Comparing diagnostic criteria for the diagnosis of neurocognitive disorders in multiple sclerosis

The Prevalence of Cognitive Impairment in Relapsing-Remitting Multiple Sclerosis: A Systematic Review and Meta-analysis

It is increasingly recognized that cognitive symptoms are a common sequelae of relapsing-remitting multiple sclerosis and are associated with adverse functional consequences. However, estimates of cognitive impairment (CIm) prevalence vary widely. This study aimed to determine the pooled prevalence of CIm among adults with RRMS and investigate moderators of prevalence rates. Following prospective registration (PROSPERO; CRD42021281815), electronic databases (Embase, Scopus, Medline, and PsycINFO) were searched from inception until March 2023. Eligible studies reported the prevalence of CIm among adults with RRMS, as determined through standardized neuropsychological testing and defined as evidence of reduced performance across at least two cognitive domains (e.g., processing speed, attention) relative to normative samples, healthy controls, or premorbid estimates. The electronic database search yielded 8695 unique records, of which 50 met selection criteria. The pooled prevalence of cognitive impairment was 32.5% (95% confidence interval 29.3-36.0%) across 5859 participants. Mean disease duration and age were significant predictors of cognitive impairment prevalence, with samples with longer disease durations and older age reporting higher prevalence rates. Studies which administered more extensive test batteries also reported significantly higher cognitive impairment prevalence. Approximately one third of adults with RRMS experience clinical levels of CIm. This finding supports the use of routine cognitive testing to enable early detection of CIm, and to identify individuals who may benefit from additional cognitive and functional support during treatment planning.

Cognitive phenotypes in multiple sclerosis: mapping the spectrum of impairment

BACKGROUND

Available criteria for cognitive phenotypes in multiple sclerosis (MS) do not consider the severity of impairment.

OBJECTIVES

To identify cognitive phenotypes with varying degrees of impairment in MS patients and describe their demographic, clinical and MRI characteristics.

METHODS

Two hundred and forty-three MS patients and 158 healthy controls underwent neuropsychological tests to assess memory, attention, and executive function. For each domain, mild impairment was defined as performing 1.5 standard deviations below the normative mean on two tests, while the threshold for significant impairment was 2 standard deviations. Patients were classified into cognitive phenotypes based on severity of the impairment (mild/significant) and number of domains affected (one/more).

RESULTS

Five cognitive phenotypes emerged: Preserved cognition (PC; 56%), Mild Single-Domain Impairment (MSD; 15%), Mild Multi-Domain Impairment (MMD; 9%), Significant Single-Domain Impairment (SSD; 12%), Significant Multi-Domain Impairment (SMD; 8%). Compared with PC, MSD patients were older, had longer disease duration (DD) and higher T2-hyperintense lesion volume (LV; all p ≤ 0.02); MMD patients were older, had longer DD, higher disability, higher T2 LV and lower thalamic volume (all p ≤ 0.01); SSD patients had longer DD and lower gray matter cortical volume, thalamic, caudate, putamen and accumbens volumes (all p ≤ 0.04); and SMD patients were older, had longer DD, higher disability and more extensive structural damage in all brain regions explored (all p ≤ 0.03), except white matter and amygdala volumes.

CONCLUSIONS

We identified five cognitive phenotypes with graded levels of impairment. These phenotypes were characterized by distinct demographic, clinical and MRI features, indicating potential variations in the neural substrates of dysfunction throughout disease stages.

Domain-specific cognitive impairment in multiple sclerosis: A systematic review and meta-analysis

OBJECTIVE

Methods of cognitive measurements in multiple sclerosis (MS) are not standardized. We aimed to identify the prevalence of cognitive domain-specific impairment (DSI) in MS by using subtests of the Brief Repeatable Battery of Neuropsychological Tests (BRB-N) with analyzing different cutoff values.

METHODS

The systematic review and meta-analysis were registered on PROSPERO (ID: CRD42021287004). The systematic literature search was performed via PubMed, Embase, and CENTRAL on 24 October 2021. Inclusion criteria were adults of different MS subtypes (CIS, RRMS, PPMS, and SPMS) with the condition of distinct DSI measured by BRB-N. Pediatric MS, computerized versions of BRB-N, and patients receiving steroids were excluded. Primary outcome was pooled prevalence rates of impaired patients within each cutoff and MS subtype, with 95% confidence interval, I-squared statistics for heterogeneity, and chi-squared test for subgroup differences. Risk of bias was assessed using the "JBI Quality Assessment Tool for Prevalence Studies."

RESULTS

In 48 eligible observational studies (n = 3431 patients), the three most prevalent thresholds were the 2.0 SD and 1.5 SD below the mean of normative values, and the score below the fifth percentile of the normative values. A progressively increasing worsening of the overall DSI was observed from CIS, moving toward RRMS, PPMS, and SPMS.

