Cognitive Impairment in Neuromyelitis Optica Spectrum Disorders: A Review of Clinical and Neuroradiological Features

The association between information processing speed and clinical features in people with multiple sclerosis and neuromyelitis optica: a comparative study

Multiple Sclerosis (MS) and Neuromyelitis Optica Spectrum Disorder (NMOSD) are both autoimmune inflammatory disorders affecting the central nervous system. Cognitive decline is a common symptom in both disorders, particularly affecting information processing speed (IPS). The current study investigated the association between IPS and clinical parameters in people with MS (PwMS) and NMOSD (PwNMOSD). A total of 945 participants were enrolled in the study, including 617 PwMS, 128 PwNMOSD, and 200 healthy controls. IPS was evaluated using the Symbol Digit Modalities Test (SDMT). Clinical, serological, and radiological factors were retrospectively collected. General Linear Model (GLM) was used for data analysis. Based on GLM multivariate analysis adjusted for age, sex, and educational level, a significant association was observed between IPS and Expanded Disability Status Scale (EDSS), disease progression, disease duration, brain atrophy, and brain lesion load in PwMS. Similarly, significant association was found between IPS and EDSS, Aquaporin-4 (AQP-4) antibody positivity, brain atrophy, and number of cervical lesions in PwNMOSD. This study confirms the association between IPS and key risk factors such as EDSS, brain atrophy, and lesion load in PwMS. Additionally, it reveals a link between IPS and new factors, including AQP-4 antibody positivity and cervical lesions in PwNMOSD. Furthermore, disease progression emerged as a significant factor affecting IPS in PwMS.

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.

Progression independent of relapse activity and relapse-associated worsening in seronegative NMOSD: an international cohort study

BACKGROUND

Previous studies have indicated that progression independent of relapse activity (PIRA) is uncommon in patients with aquaporin- 4 antibody-positive (AQP4-IgG) neuromyelitis optica spectrum disorder (NMOSD). However, the patterns of disability accumulation in seronegative NMOSD are unknown. This study aimed to evaluate the prevalence of PIRA and relapse-associated worsening (RAW) in seronegative NMOSD.

METHODS

We conducted a retrospective, multicentre cohort study of seronegative NMOSD patients from the MSBase registry. Inclusion criteria required at least three recorded expanded disability status scale (EDSS) scores: baseline, progression, and 6 months confirmed disability progression (CDP). For those with 6-month CDP, the presence or absence of relapse between baseline and progression determined the classification as RAW or PIRA, respectively. Descriptive statistics were employed to present the data.

RESULTS

This study included 93 patients, with a median follow-up duration of 5.0 years (Q1 2.8, Q3 8.4). The cohort predominantly consisted of female patients (77.4%), with a median age of onset of 33.9 years (Q1 26.1, Q3 41.2). PIRA was observed in 1 case (1.1%), whilst RAW was documented in 7 cases (7.5%).

CONCLUSION

This international cohort study confirms that CDP is uncommon in seronegative NMOSD. Given more than three quarters of CDP occur due to RAW, therapeutic strategies should focus primarily on preventing relapses.

Association of peripapillary retinal nerve fiber layer atrophy with cognitive impairment in patients with neuromyelitis optica spectrum disorder

BACKGROUND

We aimed to explore the association between peripapillary retinal nerve fiber layer thickness (pRNFL), macular ganglion cell-inner plexiform layer (mGCIPL), and cognitive impairment (CI) in patients with neuromyelitis optica spectrum disorder (NMOSD).

METHOD

In this cross-sectional study, 38 (28 aquaporin-4 (AQP4) IgG-seropositive) NMOSD patients and 20 healthy controls (HC) underwent cognitive assessment using Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery. Spectral-domain optical coherence tomography (OCT) was performed for both eyes of all NMOSD patients. First, we examined the association of pRNFL and mGCIPL with cognitive function in all patients, regardless of the history of previous optic neuritis (ON). We then included only eyes without a prior history of ON, incorporating non-ON eyes in patients with unilateral ON and the average of OCT measures for both non-ON eyes in patients without a history of ON.

RESULTS

Sixteen (42.1%) NMOSD patients exhibited global CI. There was a significant decrease in pRNFL (Δ: 24.33 μm, p = 0.002) and mGCIPL (Δ: 9.20 μm, p = 0.009) in NMOSD patients with CI compared to those without. The atrophy of pRNFL showed an inverse association with CI before (OR = 1.059, 95% CI: 1.015, 1.105) and after adjustment for age, sex, and disease duration (OR = 1.072, 95%CI: 1.009, 1.139). An inverse significant association was observed between mGCIPL atrophy and CI before adjustment (OR = 1.102, 95% CI: 1.017, 1.194), but not after adjustment (OR = 1.106, 95%CI: 0.999, 1.224). After narrowing our analysis to non-ON eyes, the same results for pRNFL and CI were observed (unadjusted: OR = 1.054, 95% CI: 1.004, 1.106; adjusted: OR = 1.081, 95%CI: 1.000, 1.168). There was no significant association found between mGCIPL thickness and CI in both unadjusted and adjusted models. In sensitivity analyses, we observed no significant association between pRNFL and mGCIPL with CI in AQP-IgG-seropositive NMOSD patients.

CONCLUSION

This study, for the first time, provide a preliminary evidence for a possible relation between pRNFL atrophy and occurrence of cognitive impairment in NMOSD patients. Further studies are required to explore the possible association of OCT parameters with cognition function in NMOSD patients.

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.

Cognitive performance in patients with neuromyelitis optica: clinical and imaging characteristics

This study aimed to identify the prevalence, clinical and radiographic characteristics, and risk factors for cognitive dysfunction in patients with Neuromyelitis optica spectrum disorder (NMOSD). Eighty-three participants who were diagnosed with NMOSD were recruited. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Frontal Assessment Battery (FAB). The mean age of the patients was 47.78 ± 13.14 years, with an average of 12.05 ± 4.62 years of formal education. The majority (54%) exhibited cognitive impairment, defined by a MoCA score < 25 (mean: 22.96 ± 3.82). Disease severity (evaluated by the Expanded Disability Status Scale) and lower formal education levels were associated with cognitive impairment (p = 0.011 and < 0.001, respectively). The annualized relapse rate, disease duration, and AQP4 antibody status were not associated with cognitive impairment. Interestingly, informant-reported cognitive decline was associated with poorer cognitive performance (p = 0.027). Radiographic findings of lesion location and severity were associated with MoCA-assessed cognitive performance, particularly for lesions in the right parietal lobes (p = 0.023). Hippocampal atrophy was negatively correlated with FAB scores. In conclusion, approximately half of the Thai patients with NMOSD exhibited cognitive impairment, which was associated with age, formal education level, disease severity, relative perception, and specific radiological findings. Further studies incorporating comprehensive neuropsychological tests and subjective cognitive complaints are warranted.

