Cognitive changes in early MS: A call for a common framework

Sensitivity of conventional cognitive tests in multiple sclerosis: Application of item response theory

BACKGROUND

Cognitive impairment (CI) is common in Multiple Sclerosis (MS), and its prevalence rate ranges between 22% and 70%. Because CI significantly impacts vocational status, caregiver burden, and quality of life, an accurate neuropsychological assessment is required. Three widely used and validated batteries for MS-associated CI are the Brief Repeatable Neuropsychological Battery (BRN-B), the Minimal Assessment of Cognitive Function (MACFIMS), and the Brief International Cognitive Assessment (BICAMS). Although similar, these batteries differ in time-consuming and in specific tests employed. This study aims to assess the sensitivity of cognitive tests included in these batteries through an Item Response Theory approach.

METHODS

Ninety-seven patients with MS and 91 demographically matched controls (HC) were consecutively assessed using the three neuropsychological batteries (i.e., BRN-B, MACFIMS, and BICAMS). Continuous Response Model (CRM) was used to identify the cognitive test(s) that best discriminate patients with MS from HC. Receiver Operating Characteristic (ROC) curve analysis was used to determine the accuracy of the CRM results.

RESULTS

Cognitive tests loaded on two different latent variables: the 'higher-order executive functioning,' consisting of tests assessing concept formation, problem-solving, and inhibitory control, and the 'memory and information processing speed,' comprising tests assessing long-term, working memory, and information processing speed. The Delis Kaplan Executive Functioning System-Sorting Test and the Stroop Test were the most sensitive tests in differentiating cognitive functioning between MS and HC.

CONCLUSIONS

This study confirms the importance of including a more extensive executive assessment in MS clinical practice since higher-order executive functions (e.g., abstraction and inhibitory control) significantly impact patients' quality of life and functional autonomy. Clinical implications of careful dissection of executive functioning in MS neuropsychological assessment are discussed.

Cognitive Performance of Patients With Multiple Sclerosis and Optic Neuritis at Presentation

BACKGROUND

Cognitive dysfunction is common among patients with multiple sclerosis (MS), but the effect of coexisting optic neuritis (ON) at the first presentation of multiple sclerosis on the course of cognitive decline is unknown. The purpose of this study was to assess whether ON at presentation has any effect on the progression of cognitive decline in MS.

METHODS

Historical cohort study. We retrospectively compared the cognitive performance of patients with relapsing-remitting MS with and without ON at the time of MS diagnosis. Subjects were included if cognitive test results were available both at baseline and after at least 36 months from presentation and grouped based on the presence (MS-ON) or absence (MS-non-ON) of optic neuritis at presentation.

RESULTS

One hundred seventy consecutive subjects with MS were found suitable, with a 1:2 male:female ratio and a mean age at diagnosis of 33.0 ± 10.9 years. Forty-six patients (27.1%) presented with ON. No significant differences were found in cognitive performance at onset between the 2 groups. Both groups had a similar follow-up duration. The prevalence of cognitive decline in the general score was significantly higher in the MS-ON group compared with the MS-non-ON group (6.5% vs 0%, respectively; P < 0.001), as well as in the attention (8.7% vs 1.6%; P = 0.046) and the executive function (17.4% vs 2.4%; P = 0.001) domains.

CONCLUSIONS

Optic neuritis at presentation of MS is associated with a higher prevalence of cognitive decline over time. Potential benefit of early intervention to prevent cognitive decline may be warranted.

Optical Coherence Tomography Is Associated With Cognitive Impairment in Multiple Sclerosis

BACKGROUND

Optical coherence tomography (OCT) is a sensitive method for quantifying retinal neuronal and axonal structures. Reductions in retinal nerve fiber layer (RNFL) and ganglion cell inner plexiform layer (GCIPL) thicknesses have a reported association with white and grey matter atrophy in multiple sclerosis (MS). We hypothesized that the thinning of intraretinal layer measurements associates with cognitive decline in MS patients with no prior event of optic neuritis (ON).

METHODS

OCT and NeuroTrax computerized cognitive assessments were performed in 204 relapsing remitting MS patients with no history of ON or other conditions affecting the eye. Data were collected between 2010 and 2020 and retrospectively analyzed. Correlations were examined between cognitive performance and a lower RNFL or GCIPL thickness. A multilinear regression model was generated to assess the significance of these correlations regarding the disability score and disease duration.

RESULTS

The 204 study participants had a mean age of 40.52 ± 11.8 years (mean ± SD) and disease duration of 9.80 ± 9.40 years. The mean RNFL thickness in this whole cohort was 82.22 ± 10.85 μm and the global cognitive score was 95.32 ± 12.32. The mean GCIPL thickness measured in a subgroup of 104 patients was 74.27 ± 10.37 μm. The RNFL and GCIPL both correlated with the global cognitive score (r = 0.174, P = 0.013 and r = 0.29, P = 0.03, respectively), and with various cognitive domains. However, the GCIPL showed stronger correlations than RNFL, particularly with executive function (r = 0.29, P = 0.003), attention (r = 0.332, P = 0.001), and the information processing speed (r = 0.25, P = 0.012). These correlations remained significant after correcting for confounders.

CONCLUSION

OCT measurements correlate with cognitive performance in MS patients. OCT can thus be used to evaluate central nervous system neurodegeneration in MS, as reflected by cognitive decline.

Targeted cognitive game training enhances cognitive performance in multiple sclerosis patients treated with interferon beta 1-a

Background

Prevention of cognitive decline in Multiple Sclerosis (MS) is of major importance. We explored the effect of a 6 months computerized game training program on cognitive performance in MS patients with mild cognitive impairment.

Methods

This was a single-center, randomized prospective study. We enrolled in this study 100 eligible MS patients treated with Interferon-beta-1a (Rebif). All had mild cognitive impairment in either executive function or information processing speed. Patients were randomized 1:1 to either use the cognitive games platform by HappyNeuron (HN) or receive no intervention. Executive function and information processing speed scores were measured at 3 and 6 months from baseline to evaluate the effect of game training on cognitive scores.

