Brain atrophy as a marker of cognitive impairment in mildly disabling relapsing-remitting multiple sclerosis

Differences in Brain Atrophy Pattern between People with Multiple Sclerosis and Systemic Diseases with Central Nervous System Involvement Based on Two-Dimensional Linear Measures

Conventional brain magnetic resonance imaging (MRI) in systemic diseases with central nervous system involvement (SDCNS) may imitate MRI findings of multiple sclerosis (MS). In order to better describe the MRI characteristics of these conditions, in our study we assessed brain volume parameters in MS (n = 58) and SDCNS (n = 41) patients using two-dimensional linear measurements (2DLMs): bicaudate ratio (BCR), corpus callosum index (CCI) and width of third ventricle (W3V). In SDCNS patients, all 2DLMs were affected by age (CCI p = 0.005, BCR p < 0.001, W3V p < 0.001, respectively), whereas in MS patients only BCR and W3V were (p = 0.001 and p = 0.015, respectively). Contrary to SDCNS, in the MS cohort BCR and W3V were associated with T1 lesion volume (T1LV) (p = 0.020, p = 0.009, respectively) and T2 lesion volume (T2LV) (p = 0.015, p = 0.009, respectively). CCI was associated with T1LV in the MS cohort only (p = 0.015). Moreover, BCR was significantly higher in the SDCNS group (p = 0.01) and CCI was significantly lower in MS patients (p = 0.01). The best predictive model to distinguish MS and SDCNS encompassed gender, BCR and T2LV as the explanatory variables (sensitivity 0.91; specificity 0.68; AUC 0.86). Implementation of 2DLMs in the brain MRI analysis of MS and SDCNS patients allowed for the identification of diverse patterns of local brain atrophy in these clinical conditions.

Predictive value of brain atrophy, serum biomarkers and information processing speed for early disease progression in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic autoimmune-mediated demyelinating disease of the central nervous system (CNS). A clinical presentation of the disease is highly differentiated even from the earliest stages of the disease. The application of stratifying tests in clinical practice would allow for improving clinical decision-making including a proper assessment of treatment benefit/risk balance.

METHODS

This prospective study included patients with MS diagnosed up to 1 year before recruitment. We analyzed serum biomarkers such as CXCL13, CHI3L1, OPN, IL-6, and GFAP and neurofilament light chains (NfLs); brain MRI parameters of linear atrophy such as bicaudate ratio (BCR), third ventricle width (TVW); and information processing speed were measured using the Symbol Digit Modalities Test (SDMT) during the 2 years follow-up.

RESULTS

The study included a total of 50 patients recruited shortly after the diagnosis of MS diagnosis (median 0 months; range 0-11 months), and the mean time of observation was 28 months (SD = 4.75). We observed a statistically significant increase in the EDSS score (Wilcoxon test: Z = 3.06, p = 0.002), BCR (Wilcoxon test: Z = 4.66, p < 0.001), and TVW (Wilcoxon test: Z = 2.84, p = 0.005) after 2 years of disease. Patients who had a significantly higher baseline level of NfL suffered from a more severe disease course as per the EDSS score (Mann-Whitney U-test: U = 107, Z = -2,74, p = 0.006) and presence of relapse (Mann-Whitney U-test: U = 188, Z = -2.01, p = 0.044). In the logistic regression model, none of the parameters was a significant predictor for the achieving of no evidence of disease activity status (NEDA). In the model considering all assessed parameters, only the level of NfL had a significant impact on disease progression, measured as the increase in EDSS (logistic regression: β = 0.002, p = 0.017).

CONCLUSION

We confirmed that NfL levels in serum are associated with more active disease. Moreover, we found that TVW at the time of diagnosis was associated with an impairment in cognitive function measured by information processing speed at the end of the 2-year observation. The inclusion of serum NfL and TVW assessment early in the disease may be a good predictor of disease progression independent of NEDA.

Effect of deep gray matter atrophy on information processing speed in early relapsing-remitting multiple sclerosis

BACKGROUND

Cognitive dysfunction, including reduced Information processing speed (IPS), is relatively common in multiple sclerosis(MS). IPS deficits have profound effects on several aspects of patients' life. Previous studies showed that deep gray matter atrophy is highly correlated with overall cognitive impairment in MS. However, the effect of deep gray matter atrophy on IPS deficits is not well understood. In this study, we evaluated the effects of deep gray matter volume changes on IPS in people with early relapse-remitting MS (RRMS) compared to healthy control.

METHODS

In this case-control study, we enrolled 63 case with RRMS and 36 healthy controls. All patients were diagnosed within 6 years. IPS was evaluated using the Integrated Cognitive Assessment (ICA) test. We also performed a 1.5T MRI to evaluate deep gray matter structures.

RESULTS

People with RRMS had lower accuracy in the ICA test (p = .01). However, the reaction time did not significantly differ between RRMS and control groups (p = .6). Thalamus volume was significantly lower in the RRMS group with impaired IPS compared to the RRMS with normal IPS and control groups (p < 10-4). Other deep gray matter structures were not significantly different between the RRMS with impaired IPS group and the RRMS with normal IPS group.

CONCLUSION

Some people with MS are impaired in IPS even in the early stages of the disease. Thalamic atrophy affected IPS in these patients, however atrophy in other deep gray matter structures, including caudate, putamen, globus pallidus, hippocampus, amygdala, accumbens, and cerebellum, were not significantly correlated with IPS impairment in early RRMS.

Corpus callosum damage to account for cognitive, affective, and social-cognitive dysfunctions in multiple sclerosis: A model of callosal disconnection syndrome?

The corpus callosum (CC) is the major commissure interconnecting the two hemispheres and is particularly affected in multiple sclerosis (MS). In the present review, we aimed to investigate the role played by callosal damages in the pathogenesis of MS-related dysfunctions and examine whether a model of callosal disconnection syndrome is a valid model for MS. For this purpose, we will first review structural and functional evidence of callosal pathology in MS. Second, we will account for the potential role of CC abnormalities in MS-related dysfunctions. Finally, we will report data concurring with a "multiple disconnection hypothesis" that has been proposed to explain those dysfunctions, and we will examine evidence pointing toward MS as a "callosal disconnection syndrome." We will end by discussing the contribution of this interpretation to the understanding of MS and MS-related deficits.