Retinal structural thicknesses reflect clinically relevant microstructural white matter abnormalities in neuromyelitis optica spectrum disorders

BACKGROUND

Thinning of retinal thickness seen on optical coherence tomography (OCT) is frequent in patients with neuromyelitis optica spectrum disorder (NMOSD). We explored the association between OCT metrics, MRI measurements and clinical outcomes in NMOSD.

METHODS

44 NMOSD and 60 controls underwent OCT and MR imaging. Mean peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell complex (GCC) thicknesses were measured. Diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) was used to measure the white matter microstructural integrity. In NMOSD patients, Expanded Disability Status Scale (EDSS) was used to quantify disability. Visual acuity (VA) was also performed for all participants.

RESULTS

pRNFL thickness was positively associated with mean diffusivity in left posterior thalamic radiation (pp = 0.010) and axial kurtosis in inferior cerebellar peduncle (p = 0.023). Similarly, GCC thickness in NMOSD patients was positively associated with fractional anisotropy in right superior longitudinal fascicules (p = 0. 041) and axial kurtosis of left cerebellar peduncle (p = 0.011).

CONCLUSIONS

In NMOSD, pRNFL and GCC reflect integrity of clinically relevant white matter structures underlying the value of OCT metrics as markers of neuronaxonal loss and disability.

Identification of neurotransmitter imbalances in the cingulate cortex of NMOSD patients using magnetic resonance spectroscopy

Cognitive impairment affects 29-67% of patients with neuromyelitis optica spectrum disorder. Previous studies have reported glutamate homeostasis disruptions in astrocytes, leading to imbalances in gamma-aminobutyric acid levels. However, the association between these neurotransmitter changes and cognitive deficits remains inadequately elucidated. Point RESolved Spectroscopy and Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy techniques were utilized to evaluate gamma-aminobutyric acid, glutamate, glutathione levels, and excitation/inhibition balance in the anterior cingulate cortex, posterior cingulate cortex, and occipital cortex of 39 neuromyelitis optica spectrum disorder patients and 41 healthy controls. Cognitive function was assessed using neurocognitive scales. Results showed decreased gamma-aminobutyric acid levels alongside increased glutamate, glutathione, and excitation/inhibition ratio in the anterior cingulate cortex and posterior cingulate cortex of neuromyelitis optica spectrum disorder patients. Specifically, within the posterior cingulate cortex of neuromyelitis optica spectrum disorder patients, decreased gamma-aminobutyric acid levels and increased excitation/inhibition ratio correlated significantly with anxiety scores, whereas glutathione levels predicted diminished executive function. The results suggest that neuromyelitis optica spectrum disorder patients exhibit dysregulation in the GABAergic and glutamatergic systems in their brains, where the excitation/inhibition imbalance potentially acts as a neuronal metabolic factor contributing to emotional disorders. Additionally, glutathione levels in the posterior cingulate cortex region may serve as predictors of cognitive decline, highlighting the potential benefits of reducing oxidative stress to safeguard cognitive function in neuromyelitis optica spectrum disorder patients.

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.

Cognitive and psychopathological features of neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease: A narrative review

Clinicians are becoming increasingly aware of the cognitive and psychopathological consequences of neurological diseases, which were once thought to manifest with motor and sensory impairments only. The cognitive profile of multiple sclerosis, in particular, is now well-characterised. Similar efforts are being made to better characterise the cognitive profile of other central nervous system inflammatory demyelinating autoimmune disorders. This review discusses the current understanding of the cognitive and psychological features of neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Detailed analysis of the cognitive sequelae of the above conditions can not only assist with understanding disease pathogenesis but also can guide appropriate management of the symptoms and consequently, improve the quality of life and long-term outcomes for these patients. This narrative review will also identify research gaps and provide recommendations for future directions in the field.

Cognitive impairment and its association with clinical variables in Mexican persons with neuromyelitis optica spectrum disorder

INTRODUCTION

Cognitive impairment has a substantial impact on the daily function of people living with demyelinating diseases. However, the study of cognitive failures and their association with clinical variables in people suffering from neuromyelitis optica spectrum disorder (NMOSD) has been scarce, especially in the latin american (Mexican) population at early and middle stages of the disease.

METHOD

We applied the Rao's Brief Repeatable Battery of Neuropsychological tests and obtained data of lesion burden through magnetic resonance imaging (MRI), expression of AQPQ4-IgG antibodies, and degree of disability in 30 patients with NMOSD and 30 healthy participants as a control group.

RESULTS

About half of the NMOSD patients (47%) showed some degree of cognitive impairment, especially in the executive domain compared to the control group. Executive function scores were positively associated with the degree of physical disability. We found no associations between cognitive dysfunction and disease duration, AQPQ4-IgG antibodies, lesion burden, nor depression.

CONCLUSIONS

Executive functioning impairment is present in NMOSD and may predict the degree of functional disability in patients. Cognitive failures were not associated with immunological or radiological data, which emphasizes the relevance of applying systematic neuropsychological assessments in this clinical population.

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Association between myasthenia gravis and cognitive disorders: a PRISMA-compliant meta-analysis

OBJECTIVE

This meta-analysis assessed the association between myasthenia gravis (MG) and cognitive disorders.

METHODS

The PubMed, Web of Science, OVID, EMBASE, CNKI and Wanfang electronic databases were comprehensively searched from inception to October 2020 for relevant studies. The primary outcomes were scores of the cognitive function battery. A random effects model was used to evaluate the cognitive function of patients with MG.

RESULTS

Eight cross-sectional studies containing 381 patients and 220 healthy controls were included in this meta-analysis. In relation to global cognitive function, patients with MG performed significantly worse than healthy individuals (SMD = -0.4, 95% CI = -0.63 to -0.16, p < 0.001, I2 = 10%). Specifically, the impaired cognitive domains included language, visuospatial function, information processing, verbal immediate and delayed recall memory, visual immediate recall memory, and response fluency, while attention, executive function, and visual delayed recall memory were unimpaired. The patients with early-onset (SMD= -0.527, 95% CI = -0.855 to -0.199, p = 0.002) and generalized MG (SMD= -0.577, 95% CI = -1.047 to -0.107, p = 0.016) had poorer global cognitive performance than the healthy population.

CONCLUSIONS

Patients with MG may have cognitive disorders, including those associated with the domains of language, visuospatial function, information processing, verbal immediate and delayed recall memory, visual immediate recall memory and response fluency. Furthermore, the age of onset and disease severity may be associated with cognitive disorders in patients with MG.

The risk of dementia in multiple sclerosis and neuromyelitis optica spectrum disorder

Introduction

Cognitive impairment is a common feature of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). However, there is a lack of population-based study of dementia risk in these disorders. In the present study, the risk of dementia in MS and NMOSD patients in Republic of Korea was estimated.

Methods

Data analyzed in this study were obtained from the Korean National Health Insurance Service (KNHIS) database between January 2010 and December 2017. The study included 1,347 MS patients and 1,460 NMOSD patients ≥40 years of age who had not been diagnosed with dementia within 1 year prior to the index date. Matched controls were selected based on age, sex, and the presence of hypertension, diabetes mellitus, or dyslipidemia.