Results

In both executive function and information processing speed, the game Training group showed significant improvement after 3 and 6 months. The Non-Training group showed mild deterioration in both domains at 3 months, and further deterioration that became significant at 6 months in executive function. Furthermore, at 6 months, the percent of patients in the Training group that improved or remained stable in both cognitive domains was significantly higher compared to the Non-Training group.

Conclusions

Our findings suggest that cognitive game training has a beneficial effect on cognitive performance in MS patients suffering from mild cognitive impairment. While further evaluation is required to assess the longevity of that effect, we nonetheless recommend to MS patients to be engaged in cognitive gaming practice as part of a holistic approach to treating their condition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00968-3.

Comprehensive Approach to Management of Multiple Sclerosis: Addressing Invisible Symptoms-A Narrative Review

Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease of the central nervous system, leading to neurodegeneration and manifesting as a variety of symptoms. These can include "invisible" symptoms, not externally evident to others, such as fatigue, mood disorders, cognitive impairments, pain, bladder/bowel dysfunction, sexual dysfunction, and vision changes. Invisible symptoms are highly prevalent in people living with MS, with multifactorial etiology and potential to impact the disease course. Patient experiences of these symptoms include both physical and psychosocial elements, which when unaddressed negatively influence many aspects of quality of life and perception of health. Despite the high impact on patient lives, gaps persist in awareness and management of these hidden symptoms. The healthcare provider and patient author experiences brought together here serve to raise the profile of invisible symptoms and review strategies for a team-based approach to comprehensive MS care. We summarize the current literature regarding the prevalence and etiology of invisible symptoms to convey the high likelihood that a person living with MS will contend with one or more of these concerns. We then explore how open communication between people living with MS and their care team, stigma mitigation, and shared decision-making are key to comprehensive management of invisible symptoms. We recommend validated screening tools and technological advancements that may be incorporated into MS care to regularly monitor these symptoms, offering insight into how healthcare providers can both educate and listen to patients, with the goal of improved patient quality of life. By pairing clinical knowledge with an understanding and consideration of the patient perspective, providers will be equipped to foster a patient-centered dialogue that encourages shared decision-making. Invisible symptoms of MS.

Cognitive Dysfunction in the Early Stages of Multiple Sclerosis-How Much and How Important?

Purpose of Review

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that mainly affects young adults and that is one of the leading causes of disability in this age group, with cognitive impairment occurring early in the course of the disease. This article summarizes the current knowledge about cognitive dysfunction in the early phase of MS, including biomarkers, MRI correlates, and its value as a prognostic marker.

Recent Findings

New sets of neuropsychological tests have been established to screen for cognitive dysfunction more easily and accurately. Moreover, structural changes detected by brain MRI and several biomarkers found in cerebrospinal fluid and blood serum have been recently correlated with decreased cognitive performance. Additionally, factors influencing cognition in MS, such as disease-modifying therapy, mood disorders, and lifestyle, are better described.

Summary

Cognitive impairment early in the course of MS is suggested as a prognostic factor for disease progression. However, clear-cut definitions of the early stage of MS as well as unified criteria for the diagnosis of cognitive impairment are still lacking. New and more reliable tools for evaluating cognition in MS patients should be developed and introduced into everyday practice to facilitate the implementation of effective disease-modifying therapy, cognitive rehabilitation, and lifestyle management.

The therapeutic effect of treatment with RehaCom software on verbal performance in patients with multiple sclerosis

Multiple sclerosis (MS) is characterized by central nervous system lesions that lead to neurological dysfunctions including fatigue, depression and anxiety. MS is affecting almost 2.3 million people around the world, with the significant highest prevalence in the North America. MS also affects different cognitive abilities, such as attention, memory and executive functions. Furthermore, a significant impairment in verbal fluency and naming abilities in patients with MS has been reported. RehaCom, is a software that has improvement effects on cognitive functions. The goal of this research is to investigate the effect of treatment with RehaCom on verbal performance in patients with MS. To select the participants, 60 patients with MS who referred to our clinic were chosen randomly and divided into Control (n = 30) and Experimental (n = 30) groups. The participants in the experimental group were treated by RehaCom software for 10 sessions during 5 weeks (2 sessions per week and each session was 1 h). Controlled Oral Word Association Test (COWAT) and California Verbal Learning Test - Second Edition (CVLT-II), were used to assess verbal performance (verbal fluency, and verbal learning and memory) at weeks 0 (baseline), 5 (post-test) and 10 (follow-up). The results showed that, treatment with RehaCom improved verbal performance in patient with MS, at both post-test and follow-up stages. In conclusion, treatment with RehaCom cognitive rehabilitation software can improve verbal fluency, and verbal learning and memory in patient with MS, possibly by affecting the brain regions involved in language performance.

Second language learning induces grey matter volume increase in people with multiple sclerosis

Background

Grey matter volume (GMV) decline is a frequent finding in multiple sclerosis (MS), the most common chronic neurological disease in young adults. Increases of GMV were detected in language related brain regions following second language (L2) learning in healthy adults. Effects of L2 learning in people with MS (pwMS) have not been investigated so far.

Methods

This study prospectively evaluated the potential of an eight-week L2 training on grey matter plasticity measured by 3T-MRI, L2 proficiency and health-related quality of life (HRQoL) in people with relapsing-remitting MS (pwMS, n = 11) and healthy, sex- and age-matched controls (HCs; n = 12).

Results

Categorical voxel-based analysis revealed significantly less GMV bilaterally of the insula extending to the temporal pole in pwMS at baseline. Following L2 training, significant increases of GMV were evident in the right hippocampus, parahippocampus and putamen of pwMS and in the left insula of HCs. L2 training resulted in significant improvements of listening comprehension, speaking fluency and vocabulary knowledge in both pwMS and HCs. GMV increases of right hippocampus and parahippocampus significantly correlated with vocabulary knowledge gain and L2 learning was associated with a significant increase of HRQoL in pwMS.