Symptom Interconnectivity in Multiple Sclerosis: A Narrative Review of Potential Underlying Biological Disease Processes

Introduction

Fatigue, cognitive impairment, depression, and pain are highly prevalent symptoms in multiple sclerosis (MS). These often co-occur and may be explained by a common etiology. By reviewing existing literature, we aimed to identify potential underlying biological processes implicated in the interconnectivity between these symptoms.

Methods

A literature search was conducted to identify articles reporting research into the biological mechanisms responsible for the manifestation of fatigue, cognitive impairment, depression, and pain in MS. PubMed was used to search for articles published from July 2011 to July 2021. We reviewed and assessed findings from the literature to identify biological processes common to the symptoms of interest.

Results

Of 693 articles identified from the search, 252 were selected following screening of titles and abstracts and assessing reference lists of review articles. Four biological processes linked with two or more of the symptoms of interest were frequently identified from the literature: (1) direct neuroanatomical changes to brain regions linked with symptoms of interest (e.g., thalamic injury associated with cognitive impairment, fatigue, and depression), (2) pro-inflammatory cytokines associated with so-called ‘sickness behavior,’ including manifestation of fatigue, transient cognitive impairment, depression, and pain, (3) dysregulation of monoaminergic pathways leading to depressive symptoms and fatigue, and (4) hyperactivity of the hypothalamic–pituitary-adrenal (HPA) axis as a result of pro-inflammatory cytokines promoting the release of brain noradrenaline, serotonin, and tryptophan, which is associated with symptoms of depression and cognitive impairment.

Conclusion

The co-occurrence of fatigue, cognitive impairment, depression, and pain in MS appears to be associated with a common set of etiological factors, namely neuroanatomical changes, pro-inflammatory cytokines, dysregulation of monoaminergic pathways, and a hyperactive HPA axis. This association of symptoms and biological processes has important implications for disease management strategies and, eventually, could help find a common therapeutic pathway that will impact both inflammation and neuroprotection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00368-2.

Predictive Value of the Third Ventricle Width for Neurological Status in Multiple Sclerosis

The third ventricle width (3VW) is an easily calculated measure of brain atrophy. The aim of this study was to evaluate the relation of 3VW to cognitive impairment with adjustment for demographic and clinical confounders, including depression, anxiety, and fatigue, as well as to disability in patients with multiple sclerosis (MS). Symbol Digit Modalities Test, California Verbal Learning Test, Brief Visuospatial Memory Test-Revised, Expanded Disability Status Scale (EDSS), Hospital Anxiety and Depression Scale, and Modified Fatigue Impact Scale (MFIS) were analysed in 93 patients with MS. Neuropsychological performance was compared to that of 150 healthy controls. Axial images from 3D FLAIR were used to measure 3VW. In total, 25% of MS patients were impaired in at least two neuropsychological tests. Cognitive impairment and EDSS were associated with 3VW. Age and 3VW were the strongest predictors of cognitive impairment. The multiple regression model including age, 3VW, education, EDSS, and MFIS explained 63% of the variance of neuropsychological tests results, whereas 3VW, age and duration of the disease were significant predictors of EDSS. This study confirms the predictive value of 3VW for neurological status of patients with MS, especially for cognitive impairment after adjustment for demographic and clinical confounders.

Tunisian version of the brief international cognitive assessment for multiple sclerosis: Validation and normative values

BACKGROUND

The Brief International cognitive assessment for Multiple sclerosis (BICAMS) is a specific batterie used to identify cognitive impairment in Multiple Sclerosis (MS) in a reliable and easy way. To date, for the Arabic-speaking Tunisian MS patients, there is no consensus for the use of specific cognitive batteries in MS.

OBJECTIVE

The aim of our work was to develop and validate the Tunisian version of the BICAMS (T-BICAMS) and to determine our own normative values.

MATERIAL AND METHODS

Patients diagnosed with MS and followed up in the department of Neurology of Razi Hospital were recruited and matched to healthy controls according to age, sex and educational level. T-BICAMS validity was established by comparing MS and healthy controls for symbol digit modalities test (SDMT), brief visual memory test (BVMT-R) and Tunisian verbal learning tests (TVLT) which was used instead of the California verbal learning test (CVLT-II).

RESULTS

The 104 MS patients and 104 healthy controls were comparable for age, sex and educational level. The MS group exhibited lower performances in all T-BICAMS domains compared to healthy controls: SDMT (x003Dp<10^-3), BVMT-R (p = 0.002) and TVLT (p x003D<10^-3). T-BICAMS Cronbach alpha value was 0.741. Normative values were identified for patients with MS: SDMT [39-40], BVMT-R [26-27] and TVLT [43-44]. Cognitive impairment was identified among 76 patients (73.1%). Males, lower educational levels and progressive MS were associated with a more severe cognitive impairment.

CONCLUSIONS

The current study has established the BICAMS as a valid and reliable tool for the identification of cognitive impairment in the Tunisian MS population.

Local White Matter Fiber Clustering Differentiates Parkinson's Disease Diagnoses

Scans without evidence of dopaminergic deficit (SWEDD) patients are often misdiagnosed with Parkinson's disease (PD) but have normal dopamine transporter scans. We hypothesised that white matter tracts associated with motor and cognition functions may be affected differently by SWEDD and PD. Automatically annotated fibre clustering (AAFC) is a novel clustering method based on diffusion magnetic resonance imaging (dMRI) tractography that enables highly robust reconstruction of white matter tracts that are composed of corresponding clusters. This study aimed to investigate the white matter properties in the subdivisions of white matter tracts among SWEDD and PD groups. We applied AAFC to identify white matter tracts related to motion and cognition functions in the dataset consisting of SWEDD (n = 22), PD (n = 30) and normal control (NC) (n = 30). Then, we resampled 200 nodes along fibres of cluster, and the diffusion metric values corresponding to each node were calculated and used for comparison. Compared with NC, PD showed significant difference (p < 0.05) in two clusters in thalamo-frontal (TF), one cluster in thalamo-parietal (TP) and one cluster in thalamo-occipital (TO), whereas SWEDD presented no significant difference. Three clusters in cingulum bundle (CB) commonly exhibited significant differences in PD versus SWEDD and NC versus SWEDD. The support vector machine classifier achieved high accuracies in PD-NC, PD-SWEDD and NC-SWEDD classifications. This outcome validated these local white matter differences were useful to separate the three groups. These results suggest that PD exerts more significant effects on thalamo tracts than SWEDD, and unique microstructural changes occur in CB tract in SWEDD.