Results

In MS and NMOSD patients, the risk of developing any dementia [adjusted hazard ratio (aHR) = 2.34; 95% confidence interval (CI) = 1.84-2.96 and aHR = 2.19; 95% CI = 1.61-3.00, respectively], Alzheimer's disease [AD; aHR = 2.23; 95% confidence interval (CI) = 1.70-2.91 and aHR = 1.99; 95% CI = 1.38-2.88, respectively], and vascular dementia (aHR = 3.75; 95% CI = 1.91-7.35 and aHR = 3.21; 95% CI = 1.47-7.02, respectively) was higher compared with the matched controls. NMOSD patients had a lower risk of any dementia and AD compared with MS patients after adjusting for age, sex, income, hypertension, diabetes, and dyslipidemia (aHR = 0.67 and 0.62).

Conclusion

The risk of dementia increased in MS and NMOSD patients and dementia risk was higher in MS than in NMOSD.

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.

Paths to hippocampal damage in neuromyelitis optica spectrum disorders

AIMS

Many patients with neuromyelitis optica spectrum disorders (NMOSD) suffer from cognitive impairment affecting memory, processing speed and attention and suffer from depressive symptoms. Because some of these manifestations could trace back to the hippocampus, several magnetic resonance imaging (MRI) studies have been performed in the past, with a number of groups describing volume loss of the hippocampus in NMOSD patients, whereas others did not observe such changes. Here, we addressed these discrepancies.

METHODS

We performed pathological and MRI studies on the hippocampi of NMOSD patients, combined with detailed immunohistochemical analysis of hippocampi from experimental models of NMOSD.

RESULTS

We identified different pathological scenarios for hippocampal damage in NMOSD and its experimental models. In the first case, the hippocampus was compromised by the initiation of astrocyte injury in this brain region and subsequent local effects of microglial activation and neuronal damage. In the second case, loss of hippocampal volume was seen by MRI in patients with large tissue-destructive lesions in the optic nerves or the spinal cord, and the pathological work-up of tissue derived from a patient with such lesions revealed subsequent retrograde neuronal degeneration affecting different axonal tracts and neuronal networks. It remains to be seen whether remote lesions and associated retrograde neuronal degeneration on their own are sufficient to cause extensive volume loss of the hippocampus, or whether they act in concert with small astrocyte-destructive, microglia-activating lesions in the hippocampus that escape detection by MRI, either due to their small size or due to the chosen time window for examination.

CONCLUSIONS

Different pathological scenarios can culminate in hippocampal volume loss in NMOSD patients.

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

BACKGROUND

There is limited and inconsistent information on the prevalence of cognitive impairment in neuromyelitis optica spectrum disorders (NMOSD).

OBJECTIVE

To assess cognitive performance and changes over time in NMOSD.

METHODS

This study included data from 217 aquaporin-4-IgG-seropositive (80%) and double-seronegative NMOSD patients. Cognitive functions measured by Symbol Digit Modalities Test (SDMT), Paced Auditory Serial-Addition Task (PASAT), and/or Multiple Sclerosis Inventory Cognition (MuSIC) were standardized against normative data (N = 157). Intraindividual cognitive performance at 1- and 2-year follow-up was analyzed. Cognitive test scores were correlated with demographic and clinical variables and assessed with a multiple linear regression model.

RESULTS

NMOSD patients were impaired in SDMT (p = 0.007), MuSIC semantic fluency (p < 0.001), and MuSIC congruent speed (p < 0.001). No significant cognitive deterioration was found at follow-up. SDMT scores were related to motor and visual disability (p_Bon < 0.05). No differences were found between aquaporin-4-IgG-seropositive and double-seronegative NMOSD.

CONCLUSIONS

A subset of NMOSD patients shows impairment in visual processing speed and in semantic fluency regardless of serostatus, without noticeable changes during a 2-year observation period. Neuropsychological measurements should be adapted to physical and visual disabilities.

The Characteristics of Cognitive Proficiency in Patients with Acute Neuromyelitis Optica Spectrum Disease and its Correlation with Serum Aquaporin-4 Antibody Titer

Objective: To explore the characteristics and dynamic evolution of cognitive impairment in patients with neuromyelitis optica spectrum disorder (NMOSD). Methods: Twenty-five patients with acute NMOSD and 30 age-matched healthy individuals were consecutively recruited in this study. The Montreal Cognitive Assessment (MoCA), Chinese Version of Rey Auditory Vocabulary Learning Test (CRAVLT), Verbal Fluency Test (VFT), Digital Span Test (DST), Paced Auditory Serial Addition Task 3/2s version (PASAT-3/2), Rey−Osterrieth Complex Figure Test (ROCF) and Stroop Color and Word Test (CWT) were used to evaluate cognitive function. The correlations between cognitive function and serum aquaporin-4 (AQP-4) antibody titer were analyzed. Results: Sixty-four percent of patients with acute NMOSD had cognitive dysfunction. MoCA (p < 0.001), CRAVLT-N7 (p = 0.004), CRAVLT-N8 (p = 0.011), ROCF-C (p = 0.005), ROCF-R (p < 0.001), PASAT-3 (p = 0.013), PASAT-2 (p = 0.001) and CWT-A (p = 0.017) were significantly worse in patients with acute NMOSD than those in control group. During follow-up visits, significant differences of serum AQP-4 antibody titers were still noted in NMOSD patients (p < 0.001), while no significant differences were found by MoCA. Conclusion: A high number of patients with acute NMOSD suffer from cognitive dysfunction. Serum AQP-4 antibody titers can decrease during disease remission, while obvious cognitive decline in these patients still exists.

Altered functional connectivity associated with cognitive impairment in neuromyelitis optica spectrum disorder

BACKGROUND

Cognitive impairment is one of the common symptoms in patients with neuromyelitis optica spectrum disorder (NMOSD). However, the underlying mechanism remains unclear. Resting-state functional magnetic resonance imaging (rs-fMRI) offers the opportunity to reveal the patterns of brain activity in patients with different cognitive states. Accordingly, this study investigated functional connectivity (FC) abnormalities within and between the main cognitive networks in cognitively impaired (CI) patients with NMOSD and their correlations with cognitive performance.

METHODS

Thirty-four patients with NMOSD and 39 healthy controls (HC) were included. Neuropsychological evaluations and rs-fMRI scanning were performed. Patients were classified as CI (n = 16) or cognitively preserved (CP; n = 18) according to neuropsychological evaluations. Seven components representing six main cognitive networks were selected by group independent component analysis. The differences in inter- and intranetwork FC among CI, CP, and HC groups were assessed. The correlation between FC values and neuropsychological data in NMOSD was calculated.

RESULTS

The CI group showed decreased intranetwork connectivity in the posterior default mode network (pDMN) compared with the HC group (P < 0.05, GRF corrected), and decreased internetwork connectivity between the salience network (SN) and pDMN, and between the SN and right frontoparietal network (rFPN) compared with CP and HC groups. The altered FC values were significantly correlated with cognitive performance in the whole NMOSD group.