INTERPRETATION

Cognitive impairment is observed in all MS phenotypes, with varying degrees. Due to several potential influencing factors, our comprehensive literature review has not revealed consistent findings, and we, therefore, recommend considering a more sophisticated, "individual referencing" approach, acknowledging the diverse clinical and sociodemographic characteristics among populations and disparities in cognitive testing.

Balance rehabilitation for patients with Multiple Sclerosis using a Kinect®-based virtual training program

BACKGROUND

Patients with multiple sclerosis (MS) often experience balance issues during physical activities. Traditional rehabilitation exercises such as stretching, resistance, and aerobic training have been found to be effective, but can be repetitive and tedious, leading to reduced patient motivation and adherence. Furthermore, direct supervision by a therapist is not always possible.

METHODS

The aim of this study was to develop and evaluate the effectiveness of a virtual training program incorporating visual feedback from the Kinect® sensor in male patients with multiple sclerosis. Forty-five participants, with an age range of 22-56 years (mean age = 39), were randomly assigned to one of three equal groups, including two experimental groups and one control group. The experimental groups participated in eight-week exercise interventions, with each session lasting 20 to 30 min and occurring three times per week. In contrast, the control group received no interventions. Within the experimental groups, one was exposed to conventional balance exercises, whereas the other engaged in the proposed virtual training program. Both of these groups undertook three balance exercises, namely the single-foot stance, lunge maneuvers, and arm/leg stretching routines. The assessment encompassed diverse facets of balance, including parameters of 10 Meter Walk Time, Berg Balance Scale, Static Balance Score, and Time-Up and Go Scale, as well as the quality of life, gauged through the Multiple Sclerosis Quality of Life (MSQOL)-54 Questionnaire. The effect of test variables was investigated using analysis of covariance (ANCOVA), while the independent samples t-test was used to check for significant differences among the groups. The effects of the groups were compared using a paired samples t-test.

RESULTS

The findings revealed that both rehabilitation programs positively affected the dependent variables compared to the control group. However, the significant difference between the pre-test and post-test scores of the experimental groups indicated the effectiveness of the proposed program compared to the traditional method.

CONCLUSIONS

Entertaining virtual training programs utilizing visual feedback can be effective for rehabilitating patients with MS. The proposed method enables patients to perform rehabilitation exercises at home with high motivation, while accurate information about the treatment process are provided to the therapist.

Altered social cognition in early relapsing remitting multiple sclerosis

INTRODUCTION

People with multiple sclerosis (pwMS) may suffer from some degree of impaired social cognition (SC), the process that integrates the mental operations underlying social interactions. SC is still not clearly characterized in the early stages of MS, and it is not defined whether SC is independent of cognitive impairment.

METHODS

In this cross-sectional study, we aimed to compare SC measures in a population of early (≤5 years) relapsing-remitting MS (RRMS) with an age, sex, and education-matched control group. All participants performed a clinical and a comprehensive neuropsychological assessment. SC evaluation included assessment of facial emotion recognitionn by the Emotion Recognition Task, affective theory of mind (ToM) by the Reading the Mind in the eyes Test (RMET) and cognitive ToM by the Faux Pas test (FPT). Depression, anxiety, fatigue, and quality of life were also assessed. We included 38 pwMS (mean age 34.8 ± 8.7, 78.9% female sex, mean disease duration 1.9±1.3 years) and 38 healthy controls (mean age 34.9 ± 8.4, 81.6% female sex).

RESULTS

Altered social cognition was present in 34.2% of pwMS. Participants with MS performed worse than controls on measures of cognitive ToM, and affective ToM. There were no differences regarding FER. Cognitive ToM and FER correlated with cognitive functions, but no correlation was found between affective ToM and cognitive tests. The only clinical factor associated with altered SC was poor quality of life.

CONCLUSIONS

Social cognition impairment is already present in a significant percentage of early RRMS patients, namely ToM deficits. While cognitive ToM and FER appears to correlate with impaired cognitive results, affective ToM is likely independent of other cognitive functions.

Assessing everyday functional activity in cognitively impaired people with multiple sclerosis: The use of Actual RealityTM

BACKGROUND

There is considerable evidence that persons with multiple sclerosis (PwMS) who experience cognitive impairments (CIs) are at risk of having significant limitations in activities of daily living (ADLs). However, ADL assessment often consists of proxies or self-report of ADLs. This study examined whether the performance of instrumental ADLs (I-ADL) is impaired in PwMS with and without CI.

METHODS

Participants included 72 PwMS and 48 matched healthy controls (HCs). PwMS were divided into MS-CI (n = 25) and MS-not-impaired (n = 47) groups based on the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) scores. All participants performed the Actual RealityTM (AR) test, measuring I-ADL using authentic websites.

RESULTS

The MS-CI performed significantly worse on AR compared with HC and MS-not-impaired. In addition, the MS-not-impaired performed significantly worse than HC on AR. AR differentiates well between PwMS with and without CI.

CONCLUSIONS

While CI in MS results in significant limitations in the performance of I-ADL, PwMS who do not show evidence of CI can have limitations in I-ADL. AR assessment is a valid and reliable tool sensitive to CI. It should be used in addition to traditional cognitive assessments to detect early functional deterioration through the course of MS.