Predicting clinical progression in multiple sclerosis after 6 and 12 years

BACKGROUND AND PURPOSE

To predict disability and cognition in multiple sclerosis (MS) after 6 and 12 years, using early clinical and imaging measures.

METHODS

A total of 115 patients with MS were selected and followed up after 2 and 6 years, with 79 patients also being followed up after 12 years. Disability was measured using the Expanded Disability Status Scale (EDSS); cognition was measured only at follow-up using neuropsychological testing. Predictors of interest included EDSS score, baseline brain and lesion volumes and their changes over 2 years, baseline age, clinical phenotype, sex and educational level.

RESULTS

Higher 6-year EDSS score was predicted by early EDSS score and whole-brain volume changes and baseline diagnosis of primary progressive MS (adjusted R²  = 0.56). Predictors for 12-year EDSS score included larger EDSS score changes and higher T1-hypointense lesion volumes (adjusted R²  = 0.38). Year 6 cognition was predicted by primary progressive MS phenotype, lower educational level, male sex and early whole-brain atrophy (adjusted R²  = 0.26); year 12 predictors included male sex, lower educational level and higher baseline T1-hypointense lesion volumes (adjusted R²  = 0.14).

CONCLUSIONS

Patients with early signs of neurodegeneration and a progressive disease onset were more prone to develop both disability progression and cognitive dysfunction. Male sex and lower educational level only affected cognitive dysfunction, which remains difficult to predict and probably needs more advanced imaging measures.

Characterization of inhibitory failure in Multiple Sclerosis: Evidence of impaired conflict resolution

INTRODUCTION

Inhibitory control deficits are frequently reported in Multiple Sclerosis (MS), although it is unclear whether these deficits represent a global or process-specific failure. Notably, most models of inhibitory control recognize at least two dissociable processes, the most consistent being: (a) the inhibition of a dominant response: response suppression, and (b) the inhibition of a dominant response and initiation of a nondominant response: executive control. This study aimed to ascertain the processes underlying inhibitory failure in MS.

METHOD

Twenty-three MS patients and 25 healthy controls completed a battery of commonly used inhibitory tasks, with measures from each task entered into a principal components analysis with orthogonal (varimax) rotation.

RESULTS

As anticipated, two components emerged, with tasks evaluating response suppression (stop signal, go/no go) loading on a common component, and tasks evaluating executive control (Stroop, antisaccade, endogenously-cued saccade) loading on a separate common component. Composite scores were generated for each component and compared between groups. Unlike response suppression scores, executive control scores were significantly poorer for MS patients.

CONCLUSIONS

Inhibitory control deficits in MS may reflect poor resolution in the context of competing processes, rather than difficulty in preventing the execution of an inappropriate response.

Sex: A Significant Risk Factor for Neurodevelopmental and Neurodegenerative Disorders

Males and females sometimes significantly differ in their propensity to develop neurological disorders. Females suffer more from mood disorders such as depression and anxiety, whereas males are more susceptible to deficits in the dopamine system including Parkinson's disease (PD), attention-deficit hyperactivity disorder (ADHD) and autism. Despite this, biological sex is rarely considered when making treatment decisions in neurological disorders. A better understanding of the molecular mechanism(s) underlying sex differences in the healthy and diseased brain will help to devise diagnostic and therapeutic strategies optimal for each sex. Thus, the aim of this review is to discuss the available evidence on sex differences in neuropsychiatric and neurodegenerative disorders regarding prevalence, progression, symptoms and response to therapy. We also discuss the sex-related factors such as gonadal sex hormones and sex chromosome genes and how these might help to explain some of the clinically observed sex differences in these disorders. In particular, we highlight the emerging role of the Y-chromosome gene, SRY, in the male brain and its potential role as a male-specific risk factor for disorders such as PD, autism, and ADHD in many individuals.

Clinical significance of cortical lesions in patients with multiple sclerosis: A neuropsychological and neuroimaging study

INTRODUCTION

This study aims to investigate the association between the presence and frequency of cortical lesions (CLs), and the clinical and psychological features of multiple sclerosis (MS).

METHODS

A total of 19 patients with MS were examined using double inversion recovery (DIR) sequences with 3T magnetic resonance imaging (MRI) and classified into two groups: CL and non-CL. In-house software was used to quantitatively determine the atrophy of each brain region. Activities of daily living (ADL) were estimated using the Kurtzke Expanded Disability Status Scale (EDSS). Cognitive function was assessed using the following tests: Mini-Mental State Examination (MMSE), Trail Making Test (TMT), and Paced Auditory Serial Addition Task (PASAT). Z-scores were used to assess significant differences in the neuropsychological test outcomes between the groups.

RESULTS

Six of 19 patients had subcortical and deep WM lesions (non-CL group; diagnosed with relapsing-remitting MS). Thirteen of 19 patients had both subcortical and cortical lesions (CL group; 9-relapsing-remitting MS; 4-primary/secondary progressive MS). There were no significant differences in age, education, and disease duration, but EDSS scores were significantly higher in the CL group compared to the non-CL group. There were no significant differences in gray and white matter volume between the CL and the non-CL groups, but the white matter lesion volume was significantly higher in the CL group compared to the non-CL group. Neuropsychological tests showed significant performance worsening in the CL group as compared to the standard values for healthy individuals in their age group, especially in the TMT data.

CONCLUSIONS

Progressive MS, which was associated with decreased physical functioning, ADL, and cognitive impairment, was found in patients in the CL group.

Structural MRI correlates of cognitive function in multiple sclerosis

BACKGROUND

Cognitive impairment (CI) has been associated with numerous magnetic resonance imaging (MRI) indices in multiple sclerosis (MS) patients. In this study we investigated the association of a large set of 2D and 3D MRI markers with cognitive function in MS.