CONCLUSION

The disconnection within the pDMN and between the SN and pDMN or rFPN might suggest the neural substrates underlying cognitive impairment in NMOSD.

Identifying different cognitive phenotypes and their relationship with disability in neuromyelitis optica spectrum disorder

Background

The existence, frequency, and features of cognitive impairment (CI) in patients with neuromyelitis optica spectrum disorder (NMOSD) are still debated. A precise classification and characterization of cognitive phenotypes in patients with NMOSD are lacking.

Methods

A total of 66 patients with NMOSD and 22 healthy controls (HCs) underwent a neuropsychological assessment. Latent profile analysis (LPA) on cognitive test z scores was used to identify cognitive phenotypes, and ANOVA was used to define the clinical features of each phenotype. Univariate and multivariate analyses were used to explore the predictors of severe CI, and a corresponding nomogram was created to visualize the predictive model.

Results

LPA results suggested four distinct meaningful cognitive phenotypes in NMOSD: preserved cognition (n = 20, 30.3%), mild-attention (n = 21, 31.8%), mild-multidomain (n = 18, 27.3%), and severe-multidomain (n = 7, 10.6%). Patients with the last three phenotypes were perceived to have CI, which accounts for 67.6% of patients with NMOSD. Patients with NMOSD and worse cognitive function were older (p < 0.001) and had lower educational levels (p < 0.001), later clinical onset (p = 0.01), worse Expanded Disability Status Scale scores (p = 0.001), and poorer lower-limb motor function (Timed 25-Foot Walk, p = 0.029; 12-item Multiple Sclerosis Walking Scale [MSWS-12], p < 0.001). Deterioration of Nine-Hole Peg Test (odds ratio, OR: 1.115 [1, 1.243], p = 0.05) and MSWS-12 (OR: 1.069 [1.003, 1.139], p = 0.04) were the independent risk factors for severe cognitive dysfunction. Finally, a nomogram was built based on the entire cohort and the above factors to serve as a useful tool for clinicians to evaluate the risk of severe cognitive dysfunction.

Conclusions

We introduced a classification scheme for CI and highlighted that the deterioration of upper- and lower-limb motor disability potentially predicts cognitive phenotypes in NMOSD.

Time-varying connectivity of the precuneus and its association with cognition and depressive symptoms in neuromyelitis optica: A pilot MRI study

Background:

The precuneus is involved in cognition and depression; static functional connectivity (SFC) abnormalities of this region have been observed in neuromyelitis optica spectrum disorders (NMOSD). Time-varying functional connectivity (TVC) underpins dynamic variations of brain connectivity.

Objective:

The aim of this study was to explore precuneus SFC and TVC in NMOSD patients and their associations with neuropsychological features.

Methods:

This retrospective study includes 27 NMOSD patients and 30 matched healthy controls undergoing resting state functional magnetic resonance imaging (MRI) and a neuropsychological evaluation of cognitive performance and depressive symptoms. A sliding-window correlation analysis using bilateral precuneus as seed region assessed TVC, which was quantified by the standard deviation of connectivity across windows. Mean connectivity indicated SFC.

Results:

Compared to controls, patients had reduced SFC between precuneus, temporal lobe, putamen and cerebellum, and reduced TVC between precuneus and prefronto-parietal-temporo-occipital cortices and caudate. Patients also had increased intra-precuneal TVC and increased TVC between the precuneus and the temporal cortex. More severe depressive symptoms correlated with increased TVC between the precuneus and the temporal lobe; worse cognitive performance mainly correlated with higher TVC between the precuneus and the parietal lobe.

Conclusion:

TVC rather than SFC of the precuneus correlates with NMOSD neuropsychological features; different TVC abnormalities underlie depressive symptoms and cognitive impairment.

Chronic Cognitive Impairment in AQP4+ NMOSD With Improvement in Cognition on Eculizumab: A Report of Two Cases

Cognitive impairment may be associated with aquaporin-4 antibody positive (AQP4+) NMOSD, particularly where there is prominent cerebral, corpus callosum, or thalamic involvement. It is unclear to what extent this phenomenon may be treatable after months to years. We describe two cases of AQP4+ NMOSD with cognitive impairment persisting over more than 6 months, where cognition improved after eculizumab was initiated. In the first case, a 51-year-old woman presented with a 2-month history of cognitive decline and ataxia, and diffuse involvement of the corpus callosum on MRI. AQP4 antibody testing returned positive. Cognitive impairment persisted on therapy with mycophenolate, then rituximab. She was switched to eculizumab from rituximab 18 months after disease onset because of breakthrough optic neuritis; memory and cognitive function improved on eculizumab. In the second case, a 26-year-old woman initially presented with visual, auditory and tactile hallucinations, and impairment in activities of daily living, and was given a diagnosis of schizophrenia. Nine months later she was hospitalized for increasing confusion. MRI showed leukoencephalopathy and diffuse involvement of the corpus callosum with multiple enhancing callosal lesions. AQP4 antibody testing was positive and CSF testing for other antibodies of autoimmune encephalitis was negative. She had some improvement in cognition with high dose corticosteroids but remained significantly impaired. On follow-up, her repeat MRI showed a small new right inferomedial frontal enhancing lesion although she did not complain of any new cognitive issues, her MOCA score was 21/30, and she was started on eculizumab. Two months after eculizumab initiation she and her family reported cognitive improvement and MOCA score was 25/30. Common features of these two cases included extensive callosal involvement and an element of ongoing gadolinium enhancement on MRI. Our experience suggests the possibility that cognitive impairment may be amenable to immunotherapy in certain cases of NMOSD.

A Rare Case of Neuromyelitis Optica Spectrum Disorders With Unknown Fever and Subacute Cognitive Decline With Normal Images

We report the case of a 69-year-old Japanese man who came to our hospital with a chief complaint of fever and cognitive decline for three weeks. There were no neurological abnormalities other than the decreased level of consciousness. He developed urinary retention after admission, so we performed a lumbar puncture, although his head and neck magnetic resonance imaging (MRI) showed no abnormal findings. The cerebrospinal fluid (CSF) examination showed albuminocytologic dissociation and the anti-aquaporin 4 antibody was positive. Thus, we diagnosed him with neuromyelitis optica spectrum disorder (NMOSD). NMOSD is an autoimmune disease that causes demyelination. The clue to diagnosing NMOSD is demyelinating findings on MRI. Therefore, it is difficult to diagnose NMOSD if there are no abnormalities on the images. However, abnormal MRI findings are not necessary for the diagnosis of NMOSD. Thus, NMOSD cannot be ruled out even if MRI findings are normal and the real clue to diagnosing NMOSD is the anti-aquaporin 4 antibody.

