Immunomodulatory treatments and cognition in MS

Current Status of Oral Disease-Modifying Treatment Effects on Cognitive Outcomes in Multiple Sclerosis: A Scoping Review

INTRODUCTION

Cognitive impairment represents one of the most hidden and disabling clinical aspects of multiple sclerosis (MS). In this regard, the major challenges are represented by the need for a comprehensive and standardised cognitive evaluation of each patient, both at disease onset and during follow-up, and by the lack of clear-cut data on the effects of treatments. In the present review, we summarize the current evidence on the effects of the available oral disease-modifying treatments (DMTs) on cognitive outcome measures.

MATERIALS AND METHODS

In this systematised review, we extract all the studies that reported longitudinally acquired cognitive outcome data on oral DMTs in MS patients.

RESULTS

We found 29 studies that evaluated at least one oral DMT, including observational studies, randomised controlled trials, and their extension studies. Most of the studies (n = 20) evaluated sphingosine-1-phosphate (S1P) modulators, while we found seven studies on dimethyl fumarate, six on teriflunomide, and one on cladribine. The most frequently used cognitive outcome measures were SDMT and PASAT. Most of the studies reported substantial stability or mild improvement in cognitive outcomes in a short-time follow-up (duration of most studies ≤2 years). A few studies also reported MRI measures of brain atrophy.

CONCLUSION

Cognitive outcomes were evaluated only in a minority of prospective studies on oral DMTs in MS patients with variable findings. More solid and numerous data are present for the S1P modulators. A standardised cognitive evaluation remains a yet unmet need to better clarify the possible positive effect of oral DMTs on cognition.

Effects on cognition of DMTs in multiple sclerosis: moving beyond the prevention of inflammatory activity

In this review, we critically summarize recent findings derived from randomized controlled trials (RCTs), observational studies and meta-analyses that have been published in the last 3 years and that included the effects of DMTs on cognitive performances among their outcomes.

On the Reliability of Examining Dual-Tasking Abilities Using a Novel E-Health Device—A Proof of Concept Study in Multiple Sclerosis

The assessment of neuropsychological functions and especially dual-tasking abilities is considered to be increasingly relevant in the assessment of neurological disease, and Multiple Sclerosis (MS) in particular. However, the assessment of dual-tasking abilities is hindered by specific software requirements and extensive testing times. We designed a novel e-health (progressive web application-based) device for the assessment of dual-tasking abilities usable in “bedside” and outpatient clinic settings and examined its reliability in a sample of N = 184 MS patients in an outpatient setting. Moreover, we examined the relevance of dual-tasking assessment using this device with respect to clinically relevant parameters in MS. We show that a meaningful assessment of dual-tasking is possible within 6 min and that the behavioral readouts overall show good reliability depending on dual-tasking difficulty. We show that dual-tasking readouts were correlated with clinically relevant parameters (e.g., EDSS, disease duration, processing speed) and were not affected by fatigue levels. We consider the tested dual-tasking assessment device suitable for routine clinical neuropsychological assessments of dual-tasking abilities. Future studies may further evaluate this test regarding its suitability in the long-term follow up assessments and to assess dual-tasking abilities in other neurological and psychiatric disorders.

Experimental autoimmune encephalopathy (EAE)-induced hippocampal neuroinflammation and memory deficits are prevented with the non-opioid TLR2/TLR4 antagonist (+)-naltrexone

