Trait Conscientiousness predicts rate of longitudinal SDMT decline in multiple sclerosis

Cognitive performance and magnetic resonance imaging in people with multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Several studies have shown the different relationships between cognitive functions and structural magnetic resonance imaging (MRI) measurements in people with multiple sclerosis (pwMS). However, there is an ongoing debate regarding the magnitude of correlation between MRI measurements and specific cognitive function tests. This systematic review and meta-analysis aimed to synthesize the most consistent correlations between MRI measurements and cognitive function in pwMS.

METHODS

PubMed/MEDLINE, Embase, Scopus, and Web of Science databases were systematically searched up to February 2023, to find relevant data. The search utilized syntax and medical subject headings (MeSH) relevant to cognitive performance tests and MRI measurements in pwMS. The R software version 4.3.3 with random effect models was used to estimate the pooled effect sizes.

RESULTS

13,559 studies were reviewed, of which 136 were included. The meta-analyses showed that thalamic volume had the most significant correlations with Symbol Digit Modalities Test (SDMT) r = 0.47 (95 % CI: 0.39 to 0.56, p < 0.001, I2 = 88 %), Brief Visual Memory Test-Revised-Total Recall (BVMT-TR) r = 0.51 (95 % CI: 0.36 to 0.66, p < 0.001, I2 = 81 %), California Verbal Learning Test-II-Total Recall (CVLT-TR) r = 0.47 (95 % CI: 0.34 to 0.59, p < 0.001, I2 = 69 %,), and Delis-Kaplan Executive Function System (DKEFS) r = 0.48 (95 % CI: 0.34 to 0.63, p < 0.001, I2 = 22 %,).

CONCLUSION

We conclude that thalamic volume exhibits highest relationships with information processing speed (IPS), visuospatial learning-memory, verbal learning-memory, and executive function in pwMS. A comprehensive understanding of the intricacies of the mechanisms underpinning this association requires additional research.

Systematic review of cognitive reserve in multiple sclerosis: Accounting for physical disability, fatigue, depression, and anxiety

BACKGROUND

Cognitive reserve (CR) describes an individual's ability to adapt cognitive processes in response to brain atrophy, and has been reported to explain some of the discrepancy between brain atrophy and cognitive functioning outcomes in multiple sclerosis (MS). CR in MS is typically investigated by assessing an individual's pre- and/or post-diagnosis enrichment, which includes premorbid intellectual abilities, educational level, occupational attainment, and engagement in cognitively enriching leisure activities. Common MS symptoms (e.g., physical disability, fatigue, depression, anxiety) may impact an individual's ability to engage in various CR-enhancing activities post-diagnosis. It is unknown to what extent these MS symptoms have been taken into account in MS research on CR. As such, we identified whether studies assessed CR using measures of premorbid or continuous (including post-diagnosis) enrichment. For studies investigating continuous enrichment, we identified whether studies accounted for MS-impact, which MS symptoms were accounted for, and how, and whether studies acknowledged MS symptoms as potential CR-confounds.

METHODS

Three electronic databases (PsycINFO, PubMed, Scopus) were searched. Eligible studies investigated CR proxies (e.g., estimated premorbid intellectual abilities, vocabulary knowledge, educational level, occupational attainment, cognitively enriching leisure activities, or a combination thereof) in relation to cognitive, brain atrophy or connectivity, or daily functioning outcomes in adult participants with MS. We extracted data on methods and measures used, including any MS symptoms taken into account. Objectives were addressed using frequency analyses and narrative synthesis.

RESULTS

115 studies were included in this review. 47.8% of all studies investigated continuous enrichment. Approximately half of the studies investigating continuous enrichment accounted for potential MS-impact in their analyses, with only 31.0% clearly identifying that they treated MS symptoms as potential confounds for CR-enhancement. A narrative synthesis of studies which investigated CR with and without controlling statistically for MS-impact indicated that accounting for MS symptoms may impact findings concerning the protective nature of CR.

CONCLUSION

Fewer than half of the studies investigating CR proxies in MS involved continuous enrichment. Just over half of these studies accounted for potential MS-impact in their analyses. To achieve a more complete and accurate understanding of CR in MS, future research should investigate both pre-MS and continuous enrichment. In doing so, MS symptoms and their potential impact should be considered. Establishing greater consistency and rigour across CR research in MS will be crucial to produce an evidence base for the development of interventions aimed at improving quality of care and life for pwMS.