Cognitive Performance and Health-Related Quality of Life in Patients with Neuromyelitis Optica Spectrum Disorder

Background: The frequency of cognitive impairment (CI) reported in neuromyelitis optica spectrum disorder (NMOSD) is highly variable, and its relationship with demographic and clinical characteristics is poorly understood. We aimed to describe the cognitive profile of NMOSD patients, and to analyse the cognitive differences according to their serostatus; furthermore, we aimed to assess the relationship between cognition, demographic and clinical characteristics, and other aspects linked to health-related quality of life (HRQoL). Methods: This cross-sectional study included 41 patients (median age, 44 years; 85% women) from 13 Spanish centres. Demographic and clinical characteristics were collected along with a cognitive z-score (Rao’s Battery) and HRQoL patient-centred measures, and their relationship was explored using linear regression. We used the Akaike information criterion to model which characteristics were associated with cognition. Results: Fourteen patients (34%) had CI, and the most affected cognitive domain was visual memory. Cognition was similar in AQP4-IgG-positive and -negative patients. Gender, mood, fatigue, satisfaction with life, and perception of stigma were associated with cognitive performance (adjusted R2 = 0.396, p < 0.001). Conclusions: The results highlight the presence of CI and its impact on HRQoL in NMOSD patients. Cognitive and psychological assessments may be crucial to achieve a holistic approach in patient care.

Comparative Study of Brain fMRI of Olfactory Stimulation in Neuromyelitis Optica Spectrum Disease and Multiple Sclerosis

Objective: To observe the characteristics of brain fMRI during olfactory stimulation in patients with neuromyelitis optica spectrum disease (NMOSD) and multiple sclerosis (MS), compare the differences of brain functional activation areas between patients with NMOSD and MS, and explore the characteristics of olfactory-related brain networks of NMOSD and MS.

Methods: Nineteen patients with NMOSD and 16 patients with MS who met the diagnostic criteria were recruited, and 19 healthy controls matched by sex and age were recruited. The olfactory function of all participants was assessed using the visual analog scale (VAS). Olfactory stimulation was alternately performed using a volatile body (lavender and rose solution) and the difference in brain activation was evaluated by task-taste fMRI scanning simultaneously.

Results: Activation intensity was weaker in the NMOSD group than in the healthy controls, including the left rectus, right superior temporal gyrus, and left cuneus. The activation intensity was stronger for the NMOSD than the controls in the left insula and left middle frontal gyrus (P < 0.05). Activation intensity was weaker in the MS group than the healthy controls in the bilateral hippocampus, right parahippocampal gyrus, right insula, left rectus gyrus, and right precentral gyrus, and stronger in the left paracentral lobule among the MS than the controls (P < 0.05). Compared with the MS group, activation intensity in the NMOSD group was weaker in the right superior temporal gyrus and left paracentral lobule, while it was stronger among the NMOSD group in the bilateral insula, bilateral hippocampus, bilateral parahippocampal gyrus, left inferior orbital gyrus, left superior temporal gyrus, left putamen, and left middle frontal gyrus (P < 0.05).

Conclusion: Olfactory-related brain networks are altered in both patients, and there are differences between their olfactory-related brain networks. It may provide a new reference index for the clinical differentiation and disease evaluation of NMOSD and MS. Moreover, further studies are needed.

Sparser macula microvasculature in neuromyelitis optica spectrum disorder occurs independently of optic neuritis

PURPOSE

To evaluate the macula microvascular perfusion in neuromyelitis optica spectrum disorder (NMOSD) patients and assess the correlation with their clinical features.

METHODS

35 aquaporin-4 seropositive NMOSD patients (38 NMOSD eyes without optic neuritis, NMOSD-NON, and 32 NMOSD eyes with optic neuritis) and 35 healthy controls (HC) were included in our study. Swept-source optical coherence tomography angiography (SS-OCTA) was used to image and segment the macula microvasculature into the inner macula vascular complex (IVC), superficial vascular plexus (SVC), and deep vascular plexus (DVC). An inbuilt software within the OCTA tool was used to measure the microvascular perfusion in these two plexuses.

RESULTS

NMOSD eyes without optic neuritis showed sparser (P < 0.05) IVC and SVC compared with healthy controls; NMOSD eyes with optic neuritis showed significantly sparser (P < 0.001) IVC, SVC, and DVC when compared with healthy controls respectively. NMOSD eyes with optic neuritis showed significantly sparser IVC (P = 0.002), SVC (P = 0.001) and DVC (P = = 0.040) when compared with eyes without optic neuritis.

CONCLUSIONS

Microvascular impairment in NMOSD patients occurs independently of ON. Microvascular impairment is associated with reduced visual acuity and frequency of ON.

Superficial Macula Capillary Complexity Changes Are Associated With Disability in Neuromyelitis Optica Spectrum Disorders

Purpose: We examined the macular microvascular changes of the macula in neuromyelitis optica spectrum disorder (NMOSD) patients and its association with their disability and other clinical variables.

Methods: Thirty-four NMOSD (13 patients without optic neuritis, NMOSD-NON, and 21 patients with a history of optic neuritis, NMOSD-ON) and 44 healthy controls (HCs) were included in the study. Optical coherence tomographic angiography (OCTA) was used to image the superficial (SCP), deep (DCP), and whole capillary plexus (WCP) in a 2.5-mm-diameter concentric circle [excluding the foveal avascular zone (FAZ)]. An algorithm (D_box) was used to quantify the complexity of the three capillary layers by fractal analysis. We also evaluated the expanded disability scale status (EDSS).

Results: D_box values were significantly reduced in SCP (p < 0.001), DCP (p < 0.001), and WCP (p = 0.003) of NMOSD when compared with HCs. D_box values were significantly reduced in NMOSD eyes with optic neuritis when compared with healthy controls (p < 0.001) and eyes without optic neuritis (p = 0.004) in the SCP. In the DCP, eyes with optic neuritis showed significantly reduced D_box values when compared with eyes without optic neuritis (p = 0.016) and healthy controls (p < 0.001); eyes without optic neuritis showed significantly reduced D_box values (p = 0.007) in the DCP when compared with healthy controls. A significant negative correlation (Rho = −0.475, p = 0.005) was shown between the superficial macula D_box values and the EDSS in NMOSD patients. Additionally, a negative correlation (Rho = −0.715, p = 0.006) was seen in the superficial D_box values in [e]eyes without optic neuritis and EDSS.

Conclusions: Macular microvascular damage in the superficial plexus is associated with disability in NMOSD. Macular microvascular alterations arise independently of the occurrence of ON in NMOSD.

Volume of hippocampal subfields and cognitive deficits in neuromyelitis optica spectrum disorders

BACKGROUND

Aquaporin-4 (AQP4) water channel is involved in hippocampal plasticity and is the target of neuromyelitis optica spectrum disorders (NMOSD) autoimmunity. We measured volumes of hippocampal subfields and their association with cognitive performance in AQP4-seropositive NMOSD patients.

METHODS

Global and regional hippocampal volumes were derived from 28 AQP4-seropositive NMOSD patients and 101 healthy controls (HC) from 3D-T1-weighted images. Normalized brain volumes were also calculated. A neuropsychological evaluation, including the Brief Repeatable Battery of Neuropsychological Tests, was performed in patients. Based on HC data, we estimated mean z-scores of volumes in the whole NMOSD group and compared them according to the status of global and domain-selective cognitive impairment.