METHODS

A sample of 61 RRMS patients (mean age 41.8 ± 10.6 years old, 44 women, mean disease duration 137.9 ± 83.9 months) along with 51 age and gender matched healthy controls was used in this cross-sectional study. Neuropsychological and other tests, along with a large set of 2D/3D MRI evaluations were made.

RESULTS

44.3% of patients had CI. CI patients had more disability, physical fatigue than non-CI patients and more psychological distress than non-CI patients and HCs. Also, CI patients had significantly larger third ventricle width and volume, smaller coprus callosum index and larger lesion volume than non-CI patients. These MRI markers also significantly predicted cognitive scores after adjusting for age and education, explaining about 30.6% of the variance of the total cognitive score.

CONCLUSIONS

Selected linear and volumetric MRI indices predict cognitive function in MS. Future studies should expand these results by exploring longitudinal changes and producing normative data.

New brain lesions with no impact on physical disability can impact cognition in early multiple sclerosis: A ten-year longitudinal study

OBJECTIVE

In early multiple sclerosis, although brain T2 lesions accrual are hallmark of the disease, only weak correlations were found between T2 lesions accrual and EDSS progression, the disability scale commonly used in multiple sclerosis studies. This may be related to the very poor sensitivity of EDSS to cognitive dysfunctions that may occur and progress from the first stage of the disease. In the present study, we aimed to demonstrate that cognitive deficits progress during the first ten years of MS and are significantly impacted by new T2 lesions.

METHODS

EDSS and extensive neuropsychological battery (22 measures) exploring memory, attention/speed of information processing and executive functions were assessed at baseline, Year 1 and Year 10 in 26 patients enrolled after their first clinical attack. To limit the bias of test-retest effect, only measures obtained at Year 1 and Year 10 were reported in the analysis. Raw scores of patients were transformed into z-scores using published normative data when available or scores of matched controls. Lesion probability mapping was used to assess the potential relationships between T2 lesions accumulation, cognitive decline and EDSS progression (P<0.05, FWE-corrected).

RESULTS

At Year 1, 27% of patients showed attention/speed of information processing deficits, 11.5% executive dysfunction and 11.5% memory impairment. During the follow-up, frequency and severity of executive dysfunction increased (from 11.5% of patients at Year 1 to 42% at Year 10, p<0.01) while no significant changes were evidenced for the other cognitive domains. Median EDSS increased from 0.5 [range: 0-3] at Year 1 to 2.5 [range: 0-6.5] at Year 10 (p<0.001). During the ten-year follow-up, lesions accumulation in the left cerebellum and semi-ovale centers was associated with EDSS progression. In contrast, most lesions accumulation in the frontal, parietal and temporal lobes were associated with cognitive decline but had no effect on EDSS progression.

CONCLUSION

The present study provides strong evidence that clinically silent T2 lesions impact cognition in early MS. In daily practice, early prevention of T2 lesions accrual may be useful to limit cognitive decline.

Corpus callosum atrophy as a marker of clinically meaningful cognitive decline in secondary progressive multiple sclerosis. Impact on employment status

Cognitive impairment in Multiple Sclerosis (MS) is more frequent and pronounced in secondary progressive MS (SPMS). Cognitive decline is an important predictor of employment status in patients with MS. Magnetic Resonance Imaging (MRI) markers have been used to associate tissue damage with cognitive dysfunction. The aim of the study was to designate the MRI marker that predicts cognitive decline in SPMS and explore its effect on employment status. 30 SPMS patients and 30 healthy participants underwent neuropsychological assessment using the Trail Making Test (TMT) parts A and B, semantic and phonological verbal fluency task and a computerized cognitive screening battery (Central Nervous System Vital Signs). Employment status was obtained as a quality of life measure. Brain MRI was performed in all participants. We measured total lesion volume, third ventricle width, thalamic and corpus callosum atrophy. The frequency of cognitive decline for our SPMS patients was 80%. SPMS patients differed significantly from controls in all neuropsychological measures. Corpus callosum area was correlated with cognitive flexibility, processing speed, composite memory, executive functions, psychomotor speed, reaction time and phonological verbal fluency task. Processing speed and composite memory were the most sensitive markers for predicting employment status. Corpus callosum area was the most sensitive MRI marker for memory and processing speed. Corpus callosum atrophy predicts a clinically meaningful cognitive decline, affecting employment status in our SPMS patients.

Disability-Specific Atlases of Gray Matter Loss in Relapsing-Remitting Multiple Sclerosis

IMPORTANCE

Multiple sclerosis (MS) is characterized by progressive gray matter (GM) atrophy that strongly correlates with clinical disability. However, whether localized GM atrophy correlates with specific disabilities in patients with MS remains unknown.

OBJECTIVE

To understand the association between localized GM atrophy and clinical disability in a biology-driven analysis of MS.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, magnetic resonance images were acquired from 133 women with relapsing-remitting MS and analyzed using voxel-based morphometry and volumetry. A regression analysis was used to determine whether voxelwise GM atrophy was associated with specific clinical deficits. Data were collected from June 28, 2007, to January 9, 2014.

MAIN OUTCOMES AND MEASURES

Voxelwise correlation of GM change with clinical outcome measures (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite scores).

RESULTS

Among the 133 female patients (mean [SD] age, 37.4 [7.5] years), worse performance on the Multiple Sclerosis Functional Composite correlated with voxelwise GM volume loss in the middle cingulate cortex (P < .001) and a cluster in the precentral gyrus bilaterally (P = .004). In addition, worse performance on the Paced Auditory Serial Addition Test correlated with volume loss in the auditory and premotor cortices (P < .001), whereas worse performance on the 9-Hole Peg Test correlated with GM volume loss in Brodmann area 44 (Broca area; P = .02). Finally, voxelwise GM loss in the right paracentral lobulus correlated with bowel and bladder disability (P = .03). Thus, deficits in specific clinical test results were directly associated with localized GM loss in clinically eloquent locations.

CONCLUSIONS AND RELEVANCE

These biology-driven data indicate that specific disabilities in MS are associated with voxelwise GM loss in distinct locations. This approach may be used to develop disability-specific biomarkers for use in future clinical trials of neuroprotective treatments in MS.

The clinico-radiological paradox of cognitive function and MRI burden of white matter lesions in people with multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Moderate correlation exists between the imaging quantification of brain white matter lesions and cognitive performance in people with multiple sclerosis (MS). This may reflect the greater importance of other features, including subvisible pathology, or methodological limitations of the primary literature.