Instruments measuring change in cognitive function in multiple sclerosis: A systematic review

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating/neurodegenerative disease associated with change in cognitive function (CF) over time. This systematic review aims to describe the instruments used to measure change in CF over time in people with MS (PwMS).

METHODS

PubMed, OVID, Web of Science, and Scopus databases were searched in English until May 2021. Articles were included if they had at least 100 participants and at least a 1-year interval between baseline and last follow-up measurement of CF. Results were quantitatively synthesized, presented in tables and risk of bias was assessed with the Newcastle-Ottawa Scale.

RESULTS

Fifty-seven articles met the inclusion criteria (41,623 PwMS and 1105 controls). An intervention (drug/rehabilitation) was assessed in 22 articles. In the studies that used a test battery, Visual and verbal learning and memory were the most frequently measured domains, but when studies that used test battery or a single test are combined, Information processing speed was the most measured. The Symbol Digit Modalities Test (SDMT) was the most frequently used test as a single test and in a test battery combined. Most studied assessed "change in CF" as cognitive decline defined as 1 or more tests measured as ≥ 1.5 SD from the study control or normative mean in a test battery at baseline and follow-up. Meta-analysis of change in SDMT scores with seven articles indicated a nonstatistically significant -0.03 (95% CI -0.14, 0.09) decrease in mean SDMT score per year.

CONCLUSION

This study highlights the slow rate of measured change in cognition in PwMS and emphasizes the lack of a gold standard test and consistency in measuring cognitive change at the population level. More sensitive testing utilizing multiple domains and longer follow-up may define subgroups where CF change follows different trajectories thus allowing targeted interventions to directly support those where CF is at greatest risk of becoming a clinically meaningful issue.

Working Memory Phenotypes in Early Multiple Sclerosis: Appraisal of Phenotype Frequency, Progression and Test Sensitivity

Working memory (WM) impairments are common and debilitating symptoms of multiple sclerosis (MS), often emerging early in the disease. Predominantly, WM impairments are considered in a binary manner, with patients considered either impaired or not based on a single test. However, WM is comprised of different activated subcomponents depending upon the type of information (auditory, visual) and integration requirements. As such, unique WM impairment phenotypes occur. We aimed to determine the most frequent WM phenotypes in early MS, how they progress and which WM test(s) provide the best measure of WM impairment. A total of 88 participants (63 early relapsing–remitting MS: RRMS, 25 healthy controls) completed five WM tests (visual–spatial, auditory, episodic, executive) as well as the symbol digit modalities test as a measure of processing speed. RRMS patients were followed-up for two years. Factors affecting WM (age/gender/intelligence/mood) and MS factors (disease duration/disability) were also evaluated. Some 61.9% of RRMS patients were impaired on at least one WM subcomponent. The most subcomponents impaired were visual,–spatial and auditory WM. The most common WM phenotypes were; (1) visual–spatial sketchpad + episodic buffer + phonological loop + central executive, (2) visual–spatial sketchpad + central executive. The test of visual–spatial WM provided the best diagnostic accuracy for detecting WM impairment and progression. The SDMT did not achieve diagnostic accuracy greater than chance. Although this may be unsurprising, given that the SDMT is a measure of cognitive processing speed in MS, this does highlight the limitation of the SDMT as a general screening tool for cognitive impairment in early MS.

Preliminary Support of a Behavioral Intervention for Trait Conscientiousness in Multiple Sclerosis

Background

Conscientiousness, or the proclivity for deliberation, achievement, and order, declines in many individuals with multiple sclerosis (MS). Decreased conscientiousness predicts future cognitive deterioration, brain atrophy, and employment loss in individuals with MS. As a psychological trait, it may be an actionable antecedent to these important outcomes. We pilot tested an application (app)-facilitated behavioral intervention to help adaptation to low conscientiousness and, in turn, improve employment.