Conclusion

Our findings demonstrate distinct patterns of GMV increases of language related brain regions in pwMS and HCs and indicate disease-related compensatory cortical and subcortical plasticity to acquire L2 proficiency in pwMS.

Cognitive function in multiple sclerosis: A long-term look on the bright side

Background

Multiple sclerosis (MS) may lead to cognitive decline over-time.

Objectives

Characterize cognitive performance in MS patients with long disease duration treated with disease modifying drugs (DMD) in relation to disability and determine the prevalence of cognitive resilience.

Methods

Cognitive and functional outcomes were assessed in 1010 DMD-treated MS patients at least 10 years from onset. Cognitive performance was categorized as high, moderate or low, and neurological disability was classified according to the Expanded Disability Status Scale (EDSS) as mild, moderate or severe. Relationship between cognitive performance and disability was examined.

Results

After a mean disease duration of 19.6 (SD = 7.7) years, low cognitive performance was observed in 23.7% (N = 239), moderate performance in 42.7% (N = 431), and 33.7% (N = 340) had high cognitive performance, meeting the definition of cognitively resilient patients. Within the group of patients with low cognitive performance, severe disability was observed in 50.6% (121/239), while in the group of patients with high cognitive performance, mild disability was observed in 64.4% (219/340). Differences between the group of patients with high cognitive performance and severe disability (4.5%) and the group of patients with low cognitive performance and mild disability (5.0%) were not accounted for by DMD treatment duration.

Conclusions

The majority of DMD treated MS patients did not have cognitive decline that could impair their quality of life after disease of extended duration.

Association Between White Matter Microstructure and Verbal Fluency in Patients With Multiple Sclerosis

Verbal fluency refers to the ability to generate words quickly and efficiently according to predefined phonological or semantic criteria. Deficits in verbal fluency limit patients’ ability to communicate effectively and to function well in social setups. Multiple sclerosis (MS) patients suffer from various cognitive impairments, and some of them experience language deficits as well. The goal of this study is to examine the contribution of the dorsal and ventral language pathways to verbal fluency in MS patients. All patients (N = 33) underwent diffusion MRI (dMRI) and fluency measurements. Diffusion parameters were calculated along dorsal and ventral language-related pathways and their right-hemispheric homologs, identified individually in each patient. Significant correlations were found between fluency measures and mean fractional anisotropy (FA) in several pathways, including the left fronto-temporal arcuate fasciculus (AF_ft), bilateral inferior fronto-occipital fasciculus (IFOF), and bilateral frontal aslant tract. Along-tract correlations revealed a more selective pattern of associations: letter-based fluency was associated with FA in a segment of the left AF_ft (dorsal pathway), while category-based fluency was associated with FA in a segment of the right IFOF (ventral pathway). The observed pattern of associations, mapping letter-based fluency to the dorsal stream and category-based fluency to the ventral stream, fits well within the dual stream framework of language processing. Further studies will be necessary to assess whether these associations generalize to the typical adult population or whether they are tied to the clinical state.

Learning ability correlates with brain atrophy and disability progression in RRMS

OBJECTIVE

To assess the prognostic value of practice effect on Paced Auditory Serial Addition Test (PASAT) in multiple sclerosis.

METHODS

We compared screening (day -14) and baseline (day 0) PASAT scores of 1009 patients from the FTY720 Research Evaluating Effects of Daily Oral therapy in Multiple Sclerosis (FREEDOMS) trial. We grouped patients into high and low learners if their PASAT score change was above or below the median change in their screening PASAT quartile group. We used Wilcoxon test to compare baseline disease characteristics between high and low learners, and multiple regression models to assess the respective impact of learning ability, baseline normalised brain volume and treatment on brain volume loss and 6-month confirmed disability progression over 2 years.

RESULTS

The mean PASAT score at screening was 45.38, increasing on average by 3.18 from day -14 to day 0. High learners were younger (p=0.003), had lower Expanded Disability Status Scale score (p=0.031), higher brain volume (p<0.001) and lower T2 lesion volume (p=0.009) at baseline. Learning status was not significantly associated with disability progression (HR=0.953, p=0.779), when adjusting for baseline normalised brain volume, screening PASAT score and treatment arm. However, the effect of fingolimod on disability progression was more pronounced in high learners (HR=0.396, p<0.001) than in low learners (HR=0.798, p=0.351; p for interaction=0.05). Brain volume loss at month 24 tended to be higher in low learners (0.17%, p=0.058), after adjusting for the same covariates.

CONCLUSIONS

Short-term practice effects on PASAT are related to brain volume, disease severity and age and have clinically meaningful prognostic implications. High learners benefited more from fingolimod treatment.

Monitoring cognitive change in multiple sclerosis using a computerized cognitive battery

Background

Cognitive monitoring that can detect short-term change in multiple sclerosis is challenging. Computerized cognitive batteries such as the CogState Brief Battery can rapidly assess commonly affected cognitive domains.

Objectives

The purpose of this study was to establish the acceptability and sensitivity of the CogState Brief Battery in multiple sclerosis patients compared to controls. We compared the sensitivity of the CogState Brief Battery to that of the Paced Auditory Serial Addition Test over 12 months.

Methods

Demographics, Expanded Disability Status Scale scores, depression and anxiety scores were compared with CogState Brief Battery and Paced Auditory Serial Addition Test performances of 51 patients with relapsing-remitting multiple sclerosis, 19 with secondary progressive multiple sclerosis and 40 healthy controls. Longitudinal data in 37 relapsing-remitting multiple sclerosis patients were evaluated using linear mixed models.