RESULTS

Global cognitive impairment was detected in 46.4% of NMOSD patients, with attentive (60.7%) and executive (21.4%) domains being the most affected. NMOSD patients had left hippocampal atrophy at global (p = 0.012) and regional level (fimbria, Cornu Ammonis [CA] 3, molecular layer, dentate gyrus [DG], and subicular complex, p values ranging between 0.033 and <0.001). On the right side the fimbria and hippocampal tail were atrophic (p = 0.024 for both). Cognitively impaired patients showed atrophy in the left CA3 and CA4 (p = 0.025-0.028), while patients presenting verbal and visual memory impairment had significant CA3 and DG atrophy. Those patients with attentive or executive impairment had preserved brain and hippocampal volumes.

CONCLUSIONS

NMOSD patients showed hippocampal atrophy associated with verbal and visual memory impairment. Such damage did not explain attention and executive function alterations, which were the most common cognitive deficits in this population.

A comparison of cognitive performances between neuromyelitis optica spectrum disorder and multiple sclerosis patients in Indian context

Background

To compare the frequency and pattern of cognitive impairment in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) patients.

Results

Twenty NMOSD and forty MS patients were included. Clinical and detailed neuropsychological assessment was done using frontal assessment battery and Kolkata cognitive battery supplemented with additional standard tests for different domains of cognitive functions. Domain wise tests were performed and compared. 15/20 (75%) NMOSD and 32/40 (80%) MS patients had cognitive impairment (p = 0.65). Executive function, verbal fluency, information processing speed, visuo-constructional ability, attention, complex calculation, and memory were more commonly involved in NMOSD in decreasing order. Compared to MS, the pattern was similar except that verbal fluency was more impaired in NMOSD. Expanded Disability Status scale (EDSS) correlated with cognitive involvement in NMOSD (p = 0.02) as against MS.

Conclusions

Executive function, verbal fluencies, and information processing speed were more affected compared to visual and verbal memory in NMOSD patients. The pattern of cognitive performance was similar in the MS group, even though clinical and radiological characteristics and pathophysiology is different, suggesting similar brain involvement.

AQP4-IgG autoimmunity in Japan and Germany: Differences in clinical profiles and prognosis in seropositive neuromyelitis optica spectrum disorders

BACKGROUND

Clinical outcomes in neuromyelitis optica spectrum disorders (NMOSD) vary across different regions.

OBJECTIVE

To describe clinical profiles in Japanese and German NMOSD patients.

METHODS

Medical records of aquaporin-4-immunoglobulin G (AQP4-IgG) positive NMOSD patients from Japan (n = 54) and Germany (n = 38) were retrospectively analyzed.

RESULTS

The disability status was similar between both cohorts, although Japanese patients had a longer disease duration (13.3 ± 11.1 vs. 8.1 ± 6.9 years, p = 0.018) but similar relapse rates. Optic neuritis and myelitis were the most frequent attacks in both cohorts. Brain attacks occurred more frequently in Japanese patients (40.7% vs. 15.8%, p = 0.020). The time from disease onset (median [interquartile range] 2.3 [0.3-10.1] vs. 0.6 [0.2-1.9] years, p = 0.009) and the number of attacks (2.5 [1-7] vs. 2 [1-3], p = 0.047) until start of the first immunotherapy were higher in the Japanese cohort. Rituximab was the most common drug in the German cohort (52.6%) and not given in the Japanese cohort (p < 0.001), where oral prednisolone was the most common drug (92.6% vs. 15.8%, p < 0.001). The frequency of autoimmune comorbidities was higher in the German cohort (39.5% vs. 18.5%, p = 0.047).

CONCLUSION

Compared with Japanese NMOSD patients, German patients presented with similar disability despite shorter disease duration and earlier and more frequent immunosuppressive therapy.

Staging of astrocytopathy and complement activation in neuromyelitis optica spectrum disorders

Aquaporin 4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD) is an autoimmune astrocytopathic disease pathologically characterized by the massive destruction and regeneration of astrocytes with diverse types of tissue injury with or without complement deposition. However, it is unknown whether this diversity is derived from differences in pathological processes or temporal changes. Furthermore, unlike for the demyelinating lesions in multiple sclerosis, there has been no staging of astrocytopathy in AQP4-IgG+NMOSD based on astrocyte morphology. Therefore, we classified astrocytopathy of the disease by comparing the characteristic features, such as AQP4 loss, inflammatory cell infiltration, complement deposition and demyelination activity, with the clinical phase. We performed histopathological analyses in eight autopsied cases of AQP4-IgG+NMOSD. There were six women and two men, with a median age of 56.5 years (range, 46-71 years) and a median disease duration of 62.5 months (range, 0.6-252 months). Astrocytopathy in AQP4-IgG+NMOSD was classified into the following four stages defined by the astrocyte morphology and immunoreactivity for glial fibrillary acidic protein (GFAP): (a) astrocyte lysis: Extensive loss of astrocytes with fragmented and/or dust-like particles; (b) progenitor recruitment: Loss of astrocytes except small nucleated cells with GFAP-positive fibre-forming foot processes; (c) protoplasmic gliosis: Presence of star-shaped astrocytes with abundant GFAP-reactive cytoplasm; and (d) fibrous gliosis: Lesions composed of densely packed mature astrocytes. The astrocyte lysis and progenitor recruitment stages dominated in clinically acute cases (within 2 months after the last recurrence). Findings common to both stages were the loss of AQP4, a decreased number of oligodendrocytes, the selective loss of myelin-associated glycoprotein and active demyelination with phagocytic macrophages. The infiltration of polymorphonuclear cells and T cells (CD4-dominant) and the deposition of activated complement (C9neo), which reflects the membrane attack complex, a hallmark of acute NMOSD lesions, were selectively observed in the astrocyte lysis stage (98.4% in astrocyte lysis, 1.6% in progenitor recruitment, and 0% in protoplasmic gliosis and fibrous gliosis). Although most of the protoplasmic gliosis and fibrous gliosis lesions were accompanied by inactive demyelinated lesions with a low amount of inflammatory cell infiltration, the deposition of complement degradation product (C3d) was observed in all four stages, even in fibrous gliosis lesions, suggesting the past or chronic occurrence of complement activation, which is a useful finding to distinguish chronic lesions in NMOSD from those in multiple sclerosis. Our staging of astrocytopathy is expected to be useful for understanding the unique temporal pathology of AQP4-IgG+NMOSD.

