Serial neuropsychological assessment and magnetic resonance imaging analysis in multiple sclerosis

T1 and T2 weighted lesions and cognition in multiple Sclerosis: A systematic review and meta-analysis

BACKGROUND

Considering the different results regarding the correlation between Magnetic Resonance Imaging (MRI) structural measures and cognitive dysfunction in patients with MS, we aimed to perform a systematic review and meta-analysis study to investigate the correlation between T1 and T2 weighted lesions and cognitive scores to find the most robust MRI markers for cognitive function in MS population.

METHODS

The literature of this paper was identified through a comprehensive search of electronic datasets including PubMed, Scopus, Web of Science, and Embase in February 2022. Studies that reported the correlation between cognitive status and T1 and T2 weighted lesions in MS patients were selected.

RESULTS

21 studies with a total of 3771 MS patients with mean ages ranging from 30 to 57 years were entered into our study. Our analysis revealed that the volume of T1 lesions was significantly correlated with Symbol Digit Modality test (SDMT) (r: -0.30, 95 %CI: -0.59, -0.01) and Paced Auditory Serial-Addition Task (PASAT) scores (r: -0.23, 95 %CI: -0.36, -0.10). We investigated the correlation between T2 lesions and cognitive scores. The pooled estimates of z scores were significant for SDMT (r: -0.27, 95 %CI: -0.51, -0.03) and PASAT (r: -0.27, 95 %CI: -0.41, -0.13).

CONCLUSION

In conclusion, our systematic review and meta-analysis study provides strong evidence of the correlation between T1 and T2 lesions and cognitive function in MS patients. Further research is needed to explore the potential mechanisms underlying this relationship and to develop targeted interventions to improve cognitive outcomes in MS patients.

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.

Neuroimaging Correlates of Cognitive Dysfunction in Adults with Multiple Sclerosis

Cognitive impairment is a frequent and meaningful symptom in multiple sclerosis (MS), caused by the accrual of brain structural damage only partially counteracted by effective functional reorganization. As both these aspects can be successfully investigated through the application of advanced neuroimaging, here, we offer an up-to-date overview of the latest findings on structural, functional and metabolic correlates of cognitive impairment in adults with MS, focusing on the mechanisms sustaining damage accrual and on the identification of useful imaging markers of cognitive decline.

Tracking cognitive impairment in multiple sclerosis using the Brain on Track test: a validation study

BACKGROUND

The accurate and regular monitoring cognitive performance in multiple sclerosis (MS) patients is critical to develop new prevention and management strategies for cognitive impairment (CI). The Brain on Track (BoT) test is a self-administered web-based tool developed for cognitive screening and monitoring. The objective of this study was to validate the use of the BoT in MS, by assessing its ability to distinguish between MS patients and matched controls, as well as detect CI among MS patients, by analysing its correlation with standard cognitive tests and its reliability and learning effects in repeatable use.

METHODS

The BoT was applied in 30 patients with MS consecutively selected and 30 age- and education-matched controls, first in a hospital clinic, under supervision, and then 1 week later from home. After these first two trials, MS patients repeated the test from home every 4 weeks for 3 months. A standard neuropsychological battery was also applied to MS patients at baseline.

RESULTS

The Cronbach's alpha was 0.89. Test scores were significantly different between MS patients and controls (Cohen's d = 0.87; p < 0.01). Among MS patients, scores were significantly lower in those with CI documented in the standard neuropsychological battery than in their cognitively preserved counterparts (Cohen's d = 2.0; p < 0.001). The BoT scores presented a good correlation with standard neuropsychological tests, particularly for information processing speed. Regarding test-retest reliability, 10/11 subtests presented two-way mixed single intraclass consistency correlation coefficients > 0.70.

CONCLUSION

The BoT showed good neuropsychological parameters in MS patients, endorsing the use of self-administered computerized tests in this setting.

Apathy as a herald of cognitive changes in multiple sclerosis: A 2-year follow-up study

Background:

Behavioral symptoms, such as apathy and depression, are common in multiple sclerosis (MS) but their relationship with cognitive and clinical characteristics often remains underinvestigated and not monitored over time.

Objective:

The aim of this study was to assess the evolution of cognitive profile of patients affected by MS in relation to apathy and depression using a 2-year follow-up study.

Methods:

Two years after the first assessment, 100 of 125 MS patients were re-evaluated on a comprehensive neuropsychological battery, and on specific scales for assessment of apathy (Apathy Evaluation Scale—Self-reported) and depression (Hamilton Depression Rating Scale).

Results:

After 2 years (T1), we found a relatively consistent prevalence of apathy (about 40%) and a reduction in prevalence of depression (from 44% to 30%). Higher level of apathy at baseline predicted the progressive cognitive changes at follow-up; and patients with apathy without depression (“pure” apathy) than patients without apathy had poorer performance on the interference task of the Stroop test assessing inhibitory control.

Conclusion:

The present results suggested that apathy in MS was associated with more severe executive dysfunctions (in particular cognitive control). Apathy rather than depression predicted cognitive impairment in MS over time.