OBJECTIVES

To summarise the cognitive clinico-radiological paradox and explore the potential methodological factors that could influence the assessment of this relationship.

METHODS

Systematic review and meta-analysis of primary research relating cognitive function to white matter lesion burden.

RESULTS

Fifty papers met eligibility criteria for review, and meta-analysis of overall results was possible in thirty-two (2050 participants). Aggregate correlation between cognition and T2 lesion burden was r = -0.30 (95% confidence interval: -0.34, -0.26). Wide methodological variability was seen, particularly related to key factors in the cognitive data capture and image analysis techniques.

CONCLUSIONS

Resolving the persistent clinico-radiological paradox will likely require simultaneous evaluation of multiple components of the complex pathology using optimum measurement techniques for both cognitive and MRI feature quantification. We recommend a consensus initiative to support common standards for image analysis in MS, enabling benchmarking while also supporting ongoing innovation.

Information processing speed in multiple sclerosis: Past, present, and future

BACKGROUND

Information processing speed (IPS) is a prevalent cognitive impairment in multiple sclerosis (MS).

OBJECTIVES

This review aims to summarize the methods applied to assess IPS in MS and its theoretical conceptualization. A PubMed search was performed to select articles published between 1 January 2004 and 31 December 2013, resulting in 157 articles included.

RESULTS

The majority (54%) of studies assessed IPS with heterogeneous samples (several disease courses). Studies often report controlling for presence of other neurological disorders (60.5%), age (58.6%), education (51.6%), alcohol history (47.8%), or use of steroids (39.5%). Potential confounding variables, such as recent relapses (50.3%), history of developmental disorders (19.1%), and visual problems (29.9%), were often neglected. Assessments used to study IPS were heterogeneous (ranging from simple to complex tasks) among the studies under review, with 62 different tasks used. Only 9.6% of articles defined the construct of IPS and 22.3% discussed IPS in relation to a theoretical model.

FUTURE DIRECTIONS

The challenges for the upcoming decade include clarification of the definition of IPS as well as its theoretical conceptualization and a consensus on assessment. Based on the results obtained, we propose a new theoretical model, the tri-factor model of IPS.

Widespread cortical thinning in patients with neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Studies on cortical involvement and its relationship with cognitive function in patients with neuromyelitis optica spectrum disorder (NMOSD) remain scarce. The objective of this study was to compare cortical thickness on magnetic resonance imaging (MRI) between patients with NMOSD and multiple sclerosis (MS) and to investigate its relationship with clinical features and cognitive function.

METHODS

This observational clinical imaging study of 91 patients with NMOSD, 52 patients with MS and 44 healthy controls was conducted from 1 December 2013 to 30 April 2015 at the institutional referral center. Three tesla MRI of the brain and neuropsychological tests were performed. Cortical thickness was measured using three-dimensional surface-based analysis.

RESULTS

Both sets of patients exhibited cortical thinning throughout the entire brain cortex. Patients with MS showed a significantly greater reduction in cortical thickness over broad regions of the bilateral frontal and parieto-temporal cortices and the left precuneus compared to those with NMOSD. Memory functions in patients with MS were correlated with broad regional cortical thinning, whereas no significant associations were observed between cortical thickness and cognitive function in patients with NMOSD.

CONCLUSIONS

Widespread cortical thinning was observed in patients with NMOSD and MS, but the extent of cortical thinning was greater in patients with MS. The more severe cortical atrophy may contribute to memory impairment in patients with MS but not in those with NMOSD. These results provide in vivo evidence that the severity and clinical relevance of cortical thinning differ between NMOSD and MS.

Cortical Perfusion Alteration in Normal-Appearing Gray Matter Is Most Sensitive to Disease Progression in Relapsing-Remitting Multiple Sclerosis

BACKGROUND AND PURPOSE

The role of gray matter in multiple sclerosis is increasingly evident; however, conventional images demonstrate limitations in cortical lesion identification. Perfusion imaging appears sensitive to changes in tissue type and disease severity in MS. We sought to use bookend perfusion to quantify parameters in healthy controls and normal-appearing and lesional tissue at different relapsing-remitting MS stages.

MATERIALS AND METHODS

Thirty-nine patients with relapsing-remitting MS and 19 age-matched healthy controls were prospectively recruited. The Minimal Assessment of Cognitive Function in MS battery was used to assess cognitive performance. Perfusion parameters, including cerebral blood flow and volume and mean transit time, were compared for healthy controls and normal-appearing and lesional tissue for all study groups. Dispersion of perfusion measures for white matter lesions and cortical lesions was assessed.

RESULTS

Twenty of the 39 patients with relapsing-remitting MS were cognitively impaired. Significant differences were displayed between all relapsing-remitting MS subgroups and healthy controls in all comparisons except for normal-appearing gray matter CBV between healthy controls and unimpaired patients with relapsing-remitting MS and for all normal-appearing white matter perfusion parameters between healthy controls and unimpaired patients with relapsing-remitting MS. White matter lesion but not cortical lesion perfusion was significantly reduced in cognitively impaired patients with relapsing-remitting MS versus unimpaired patients with relapsing-remitting MS. Perfusion reduction with disease progression was greater in normal-appearing gray matter and normal-appearing white matter compared with cortical lesions and white matter lesions. Smaller dispersion was observed for cortical lesions compared with white matter lesions for each perfusion parameter.

CONCLUSIONS

Quantitative GM and WM analysis demonstrated significant but disproportionate white matter lesion, cortical lesion, normal-appearing white matter, and normal-appearing gray matter changes present between healthy controls and patients with relapsing-remitting MS with and without cognitive impairment, necessitating absolute rather than relative lesion perfusion measurement.

Brain atrophy in multiple sclerosis: therapeutic, cognitive and clinical impact

ABSTRACT Multiple sclerosis (MS) was always considered as a white matter inflammatory disease. Today, there is an important body of evidence that supports the hypothesis that gray matter involvement and the neurodegenerative mechanism are at least partially independent from inflammation. Gray matter atrophy develops faster than white matter atrophy, and predominates in the initial stages of the disease. The neurodegenerative mechanism creates permanent damage and correlates with physical and cognitive disability. In this review we describe the current available evidence regarding brain atrophy and its consequence in MS patients.