Transdiagnostic hippocampal damage patterns in neuroimmunological disorders

Hippocampal damage and associated cognitive deficits are frequently observed in neuroimmunological disorders, but comparative analyses to identify shared hippocampal damage patterns are missing. Here, we adopted a transdiagnostic analytical approach and investigated hippocampal shape deformations and associated cognitive deficits in four neuroimmunological diseases. We studied 120 patients (n = 30 in each group), including patients with multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), anti-NMDAR and anti-LGI1 encephalitis. A control group was matched to each patient sample from a pool of 79 healthy participants. We performed an MRI-based vertex-wise hippocampal shape analysis, extracted hippocampal volume estimates and scalar projection values as a measure of surface displacement. Cognitive testing included assessment of verbal memory and semantic fluency performance. Our cross-sectional analyses revealed characteristic patterns of bilateral inward deformations covering up to 32% of the hippocampal surface in MS, anti-NMDAR encephalitis, and anti-LGI1 encephalitis, whereas NMOSD patients showed no deformations compared to controls. Significant inversions were noted mainly on the hippocampal head, were accompanied by volume loss, and correlated with semantic fluency scores and verbal episodic memory in autoimmune encephalitis and MS. A deformation overlap analysis across disorders revealed a convergence zone on the left anterior hippocampus that corresponds to the CA1 subfield. This convergence zone indicates a shared downstream substrate of immune-mediated damage that appears to be particularly vulnerable to neuroinflammatory processes. Our transdiagnostic morphological view sheds light on mutual pathophysiologic pathways of cognitive deficits in neuroimmunological diseases and stimulates further research into the mechanisms of increased susceptibility of the hippocampus to autoimmunity.

Cognitive impairment in NMOSD-More questions than answers

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is a type of central nervous system antibody-mediated disease which affects mainly optic nerves and spinal cord, but may also present with acute brainstem syndrome, acute diencephalic syndrome, and cerebral syndrome with typical brain lesions. One of the most disabling symptoms, diagnosed in 29%-67% of cases, is cognitive dysfunction, with such processes as memory, processing speed, executive function, attention, and verbal fluency being predominantly affected. However, description of cognition in NMOSD patients is still a relatively new area of research.

METHODS

A systematic MEDLINE search was performed to retrieve all studies that investigated cognitive impairment and its clinical correlates in patients with NMOSD.

RESULTS

We summarize the current knowledge on cognitive impairment profile, neuropsychological tests used to examine NMOSD patients, clinical and demographical variables affecting cognition, and magnetic resonance imaging correlates. We provide a comparison of cognitive profile of patients with multiple sclerosis and NMOSD.

CONCLUSION

Patients with NMOSD are at significant risk of cognitive deficits. However, the knowledge of cognitive symptoms in NMOSD and potential modifying interventions is still scarce. Further accumulation of clinical data may facilitate effective therapeutic interventions.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

NMOSD acute attack: Understanding, treatment and innovative treatment prospect

Neuromyelitis optica spectrum disorder (NMOSD) is a group of severe inflammatory demyelinating disorders of the central nervous system that involves the optic nerve and spinal cord. Currently the therapeutic options for an acute attack in NMOSD are limited and rarely characterized in clinical studies. This review discussed the overall characteristics of acute attack of NMOSD, related risk factor, prognosis and management. Considering the huge unmet needs and the emergence of new therapeutic targets, we also reviewed innovative treatments that might alleviate attack damage, along with the challenges to evaluate new drug for acute attack in NMOSD.

Brain MRI characteristics in neuromyelitis optica spectrum disorders: A large multi-center retrospective study in China

PURPOSE

To investigate the brain MRI features in neuromyelitis optica spectrum disorders (NMOSD) and its clinical relevance in a large multi-center cohort in China.

METHODS

270 NMOSD patients were recruited from seven centers. The brain MRI were classified as normal, NMOSD-specific lesions, multiple sclerosis-like, nonspecific white matter changes. Brain volumes including whole brain, white, gray matter, cortex and subcortex gray matter volume were measured. The relationship between MRI measures, clinical disability and cognitive impairment were investigated.

RESULTS

98 patients (36.3%) had normal brain MRI; 48 patients (17.7%) had NMOSD-specific lesions located in dorsal brainstem, corticospinal tract corpus, callosum and periependymal lesions surrounding the ventricular system; 16 patients (6%) had multiple sclerosis-like lesions; and 108 patients (40%) had nonspecific white matter changes. NMOSD patients with brain lesions had a trend of lower subcortex gray matter volume compared to patients without lesions. 52.5% patients with normal brain MRI and 50.8% patients with abnormal brain MRI showed cognitive impairment. No significant differences were identified in brain volume between cognitive impairment and cognitive preserved groups.

CONCLUSION

In this large multicenter NMOSD cohort, nonspecific white matter changes were the most common findings (40%). NMOSD patients with brain lesions demonstrated a trend of having lower brain volume than patients without lesions. Approximately 50% NMOSD patients presented cognitive impairment independent of brain lesions.

Emerging drugs for the treatment of neuromyelitis optica

INTRODUCTION

Evidence-based treatment options for neuromyelitis optica spectrum disorders (NMOSD) patients are beginning to enter the market. Where previously, there was only the exclusive use of empiric and off-label immunosuppressants in this rare and devastating central nervous system autoimmune disease.

AREAS COVERED

In accordance to expanding pathogenetic insights, drugs in phase II and III clinical trials are presented in the context of the current treatment situation for acute attacks and immunopreventative strategies in NMOSD. Some such drugs are the 2019-approved complement inhibitor eculizumab, other compounds in late development include its modified successor ravulizumab, IL-6 receptor antibody satralizumab, CD19 targeting antibody inebilizumab and the TACI-Fc fusion protein telitacicept.

EXPERT OPINION

Moving from broad immunosuppression to tailored treatment strategies, the prospects for efficient NMOSD therapy are positive. For the first time in this disease, class I treatment evidence is available, but long-term data will be necessary to confirm the overall promising study results of the compounds close to approval. While drug development still centers around AQP4 antibody seropositive patients, current and future research requires consideration of possible diverging treatment demands for the smaller group of seronegative patients and patients with presence of MOG antibodies.

Pain in NMOSD and MOGAD: A Systematic Literature Review of Pathophysiology, Symptoms, and Current Treatment Strategies

Neuromyelitis optica spectrum disorders (NMOSDs) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) are autoimmune inflammatory disorders of the central nervous system (CNS). Pain is highly prevalent and debilitating in NMOSD and MOGAD with a severe impact on quality of life, and there is a critical need for further studies to successfully treat and manage pain in these rare disorders. In NMOSD, pain has a prevalence of over 80%, and pain syndromes include neuropathic, nociceptive, and mixed pain, which can emerge in acute relapse or become chronic during the disease course. The impact of pain in MOGAD has only recently received increased attention, with an estimated prevalence of over 70%. These patients typically experience not only severe headache, retrobulbar pain, and/or pain on eye movement in optic neuritis but also neuropathic and nociceptive pain. Given the high relevance of pain in MOGAD and NMOSD, this article provides a systematic review of the current literature pertaining to pain in both disorders, focusing on the etiology of their respective pain syndromes and their pathophysiological background. Acknowledging the challenge and complexity of diagnosing pain, we also provide a mechanism-based classification of NMOSD- and MOGAD-related pain syndromes and summarize current treatment strategies.

Mapping white matter damage distribution in neuromyelitis optica spectrum disorders with a multimodal MRI approach

BACKGROUND

The pathogenetic mechanisms sustaining neuroinflammatory disorders may originate from the cerebrospinal fluid.