Basal forebrain cholinergic system volume is associated with general cognitive ability in the elderly

OBJECTIVE

At the present, it is unclear whether association of basal forebrain cholinergic system (BFCS) volume with cognitive performance exists in healthy as well as in cognitively impaired elderly subjects. Whereas one small study reported an association of BFCS volume with general cognitive ability 'g' in healthy ageing, effects on specific cognitive domains have only been found in subjects with cognitive decline. Here we aim to clarify whether an association of BFCS volume and 'g' is present in a larger sample of elderly subjects without obvious symptoms of dementia and whether similar associations can also be observed in specific cognitive domains.

METHODS

282 pre-surgical patients from the BioCog study (aged 72.7 ± 4.9 years with a range of 65-87 years, 110 women) with a median MMSE score of 29 points (range 24-30) were investigated. BFCS and brain volume as well as brain parenchymal fraction were assessed in T1-weighted MR images using SPM12 and a probabilistic map of the BFCS. Neuropsychological assessment comprised the CANTAB cognitive battery and paper-and-pencil based tests. For data analysis, generalised linear models and quantile regression were applied.

RESULTS

Significant associations of BFCS volume with 'g' and several cognitive domains were found, with the strongest association found for 'g'. BFCS volume explained less variance in cognitive performance than brain volume. The association was not confounded by brain parenchymal fraction. Furthermore, the association of BFCS volume and 'g' was similar in high- and low-performers.

CONCLUSION

Our results extend previous study findings on BFCS volume associations with cognition in elderly subjects. Despite the observed associations of BFCS volume and cognitive performance, this association seems to reflect a more general association of brain volume and cognition. Accordingly, a specific association of BFCS volume and cognition in non-demented elderly subjects is questionable.

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.

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.

Cognition, depression, fatigue, and quality of life in primary Sjögren's syndrome: correlations

OBJECTIVE

The aim of the present study was to investigate the prevalence and pattern of cognitive dysfunction observed in primary Sjögren's syndrome (PSS) and to examine the relationships between cognitive abilities, depression, fatigue, and quality of life.

MATERIALS AND METHODS

Thirty-two subjects with PSS were compared with 19 healthy controls on comprehensive neuropsychological, depression, fatigue, health state, and daily-life activities tests.

RESULTS

There was low performance in Clock Drawing, COWAT, Paced Auditory Serial Addition Test (PASAT), Colorless Word Reading (Stroop1) and Recognizing Colors (Stroop2) Patterns of STROOP test, SDLT, Auditory-Verbal Learning Test (AVLT), immediate and long-term verbal memory, Benton Judgment of Line Orientation Test (BJLOT), and in all the patterns of RCFT in PSS patients compared to the healthy control group (p < .05). It was observed an increased depression frequency and fatigue severity, impairment in health condition, and a decreased quality of life in PSS cases compared to the healthy controls (p < .05). All the depression, fatigue severity, and quality of life tests showed a significant positive correlation with each other (p < .05). A significant negative correlation between Clock Drawing and SF-36-BP (p = .031, r = -.382) and SF-36-GH (p = .027, r = -.392) was observed.

CONCLUSIONS

Clock Drawing, PASAT, and AVLT are very useful tests to determine the subclinical and clinical cognitive dysfunction to evaluate attention, information processing speed, executive functions, and short-term and long-term verbal memory in PSS patients. Depression and fatigue may not affect the neuropsychological tests performance.

Identification of multiple sclerosis patients at highest risk of cognitive impairment using an integrated brain magnetic resonance imaging assessment approach

BACKGROUND AND PURPOSE

While impaired cognitive performance is common in multiple sclerosis (MS), it has been largely underdiagnosed. Here a magnetic resonance imaging (MRI) screening algorithm is proposed to identify patients at highest risk of cognitive impairment. The objective was to examine whether assessment of lesion burden together with whole brain atrophy on MRI improves our ability to identify cognitively impaired MS patients.

METHODS

Of the 1253 patients enrolled in the study, 1052 patients with all cognitive, volumetric MRI and clinical data available were included in the analysis. Brain MRI and neuropsychological assessment with the Brief International Cognitive Assessment for Multiple Sclerosis were performed. Multivariable logistic regression and individual prediction analysis were used to investigate the associations between MRI markers and cognitive impairment. The results of the primary analysis were validated at two subsequent time points (months 12 and 24).

RESULTS

The prevalence of cognitive impairment was greater in patients with low brain parenchymal fraction (BPF) (<0.85) and high T2 lesion volume (T2-LV) (>3.5 ml) than in patients with high BPF (>0.85) and low T2-LV (<3.5 ml), with an odds ratio (OR) of 6.5 (95% CI 4.4-9.5). Low BPF together with high T2-LV identified in 270 (25.7%) patients predicted cognitive impairment with 83% specificity, 82% negative predictive value, 51% sensitivity and 75% overall accuracy. The risk of confirmed cognitive decline over the follow-up was greater in patients with high T2-LV (OR 2.1; 95% CI 1.1-3.8) and low BPF (OR 2.6; 95% CI 1.4-4.7).