Methods

Eleven individuals with MS (5 treatment, 6 control) with low conscientiousness were recruited for a 12-week randomized controlled trial. The treatment group received a newly developed behavioral treatment and smartphone app designed to help people behave more conscientiously, 2 teleconference booster sessions, and weekly telephone calls to monitor progress. Employment changes were recorded at baseline and follow-up. Patients provided detailed posttreatment interviews.

Results

Participant groups were matched on baseline age, sex, education, disease duration, hours worked, and conscientiousness. All participants in the treatment arm reported benefits, found the app easy to use, and would recommend it to others. The treatment group reported significantly more positive work outcomes relative to controls at follow-up (P = .028). Other positive life changes were described by treatment participants during post-treatment interviews.

Conclusions

These results support the hypothesis that behaviors typically associated with low conscientiousness may be addressed by behavioral therapy in the MS population. In addition to the positive employment changes in the treatment group, several other quality of life changes were described by study participants. Additional research is needed.

Towards Multimodal Machine Learning Prediction of Individual Cognitive Evolution in Multiple Sclerosis

Multiple sclerosis (MS) manifests heterogeneously among persons suffering from it, making its disease course highly challenging to predict. At present, prognosis mostly relies on biomarkers that are unable to predict disease course on an individual level. Machine learning is a promising technique, both in terms of its ability to combine multimodal data and through the capability of making personalized predictions. However, most investigations on machine learning for prognosis in MS were geared towards predicting physical deterioration, while cognitive deterioration, although prevalent and burdensome, remained largely overlooked. This review aims to boost the field of machine learning for cognitive prognosis in MS by means of an introduction to machine learning and its pitfalls, an overview of important elements for study design, and an overview of the current literature on cognitive prognosis in MS using machine learning. Furthermore, the review discusses new trends in the field of machine learning that might be adopted for future studies in the field.

Functional network dynamics and decreased conscientiousness in multiple sclerosis

BACKGROUND

Conscientiousness is a personality trait that declines in people with multiple sclerosis (PwMS) and its decline predicts worse clinical outcomes. This study aims to investigate the neural underpinnings of lower Conscientiousness in PwMS by examining MRI anomalies in functional network dynamics.

METHODS

70 PwMS and 50 healthy controls underwent personality assessment and resting-state MRI. Associations with dynamic functional network properties (i.e., eigenvector centrality) were evaluated, using a dynamic sliding-window approach.

RESULTS

In PwMS, lower Conscientiousness was associated with increased variability of centrality in the left insula (t_max = 4.21) and right inferior parietal lobule (t_max = 3.79); a relationship also observed in regressions accounting for handedness, disease duration, disability, and tract disruption in relevant structural networks (ΔR² = 0.071, p = 0.003; ΔR² = 0.094, p = 0.004). Centrality dynamics of the observed regions were not associated with Neuroticism (R² < 0.001, p = 0.956; R² < 0.001, p = 0.945). As well, higher Conscientiousness was associated with greater variability in connectivity for the left insula with the default-mode network (F = 3.92, p = 0.023) and limbic network (F = 5.66, p = 0.005).

CONCLUSION

Lower Conscientiousness in PwMS was associated with increased variability in network centrality, most prominently for the left insula and right inferior parietal cortex. This effect, specific to Conscientiousness and significant after accounting for disability and structural network damage, could indicate that overall stable network centrality is lost in patients with low Conscientiousness, especially for the insula and right parietal cortex. The positive relationship between Conscientiousness and variability of connectivity between left insula and default-mode network potentially affirms that dynamics between the salience and default-mode networks is related to the regulation of behavior.

Structural and Functional Connectivity Substrates of Cognitive Impairment in Multiple Sclerosis