Decision-making under explicit risk is impaired in multiple sclerosis: relationships with ventricular width and disease disability

BACKGROUND

Decision-making is an essential function of everyday life. Decision-making under explicit risk requires developing advantageous decision strategies based on fixed outcomes (e.g., probabilities of winning or losing a bet). Decision-making and its neural substrates have been rarely studied in MS. We expected performance in decision-making under risk to be lowered in MS patients, and negatively correlated with disease-related disability, cognition, and ventricular width.

METHODS

Three groups were included: 32 MS patients and 20 healthy controls were examined with conventional neuropsychological tests and the Game-of-Dice Task (GDT) assessing decision-making under explicit risk. Linear 2-D ventricular width was assessed on MS patients' clinical MRIs and compared to a third group, 20 non-MS neurological control patients.

RESULTS

Compared to healthy controls, MS patients showed impaired GDT and neuropsychological performance, depending on the MS-subtype (relapsing-remitting (RR), n = 22; secondary progressive, n = 10) and disability severity among RR-MS patients. In MS patients, GDT performance correlated with processing speed, intercaudate ratio, and third ventricle ratio (p's < 0.05). Mediation analysis showed that the link between GDT performance and processing speed was fully explained by ventricular size.

CONCLUSION

Decision-making under explicit risk was reduced in MS patients, but only those with more pronounced disability. Independent of processing speed, decision-making under explicit risk correlates inversely with central atrophy in MS.

Clinical and imaging assessment of cognitive dysfunction in multiple sclerosis

In patients with multiple sclerosis (MS), grey matter damage is widespread and might underlie many of the clinical symptoms, especially cognitive impairment. This relation between grey matter damage and cognitive impairment has been lent support by findings from clinical and MRI studies. However, many aspects of cognitive impairment in patients with MS still need to be characterised. Standardised neuropsychological tests that are easy to administer and sensitive to disease-related abnormalities are needed to gain a better understanding of the factors affecting cognitive performance in patients with MS than exists at present. Imaging measures of the grey matter are necessary, but not sufficient to fully characterise cognitive decline in MS. Imaging measures of both lesioned and normal-appearing white matter lend support to the hypothesis of the existence of an underlying disconnection syndrome that causes clinical symptoms to trigger. Findings on cortical reorganisation support the contribution of brain plasticity and cognitive reserve in limiting cognitive deficits. The development of clinical and imaging biomarkers that can monitor disease development and treatment response is crucial to allow early identification of patients with MS who are at risk of cognitive impairment.

Corpus callosum atrophy is strongly associated with cognitive impairment in multiple sclerosis: Results of a 17-year longitudinal study

Background:

Cognitive impairment is common in multiple sclerosis (MS) and may be subtle. The corpus callosum is essential for connectivity-demanding cognitive tasks and is significantly affected in MS, therefore it may serve as a marker for cognitive function.

Objective:

The objective of this paper is to longitudinally study the normalized corpus callosum area (nCCA) as a marker of cognitive function and disability in MS.

Methods:

Thirty-seven MS patients were followed from 1996 with follow-ups in 2004 and 2013. A healthy matched control group was recruited. The Expanded Disability Status Scale (EDSS) and Symbol Digit Modalities Test (SDMT) were assessed. The nCCA was measured on T2-weighted images. Volumetry was performed with FreeSurfer.

Results:

Disease duration spanned five decades (1.6–46 years). Annual corpus callosal atrophy rate decreased with disease duration. nCCA was strongly correlated with SDMT ( r = 0.793, p < 0.001) and moderately correlated with EDSS ( r = −0.545, p < 0.001) after adjusting for disease duration, age and sex. The correlations of brain parenchymal fraction, white matter fraction, gray matter fraction and normalized lesion volume were less strong.

Conclusions:

The nCCA correlates well with physical and cognitive disability in time perspectives close to two decades, outperforming volumetric measurements. The nCCA is fast and could be feasible for clinical implementation where it may help identify patients in need of neuropsychological evaluation.

Cognitive dysfunction in pediatric multiple sclerosis

Cognitive and neuropsychological impairments are well documented in adult multiple sclerosis (MS). Research has only recently focused on cognitive disabilities in pediatric cases, highlighting some differences between pediatric and adult cases. Impairments in several functions have been reported in children, particularly in relation to attention, processing speed, visual-motor skills, and language. Language seems to be particularly vulnerable in pediatric MS, unlike in adults in whom it is usually preserved. Deficits in executive functions, which are considered MS-specific in adults, have been inconsistently reported in children. In children, as compared to adults, the relationship between cognitive dysfunctions and the two other main symptoms of MS, fatigue and psychiatric disorders, was poorly explored. Furthermore, data on the correlations of cognitive impairments with clinical and neuroimaging features are scarce in children, and the results are often incongruent; interestingly, involvement of corpus callosum and reduced thalamic volume differentiated patients identified as having a cognitive impairment from those without a cognitive impairment. Further studies about pediatric MS are needed in order to better understand the impact of the disease on brain development and the resulting effect on cognitive functions, particularly with respect to different therapeutic strategies.

Gray matters in multiple sclerosis: cognitive impairment and structural MRI

Multiple sclerosis (MS) is an immune-mediated disease affecting central nervous system (CNS). Although MS is classically considered a white matter (WM) disease, the involvement of gray matter (GM) in the pathogenic process has been confirmed by pathology studies and MRI studies. Impairment of cognitive domains such as memory, mental processing speed, attention, and executive function can occur from the early stage of the disease and tends to worsen over time, despite stable physical symptoms. WM demyelination is moderately correlated with CI, suggesting that probably WM abnormalities alone cannot fully explain the extent of clinical symptoms in MS, including CI. Several MRI techniques have shown the involvement of GM in MS and the association between GM damage, physical disability, and CI. The aim of this review is to provide an overview of CI and GM damage assessed by structural brain MRI.