OBJECTIVE

To evaluate white matter damage with diffusion tensor imaging and T1/T2-weighted ratio at progressive distances from the ventricular system in neuromyelitis optica spectrum disorders and multiple sclerosis.

METHODS

Fractional anisotropy, mean, axial, and radial diffusivity and T1/T2-weighted ratio maps were obtained from patients with seropositive neuromyelitis optica spectrum disorders, multiple sclerosis, and healthy controls (n = 20 each group). White matter damage was assessed as function of ventricular distance within progressive concentric bands.

RESULTS

Compared to healthy controls, neuromyelitis optica spectrum disorders patients had similar fractional anisotropy, radial and axial diffusivity, increased mean diffusivity (p = 0.009-0.013) and reduced T1/T2-weighted ratio (p = 0.024-0.037) in all bands. In multiple sclerosis, gradient of percentage lesion volume and intra-lesional mean and axial diffusivity were higher in periventricular bands. Compared to healthy controls, multiple sclerosis patients had reduced fractional anisotropy (p = 0.001-0.043) in periventricular bands, increased mean (p < 0.001), radial (p < 0.001-0.004), and axial diffusivity (p = 0.002-0.008) and preserved T1/T2-weighted ratio in all bands.

CONCLUSION

White matter damage is higher at periventricular level in multiple sclerosis and diffuse in neuromyelitis optica spectrum disorders. Fractional anisotropy preservation, associated with increased mean diffusivity and reduced T1/T2-weighted ratio may reflect astrocyte damage.

Evaluation of emotional intelligence (EI) in neuromyelitis optica spectrum disorder (NMOSD) patients compared to healthy individuals

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is known as an autoimmune astrocytopathic disorder involving central nervous system (CNS). The aim of this study was to compare Emotional Intelligence (EI) score between NMOSD patients and healthy individuals, and to find out the possible effect of this disease on EI.

METHODS

A total of 45 NMOSD participants and 48 healthy individuals were enrolled in this study. Demographic information (e.g., gender and age) of all participants as well as their level of education, and data on the patients' duration of disease were collected. EI of each participant was assessed using Persian version of Emotional Quotient inventory (EQ-i) questionnaire.

RESULTS

The mean total EI score was significantly different between the participants and controls (322±36.7 vs 338±31.5, p value<0.03). Compared to controls, patients had a poor performance in 4 of 15 EI subscales including emotional self-awareness (21.29±3.6 vs 22.85±3, p value<0.03), optimism (22.4±4 vs 24.1±3.1, p value<0.03), self-regard (22.7±4.6 vs 24.5±3.4, p value<0.04), and impulse control (16.9±6.5 vs 19.5±5.5, p value<0.05). No difference was found between anti-aquaporin-4 antibody (AQP4-IgG) positive and AQP4-IgG negative patients regarding EI score or its subscale scores, except for self-actualization (p value<0.05).

CONCLUSION

Our study showed that EI could be regarded as a tool for understanding emotions, thoughts, and behavior of NMOSD patients. It was implied that taking therapeutic steps could improve the performance of NMOSD patients with EI impairment in social life.

Visualizing the Central Nervous System: Imaging Tools for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are autoimmune central nervous system conditions with increasing incidence and prevalence. While MS is the most frequent inflammatory CNS disorder in young adults, NMOSD is a rare disease, that is pathogenetically distinct from MS, and accounts for approximately 1% of demyelinating disorders, with the relative proportion within the demyelinating CNS diseases varying widely among different races and regions. Most immunomodulatory drugs used in MS are inefficacious or even harmful in NMOSD, emphasizing the need for a timely and accurate diagnosis and distinction from MS. Despite distinct immunopathology and differences in disease course and severity there might be considerable overlap in clinical and imaging findings, posing a diagnostic challenge for managing neurologists. Differential diagnosis is facilitated by positive serology for AQP4-antibodies (AQP4-ab) in NMOSD, but might be difficult in seronegative cases. Imaging of the brain, optic nerve, retina and spinal cord is of paramount importance when managing patients with autoimmune CNS conditions. Once a diagnosis has been established, imaging techniques are often deployed at regular intervals over the disease course as surrogate measures for disease activity and progression and to surveil treatment effects. While the application of some imaging modalities for monitoring of disease course was established decades ago in MS, the situation is unclear in NMOSD where work on longitudinal imaging findings and their association with clinical disability is scant. Moreover, as long-term disability is mostly attack-related in NMOSD and does not stem from insidious progression as in MS, regular follow-up imaging might not be useful in the absence of clinical events. However, with accumulating evidence for covert tissue alteration in NMOSD and with the advent of approved immunotherapies the role of imaging in the management of NMOSD may be reconsidered. By contrast, MS management still faces the challenge of implementing imaging techniques that are capable of monitoring progressive tissue loss in clinical trials and cohort studies into treatment algorithms for individual patients. This article reviews the current status of imaging research in MS and NMOSD with an emphasis on emerging modalities that have the potential to be implemented in clinical practice.

Imaging markers of disability in aquaporin-4 immunoglobulin G seropositive neuromyelitis optica: a graph theory study

Neuromyelitis optica spectrum disorders lack imaging biomarkers associated with disease course and supporting prognosis. This complex and heterogeneous set of disorders affects many regions of the central nervous system, including the spinal cord and visual pathway. Here, we use graph theory-based multimodal network analysis to investigate hypothesis-free mixed networks and associations between clinical disease with neuroimaging markers in 40 aquaporin-4-immunoglobulin G antibody seropositive patients (age = 48.16 ± 14.3 years, female:male = 36:4) and 31 healthy controls (age = 45.92 ± 13.3 years, female:male = 24:7). Magnetic resonance imaging measures included total brain and deep grey matter volumes, cortical thickness and spinal cord atrophy. Optical coherence tomography measures of the retina and clinical measures comprised of clinical attack types and expanded disability status scale were also utilized. For multimodal network analysis, all measures were introduced as nodes and tested for directed connectivity from clinical attack types and disease duration to systematic imaging and clinical disability measures. Analysis of variance, with group interactions, gave weights and significance for each nodal association (hyperedges). Connectivity matrices from 80% and 95% F-distribution networks were analyzed and revealed the number of combined attack types and disease duration as the most connected nodes, directly affecting changes in several regions of the central nervous system. Subsequent multivariable regression models, including interaction effects with clinical parameters, identified associations between decreased nucleus accumbens (β = −0.85, P = 0.021) and caudate nucleus (β = −0.61, P = 0.011) volumes with higher combined attack type count and longer disease duration, respectively. We also confirmed previously reported associations between spinal cord atrophy with increased number of clinical myelitis attacks. Age was the most important factor associated with normalized brain volume, pallidum volume, cortical thickness and the expanded disability status scale score. The identified imaging biomarker candidates warrant further investigation in larger-scale studies. Graph theory-based multimodal networks allow for connectivity and interaction analysis, where this method may be applied in other complex heterogeneous disease investigations with different outcome measures.