Results

Both the CogState Brief Battery and the Paced Auditory Serial Addition Test discriminated between multiple sclerosis and healthy controls at baseline (p<0.001). CogState Brief Battery tasks were more acceptable and caused less anxiety than the Paced Auditory Serial Addition Test (p<0.001). In relapsing-remitting multiple sclerosis patients, reaction time slowed over 12 months (p<0.001) for the CogState Brief Battery Detection (mean change -34.23 ms) and Identification (-25.31 ms) tasks. Paced Auditory Serial Addition Test scores did not change over this time.

Conclusions

The CogState Brief Battery is highly acceptable and better able to detect cognitive change than the Paced Auditory Serial Addition Test. The CogState Brief Battery could potentially be used as a practical cognitive monitoring tool in the multiple sclerosis clinic setting.

Cognitive Impairment in Multiple Sclerosis: A Review of Neuropsychological Assessments

Of the more than two million people worldwide with multiple sclerosis, 40% to 65% experience cognitive impairment, many of them early in the course of the disease. Cognitive impairment has been found in patients with all subtypes of multiple sclerosis. Because both pharmacologic and nonpharmacologic interventions may improve patients' brain function, cognitive assessment should be a routine part of the clinical evaluation. Traditional paper-and-pencil neuropsychological tests and batteries can help detect and monitor patients' cognitive problems. Computerized cognitive batteries also show promise. Controversy continues over which test is most reliable at assessing cognitive impairment in both everyday clinical practice and research. Each battery has possible disadvantages, such as practice effects, poor sensitivity and specificity, and questionable applicability to multiple sclerosis. Based on our review of the literature, we describe the tests that are currently being used or that might be used in assessing cognitive deficits in patients with multiple sclerosis, and we summarize the strengths and limitations of each.

Neurobehavioral burden of multiple sclerosis with nanotheranostics

Multiple sclerosis (MS) is a chronic demyelinating neurological disorder affecting people worldwide; women are affected more than men. MS results in serious neurological deficits along with behavioral compromise, the mechanisms of which still remain unclear. Behavioral disturbances such as depression, anxiety, cognitive impairment, psychosis, euphoria, sleep disturbances, and fatigue affect the quality of life in MS patients. Among these, depression and psychosis are more common than any other neurological disorders. In addition, depression is associated with other comorbidities. Although anxiety is often misdiagnosed in MS patients, it can induce suicidal ideation if it coexists with depression. An interrelation between sleep abnormalities and fatigue is also reported among MS patients. In addition, therapeutics for MS is always a challenge because of the presence of the blood-brain barrier, adding to the lack of detailed understanding of the disease pathology. In this review, we tried to summarize various behavioral pathologies and their association with MS, followed by its conventional treatment and nanotheranostics.

Reduced information processing speed as primum movens for cognitive decline in MS

Background:

Cognitive impairment affects half of the multiple sclerosis (MS) patient population and is an important contributor to patients’ daily activities. Most cognitive impairment studies in MS are, however, cross-sectional or/and focused on the early disease stages.

Objective:

We aim to assess the time course of decline of different cognitive domains.

Methods:

We collected neuropsychological data on 514 MS patients to construct Kaplan-Meier survival curves of the tests included in the Neuropsychological Screening Battery for MS (NSBMS) and the Symbol Digit Modalities Test (SDMT). Cox-proportional hazard models were constructed to examine the influence of MS onset type, age at onset, gender, depression and level of education on the time course, expressed as age or disease.

Results:

Survival curves of tests focusing on information processing speed (IPS) declined significantly faster than tests with less specific demands of IPS. Median age for pathological decline was 56.2 years (95% CI: 54.4–58.2) on the SDMT and 63.9 years (95% CI: 60–66.9) on the CLTR, a memory task.

Conclusion:

In conclusion, IPS is the cognitive domain not only most widely affected by MS but it is also the first cognitive deficit to emerge in MS.

Thalamic atrophy and cognitive impairment in clinically isolated syndrome and multiple sclerosis

BACKGROUND

Cognitive deficits worsen the quality of life in multiple sclerosis and may be predicted by deep gray matter atrophy, especially thalamic atrophy. This relationship has not been studied in the clinically isolated syndrome (CIS). The aims of this study were to assess cognitive deficits in patients with CIS and relapsing-remitting multiple sclerosis (RRMS) using neuropsychological testing, to search for thalamic atrophy on brain MRI, and to test for their correlations.

METHODS

Forty-three patients (19 with CIS and 24 with RRMS) underwent brain MRI and neuropsychological testing involving multiple cognitive domains and the severity of depression. Thalamic volumes automatically segmented from MRI data were compared to 19 healthy controls. Correlations were sought between cognitive performance and thalamic volume.

RESULTS

Cognitive impairment was detected in the majority of both CIS and MS patients, most affected in executive functions, auditory memory, lexical verbal fluency, distribution of attention and psychomotor speed. Cognitive impairment and depression were not significantly correlated to disease duration. Both CIS and MS patients demonstrated thalamic atrophy compared to controls, while many cognitive deficits correlated with thalamic volume in both patient groups.

CONCLUSION

Cognitive deficits in CIS resemble those found in the later stages of MS and may be directly related to the amount of thalamic damage.

Reduced magnetisation transfer ratio in cognitively impaired patients at the very early stage of multiple sclerosis: a prospective, multicenter, cross-sectional study

OBJECTIVES

Cognitive impairment belongs to the core symptoms in multiple sclerosis (MS) and can already be present at the very early stages of the disease. The present study evaluated cognitive functioning after the first clinical presentation suggestive of MS and brain tissue damage in a non-lesion focused MRI approach by using magnetisation transfer imaging (MTI).

SETTING AND PARTICIPANTS

47 patients (15 men and 32 women; mean age: 31.17 years) after the first clinical event suggestive of MS were recruited in six different MS centres in Germany and underwent a neuropsychological test battery including tests for attention, memory and executive function as well as depression and fatigue. MTI and conventional MRI measures (T1/T2 lesion load) were assessed. In addition, Magnetisation Transfer Ratio (MTR) maps were calculated. Primary outcome measure was the investigation of cognitive dysfunction in very early MS in correlation to MRI data.