Multiple sclerosis (MS) is associated with burdensome memory impairments and preclinical literature suggests that these impairments are linked to neuroinflammation. Previously, we have shown that toll-like receptor 4 (TLR4) antagonists, such as (+)-naltrexone [(+)-NTX], block neuropathic pain and associated spinal inflammation in rats. Here we extend these findings to first demonstrate that (+)-NTX blocks TLR2 in addition to TLR4. Additionally, we examined in two rat strains whether (+)-NTX could attenuate learning and memory disturbances and associated neuroinflammation using a low-dose experimental autoimmune encephalomyelitis (EAE) model of MS. EAE is the most commonly used experimental model for the human inflammatory demyelinating disease, MS. This low-dose model avoided motor impairments that would confound learning and memory measurements. Fourteen days later, daily subcutaneous (+)-NTX or saline injections began and continued throughout the study. Contextual and auditory-fear conditioning were conducted at day 21 to assess hippocampal and amygdalar function. With this low-dose model, EAE impaired long-term, but not short-term, contextual fear memory; both long-term and short-term auditory-cued fear memory were spared. This was associated with increased mRNA for hippocampal interleukin-1β (IL-1β), TLR2, TLR4, NLRP3, and IL-17 and elevated expression of the microglial marker Iba1 in CA1 and DG regions of the hippocampus, confirming the neuroinflammation observed in higher-dose EAE models. Importantly, (+)-NTX completely prevented the EAE-induced memory impairments and robustly attenuated the associated proinflammatory effects. These findings suggest that (+)-NTX may exert therapeutic effects on memory function by dampening the neuroinflammatory response in the hippocampus through blockade of TLR2/TLR4. This study suggests that TLR2 and TLR4 antagonists may be effective at treating MS-related memory deficits.

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.

Disease-modifying treatments and cognition in relapsing-remitting multiple sclerosis

Objective

Disease-modifying treatments (DMTs) are the gold standard for slowing disability progression in multiple sclerosis (MS), but their effects on cognitive impairment, a key symptom of the disease, are mostly unknown. We conducted a systematic review and meta-analysis to evaluate the differential effects of DMTs on cognitive test performance in relapsing-remitting MS (RRMS).

Methods

PubMed, Scopus, and Cochrane Library were searched for studies reporting longitudinal cognitive performance data related to all major DMTs. The standardized mean difference (Hedges g) between baseline and follow-up cognitive assessment was used as the main effect size measure.

Results

Forty-four studies, including 55 distinct MS patient samples, were found eligible for the systematic review. Twenty-five studies were related to platform therapies (mainly β-interferon [n = 17] and glatiramer acetate [n = 4]), whereas 22 studies were related to escalation therapies (mainly natalizumab [n = 14] and fingolimod [n = 6]). Reported data were mostly confined to the cognitive domain processing speed. A meta-analysis including 41 studies and 7,131 patients revealed a small to moderate positive effect on cognitive test performance of DMTs in general (g = 0.27, 95% confidence interval [CI] = [0.21–0.33]), but no statistically significant differences between platform (g = 0.27, 95% CI = [0.18–0.35]) and escalation therapies (g = 0.28, 95% CI = [0.19–0.37]) or between any single DMT and β-interferon.

Conclusions

DMTs are effective in improving cognitive test performance in RRMS, but a treatment escalation mainly to amend cognition is not supported by the current evidence. Given the multitude of DMTs and their widespread use, the available data regarding differential treatment effects on cognitive impairment are remarkably scant. Clinical drug trials that use more extensive cognitive outcome measures are urgently needed.

Enhanced cognitive performance in experimental autoimmune encephalomyelitis mice treated with dimethyl fumarate after the appearance of disease symptoms

In multiple sclerosis (MS), cognitive dysfunction is common but difficult to treat. We analyzed the impact of dimethyl fumarate, an MS drug with neuroprotective properties, in spatial memory performance in a mouse model of MS and looked for structural correlates in the hippocampus. Treated mice presented better cognitive performance which was not associated with structural hippocampal damage but with decreased demyelination in the fimbria. Dimethyl fumarate, even if initiated after hindlimb paralysis, ameliorated memory deficits in the MS mouse model due, at least in part, to its positive impact in the demyelination of the main hippocampal output pathway.

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.

Acquisition of Early Developmental Milestones and Need for Special Education Services in Pediatric Multiple Sclerosis

Children with pediatric-onset multiple sclerosis and pediatric controls were enrolled across 16 pediatric multiple sclerosis centers in the United States and completed questionnaires that addressed time of first unaided walking and acquisition of 2-word phrases. A total of 467 (308 female) cases and 428 (209 female) controls were enrolled. Pediatric multiple sclerosis (n = 467) were not delayed in walking or using 2-word phrases compared to healthy controls (n = 428) (2.2% vs 5.7%, respectively). Children with disease onset before age 11 versus onset at 11 years or after were more likely to need an individualized education plan (P = .002), reading assistance (P = .0003), and math assistance (P = .001). Children with multiple sclerosis onset prior to age 18 are not delayed in meeting the 2 major early developmental milestones but do have a significantly increased use of special services or learning assistance at school. Further research will need to address whether other measures of development (eg, rate of language acquisition or fine motor skills) differ between pediatric multiple sclerosis and controls.

