluency (COWAT: mean score 24.68, 95 % CI: 23.70-25.70) and memory recall (CVLT: mean score 43.01, 95 % CI: 42.26-43.78) were notably impaired. Global cognitive function was mildly affected, with mean scores of 27.34 (95 % CI: 26.97-27.72) on the MMSE and 26.54 (95 % CI: 26.51-26.57) on the MoCA. High variability (I² > 80 %) in cognitive performance was attributed to differences in study methodologies and patient characteristics.

CONCLUSION

These findings underscore the prevalence of cognitive impairments in NMOSD and highlight the need for targeted neuropsychological assessments in this population. Incorporating cognitive evaluations into routine clinical practice could enhance patient management and improve quality of life.

Apheresis for the treatment of relapses in MS and NMOSD: reduced antibody reactivities, gene expression changes and potential clinical response indicators

Background

High-dose glucocorticoids are the standard treatment for acute relapses in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD). Therapeutic apheresis can be considered for the escalation of relapse therapy, but some patients still do not recover sufficiently. We aimed to explore the effects of apheresis on humoral and cellular immune parameters and to identify features that correlate with beneficial clinical outcomes.

Methods

We studied two cohorts comprising a total of 63 patients with MS or NMOSD who were undergoing relapse therapy with either methylprednisolone or apheresis. Blood samples were collected immediately before and after therapy to isolate plasma or serum as well as immune cells. We then measured (1) concentrations of the immunoglobulin isotypes IgG, IgM and IgA, (2) antibody reactivities against 12 peptides derived from potential autoantigens and Epstein-Barr virus proteins, (3) frequencies of CD19+ B cells, CD3+ T cells and CD14+ monocytes, (4) transcriptome profiles of CD19+ B cells and CD4+ T cells and (5) mRNA levels of 7 cytotoxicity-related genes in CD4+ T cells. The data were compared with regard to changes under therapy and with regard to differences between clinical responders and non-responders.

Results

The initial therapy with methylprednisolone had no significant effect on immunoglobulin levels and (auto)antibody reactivities (n max=27 MS patients). In contrast, MS patients who underwent apheresis (n max=27) showed strong immunoglobulin reduction rates, especially for IgG, and decreased antibody reactivities against all tested peptides. EBNA1 (amino acids 391-410) was the only peptide that also reached the significance level in NMOSD patients (n=9). Non-responders to apheresis (n=12) had on average higher anti-EBNA1 (391-410) reactivities than responders (n=24) at baseline. Apheresis also led to a decrease in the proportion of monocytes, an increase in the proportion of T cells (n=29 patients with MS or NMOSD) and moderate transcriptome changes (n max=4 MS patients). A gene expression signature that is characteristic of CD4+ cytotoxic T lymphocytes (CD4-CTLs) was found to be elevated at baseline in non-responders to apheresis, although this could not be validated with statistical significance (n=19 MS patients).

Conclusion

Our data reveal that therapeutic apheresis in MS rapidly leads to a significant decrease in IgG reactivities against EBNA1 (391-410) and cross-reactive targets such as GlialCAM (370-389) and also has an impact on the gene expression of B cells and T cells. Further studies are required to verify whether anti-EBNA1 (391-410) antibody reactivities and the expression of CD4-CTL-related genes may be indicative of the individual clinical response to this therapy.

Exploring subcortical pathology and processing speed in neuromyelitis optica spectrum disorder with myelin water imaging

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) affects the optic nerves and spinal cord but can also cause focal brain inflammation. Subcortical pathology may contribute to the etiology of cognitive deficits in NMOSD. Using myelin water imaging, we investigated cerebral normal-appearing white matter (NAWM) and thalamic metrics and their association with cognition in NMOSD participants compared to healthy controls (HC).

METHODS

Seventeen NMOSD participants and 21 HC were scanned on a 3.0-Tesla MRI scanner using a multicomponent driven-equilibrium single-pulse observation of T1 and T2 protocol. Tissue compartment and thalamic volumes (normalized to intracranial volume), T1 relaxation time, and myelin water fraction (MWF) were reported. Eleven NMOSD participants underwent the Symbol Digit Modalities Test (SDMT) for cognitive evaluation. Group comparisons were performed using Student's t-test. The association between thalamic metrics and SDMT score was assessed using multiple regression analysis with age as a covariate.

RESULTS

Compared to HC, NMOSD participants had reduced white matter volume (-14.2%, p < .0001), increased T1 relaxation time (+2.29%, p = .022), and lower MWF (-3.64%, p = .024) in NAWM. NMOSD group had a trend for smaller thalamic volumes than HC (-5.52%, p = .082) and no differences in thalamic MWF (p = .258) or T1 (p = .714). Thalamic T1 predicted SDMT score (adjusted R2 = .51, p = .04) when controlling for age.