RESULTS

55.3% of patients with MS failed at least one test parameter. Specifically, 6% were reduced in working memory, 14.9% in focused attention, 25.5% in figural learning and up to 14.9% in executive function. When the sample was subdivided into cognitively impaired and preserved, MTR scores within the cognitively impaired subgroup were significantly lower compared with the preserved group (t(43)=2.346, p=0.02*). No significant differences between the two groups were found in T2-weighted and T1-weighted lesion volume.

CONCLUSIONS

After the first MS-related clinical event, 55.3% of patients showed distinct cognitive deficits. Cognitively impaired patients had significantly lower whole brain MTR, but no differences in focal brain lesion volumes supporting the idea that early cognitive deficits may be related to diffuse loss of brain tissue integrity.

Quantification of relevance of quality of life assessment for patients with cognitive impairment: the suitability indices

Background

The extent to which MS patients with cognitive dysfunction can accurately self-report outcomes has been a crucial issue. The aim of this study was to quantify and compare the relevance of the quality of life (QoL) assessment between two populations with a high occurrence of cognitive dysfunction, specifically in individuals with multiple sclerosis (MS) and in individuals suffering from schizophrenia (SCZ).

Methods

Design: A cross-sectional study was performed using the following inclusion criteria: MS and SCZ patients were diagnosed according to the McDonald criteria and DSM-IV criteria, respectively. Data on sociodemographic (age, gender, education level) and clinical (disease severity, disease duration) factors, QoL (disease-specific questionnaires, MusiQoL and SQoL) and cognitive performance (executive, memory, and attention functions) were collected. Non-impaired and impaired populations were defined according to the French norms. Psychometric properties were compared to those reported in reference populations, which were assessed in the respective validation studies. Suitability indices were provided used to quantitatively compare how the structures in the different populations matched with the initial structure of the questionnaires (reference populations).

Results

One hundred and twenty-four MS patients and 113 SCZ patients were enrolled. Factor analysis was performed on the impaired populations and revealed that the questionnaire structure adequately matched the initial structure of the disease-specific QoL questionnaires. All of the suitability indices of construct and external validity in the non-impaired populations ranged from 70 to 100%.

Conclusions

Our study suggested that cognitive dysfunction did not compromise the reliability or validity of the self-reported QoL questionnaires among subjects with cognitive dysfunction, such as MS and SCZ. Thus, this report may clarify the relevance of using self-reported QoL assessments in clinical practice.

Structural correlates of subjective and objective memory performance in multiple sclerosis

Subjective and objective memory deficits represent a frequent and ill-understood aspect of multiple sclerosis (MS), and a significant cause of disability and quality of life reduction. The aim of the study is to verify the role of hippocampal and temporal associative fibers' damage in MS-related memory complaints. To reach this aim, 25 patients with low disability relapsing-remitting MS and 19 healthy controls were included in the study. All subjects underwent 3D T1 structural imaging and Diffusion Tensor Imaging. Additionally, MS patients underwent neuropsychological evaluation of objective (Selective Reminding Test and Spatial Recall Test) and of subjective (Perceived Deficit Questionnaire, Retrospective and Prospective Memory Subscales) memory deficits. Normalized hippocampal volume (NHV) and mean Fractional Anisotropy (FA) for the uncinate fasciculus (UF) and for the ventral division of the cingulum bundle (VCB) were calculated for all subjects. We showed that, compared to controls, MS subjects presented with reduced right NHV and with reduced mean FA bilaterally in the UF and the VCB. In the MS group, verbal memory scores correlated with left NHV, spatial memory scores correlated with right NHV, while perceived retrospective and prospective memory deficits correlated with left VCB and left UF mean FA respectively. Our data confirm an early involvement of memory-related brain structures in MS patients. Our data suggest that verbal and nonverbal memory as well as perceived retrospective and prospective memory deficits are related to alterations of discrete anatomical structures in the low-disability phase of MS.

Modeling of cognitive impairment by disease duration in multiple sclerosis: a cross-sectional study

BACKGROUND/AIMS

Large-scale population studies measuring rates and dynamics of cognitive decline in multiple sclerosis (MS) are lacking. In the current cross-sectional study we evaluated the patterns of cognitive impairment in MS patients with disease duration of up to 30 years.

METHODS

1,500 patients with MS were assessed by a computerized cognitive battery measuring verbal and non-verbal memory, executive function, visual spatial perception, verbal function, attention, information processing speed and motor skills. Cognitive impairment was defined as below one standard deviation (SD) and severe cognitive impairment as below 2SD for age and education matched healthy population norms.

RESULTS

Cognitive performance in our cohort was poorer than healthy population norms. The most frequently impaired domains were information processing speed and executive function. MS patients with secondary-progressive disease course performed poorly compared with clinically isolated syndrome, relapsing-remitting and primary progressive MS patients. By the fifth year from disease onset, 20.9% of patients performed below the 1SD cutoff for impairment, p=0.005, and 6.0% performed below the 2SD cutoff for severe cognitive impairment, p=0.002. By 10 years from onset 29.3% and 9.0% of patients performed below the 1SD and 2SD cutoffs, respectively, p=0.0001. Regression modeling suggested that cognitive impairment may precede MS onset by 1.2 years.

CONCLUSIONS

The rates of cognitive impairment in this large sample of MS patients were lower than previously reported and severe cognitive impairment was evident only in a relatively small group of patients. Cognitive impairment differed significantly from expected normal distribution only at five years from onset, suggesting the existence of a therapeutic window during which patients may benefit from interventions to maintain cognitive health.

What is the relevance of quality of life assessment for patients with attention impairment?

Background

Attention disturbances are frequently observed in multiple sclerosis (MS) patients. The aim of this study was to provide new evidence regarding the suitability of using self-reported QoL information in this impaired population by exploring the construct validity, reliability, and external validity of a MS-specific quality of life (QoL) instrument.