CONCLUSIONS

The integrated MRI assessment of lesion burden and brain atrophy may improve the stratification of MS patients who may benefit from cognitive assessment.

Pathology and MRI: exploring cognitive impairment in MS

Cognitive impairment is a frequent symptom in people with multiple sclerosis, affecting up to 70% of patients. This article reviews the published association of cognitive dysfunction with neuroimaging findings. Cognitive impairment has been related to focal T2 hyperintense lesions, diffuse white matter damage and corical and deep gray matter atrophy. Focal lesions cannot sufficiently explain cognitive dysfunction in MS; microstructural tissue damage detectable by diffusion tensor imaging and gray matter atrophy are probably at least as relevant. Resting state functional magnetic resonance imaging is increasingly used to investigate the contribution of functional connectivity changes to cognitive function in MS. The fact that at least one third of MS patients are not overtly cognitively impaired despite significant radiographic tissue damage argues for protective factors (brain reserve, cognitive reserve) that require further clarification. It is concluded that the reported correlations between imaging findings and cognitive function do not imply causality. Well conceived and sufficiently powered longitudinal studies are lacking. Such studies would help unravel protective mechanisms against cogniitve decline and identify suitable imaging techniques to monitor cognitive function in individual patients with MS.

Design, rationale, and baseline characteristics of the randomized double-blind phase II clinical trial of ibudilast in progressive multiple sclerosis

BACKGROUND

Primary and secondary progressive multiple sclerosis (MS), collectively called progressive multiple sclerosis (PMS), is characterized by gradual progression of disability. The current anti-inflammatory treatments for MS have little or no efficacy in PMS in the absence of obvious active inflammation. Optimal biomarkers for phase II PMS trials is unknown. Ibudilast is an inhibitor of macrophage migration inhibitor factor and phosphodiesterases-4 and -10 and exhibits possible neuroprotective properties. The goals of SPRINT-MS study are to evaluate the safety and efficacy of ibudilast in PMS and to directly compare several imaging metrics for utility in PMS trials.

METHODS

SPRINT-MS is a randomized, placebo-controlled, phase II trial of ibudilast in patients with PMS. Eligible subjects were randomized 1:1 to receive either ibudilast (100mg/day) or placebo for 96weeks. Imaging is conducted every 24weeks for whole brain atrophy, magnetization transfer ratio, diffusion tensor imaging, cortical brain atrophy, and retinal nerve fiber layer thickness. Clinical outcomes include neurologic disability and patient reported quality of life. Safety assessments include laboratory testing, electrocardiography, and suicidality screening.

RESULTS

A total of 331 subjects were enrolled, of which 255 were randomized onto active study treatment. Randomized subjects were 53.7% female and mean age 55.7 (SD 7.3) years. The last subject is projected to complete the study in May 2017.

CONCLUSION

SPRINT-MS is designed to evaluate the safety and efficacy of ibudilast as a treatment for PMS while simultaneously validating five different imaging biomarkers as outcome metrics for use in future phase II proof-of-concept PMS trials.

Primary Sjögren's syndrome is associated with significant cognitive dysfunction

AIM

Cognitive dysfunction is a neurologic manifestation in primary Sjögren syndrome (PSS). On the other hand, several antibodies are related to cognitive dysfunction. The aim of this study is to assess the cognitive dysfunction of PSS patients via detailed neurologic tests. Moreover, its associations with antibodies were also evaluated.

METHOD

Twenty-eight female patients with PSS and 17 healthy controls comprised the study groups. Short-term memory, long-term memory, verbal learning, visual memory, visual spatial perception, attention, verbal frequency function, executive functions and information processing speed were evaluated with neurologic tests in both of the study groups. Furthermore, anti-N-methyl-D-aspartate (NMDA) type anti-glutamate-receptor antibody, anti-ribosomal-p and antiganglioside antibodies were assessed in the study groups.

RESULTS

The attention, data processing speed, verbal learning, short-term verbal memory and visuo-spatial perception performances were lower in the patients with PSS when compared to the healthy controls. The difference reached statistical significance in Paced Auditory Serial Addition Test (P < 0.01), Serial Digit Learning Test (P < 0.01), clock drawing (P = 0.03), Auditory Verbal Learning Test immediate verbal memory (P = 0.01) and Benton Judgement of Line Orientation Test (P = 0.03). Even if antiganglioside antibodies were more likely to be present in the PSS group when compared to the healthy controls, no relationship was found between its positivity and cognitive dysfunction.

CONCLUSION

Results of this study suggest that cognitive dysfunction is quite prevalent in PSS patients without being associated with studied antibodies.