CONCLUSIONS

NAWM in NMOSD demonstrates diffuse abnormalities with increased water content and demyelination, suggesting a diffuse disease process overlooked by focal inflammation measures. Increased water content, as a biomarker for diffuse thalamic pathology, may partially explain cognitive impairment in NMOSD.

Cognitive Impairment, Associated Clinical Factors, and MR Volumetric Measures in Myelin Oligodendrocyte Glycoprotein-IgG-Associated Disease

BACKGROUND AND OBJECTIVES

Cognitive impairment is a common and challenging symptom in multiple sclerosis and neuromyelitis optica spectrum disease; however, data in myelin oligodendrocyte glycoprotein-IgG-associated disease (MOGAD) remain scarce. In this cross-sectional study, we investigated the frequency of cognitive impairment, associated clinical factors, and MRI volumetric measures in MOGAD.

METHODS

Participants were investigated in a single center by certified psychologists and underwent a standardized 3-T-MRI protocol. MRI data were processed with FreeSurfer for gray and white matter volume estimation, presented as a fraction of total intracranial volume. Sera screening for antineural antibodies has been conducted using cell-based assays. The following clinical factors were included in the multivariate logistic regression analysis: sex, age, overall number of previous relapses, and specifically the history of acute disseminated encephalomyelitis (ADEM)/ADEM-like episodes and other brain relapses.

RESULTS

Thirty-two patients with MOGAD (19 female, median age 29.4 years) after a median of 2 relapses with a median EDSS of 1.0 were recruited. Seven patients (21.9%) demonstrated cognitive impairment with the most prevalent deficits in mental flexibility (16.7%), attention (11.1%-14.8%), and verbal working memory (10.3%). 72.4% suffered from fatigue and 42.9% from signs of depression, moderate to severe in 28.6%. The overall number of previous relapses (odds ratio [OR] 1.789, 95% CI 1.041-3.074) and specifically ADEM/ADEM-like episodes (OR 16.929, 95% CI 1.228-233.427) were the only clinical factors associated with cognitive impairment in a multivariate logistic regression model. Screening for antineuronal antibodies remained negative. Cerebral white matter (WM) (0.300 vs 0.317, p = 0.003) and deep gray matter (DGM) (0.036 vs 0.038, p = 0.002) volumes were reduced in patients with MOGAD compared with healthy controls (n = 32). Both cognitive impairment (0.031 vs 0.036, p = 0.003) and history of ADEM/ADEM-like episodes (0.032 vs 0.036, p = 0.006) were associated with reduced DGM volume compared with unaffected patients with MOGAD.

DISCUSSION

Despite a low overall disability, every 5th patient with MOGAD experiences cognitive impairment. Cognitive impairment is associated with a higher number of relapses and particularly ADEM/ADEM-like attacks. Although both WM and DGM atrophies are apparent in MOGAD, the latter only seems to have an association with cognitive impairment.

Assessment of disability and disease burden in neuromyelitis optica spectrum disorders in the CIRCLES Cohort

Neuromyelitis optica spectrum disorders (NMOSD) comprise autoimmune diseases imposing substantial disability. We compared an NMOSD-targeted disability assessment of mobility, vision, and self-care domains (individually and composite) with the multiple sclerosis-targeted Expanded Disability Status Scale (EDSS) to assess NMOSD disease burden. An overall cohort (n = 505) and a subset of these patients with an enriched dataset (n = 198) were analyzed from the CIRCLES longitudinal, observational database of patients with AQP4-IgG-seropositive or -seronegative NMOSD in North America. Multinomial modeling was used to identify temporal correlates of disability improvement, stability, and worsening. Prior on-study relapse correlated with worsening mobility (OR, 3.08; 95% CI: 1.61-5.90), vision (OR, 3.99; 95% CI: 2.03-7.86), self-care disability (OR, 1.90; 95% CI: 1.07-3.38), and mean composite index disability (OR, 4.20; 95% CI: 1.71-10.34). Higher vision disability was associated with Black race, shorter time on-study, and AQP4-IgG-seropositive status in patients ≥ 18 years (p < 0.05). Disease onset phenotype and sex correlated with pain interference (p < 0.05). These correlates of NMOSD disability were undetected by EDSS. The CIRCLES real-world experience supports the need for NMOSD-specific disability assessment to improve recognition of disease burden, facilitate proactive clinical management, offer insights into resilience, and inform clinical trial design.