Symptomatic treatment and management of multiple sclerosis

The range of symptoms which occur in multiple sclerosis (MS) can have disabling functional consequences for patients and lead to significant reductions in their quality of life. MS symptoms can also interact with each other, making their management challenging. Clinical trials aimed at identifying symptomatic therapies have generally been poorly designed and have tended to be underpowered. Therefore, the evidence base for the management of MS symptoms with pharmacologic therapies is not strong and tends to rely upon open-label studies, case reports, and clinical trials with small numbers of patients and poorly validated clinical outcome measures. Recently, there has been a growing interest in the management of MS symptoms with pharmacologic treatments, and better-designed, randomized, double-blind, controlled trials have been reported. This chapter will describe the evidence base predominantly behind the various pharmacologic approaches to the management of MS symptoms, which in most, if not all, cases, requires multidisciplinary input. Drugs routinely recommended for individual symptoms and new therapies, which are currently in the development pipeline, will be reviewed. More interventional therapies related to symptoms that are refractory to pharmacotherapy will also be discussed, where relevant.

The relationship between total and regional corpus callosum atrophy, cognitive impairment and fatigue in multiple sclerosis patients

Objective:

The objective of this paper is to investigate the relationship between total and regional corpus callosum (CC) atrophy, neuropsychological test performance and fatigue in multiple sclerosis (MS) patients.

Methods:

We conducted a cross-sectional study in 113 MS patients: mean age 48±11 years, 75/113 women, 84/113 relapsing–remitting MS, mean disease duration 21±9 years, mean Expanded Disability Status Scale (EDSS) score 3.2±1.7. All patients underwent brain magnetic resonance imaging, standardised neurological assessment and comprehensive cognitive testing including assessments for fatigue and depression. Total and regional CC atrophy was assessed using the corpus callosum index (CCI).

Results:

CCI correlated more strongly with T2- and T1-lesion volume and whole brain volume than with disease duration or EDSS score. CCI correlated strongly with the verbal fluency test (VFT), Symbol Digit Modalities Test (SDMT) and Paced Auditory Serial Addition Test (PASAT). Multivariate regression analysis revealed that atrophy of the posterior CC segment was significantly associated with poor outcome in the PASAT, VFT and SDMT. In contrast, atrophy of the anterior CC segment was significantly associated with fatigue severity and poor outcome in the long-term memory test.

Conclusions:

Atrophy of the CC is associated with cognitive impairment and fatigue. Regional CCI results indicate that these associations are partially spatially segregated.

Cognitive impairment and "invisible symptoms" are not associated with CCSVI in MS

BACKGROUND

We investigated the association between chronic cerebrospinal venous insufficiency (CCSVI) and cognitive impairment (CI) in multiple sclerosis (MS). Moreover, we evaluated the association between CCSVI and other frequent self-reported MS symptoms.

METHODS

We looked at the presence of CI in incident MS patients with CCVSI in a population-based cohort of Catania, Italy. All subjects were group-matched by age, sex, disease duration and EDSS score with MS patients without CCSVI, serving as controls. CI was assessed with the Brief Repeatable Battery (BRB) and the Stroop Test (ST) and it was defined by the presence of at least three impaired tests. Fatigue and depressive symptoms were assessed with Fatigue Severity Scale (FSS) and Hamilton Depressive Rating Scale (HDRS), respectively. Bladder and sexual symptoms were assessed with the respective items of the Italian version of Guy's Neurological Disability Scale (GNDS). Quality of life was evaluated with Multiple Sclerosis Quality of Life-54 Instrument (MSQOL-54).

RESULTS

Out of 61 MS patients enrolled in the study, 27 were CCSVI positive and 34 were CCSVI negative. Of them, 43 were women (70.5%); the mean age was 43.9 ± 11.8 years; the mean disease duration was 159.7 ± 113.7 months; mean EDSS was 3.0 ± 2.6. Of them, 36 (59.0%) were classified relapsing-remitting (RR), 12 (19.7%) secondary progressive (SP), seven (11.5%) primary progressive (PP) and six (9.3%) Clinically Isolated Syndrome (CIS). Overall, CI was detected in 29/61 (47.5%) MS patients; particularly 13/27 (48.1%) in the CCSVI positive group and 16/34 (47.0%) in the CCSVI negative group. Presence of CCSVI was not significantly associated with the presence of CI (OR 1.04; 95% CI 0.37-2.87; p-value = 0.9). Not significant differences were found between the two groups regarding the other MS symptoms investigated.

CONCLUSIONS

Our findings suggest a lack of association between CCSVI and CI in MS patients. Fatigue, depressive, bladder/sexual symptoms and self-reported quality of life are not associated with CCSVI.

Callosal atrophy in multiple sclerosis is related to cognitive speed

BACKGROUND

Long-term changes regarding corpus callosum area (CCA) and information processing speed in cognitive and sensory-motor tasks have rarely been studied in multiple sclerosis (MS).

OBJECTIVE AND METHODS

Information processing speed in cognitive (Symbol Digit Modalities Test, SDMT), sensory (visual and auditory reaction time) and motor (finger-tapping speed, FT; right and left hand) tasks as well as auditory inter-hemispheric transfer (verbal dichotic listening, VDL) was related to CCA, measured by MRI at baseline and at follow-up after nine years in 22 patients with MS. Possible confounding by demographic (age, gender and education), clinical (symptom onset, duration, severity of disease) and relative brain volume (RBV) as well as T2 lesion load was taken into account.

RESULTS

The smaller the CCA at baseline, the slower was SDMT performance at baseline. In a similar way, CCA at follow-up was associated with poor SDMT result at follow-up. Furthermore, the higher the annual rate of change in CCA, the poorer was performance in VDL on the left ear and the more pronounced was the right ear advantage. A positive relationship between performance in VDL right ear and annual rate of change in RBV was also seen. Sensory-motor tests were not significantly associated with CCA. T2 lesion load at baseline was associated with FT performance at baseline. Demographic, clinical and radiological (RBV and T2 lesion load) characteristics did not confound the significant relation between CCA and SDMT.

CONCLUSIONS

CCA unlike RBV and T2 lesion load was associated with SDMT, which indicated a marked cognitive rather than perceptual-motor component.

Early and severe cognitive impairment in multiple sclerosis

Objectives

To report on four new cases of severe cognitive impairment in the early stages of multiple sclerosis (MS) and to review data on the subject since few cases have been reported worldwide.