Cognitive slowing in multiple sclerosis is strongly associated with brain volume reduction

Introduction In this study, we investigated the influence of in vivo disease pathology (measured as magnetic resonance imaging (MRI) lesion load and brain volume reduction) on cognitive functioning, especially the speed of processing, in multiple sclerosis (MS) patients. Since MS is characterized by cognitive slowing rather than impaired accuracy, we used the Amsterdam Neuropsychological Tasks (ANT) program, a computerized test proven to be very sensitive to cognitive slowing in MS patients.

Methods Thirty-two patients performed the ANT and underwent MRI scanning. Using the ANT computerized tests, we investigated focused, divided, sustained attention, executive function and psychomotor function, and examined associations of speed, speed fluctuation and accuracy of performance of these tests with MRI lesion load and brain volume parameters.

Results A decrease in the speed of processing and response speed stability, and a decrease in psychomotor accuracy and stability were clearly associated with less brain volume, and with higher lesion loads, in particular at frontal and occipital areas. Correlations with brain volume reduction were found for all domains, except for visuo-spatial processing. In particular, speed and speed fluctuation scores correlated with brain volume reduction, while accuracy of performance, in general, did not correlate. Only some test speed scores and speed fluctuation scores correlated with lesion load measurements.

Conclusion This study shows that, in MS patients, accuracy of processing is not compromised unless high working memory demands are involved. Problems in neurocognitive functioning in MS are mainly modulated by speed and stability of speed processing, in particular when attention-demanding controlled information processing is required. Abnormalities in these domains are most strongly associated with brain volume loss, confirming that pathology beyond focal lesions is important in MS.

Cognitive impairment is associated with subcortical magnetic resonance imaging grey matter T2 hypointensity in multiple sclerosis

Grey matter hypointensity on T2-weighted magnetic resonance imaging (MRI) scans, suggesting iron deposition, has been described in multiple sclerosis (MS) and is related to physical disability, disease course and brain atrophy. We tested the hypothesis that subcortical grey matter T2 hypointensity is related to cognitive impairment after adjusting for the effect of MRI lesion and atrophy measures. We studied 33 patients with MS and 14 healthy controls. Normalized T2 signal intensity in the caudate, putamen, globus pallidus and thalamus, total brain T1-hypointense lesion volume (T1LV), fluid-attenuated inversion-recovery-hyperintense lesion volume (FLLV) and brain parenchymal fraction (BPF) were obtained quantitatively. A neuropsychological composite score (NCS) encompassed new learning, attention, working memory, spatial processing and executive function. In each of the regions of interest, the normalized T2 intensity was lower in the MS versus control group (all P <0.001). Regression modelling tested the relative association between all MRI variables and NCS. Globus pallidus T2 hypointensity was the only variable selected in the final model ( R2 = 0.301, P = 0.007). Pearson correlations between MRI and NCS were T1LV: r = -0.319; FLLV: r = -0.347; BPF: r = 0.374; T2 hypointensity of the caudate: r = 0.305; globus pallidus: r = 0.395; putamen: r = 0.321; and thalamus: r = 0.265. Basal ganglia T2 hypointensity and BPF demonstrated the strongest associations with cognitive impairment on individual cognitive subtests. Subcortical grey matter T2 hypointensity is related to cognitive impairment in MS, supporting the clinical relevance of T2 hypointensity as a biological marker of MS tissue damage. These data implicate a role for basal ganglia iron deposition in neuropsychological dysfunction.

The association between cognitive impairment and physical disability in multiple sclerosis

Background: The association between cognitive impairment and physical disability was examined in a larger, more representative sample of patients with multiple sclerosis (MS) than in previous studies. Method: Two hundred and fifty-three patients attending an MS clinic were assessed with respect to physical disability using the Expanded Disability Status Scale and cognitive impairment using a battery of neuropsychological tests. Results: Physical disability correlated with duration of disease; cognitive impairment did not. Virtually all measures derived from the cognitive battery were significantly correlated with physical disability. Three measures of speeded information processing and one involving delayed recall of verbal material were unique predictors of disability status. The relationship between cognitive impairment and physical disability was equivalent for patients with shorter (<3 years) versus longer (>10 years) disease duration. Cognitive impairment correlated with the rate of disability progression as reflected by the progression index. Conclusion: Cognitive impairment is more closely associated with physical disability than most previous studies indicate. This relationship appears to be stable throughout the duration of MS, although this conclusion is qualified by the cross-sectional design of the study. Further attention should be paid to cognitive impairment as a possible predictor of the rate of patients’ physical decline.

Introducing demographic corrections for the 10/36 Spatial Recall Test

OBJECTIVE

The 10/36 Spatial Recall Test is a measure of visuospatial memory and has been recommended for inclusion when administering a brief cognitive assessment to patients with multiple sclerosis by multiple groups. However, a notable limitation of the measure includes a lack of normative data with demographic corrections. Thus, the primary objective of the current study was to examine demographic influences on the 10/36 Spatial Recall Test and to introduce demographically corrected normative data for the instrument.

METHODS

Data were collected from 116 participants over the age of 50 years. All study participants were free of any neurologic disease or disorder and classified as cognitively intact by a consensus conference team that was comprised of neurologists and neuropsychologists. All study participants were administered a neuropsychological evaluation that included the 10/36 Spatial Recall Test Version A at the baseline visit.