The influence of MOGAD on diagnosis of multiple sclerosis using MRI

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an immune-mediated demyelinating disease that is challenging to differentiate from multiple sclerosis (MS), as the clinical phenotypes overlap, and people with MOGAD can fulfil the current MRI-based diagnostic criteria for MS. In addition, the MOG antibody assays that are an essential component of MOGAD diagnosis are not standardized. Accurate diagnosis of MOGAD is crucial because the treatments and long-term prognosis differ from those for MS. This Expert Recommendation summarizes the outcomes from a Magnetic Resonance Imaging in MS workshop held in Oxford, UK in May 2022, in which MS and MOGAD experts reflected on the pathology and clinical features of these disorders, the contributions of MRI to their diagnosis and the clinical use of the MOG antibody assay. We also critically reviewed the literature to assess the validity of distinctive imaging features in the current MS and MOGAD criteria. We conclude that dedicated orbital and spinal cord imaging (with axial slices) can inform MOGAD diagnosis and also illuminate differential diagnoses. We provide practical guidance to neurologists and neuroradiologists on how to navigate the current MOGAD and MS criteria. We suggest a strategy that includes useful imaging discriminators on standard clinical MRI and discuss imaging features detected by non-conventional MRI sequences that demonstrate promise in differentiating these two disorders.

The burden of psychiatric morbidity in Multiple Sclerosis, AQP4-antibody NMOSD and MOGAD before and after neurological diagnosis

BACKGROUND

Psychiatric comorbidities are common in Multiple Sclerosis (MS) and are increasingly recognised in Aquaporin-4-Antibody Neuromyelitis Optica Spectrum Disorders (AQP4-Ab NMOSD) and Myelin Oligodendrocyte Glycoprotein-Antibody Associated Disease (MOGAD). However, it is unclear if these psychiatric comorbidities predate neurological diagnosis or classical neurological symptoms that are conventionally used to establish the onset of these central nervous system inflammatory demyelinating diseases. We sought to: (1) assess the frequency and incidence of psychiatrist-diagnosed psychiatric disorders before and after formal MS, AQP4-Ab NMOSD, and MOGAD diagnosis, and (2) identify potential factors associated with the presence of pre-existing psychiatric morbidity and depression severity at the first clinical visit for MS patients.

METHODS

A retrospective observational study was performed on MS, AQP4-Ab NMOSD, and MOGAD patients seen at the National Neuroscience Institute (NNI) Singapore. Individuals with psychiatrist-diagnosed psychiatric disorders before and after neurological diagnosis were identified. Demographic, clinical data, and Patient Health Questionnaire (PHQ)-9 score at first clinic visit were collected and analysed.

RESULTS

Three hundred and ninety-nine patients (249 MS, 102 AQP4-Ab NMOSD, 48 MOGAD) were included. A higher proportion of MS patients (13/249, 5.2%) had psychiatric disorders before neurological diagnosis, compared to AQP4-Ab NMOSD (1/102, 1.0%) and MOGAD (0/48, 0.0%) (p = 0.054). Within MS patients, univariate logistic regression revealed that age, sex, race, MS subtype, initial MRI lesion load, and interval between classical MS symptom onset to MS diagnosis were not associated with pre-existing psychiatric disorders. Mean PHQ-9 score for MS patients at their first MS consult was 4.4 (cut-off for no/minimal depression is ≤4); no clinical factors were predictive of higher PHQ-9 scores on univariate linear regression. The proportion of MS patients (29/236, 12.2%) who developed psychiatric illness after neurological diagnosis was not different from AQP4-Ab NMOSD (9/101, 8.9%) (p > 0.999), while this was significantly higher compared to MOGAD (0/48, 0.0%) (p = 0.021). The incidence rate of psychiatric diseases after neurological diagnosis, accounting for follow up time, was also similar between MS and AQP4-Ab NMOSD (incidence rate ratio 1.2; 95% confidence interval 0.54 - 2.8; p = 0.689).

CONCLUSION

There is a significant psychiatric burden prior to MS diagnosis compared to AQP4-Ab NMOSD and MOGAD. The increased frequency of psychiatric comorbidity after NMOSD diagnosis merits further study to investigate the determinants of this phenomenon.

Cognition in patients with myelin oligodendrocyte glycoprotein antibody-associated disease: a prospective, longitudinal, multicentre study of 113 patients (CogniMOG-Study)

BACKGROUND

Data on cognition in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are limited to studies with small sample sizes. Therefore, we aimed to analyse the extent, characteristics and the longitudinal course of potential cognitive deficits in patients with MOGAD.

METHODS

The CogniMOG-Study is a prospective, longitudinal and multicentre observational study of 113 patients with MOGAD. Individual cognitive performance was assessed using the Paced Auditory Serial Addition Task (PASAT), the Symbol Digit Modalities Test (SDMT) and the Multiple Sclerosis Inventory Cognition (MuSIC), which are standardised against normative data from healthy controls. Cognitive performance was assessed at baseline and at 1-year and 2-year follow-up assessments. Multiple linear regression was used to analyse demographic and clinical predictors of cognitive deficits identified in previous correlation analyses.