Methods

Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (Expanded Disability Status Scale, disease duration); QoL (MusiQoL and SF36); and attention performance (Wechsler Memory Scale and PASAT). According to the French norms, non-impaired and impaired populations were defined. For each population, suitability indices were provided to quantify how the structures matched with the initial structure of the reference population assessed in the validation study.

Findings

One hundred and twenty-four consecutive patients were enrolled. The factor analysis performed in the impaired populations showed that the questionnaire structure adequately matched the initial structure of the MusiQoL. The unidimensionality of the dimensions was preserved, and the internal/external validity indices were close to those of the reference population.

Conclusions

Our study suggests that attention impairment dysfunction did not compromise the reliability and validity of the self-reported QoL questionnaires.

Cognitive impairment in patients with clinically isolated syndrome

Cognitive abnormalities have been extensively studied in Multiple Sclerosis (MS). However, little is known about the cognitive involvement in patients with Clinically Isolated Syndrome (CIS).

Cognitive impairment and optic nerve axonal loss in patients with clinically isolated syndrome

OBJECTIVE

To investigate cognitive impairment, to assess optical nerve axonal loss, and to determinate whether there is correlation between optical nerve axonal loss and cognition impairment in Clinically Isolated Syndrome (CIS).

METHODS

Fifteen CIS patients and 15 controls were submitted to Wechsler memory scale, Rey Auditory Verbal Learning, Rey Complex Figure, Paced Auditory Serial Addition, Digit Span, verbal fluency, stroop color, D2, and Digit Symbol tests. CIS patients were evaluated by optical coherence tomography (OCT) (23 eyes).

RESULTS

CIS patients had worse performance in Paced Auditory Serial Addition Test (PASAT) 2 seconds (P=0.009) and fluency tests (P=0.0038). Optical nerve axonal loss was found more frequently in eyes with previous optic neuritis (ON) (85.7%) than in those without previous ON (21.7%) (P=0.0146). There were no significant correlations between optical nerve axonal loss and cognitive findings.

CONCLUSIONS

CIS patients had worse cognitive performance than controls. OCT can detect axonal loss resulting from optical neuritis and subclinical axonal loss in eyes without previous optical neuritis. Optical nerve axonal loss was not correlated with cognition.

Is the concept of quality of life relevant for multiple sclerosis patients with cognitive impairment? Preliminary results of a cross-sectional study

Background

Cognitive impairment occurs in about 50% of multiple sclerosis (MS) patients, and the use of self-reported outcomes for evaluating treatment and managing care among subjects with cognitive dysfunction has been questioned. The aim of this study was to provide new evidence about the suitability of self-reported outcomes for use in this specific population by exploring the internal structure, reliability and external validity of a specific quality of life (QoL) instrument, the Multiple Sclerosis International Quality of Life questionnaire (MusiQoL).

Methods

Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (MS subtype, Expanded Disability Status Scale, disease duration); QoL (MusiQoL and SF36); and neuropsychological performance (Stroop color-word test). Statistical analysis: confirmatory factor analysis, item-dimension correlations, Cronbach's alpha coefficients, Rasch statistics, relationships between MusiQoL dimensions and other parameters.

Principal Findings

One hundred and twenty-four consecutive patients were enrolled. QoL scores did not differ between the 69 cognitively non-impaired patients and the 55 cognitively impaired patients, except for the symptoms dimension. The confirmatory factor analysis performed among the impaired subjects showed that the structure of the questionnaire matched with the initial structure of the MusiQoL. The unidimensionality of the MusiQoL dimensions was preserved, and the internal validity indices were satisfactory and close to those of the reference population.

Conclusions/Significance

Our study suggests that executive dysfunction did not compromise the reliability and the validity of the self-reported QoL questionnaires.

Cognitive dysfunction and multiple sclerosis: developing a rationale for considering the efficacy of exercise training

Cognitive impairment is a prevalent, disabling, and poorly managed consequence of multiple sclerosis (MS). This underscores the importance of considering alternative approaches, such as exercise training, for managing cognitive impairment in persons with MS. The consideration of exercise training is warranted based on evidence summarized in literature reviews and meta-analyses that (1) aerobic fitness, physical activity, and exercise training are associated with better cognitive function in older adults; and (2) exercise training has comparable effects on mobility and quality of life outcomes in older adults and persons with MS. To date, research examining aerobic fitness, physical activity, and exercise training effects on cognition in MS is nascent and mostly includes cross-sectional designs that provide preliminary evidence for a well-designed randomized controlled trial (RCT). We believe that a future RCT should adopt research methodologies and practices from gerontology when examining exercise training and cognition in MS. This will maximize the potential for successfully generating a body of knowledge on exercise training and cognition with the potential for impacting the lives of persons with MS.

Cognitive function and quality of life in multiple sclerosis patients: a cross-sectional study

Background

Nearly half of all patients diagnosed with multiple sclerosis (MS) will develop cognitive dysfunction. Studies highlighted from no/weak impact to a strong impact of cognitive impairment on quality of life (QoL). The aim of this study was to assess the impact of cognitive dysfunction on self-reported QoL in MS patients while considering key confounding factors.

Methods

Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (MS subtype, disease duration); MS disability (Expanded Disability Status Scale, EDSS); depression (Beck Depression Inventory); fatigue (Modified Fatigue Impact Scale); QoL (SF36 and MusiQoL); and neuropsychological performance (Brief Repeatable Battery of Neuropsychological Tests, BRB-N). Statistical analysis: multiple linear regressions (forward-stepwise selection).

Results

One hundred and twenty-four patients were enrolled. Performance on BRB-N subtests varied widely (6% to 70% abnormal). The BRB-N classified 37-78% of the patients as cognitively impaired, depending on the definition of cognitive impairment. No links were found between the MusiQoL index and cognitive subtests, whereas marital status, EDSS, and depression were found to be independent predictive factors.