RESULTS

10/36 Spatial Recall Test scores were affected by age, education, and race. Gender effects were not observed. Given these effects, regression equations were used to correct for the effects of demographic variables. The z-scores obtained from these corrections were not significantly influenced by demographical variables.

CONCLUSION

The demographic corrections introduced in this paper offer the possibility to enhance the clinical utility of the 10/36 Spatial Recall Test.

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.

Aging with multiple sclerosis: cognitive, emotional and neuropathological considerations

SUMMARY 

Although individuals aging with multiple sclerosis (MS) can experience a compounding of their symptoms, in some circumstances they become more adept at coping with aging-related changes. Fortunately, individuals aging with MS often adjust well to aging, particularly if they have sufficient social support. They also do not appear to show accelerated rates of cognitive decline, and rates of some neuropathological changes have been shown to normalize compared with those seen in normal aging. Results are mixed as to whether older MS patients have higher rates of depression.

Correlations between MRI and Information Processing Speed in MS: A Meta-Analysis

Objectives. To examine relationships between conventional MRI measures and the paced auditory serial addition test (PASAT) and symbol digit modalities test (SDMT). Methods. A systematic literature review was conducted. Included studies had ≥30 multiple sclerosis (MS) patients, administered the SDMT or PASAT, and measured T2LV or brain atrophy. Meta-analysis of MRI/information processing speed (IPS) correlations, analysis of MRI/IPS significance tests to account for reporting bias, and binomial testing to detect trends when comparing correlation strengths of SDMT versus PASAT and T2LV versus atrophy were conducted. Results. The 39 studies identified frequently reported only significant correlations, suggesting reporting bias. Direct meta-analysis was only feasible for correlations between SDMT and T2LV (r = −0.45, P < 0.001) and atrophy in patients with mixed-MS subtypes (r = −0.54, P < 0.001). Familywise Holm-Bonferroni testing found that selective reporting was not the source of at least half of significant results reported. Binomial tests (P = 0.006) favored SDMT over PASAT in strength of MRI correlations. Conclusions. A moderate-to-strong correlation exists between impaired IPS and MRI in mixed MS populations. Correlations with MRI were stronger for SDMT than for PASAT. Neither heterogeneity among populations nor reporting bias appeared to be responsible for these findings.

The progress of cognitive decline in newly diagnosed MS patients

OBJECTIVES

Cognitive impairment occurs in multiple sclerosis already in the early stages of the disease. Less is known about the evolution of cognitive decline, especially in newly diagnosed MS patients. The results of existing studies are contradictory in that both cognitive preservation and progressive deterioration have been reported. The purpose of this study was to examine how cognitive impairment evolves over time in the early stages of MS.

MATERIAL AND METHODS

At baseline, the participants were 36 newly diagnosed MS patients and 37 controls. A group of 30 patients were followed longitudinally at a mean test-retest interval of 6.1 years. The test battery covered attention, information processing, memory and learning, verbal and motor functions and reasoning.

RESULTS

There was a significant decline in divided attention (dual task) and information-processing speed (SDMT) at follow-up, but no significant deterioration in overall cognitive performance.

CONCLUSIONS

Overall cognitive functioning remained quite stable during the 6-year follow-up, whereas divided attention and processing speed deteriorated. However, deterioration in performance on the SDMT and the dual task does not seem to indicate more extensive cognitive deterioration. Given the impact of cognitive impairment on patients' quality of life, early detection of its occurrence in MS is extremely important.

Update on the relationships between neuropsychological dysfunction and structural MRI in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS, characterized by demyelination and neurodegeneration. Besides the sensory and motor deficits that are the hallmark of this disease, approximately 50% of MS patients are cognitively impaired. Over the years, structural neuroimaging has been used widely in MS patients for both diagnostic and research purposes. Various conventional and nonconventional magnetic resonance imaging (MRI) measures have provided important information about the degree and mechanisms of cerebral pathology, and these measures correlate with cognitive and affective disturbances. In this article, recent contributions to the literature regarding the correlation between MRI and neuropsychological function in MS are reviewed.

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.

Cognitive trajectories in 4 patients with pediatric-onset multiple sclerosis: serial evaluation over a decade

Cognitive dysfunction is common in pediatric-onset multiple sclerosis, but long-term data on cognitive maturation in these patients are sparse. We report the clinical features and cognitive trajectories in 4 pediatric-onset multiple sclerosis patients who were 10 years or younger at first attack and were followed between 1998 and 2010. Relapses in all 4 patients were frequent early in the disease and became infrequent or absent over time. Declines on neuropsychological testing were most pronounced on measures of processing speed, specifically visuomotor speed, and executive control requiring mental sequencing and set shifting, whereas global intellectual ability and phonemic fluency remained stable or improved over time. These case studies demonstrate a negative impact of multiple sclerosis on cognitive development in the long term and suggest that continued observation into adulthood is required to appreciate the vocational consequences of pediatric-onset multiple sclerosis.