RESULTS

At baseline, the study sample of MOGAD patients showed impaired standardised performance on MuSIC semantic fluency (mean=-0.29, 95% CI (-0.47 to -0.12)) and MuSIC congruent speed (mean=-0.73, 95% CI (-1.23 to -0.23)). Around 1 in 10 patients showed deficits in two or more cognitive measures (11%). No decline in cognition was observed during the 1-year and 2-year follow-up period. Cerebral lesions were found to be negatively predictive for SDMT (B=-8.85, 95% CI (-13.57 to -4.14)) and MuSIC semantic fluency (B=-4.17, 95% CI (-6.10 to -2.25)) test performance.

CONCLUSIONS

Based on these data, we conclude that MOGAD patients show reduced visuomotor processing speed and semantic fluency to the extent that the disease burden includes cerebral lesions.

Digital symbol-digit modalities test with modified flexible protocols in patients with CNS demyelinating diseases

Cognitive impairment (CI) is prevalent in central nervous system demyelinating diseases, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). We developed a novel tablet-based modified digital Symbol Digit Modalities Test (MD-SDMT) with adjustable protocols that feature alternating symbol-digit combinations in each trial, lasting one or two minutes. We assessed 144 patients (99 with MS and 45 with NMOSD) using both MD-SDMT protocols and the traditional paper-based SDMT. We also gathered participants' feedback through a questionnaire regarding their preferences and perceived reliability. The results showed strong correlations between MD-SDMT and paper-based SDMT scores (Pearsons correlation: 0.88 for 2 min; 0.85 for 1 min, both p < 0.001). Among the 120 respondents, the majority preferred the digitalized SDMT (55% for the 2 min, 39% for the 1 min) over the paper-based version (6%), with the 2 min MD-SDMT reported as the most reliable test. Notably, patients with NMOSD and older individuals exhibited a preference for the paper-based test, as compared to those with MS and younger patients. In summary, even with short test durations, the digitalized SDMT effectively evaluates cognitive function in MS and NMOSD patients, and is generally preferred over the paper-based method, although preferences may vary with patient characteristics.

Correlation of GABA+ levels in the medial prefrontal cortex and circulating follicular helper T cells in neuromyelitis optica spectrum disorder patients with cognitive impairment

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) associated with cognitive impairment (CI) is acknowledged. However, the underlying pathogenesis and involvement of the immune system remain unclear.

OBJECTIVES

This study aimed to investigate the alterations in immune cells, cytokines, and GABA+ levels in NMOSD patients with cognitive deficits.

METHODS

Thirty-eight NMOSD patients and 38 healthy controls (HCs) were included. NMOSD patients were stratified as NMOSD-CI and NMOSD-CP groups. The difference in cognitive functions, Tfh and cytokines, and GABA+ levels were assessed, and their correlations were calculated.

RESULTS

NMOSD-CI patients showed worse performance on all cognitive tests, and the percentage of circulating follicular helper T cells (cTfh) was significantly elevated. The frequency of cTfh was positively and negatively correlated with Stroop-A and AVLT long-delayed scores, respectively. IL-21 was remarkably higher in NMOSD-CI and NMOSD-CP. The level of GABA+ in medial prefrontal cortex (mPFC) was significantly decreased in NMOSD-CI and was proved positively and negatively correlated with Symbol Digit Modalities Test and the frequency of circulating Tfh cells, respectively.

CONCLUSION

In NMOSD-CI patients, all cognitive domains were impacted, , while GABA+ levels in mPFC were decreased. GABA+ levels in NMOSD-CI were negatively correlated with the frequency of cTfh, suggesting the underlying coupling mechanism between immune responses and neurotransmitter metabolism in CI in NMOSD patients.

Update on the diagnosis and treatment of neuromyelits optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part I: Diagnosis and differential diagnosis

The term 'neuromyelitis optica spectrum disorders' (NMOSD) is used as an umbrella term that refers to aquaporin-4 immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica (NMO) and its formes frustes and to a number of closely related clinical syndromes without AQP4-IgG. NMOSD were originally considered subvariants of multiple sclerosis (MS) but are now widely recognized as disorders in their own right that are distinct from MS with regard to immunopathogenesis, clinical presentation, optimum treatment, and prognosis. In part 1 of this two-part article series, which ties in with our 2014 recommendations, the neuromyelitis optica study group (NEMOS) gives updated recommendations on the diagnosis and differential diagnosis of NMOSD. A key focus is on differentiating NMOSD from MS and from myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD), which shares significant similarity with NMOSD with regard to clinical and, partly, radiological presentation, but is a pathogenetically distinct disease. In part 2, we provide updated recommendations on the treatment of NMOSD, covering all newly approved drugs as well as established treatment options.