Conclusions

The present study demonstrated the weak and scarce association between cognitive impairment and QoL, when the key confounding factors were considered. These results need to be confirmed with larger samples and more accurate tests of cognitive function.

Cognitive impairment in relation to MRI metrics in patients with clinically isolated syndrome

Background: Cognitive deficits are frequent in multiple sclerosis (MS) and have been associated with morphologic brain changes. Less information exists on their extent and relation to MRI findings in clinically isolated syndrome (CIS). It is also unclear if structural changes as detected by magnetization transfer (MT) imaging may provide an additional explanation for cognitive dysfunction.

Objective: To analyse the extent of cognitive deficits and their relation to MRI metrics including MT imaging in CIS compared to relapsing-remitting MS (RRMS).

Methods: Forty-four CIS and 80 RRMS patients underwent the Brief Repeatable Battery of Neuropsychological Tests (BRB-N) and a 3 T MRI scan.

Results: BRB-N subtests revealed similar results in CIS and RRMS. Impaired mental processing speed was most prevalent in both groups (CIS 13.6%; RRMS 16.3%) and thus served for correlation with MRI metrics. Using stepwise linear regression analyses, the strongest predictor for decreased mental processing speed was normalized cortex volume ( p < 0.001) followed by T2-lesion load ( p < 0.05) in RRMS, whereas cortical MT ratio was the only MRI parameter associated with decreased mental processing speed in CIS ( p < 0.005).

Conclusion: Cognitive dysfunction occurs in CIS in a pattern similar to RRMS, with impaired mental processing speed being most prevalent. Cortical MT-ratio changes may be an early sign for tissue changes related to impaired mental processing speed in CIS while this association shifts to increased signs of cortical atrophy and lesion load in RRMS.

Cognitive deficits in multiple sclerosis: a systematic review

OBJECTIVE: To present the results of prospective and retrospective studies on multiple sclerosis patients cognitive dysfunctions, as well as to discuss the batteries of neuropsy- chological tests used in these investigations. METHOD: A systematic review was performed involving 40 studies published from 1997 to 2009, in PubMed, Scopus, Ovid, ISI Web of Knowledge, Scientific Electronic Library on line (Scielo) and Latin-American and Caribbean Center of Health Sciences Informations database. Clear description of multiple sclerosis patients cognitive deficits evaluation, study design, sample size; inclusion-exclusion and discontinuation criteria; instruments for neuropsychological evaluation, diagnostic methods, evaluated functions and detailed statistical analysis had been the inclusion criteria. RESULTS: There is consensus on cognitive impairment of multiple sclerosis patients, especially on memory, speed processing, executive function, attention and concentration domains. One has identified use of 23 batteries and 74 neuropsychological tests, despite the recommendation of Consortium of Multiple Sclerosis Centers to the application of MACFIMS battery. CONSIDERATIONS: The absence of the uniformization for multiple sclerosis patients cognitive evaluation battery has precluded to achieve evidences to recommend its incorporation on diagnostic routine. Nevertheless this tendency is already outlined.

Walking while talking--difficulties incurred during the initial stages of multiple sclerosis disease process

Patients with multiple sclerosis (MS) frequently experience poor gait and/or cognitive impairment, even in the early stages of the disease. As gait is often executed simultaneously with different cognitive tasks, it is essential to test gait during a cognitive load. Therefore, the main objective of this study was to assess gait and gait variations while simultaneously performing a cognitive task in patients with a clinically isolated syndrome (CIS) suggestive of MS. Fifty-two CIS patients, aged 33.8±0.2 years with an Expanded Disability Status Scale (EDSS) score of 1.7±0.2 were included in the study. The control group consisted of 28 age- and gender-matched healthy subjects. Major spatio-temporal parameters were collected via an electronic walkway (GAITRite electronic walkway system). Participants were instructed to walk under three different conditions: normal, fast, and at a normal pace while performing the modified word list generation (WLG) test. Compared to healthy subjects, the CIS patients' gait was slower and asymmetrical with a wider base of support. The combined walking and cognitive task was expressed in prolonged double support (% gait cycle) and reduced velocity in patients only. As these findings are associated with the very early phase of MS, it appears that the ongoing pathological disease process is already taking place with regard to gait abilities. Since in early MS patients, gait-cognitive dual tasking may lead to an increased risk of falling, this important function should be addressed by physical rehabilitation clinicians.

Cognitive impairment in clinically isolated syndrome: A systematic review

The pattern of cognitive abnormalities in multiple sclerosis (MS) has been extensively studied and well characterized. However, little is known about the cognitive involvement in patients with the clinically isolated syndrome (CIS).

Assessment of social cognition in patients with multiple sclerosis

We examined the capacity of patients with multiple sclerosis (MS) to attribute mental states to others and to identify cognitive abilities that subserve theory of mind (ToM). In this article, we report findings on 41 out-patients with diagnosed MS who underwent detailed neuropsychological and social-cognitive assessment. They were subdivided into a cognitively intact (n=15) and cognitively impaired (n=26) group according to their neuropsychological test results. Their results were compared with those of 20 age- and education-matched controls. MS patients with cognitive impairments were found to have more difficulties attributing mental states to others than did cognitively intact MS patients and normal controls on two ToM measures; short stories (Happé, Winner, & Brownell, 1998) and video clips (Ouellet, Bédirian, Charbonneau, & Scherzer, 2009). When attention, memory, and working memory were controlled, performance on the WAIS-III Picture Arrangement task accounted for 17.3% of the variance in performance on the video clips task. Performance on a WAIS-III index composed of Similarities and Comprehension subtests, accounted for 7.0% of the variance in performance on the short stories task. These results provide some preliminary information on the effect of MS-related cognitive deficits on the ability to attribute mental states to others.