Cognitive impairment in people with multiple sclerosis: Perception vs. performance - factors that drive perception of impairment differ for patients and clinicians

BACKGROUND

Neurologists' perceptions of the presence of cognitive impairment (CI) in people with multiple sclerosis (PwMS) may not always align with findings of objective cognitive assessment. The accuracy of self-reported CI in PwMS can also be highly variable across individuals, and may not align with objective measurement of cognitive disturbances. Research suggests that additional factors impact perceived cognitive ability, such as depression and fatigue. Objective cognitive screening regardless of patient or neurologist perception has been recommended but still is often limited in routine care. Moreover, comprehensive neuropsychological assessment is even less routinely done.

OBJECTIVE

To explore how neurologists' perceptions of PwMS' CI compare to the perception of the patient by determining whether PwMS and their clinicians are accurate in detecting the presence and degree of CI as defined by a multi-domain validated computerized test battery in PwMS, as well as investigate what factors influence perception of CI in each group.

METHODS

PwMS completed a computerized multi-domain cognitive testing battery, and self-reported measures of disease impact (MSIS-29), fatigue (MFIS), and depression (BDI-II). Disability was assessed by the clinician using the Expanded Disability Status Scale (EDSS). Clinicians and patients also provided an estimation of cognitive deficits along a Likert scale.

RESULTS

In this cohort of PwMS (N=202, age range: 20 to 88, gender: 71% female), their level of accuracy in detecting attention deficits (k = -.028, p = .010) was low but statistically significant. In contrast, clinicians' accuracy in detecting global CI (k = -.037, p < .001) and a number of specific domain deficits was moderate. Fatigue (p < .001) and cognitive performance (p = .012) significantly predicted patient perceived cognitive deficits. Clinician perceived cognitive performance was significantly predicted by multiple factors: cognitive scores (p < .001), physical disability (p = .011), age (p = .021), and depression (p = .038).

CONCLUSION

The need to objectively screen for CI in PwMS, regardless of perception, can be aided by a better understanding of the agreement and discrepancies between the patient and clinician regarding perceived cognitive disturbances and the presence of CI defined by a multi-dimensional objective screening battery.

A proposed new taxonomy of cognitive phenotypes in multiple sclerosis: The International Classification of Cognitive Disorders in MS (IC-CoDiMS)

BACKGROUND

Characterization of cognitive impairment (CI) in multiple sclerosis into distinct phenotypes holds promise for individualized treatments and biomarker exploration.

OBJECTIVE

Apply a previously validated, neuropsychologically driven diagnostic algorithm to identify a taxonomy of the type of cognitive phenotypes in multiple sclerosis.

METHODS

An algorithm developed and validated in other neurological diseases was applied to a cohort of 1281 people with multiple sclerosis who underwent clinical neuropsychological evaluation across three multiple sclerosis centers. A domain was marked impaired if scores on two tests within the domain fell below one of the two thresholds of interest (compared to controls; -1.0 SD and -1.5 SD below the mean). Results were then tabulated for each participant to determine the type of impairments across the sample.

RESULTS

At -1 SD threshold, 48.7% were intact, 21.6% had single-domain, 14.3% bi-domain, and 15.4% multi-domain impairment. At -1.5 SD threshold, 72.9% were intact, 14.0% had single-domain, 8.2% bi-domain, and 5.0% multi-domain impairment. Processing speed was the most frequent single-domain impairment, followed by executive function and memory.

CONCLUSIONS

These findings advance the taxonomy of cognitive phenotypes in multiple sclerosis and clarify the type and distribution of possible cognitive diagnoses, pave the way for further investigation of associated biomarkers, and provide clinically meaningful information to guide individualized treatment and rehabilitation.

Cognitive Decline in Older People with Multiple Sclerosis—A Narrative Review of the Literature

Several important questions regarding cognitive aging and dementia in older people with multiple sclerosis (PwMS) are the focus of this narrative review: Do older PwMS have worse cognitive decline compared to older people without MS? Can older PwMS develop dementia or other neurodegenerative diseases such as Alzheimer’s disease (AD) that may be accelerated due to MS? Are there any potential biomarkers that can help to determine the etiology of cognitive decline in older PwMS? What are the neural and cellular bases of cognitive aging and neurodegeneration in MS? Current evidence suggests that cognitive impairment in MS is distinguishable from that due to other neurodegenerative diseases, although older PwMS may present with accelerated cognitive decline. While dementia is prevalent in PwMS, there is currently no consensus on defining it. Cerebrospinal fluid and imaging biomarkers have the potential to identify disease processes linked to MS and other comorbidities—such as AD and vascular disease—in older PwMS, although more research is required. In conclusion, one should be aware that multiple underlying pathologies can coexist in older PwMS and cause cognitive decline. Future basic and clinical research will need to consider these complex factors to better understand the underlying pathophysiology, and to improve diagnostic accuracy.