Risk factors for and management of cognitive dysfunction in multiple sclerosis

Cognitive impairment is common in multiple sclerosis (MS), especially when assessed by neuropsychological tests that emphasize mental processing speed, episodic memory, and some aspects of executive function. In this Review, we question why some MS patients develop severe impairment in cognitive abilities, while cognitive ability remains intact in others. We find that the heterogeneity in neuropsychological presentation among patients with MS reflects the influence of many factors, including genetics, sex, intelligence, disease course, comorbid neuropsychiatric illness, and health behaviors. Neuropsychological deficits are also robustly correlated with brain MRI metrics. Male patients with early evidence of cerebral gray matter atrophy are most prone to impairment, whereas high premorbid intelligence improves the neuropsychological prognosis. Routine evaluation of cognition is useful for helping patients to navigate problems related to activities of daily living and work disability and, if reliable methods are employed, cognitive decline can be detected and included among the many clinical signs of disease progression or treatment failure. Pharmacological treatments for neuropsychological impairment are on the horizon, although presently no firm medical indications exist for the condition.

Relevance of cognitive deterioration in early relapsing-remitting MS: a 3-year follow-up study

OBJECTIVE

To assess longitudinally cognitive functioning in relapsing-remitting multiple sclerosis (RRMS) patients and its relationship with clinical and MRI variables.

METHODS

Early RRMS patients and matched healthy controls were assessed in parallel in three testing sessions over 3 years, using the Rao's Brief Repeatable Battery of Neuropsychological Tests. Patients also underwent an MRI analysis of T2-weighted lesion volume (T2LV), number of gadolinium-enhanced lesions and whole brain atrophy. Forty-nine RRMS patients (mean age 36.9 ± 8.9 years; mean disease duration 2.9 ± 1.7 years, mean Expanded Disability Status Scale, 1.7 ± 0.7) and 56 healthy controls were recruited.

RESULTS

At baseline, cognitive impairment was detected in 15 patients (30.6%). After 3 years, cognitive functioning worsened in the 29.3% of patients, whereas Expanded Disability Status Scale progression was observed in only three patients. The most sensitive test to detect cognitive deterioration over time was the Symbol Digit Modalities Test (SDMT). Only the presence of moderate cognitive impairment at baseline predicted further cognitive deterioration (p = 0.03). Among MRI variables, T2LV showed a weak to moderate relationship with some cognitive tasks.

CONCLUSIONS

Over a 3-year period cognitive deterioration can be expected in approximately one-third of MS patients with relatively short disease duration. The SDMT is particularly suitable for longitudinal assessment of MS-related cognitive changes.

Quality of life in multiple sclerosis: effects of current treatment options

Multiple sclerosis is the most common non-traumatic neurodegenerative disease in adults. Most of the patients present with both physical and mental deficits which reflect the dissemination of the lesions in the central nervous system, produced by the inflammatory process. The incomplete recovery after relapses, the accumulation of new deficits and the progressive nature of the condition interfere with daily activities of individuals and have a negative impact on their well-being. Indeed, studies show that quality of life measurements are constantly lower in patients with multiple sclerosis. Estimation of health-related quality of life is being increasingly recognized as necessary when analysing the effectiveness of treatment modalities and for the follow up of patients with chronic diseases such as multiple sclerosis. Current immunomodulatory interventions that are shown to reduce the frequency of relapses and delay disease progression might also have a positive effect on quality of life measurements. Additive pharmacological agents that target cognitive impairments and common symptoms such as depression, fatigue and pain, along with life-style modifications and rehabilitation programmes are also important for the appropriate management that aims to improve quality of life.

Early cognitive impairment in multiple sclerosis predicts disability outcome several years later

Cognition is frequently impaired in the early stages of multiple sclerosis (MS). The predictive value of cognitive impairment on disability is unknown. The objective of this study was to correlate cognitive impairment and the progression of disability over 7 years. Forty-five patients, recruited after MS diagnosis, were followed for 7 years by yearly Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Functional Composite (MSFC) evaluations and were classified as cognitively impaired (CI) or unimpaired (CU) according to neuropsychological testing at baseline. At baseline, 47.8% of patients were CI, with deficits in mainly memory and information processing speed (IPS). The baseline EDSS correlated significantly with one IPS test. The EDSS, but not the MSFC, deteriorated significantly over the 7 years in the whole group and the CI group, but not the CU group. A multivariate analysis showed correlations between the EDSS change over 5 and 7 years and two baseline tests evaluating IPS and verbal memory. The deterioration of the EDSS after 7 years was significantly correlated with verbal memory testing at baseline after adjustment for age and baseline EDSS. In conclusion, in this sample of MS patients early in the disease, the baseline IPS and verbal memory impairments predict the EDSS score 5 and 7 years later.