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.

Targeted proteomic analysis of cognitive dysfunction in remitted major depressive disorder: Opportunities of multi-omics approaches towards predictive, preventive, and personalized psychiatry

In order to accelerate the understanding of pathophysiological mechanisms and clinical biomarker discovery and in psychiatry, approaches that integrate multiple -omics platforms are needed. We introduce a workflow that investigates a narrowly defined psychiatric phenotype, makes use of the potent and cost-effective discovery technology of gene expression microarrays, applies Weighted Gene Co-Expression Network Analysis (WGCNA) to better capture complex and polygenic traits, and finally explores gene expression findings on the proteomic level using targeted mass-spectrometry (MS) technologies. To illustrate the effectiveness of the workflow, we present a proteomic analysis of peripheral blood plasma from patient's remitted major depressive disorder (MDD) who experience ongoing cognitive deficits. We show that co-expression patterns previous detected on the transcript level could be replicated for plasma proteins, as could the module eigengene correlation with cognitive performance. Further, we demonstrate that functional analysis of multi-omics data has the potential to point to cellular mechanisms and candidate biomarkers for cognitive dysfunction in MDD, implicating cell cycle regulation by cyclin D3 (CCND3), regulation of protein processing in the endoplasmatic reticulum by Thioredoxin domain-containing protein 5 (TXND5), and modulation of inflammatory cytokines by Tripartite Motif Containing 26 (TRI26).

SIGNIFICANCE

This paper discusses how data from multiple -omics platforms can be integrated to accelerate biomarker discovery in psychiatry. Using the phenotype of cognitive impairment in remitted major depressive disorder (MDD) as an example, we show that the application of a systems biology approach - weighted gene co-expression network analysis (WGCNA) - in the discovery phase, and targeted proteomic follow-up of results, provides a structured avenue towards uncovering novel candidate markers and pathways for personalized clinical psychiatry.

Dual-Tasking in Multiple Sclerosis - Implications for a Cognitive Screening Instrument

The monitoring of cognitive functions is central to the assessment and consecutive management of multiple sclerosis (MS). Though, especially cognitive processes that are central to everyday behavior like dual-tasking are often neglected. We examined dual-task performance using a psychological-refractory period (PRP) task in N = 21 patients and healthy controls and conducted standard neuropsychological tests. In dual-tasking, MS patients committed more erroneous responses when dual-tasking was difficult. In easier conditions, performance of MS patients did not differ to controls. Interestingly, the response times were generally not affected by the difficulty of the dual task, showing that the deficits observed do not reflect simple motor deficits or deficits in information processing speed but point out deficits in executive control functions and response selection in particular. Effect sizes were considerably large with d∼0.80 in mild affected patients and the achieved power was above 99%. There are cognitive control and dual tasking deficits in MS that are not attributable to simple motor speed deficits. Scaling of the difficulty of dual-tasking makes the test applied suitable for a wide variety of MS-patients and may complement neuropsychological assessments in clinical care and research setting.

Cumulative evidence for MS as a neural network disconnection syndrome consistent with cognitive impairment mechanisms and the confounding role of fatigue and depression-outlook from the Fourth Nordic MS symposium

The Fourth Nordic MS symposium served as a platform to present an overview over the rise and impact of cognitive impairment in people with MS, from early stages on, impairing their quality of life. After discussing MS and cognitive impairment symptoms, a review on the pathophysiology underlying cognitive impairment was given, followed by a talk on neuroimaging highlighting cortical reorganization in MS-affected brains. As a conclusion, therapy and treatment options were discussed. The symposium presented several cutting-edge research studies providing or testing working models that appear successful in predicting and explaining cognitive impairment in MS, such as the disconnection syndrome.