Methods

Retrospective evaluation of medical records of patients with severe cognitive impairment within the first five years of MS diagnosis. Results on neuropsychological tests and magnetic resonance imaging (MRI) were disclosed.

Results

Four patients from different Brazilian neurological departments in Brazil were evaluated, all presenting with severe cognitive dysfunction classified as rapidly developing dementia. MRI images showed severe brain atrophy and basal ganglia lesions in all patients.

Conclusions

Although rare, severe cognitive impairment in MS represents an important disability and may ultimately constitute another form of the disease.

Cortical pathology and cognitive impairment in multiple sclerosis

Cognitive impairment constitutes a relevant clinical aspect of multiple sclerosis (MS). Depending on the disease phase and type, 40-65% of MS patients develop various degrees of cognitive dysfunction. Pathological and MRI studies have failed to demonstrate the existence of a strict relationship between cognitive impairment and subcortical white matter pathology. The correlation is also poor when MRI metrics of whole brain (white plus gray matter) atrophy are considered. Over the last decade, increasing observations have provided evidence of a primary role of cortical pathology - that is, inflammatory focal lesions (cortical lesions) and atrophy (cortical thickness) - in determining global and/or selective cognitive disability in MS. By applying a new semi-automated software (Freesurfer) to analyze the global and regional cortical thickness and the double inversion recovery sequence to identify cortical lesions, it has been observed that specific cognitive deficits, such as memory impairment, attention deficits and reduced mental processing speed, could be better explained by cortical structural abnormalities rather than subcortical white matter lesions. Therefore, MRI evaluation of cortical pathology should be included in the routine examination of MS patients, especially those with initial signs/symptoms of cognitive dysfunctions.

Cognitive performance in relapsing remitting multiple sclerosis: a longitudinal study in daily practice using a brief computerized cognitive battery

Background

There is need for a cognitive test battery that can be easily used in clinical practice to detect or monitor cognitive performance in patients with multiple sclerosis (MS). In order to conduct, in this patient group, a preliminary investigation of the validity and utility of a brief computerized battery, the Cognitive Drug Research (CDR) battery, we longitudinally assessed cognition in patients with relapsing remitting (RR) MS.

Methods

Forty-three mildly disabled, clinically active RRMS patients were repeatedly assessed with the Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) and five composite scores derived from the CDR computerized cognitive test system (CDR System): Power of Attention, Continuity of Attention, Quality of Working Memory, Quality of Episodic Memory and Speed of Memory. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) measured disability.

Results

The composite scores from the CDR battery generally showed excellent test-retest reliability over the repeated assessments, though was low on occasions for the Quality of Working Memory and Quality of Episodic Memory measures. The CDR measures tended to be highly correlated with other measures of cognition (DSST and PASAT) and were also strongly related to disability (EDSS and MSFC). Baseline scores indicated large impairments to visual information processing speed and attention (DSST, Cohen's d 1.1; Power of Attention d 1.4 [reaction time on tasks of focussed and sustained attention]), and a moderate impairment both to sustained attention (Continuity of Attention d 0.6) and complex information processing speed (Speed of memory d 0.7 [reaction time on tasks of working and episodic Memory]), when compared to normative data derived from healthy volunteers enrolled in a series of separate, prior clinical trials. Working memory (Quality of Working Memory) and episodic memory (Quality of Episodic Memory) were unimpaired.

Conclusions

Preliminary validation of the CDR System indicated that for most, but not all measures psychometric properties were adequate and the measures were related to disability (EDSS and MSFC) and other measures of cognition.

Cortical lesions and cognitive impairment in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and degenerative disease of the central nervous system. In the last decade, pathological and magnetic resonance imaging (MRI) studies have shown that a significant portion of inflammatory lesions are located in the grey matter, especially in the cerebral cortex, of MS patients. Cortical inflammatory lesions (CL) can be demonstrated in vivo in MS patients by double inversion recovery (DIR) MRI sequence. Neuropsychological deficits constitute a major clinical aspect of MS, being demonstrated in a percentage ranging from 40 to 65% of patients, and have been shown to be associated with cortical demyelination and atrophy. Recent DIR studies in MS patients having different clinical forms of the disease have disclosed that CL burden not only correlates with the severity of physical disability, but is also one of the major structural changes associated with disease-related cognitive impairment.

Identification and clinical impact of multiple sclerosis cortical lesions as assessed by routine 3T MR imaging

BACKGROUND AND PURPOSE

Histopathologic studies have reported widespread cortical lesions in MS; however, in vivo detection by using routinely available pulse sequences is challenging. We investigated the relative frequency and subtypes of cortical lesions and their relationships to white matter lesions and cognitive and physical disability.

MATERIALS AND METHODS

Cortical lesions were identified and classified on the basis of concurrent review of 3D FLAIR and 3D T1-weighted IR-SPGR 3T MR images in 26 patients with MS. Twenty-five patients completed the MACFIMS battery. White matter lesion volume, cortical lesion number, and cortical lesion volume were assessed.

RESULTS

Overall, 249 cortical lesions were detected. Cortical lesions were present in 24/26 patients (92.3%) (range per patient, 0-30; mean, 9.6 ± 8.8). Most (94.4%, n = 235) cortical lesions were classified as mixed cortical-subcortical (type I); the remaining 5.6% (n = 14) were classified as purely intracortical (type II). Subpial cortical lesions (type III) were not detected. White matter lesion volume correlated with cortical lesion number and cortical lesion volume (r(S) = 0.652, r(S) = 0.705, respectively; both P < .001). After controlling for age, depression, and premorbid intelligence, we found that all MR imaging variables (cortical lesion number, cortical lesion volume, white matter lesion volume) correlated with the SDMT score (R(2) = 0.513, R(2) = 0.449, R(2) = 0.418, respectively; P < .014); cortical lesion number also correlated with the CVLT-II scores (R(2) = 0.542-0.461, P < .043). The EDSS scores correlated with cortical lesion number and cortical lesion volume (r(S) = 0.472, r(S) = 0.404, respectively; P < .05), but not with white matter lesion volume.

CONCLUSIONS

Our routinely available imaging method detected many cortical lesions in patients with MS and was useful in their precise topographic characterization in the context of the gray matter-white matter junction. Routinely detectable cortical lesions were related to physical disability and cognitive impairment.