Cognitive dysfunction in primary progressive multiple sclerosis: a neuropsychological and MRI study

Although cognitive dysfunction is known to occur in multiple sclerosis (MS), only few studies have reported cognitive performance in patients with primary progressive MS (PPMS). To find out the pattern of cognitive performance in PPMS, 28 PPMS patients underwent an extensive battery of neuropsychological tests. The results were compared to those of healthy controls ( n = 20) and patients with secondary progressive MS (SPMS, n = 28). Furthermore, the results of neuropsychological tests in PPMS were correlated to magnetic resonance imaging findings. Our study showed that the PPMS patients have deficits in several cognitive domains when compared to age-matched and education-matched controls, but the cognitive impairment in the PPMS and SPMS patients appeared to be similar. Cognitive deficits in PPMS patients correlated with diffuse brain lesion, T1- and T2-lesion load, but no correlations were found with atrophy.

[Cognitive impairment]

Cognitive impairment is common in multiple sclerosis (MS), occurring at all stages of the disease, even at the earliest, and can be a major source of disability, social impairment, and impoverished quality of life. Cognitive dysfunction is mainly focused on working memory, conceptual reasoning, verbal fluency, speed of information processing, attention and executive function. Measures of information-processing speed appear to be the most robust and sensitive markers of cognitive impairment in MS patients. Cognitive testing in MS patients is complex and cognitive screening tests are time- and cost-saving test instruments. A comprehensive and sensitive cognitive test procedure should be administered to detect cognitive dysfunction, and recent studies demonstrate that single, predominantly speed-related cognitive tests may be superior to extensive and time-consuming test batteries in screening cognitive decline. Additional clinical factors, including disease course, fatigue, and affective disturbance, can impact the degree of MS-related cognitive impairment. Despite weak correlation with disease duration and physical disability status, the degree of cognitive impairment in MS has been related to the extent of topographically specific neuronal tissue damage and loss. Numerous studies have applied conventional and quantitative magnetic resonance imaging (MRI) techniques to correlate the profile and degree of cognitive impairment with various MRI-detectable abnormalities. The burden of MRI-visible lesions does not fully account for the degree of MS-related cognitive impairment. Nonconventional MRI findings suggest the extent of subtle tissue damage in normal-appearing white and grey matter to correlate best with the severity of cognitive impairment in MS patients. Structural MRI approaches have recently been extended by functional MRI studies scrutinizing the brain's ability for adaptive functional reorganization in the presence of widespread tissue damage. Cognitive impairment in MS seems to be not simply the result of tissue destruction, but also a balance between tissue destruction, tissue repair, and adaptive functional reorganization. These findings highlight the need to screen for cognitive deficits in MS patients to conduct potential cognitive rehabilitation intervention.

Cognitive reserve protects against cognitive dysfunction in multiple sclerosis

Cognitive reserve theory helps to explain the neuropsychological expression of neurologic disease (e.g., Alzheimer's disease; Stern, 2006). Multiple sclerosis (MS) is a neurologic disease characterized by information processing inefficiency and verbal learning and memory deficits. The current study is the first to investigate whether higher cognitive reserve moderates the relationship between MS and cognitive functioning. A word-reading proxy of premorbid intelligence was used to estimate cognitive reserve for 58 persons with MS and 43 healthy controls. Dependent measures of simple processing efficiency, complex information processing efficiency, and verbal learning and memory were administered. There were significant Group x Cognitive Reserve interactions for complex information processing efficiency and verbal learning and memory, such that persons with MS demonstrated deficits relative to controls at lower, but not higher, levels of reserve. No such interaction was found for simple processing efficiency. The protective influence of higher cognitive reserve against disease-related cognitive deficits is discussed.

Cognitive impairment in multiple sclerosis

Multiple sclerosis (MS) is a progressive disease of the CNS that is characterised by widespread lesions in the brain and spinal cord. MS results in motor, cognitive, and neuropsychiatric symptoms, all of which can occur independently of one another. The common cognitive symptoms include deficits in complex attention, efficiency of information processing, executive functioning, processing speed, and long-term memory. These deficits detrimentally affect many aspects of daily life, such as the ability to run a household, participate fully in society, and maintain employment--factors that can all affect the overall quality of life of the patient. The increased use of neuroimaging techniques in patients with MS has advanced our understanding of structural and functional changes in the brain that are characteristic of this disease, although much remains to be learned. Moreover, examination of efforts to treat the cognitive deficits in MS is still in the early stages.

Evaluating sub-clinical cognitive dysfunction and event-related potentials (P300) in clinically isolated syndrome

OBJECTIVE

This study investigated the presence of sub-clinical cognitive dysfunction in patients with clinically isolated syndrome (CIS) and the abnormalities of cognitive event-related potentials (ERPs).

METHODS

Subclinical cognitive dysfunction was assessed in 20 patients with CIS and in 20 healthy controls.

RESULTS

Patients had impairments in verbal learning and long-term memory, evaluating attention, executive function and visuospatial skills, in decreasing order of frequency. SDLT and SIT were the most, and COWAT and BNT were the least affected tests. The N200 and P200 latencies were prolonged, and N100, N200 and P200 amplitudes were reduced in the patients relative to the controls, from the Fz, Cz and Pz electrode positions (p<0.05).