Cognitive impairment (CI) occurs in 43 to 70% of multiple sclerosis (MS) patients at both early and later disease stages. Cognitive domains typically involved in MS include attention, information processing speed, memory, and executive control. The growing use of advanced magnetic resonance imaging (MRI) techniques is furthering our understanding on the altered structural connectivity (SC) and functional connectivity (FC) substrates of CI in MS. Regarding SC, different diffusion tensor imaging (DTI) measures (e.g., fractional anisotropy, diffusivities) along tractography-derived white matter (WM) tracts showed relevance toward CI. Novel diffusion MRI techniques, including diffusion kurtosis imaging, diffusion spectrum imaging, high angular resolution diffusion imaging, and neurite orientation dispersion and density imaging, showed more pathological specificity compared to the traditional DTI but require longer scan time and mathematical complexities for their interpretation. As for FC, task-based functional MRI (fMRI) has been traditionally used in MS to brain mapping the neural activity during various cognitive tasks. Analysis methods of resting fMRI (seed-based, independent component analysis, graph analysis) have been applied to uncover the functional substrates of CI in MS by revealing adaptive or maladaptive mechanisms of functional reorganization. The relevance for CI in MS of SC–FC relationships, reflecting common pathogenic mechanisms in WM and gray matter, has been recently explored by novel MRI analysis methods. This review summarizes recent advances on MRI techniques of SC and FC and their potential to provide a deeper understanding of the pathological substrates of CI in MS.

Cognitive impairment in multiple sclerosis: clinical management, MRI, and therapeutic avenues

Multiple sclerosis is a chronic, demyelinating disease of the CNS. Cognitive impairment is a sometimes neglected, yet common, sign and symptom with a profound effect on instrumental activities of daily living. The prevalence of cognitive impairment in multiple sclerosis varies across the lifespan and might be difficult to distinguish from other causes in older age. MRI studies show that widespread changes to brain networks contribute to cognitive dysfunction, and grey matter atrophy is an early sign of potential future cognitive decline. Neuropsychological research suggests that cognitive processing speed and episodic memory are the most frequently affected cognitive domains. Narrowing evaluation to these core areas permits brief, routine assessment in the clinical setting. Owing to its brevity, reliability, and sensitivity, the Symbol Digit Modalities Test, or its computer-based analogues, can be used to monitor episodes of acute disease activity. The Symbol Digit Modalities Test can also be used in clinical trials, and data increasingly show that cognitive processing speed and memory are amenable to cognitive training interventions.

Conscientiousness and deterioration in employment status in multiple sclerosis over 3 years

Background:

Physical and cognitive symptoms of multiple sclerosis (MS) correlate with unemployment cross-sectionally. Prospective studies, rarely published, have not accounted for personality traits such as Conscientiousness.

Methods:

In a 3-year study of 70 people with MS (PwMS) and 25 healthy controls (HCs), we evaluated employment status using online interviews capturing hours worked, negative work events, employee relations, and accommodations. Deteriorating employment status (DES) was defined as reduced employment (full-time to part-time or negative work events). In PwMS, we explored workplace accommodations, disclosure of disease status, and physical/psychological predictors of DES (e.g. Conscientiousness).

Results:

At follow-up, DES was 0% in HCs and 25.7% in MS, and 62.7% of work-stable PwMS used at least one work accommodation, most frequently, flexible hours. At baseline, DES-PwMS had lower education ( p = 0.009), lower Conscientiousness ( p < 0.001), more fatigue ( p = 0.033), and performed worse on Symbol Digit Modalities Test ( p = 0.013), Brief Visuospatial Memory Test—Revised ( p = 0.041), and Nine-Hole Peg Test ( p = 0.046) relative to work-stable. The model predicting DES was significant (χ2(7) = 30.936, p < 0.001) and baseline Conscientiousness accounted for more variance in DES ( p = 0.004) than other factors. Higher Conscientiousness PwMS were more likely to disclose their condition at work ( p = 0.038).

Conclusion:

Accommodations for low Conscientiousness, flexible hours, and physical/cognitive rehabilitation may prevent DES.

Trait Conscientiousness predicts rate of brain atrophy in multiple sclerosis

BACKGROUND

Conscientiousness is a core personality trait with favorable prognosis in neuropsychiatric disease.

OBJECTIVE

We aimed to determine whether baseline Conscientiousness predicts future brain atrophy in multiple sclerosis (MS) after accounting for demographic and basic clinical characteristics.

METHODS

Trait Conscientiousness, clinical features, and Expanded Disability Status Scale (EDSS) were obtained at baseline. Lateral ventricle volume (LVV) was measured longitudinally. In a retrospective general linear mixed effects model, data from 424 patients were analyzed (mean 6 time-points, up to 15 years).

RESULTS/CONCLUSION

We observed significant age and Conscientiousness by time-from-baseline interactions indicating that younger age and higher Conscientiousness are associated with reduced progression of brain atrophy.