Sensitivity of conventional memory tests in multiple sclerosis: comparing the Rao Brief Repeatable Neuropsychological Battery and the Minimal Assessment of Cognitive Function in MS

BACKGROUND

Cognitive impairment is common in multiple sclerosis (MS) affecting roughly 45-60% of patients. Because memory deficits have significant impact on employment, caregiver burden, and social functioning, neuropsychological (NP) assessment is often recommended. Two widely used and validated NP batteries for MS are the Rao Brief Repeatable Neuropsychological Battery (BRNB) and the Minimal Assessment of Cognitive Function in MS (MACFIMS). Although similar, these batteries differ in the specific auditory/verbal and visual/spatial memory tests employed. The relative sensitivity of these memory tests is unknown.

METHODS

The BRNB and MACFIMS have considerable overlap but different memory tests: the former includes the Selective Reminding Test (SRT) and the 10/36 Spatial Recall Test (10/36) and the latter the California Verbal Learning Test, Second Edition (CVLT2) and Brief Visuospatial Memory Test, Revised (BVMTR). In 65 patients with MS and 46 demographically matched controls, we compared the sensitivity of these tests, and secondarily their respective batteries.

RESULTS

The BRNB and MACFIMS were comparable in their overall sensitivity to disease status. Although the BVMTR showed greater discriminative validity than the 10/36, the CVLT2 and SRT were comparable in sensitivity. The SDMT was the most sensitive NP test across both batteries.

CONCLUSIONS

We conclude that the BRNB and MACFIMS have comparable sensitivity among patients with MS. The sensitivity of the auditory/verbal memory tests from these batteries is similar, but the BVMTR appears to be more sensitive than the 10/36. Clinical implications are discussed.

[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 impairments in relapsing-remitting multiple sclerosis: a meta-analysis

There is debate in the literature regarding the magnitude, nature, and influence of cognitive impairment in individuals with relapsing-remitting multiple sclerosis (RRMS). Therefore, we conducted a meta-analysis that quantified the overall magnitude of cognitive impairment in individuals with RRMS and identified the domains of cognition and clinical/demographic variables that were moderators of the overall effect. We included 57 studies with 3891 participants that yielded a total of 755 effect sizes. Overall, there was a moderate decline in cognitive functioning in individuals with RRMS compared with healthy controls. Larger effects were observed in cognitive domains of motor functioning, mood status and memory and learning. Regarding demographic and clinical variables, age and gender were moderators of cognitive impairment in all cognitive domains, whereas neurological disability and disease duration primarily moderated performance on tasks assessing memory and learning.

Psychological aspects of multiple sclerosis

A significant incidence and prevalence of psychological disorders in multiple sclerosis (MS) has been reported. Their underlying mechanisms and the extent to which they are reactive to psychosocial factors or symptoms of the pathological process itself, remain unclear. Depression is the predominant psychological disturbance with lifetime prevalence around 50% and annual prevalence of 20%. Depression is commoner during relapses, may exacerbate fatigue and cognitive dysfunction and no firm evidence exists of its induction by interferon; instead, treating depression improves adherence to disease-modifying drugs. Anxiety is also frequent, occurs in newly diagnosed patients, and its co-morbidity with depression has been suggested to increase the rate of suicidal ideation. The relationship between stress and MS is an attractive issue because some studies pointed to an association between stressful life-events and MS onset/relapses; however, the evidence supporting this hypothesis is not conclusive so far. Other psychiatric illnesses, as bipolar affective disorder, pathological laughing and crying or psychosis occur less frequently in MS. Therapeutic strategies include psychotherapy, cognitive behavioural therapy, strengthen of coping, and specific medications. The "art" of the MS team in providing the best individualized care is emphasized, aiming to reduce the burden of the disease and improve the patients' quality of life.

Cognitive impairment in different MS subtypes and clinically isolated syndromes

OBJECTIVE

To investigate the pattern of cognitive impairment in patients with relapsing-remitting (RR), secondary progressive (SP), primary progressive (PP) multiple sclerosis, and patients with clinically isolated syndrome (CIS) suggestive of MS, relative to control participants in the Greek population.

METHODS

RR patients (N=75), SP patients (N=29), PP patients (N=23), CIS patients (N=33), and healthy control participants (N=43) were assessed by the Brief Repeatable Battery of Neuropsychological Tests (BRBN).

RESULTS

The overall prevalence of cognitive dysfunction in our patients was 52.8% with CIS patients excluded and 47.5% with CIS patients included. All MS patients differed significantly from controls in all BRBN measures. Similar was the pattern of cognitive dysfunction in patients with CIS suggestive of MS, although verbal learning/memory capacity (as measured by the Selective Reminding Test) remained relatively spared. The comparisons between patient groups revealed some differences in the performance mainly in favor of CIS and RRMS patients. These differences largely disappeared after controlling for physical disability (EDSS).

CONCLUSION

All MS subtypes patients exhibit a pattern of cognitive impairment running across the studied cognitive domains. The pattern of cognitive dysfunction in patients with CIS is similar with relative sparing of verbal learning.

Cognitive impairment in multiple sclerosis

PURPOSE OF REVIEW

For a long time, cognitive impairment in multiple sclerosis patients has been considered less important than, for instance, physical disability. This is no longer true because of the crucial role that cognitive deficits play in the good day-to-day adjustment of patients. This review highlights recent progress made in this area. A special focus lies on studies investigating the neural correlates of cognitive impairment in multiple sclerosis patients as detectable by conventional, quantitative and functional magnetic resonance imaging.

RECENT FINDINGS

Measures of information-processing speed appear to be the most robust and sensitive markers of cognitive impairment in multiple sclerosis patients. Recent studies demonstrate that single, predominantly speed-related cognitive tests may be superior to extensive and time-consuming test batteries in screening overall cognitive decline. Quantitative magnetic-resonance-imaging 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 multiple sclerosis patients.

SUMMARY

From neuropsychological test data, and findings from magnetic resonance imaging and functional magnetic resonance imaging it is evident that cognitive impairment in multiple sclerosis is not just the result of tissue destruction, but rather a balance between tissue destruction, tissue repair, and adaptive functional reorganization.