CONCLUSION

Detailed cognitive testing is valuable in determining subclinical cognitive dysfunction in CIS patients. ERP abnormalities as well as abnormalities in detailed cognitivetesting in patients with CIS are helpful in the diagnosis of sub-clinical cognitive dysfunction.

Stroop performance in multiple sclerosis: information processing, selective attention, or executive functioning?

Cognitive impairments in information processing speed, attention and executive functioning are widely reported in patients with multiple sclerosis (MS). Several studies have identified impaired performance on the Stroop test in people with MS, yet uncertainty remains over the cause of this phenomenon. In this study, 25 patients with MS were assessed with a neuropsychological test battery including a computerized Stroop test and a computerized test of information processing speed, the Graded Conditional Discrimination Tasks (GCDT). The patient group was compared with an individually age, sex and estimated premorbid IQ-matched healthy control group. The patients' reaction times (RTs) were significantly longer than those of the controls on all Stroop test trials and there was a significantly enhanced absolute (RT(incongruent)-RT(neutral)) and relative (100 x [RT(incongruent)-RT(neutral)]/RT(neutral)) Stroop interference effect for the MS group. The linear function relating RT to stimulus complexity in the GCDT was significantly steeper in the patient group, indicating slowed information processing. The results are discussed with reference to the difference engine model, a theory of diversity in speeded cognition. It is concluded that, in the assessment of people with MS, great caution must be used in the interpretation of performance on neuropsychological tests which rely on RT as the primary measure.

Should SDMT substitute for PASAT in MSFC? A 5-year longitudinal study

BACKGROUND

The multiple sclerosis functional composite (MSFC) includes the Paced Auditory Serial Addition test (PASAT) as a measure of cognition.

OBJECTIVES AND METHODS

We compared the MSFC incorporating the Symbol Digit Modalities test (SDMT) (MSFC [sdmt]) to the usually applied MSFC (MSFC [pasat]) in a sample of 46 ptients with relapsing-remitting MS who were followed over a five-year period. Magnetic resonance imaging was performed at baseline.

RESULTS

The Expanded Disability Status scale (EDSS) deteriorated significantly over 5 years (P < 0.01), but MSFC scores remained stable. MSFC [sdmt] correlated with EDSS at all time points of evaluation, but MSFC [pasat] correlated with EDSS only at baseline, 1, and 5 years. The 5-year EDSS correlated significantly with baseline MSFC [sdmt] and MSFC [pasat] but did not correlate after adjustment for baseline EDSS. No significant correlation was found at baseline between MSFC and imaging parameters (lesion load, brain parenchymal fraction [BPF], ventricular fraction, mean magnetization transfer ratio of lesions and normal-appearing brain tissue), but baseline BPF correlated significantly with changes of SDMT z score (P = 0.0003), MSFC [pasat] (P = 0.006), and MSFC [sdmt] (P = 0.0002) over 5 years.

CONCLUSION

We propose not to substitute PASAT by SDMT in the MSFC but to consider SDMT as a complementary useful approach to evaluate overall MS disease.

Segmentation of subtraction images for the measurement of lesion change in multiple sclerosis

BACKGROUND AND PURPOSE

Lesion volume change (LVC) assessment is essential in monitoring MS progression. LVC is usually measured by independently segmenting serial MR imaging examinations. Subtraction imaging has been proposed for improved visualization and characterization of lesion change. We compare segmentation of subtraction images (SSEG) with serial single time-point conventional segmentation (CSEG) by assessing the LVC relationship to brain atrophy and disease duration, as well as scan-rescan reproducibility and annual rates of lesion accrual.

MATERIALS AND METHODS

Pairs of scans were acquired 1.5 to 4.7 years apart in 21 patients with multiple sclerosis (MS). Scan-rescan MR images were acquired within 30 minutes in 10 patients with MS. LVC was measured with CSEG and SSEG after coregistration and normalization. Coefficient of variation (COV) and Bland-Altman analyses estimated method reproducibility. Spearman rank correlations probed associations between LVC and other measures.

RESULTS

Atrophy rate and net LVC were associated for SSEG (R = -0.446; P < .05) but not when using CSEG (R = -0.180; P = .421). Disease duration did not show an association with net lesion volume change per year measured by CSEG (R = -0.360; P = .11) but showed an inverse correlation with SSEG-derived measurements (R = -0.508; P < .05). Scan-rescan COV was lower for SSEG (0.98% +/- 1.55%) than for CSEG (8.64% +/- 9.91%).

CONCLUSION

SSEG unveiled a relationship between T2 LVC and concomitant brain atrophy and demonstrated significantly higher measurement reproducibility. SSEG, a promising tool providing detailed analysis of subtle alterations in lesion size and intensity, may provide critical outcome measures for clinical trials of novel treatments, and may provide further insight into progression patterns in MS.