Cognitive impairment in patients with multiple sclerosis using the Brief Repeatable Battery-Neuropsychology test

Digital symbol-digit modalities test with modified flexible protocols in patients with CNS demyelinating diseases

Cognitive impairment (CI) is prevalent in central nervous system demyelinating diseases, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). We developed a novel tablet-based modified digital Symbol Digit Modalities Test (MD-SDMT) with adjustable protocols that feature alternating symbol-digit combinations in each trial, lasting one or two minutes. We assessed 144 patients (99 with MS and 45 with NMOSD) using both MD-SDMT protocols and the traditional paper-based SDMT. We also gathered participants' feedback through a questionnaire regarding their preferences and perceived reliability. The results showed strong correlations between MD-SDMT and paper-based SDMT scores (Pearsons correlation: 0.88 for 2 min; 0.85 for 1 min, both p < 0.001). Among the 120 respondents, the majority preferred the digitalized SDMT (55% for the 2 min, 39% for the 1 min) over the paper-based version (6%), with the 2 min MD-SDMT reported as the most reliable test. Notably, patients with NMOSD and older individuals exhibited a preference for the paper-based test, as compared to those with MS and younger patients. In summary, even with short test durations, the digitalized SDMT effectively evaluates cognitive function in MS and NMOSD patients, and is generally preferred over the paper-based method, although preferences may vary with patient characteristics.

Cognitive Impairment Is Related to Glymphatic System Dysfunction in Pediatric Multiple Sclerosis

OBJECTIVE

The aim of this study was to investigate whether, compared to pediatric healthy controls (HCs), the glymphatic system is impaired in pediatric multiple sclerosis (MS) patients according to their cognitive status, and to assess its association with clinical disability and MRI measures of brain structural damage.

METHODS

Sixty-five pediatric MS patients (females = 62%; median age = 15.5 [interquartile range, IQR = 14.5;17.0] years) and 23 age- and sex-matched HCs (females = 44%; median age = 14.1 [IQR = 11.8;16.2] years) underwent neurological, neuropsychological and 3.0 Tesla MRI assessment, including conventional and diffusion tensor imaging (DTI). We calculated the diffusion along the perivascular space (DTI-ALPS) index, a proxy of glymphatic function. Cognitive impairment (Co-I) was defined as impairment in at least 2 cognitive domains.

RESULTS

No significant differences in DTI-ALPS index were found between HCs and cognitively preserved (Co-P) pediatric MS patients (estimated mean difference [EMD] = -0.002 [95% confidence interval = -0.069; 0.065], FDR-p = 0.956). Compared to HCs and Co-P patients, Co-I pediatric MS patients (n = 20) showed significantly lower DTI-ALPS index (EMD = -0.136 [95% confidence interval = -0.214; -0.058], FDR-p ≤ 0.004). In HCs, no associations were observed between DTI-ALPS index and normalized brain, cortical and thalamic volumes, and normal-appearing white matter (NAWM) fractional anisotropy (FA) and mean diffusivity (MD) (FDR-p ≥ 0.348). In pediatric MS patients, higher brain WM lesion volume (LV), higher NAWM MD, lower normalized thalamic volume, and lower NAWM FA were associated with lower DTI-ALPS index (FDR-p ≤ 0.016). Random Forest selected lower DTI-ALPS index (relative importance [RI] = 100%), higher brain WM LV (RI = 59.5%) NAWM MD (RI = 57.1%) and intelligence quotient (RI = 51.3%) as informative predictors of cognitive impairment (out-of-bag area under the curve = 0.762).

INTERPRETATION

Glymphatic system dysfunction occurs in pediatric MS, is associated with brain focal lesions, irreversible tissue loss accumulation and cognitive impairment. ANN NEUROL 2024;95:1080-1092.

Structural and functional imaging features of cognitive phenotypes in pediatric multiple sclerosis

OBJECTIVE

The present study aimed to identify the clinical and MRI features of the distinct cognitive phenotypes in pediatric multiple sclerosis (pedMS).

METHODS

PedMS patients (n = 73) and healthy controls (n = 30) underwent clinical examination and 3.0T MRI. All patients completed neuropsychological testing, and cognitive phenotypes were identified by performing K-means clustering on cognitive scores. MRI metrics included brain T2-hyperintese lesion volume and normalized brain volumes. Within seven cognitively relevant cortical networks, structural disconnectivity (i.e., the mean percentage of streamlines connecting each pair of cortical regions passing through a lesion) and resting-state (RS) functional connectivity (FC) were estimated.

RESULTS

Three cognitive phenotypes emerged: Preserved cognition (PC; n = 27, 37%), mild verbal learning and memory/semantic fluency involvement (MVS; n = 28, 38%), and multidomain involvement (MI; n = 18, 25%). Age, sex, and disease duration did not differ among groups. Compared with healthy subjects, PC patients had decreased RS FC within the default mode network (p = 0.045); MVS patients exhibited lower cortical volume and reduced RS FC within the frontoparietal network (all p = 0.045); and MI patients showed decreased volumes in all brain compartments except the hippocampus, and reduced RS FC within the frontoparietal network (all p ≤ 0.045). Compared to PC, MI patients had more severe disability and higher structural disconnectivity within four cortical networks (all p ≤ 0.045). Compared to PC and MVS, MI patients had lower intelligence quotient (all p ≤ 0.005).

INTERPRETATION

We identified three cognitive phenotypes in pedMS that demonstrate the existence of a spectrum of impairment. Such phenotypes showed distinct clinical and MRI characteristics that contributed to explain their cognitive profiles.

Predictive value of retinal atrophy for cognitive decline across disease duration in multiple sclerosis

BACKGROUND

We investigated the association between changes in retinal thickness and cognition in people with MS (PwMS), exploring the predictive value of optical coherence tomography (OCT) markers of neuroaxonal damage for global cognitive decline at different periods of disease.

METHOD

We quantified the peripapillary retinal nerve fibre (pRFNL) and ganglion cell-inner plexiform (GCIPL) layers thicknesses of 207 PwMS and performed neuropsychological evaluations. The cohort was divided based on disease duration (≤5 years or >5 years). We studied associations between changes in OCT and cognition over time, and assessed the risk of cognitive decline of a pRFNL≤88 µm or GCIPL≤77 µm and its predictive value.

RESULTS

Changes in pRFNL and GCIPL thickness over 3.2 years were associated with evolution of cognitive scores, in the entire cohort and in patients with more than 5 years of disease (p<0.01). Changes in cognition were related to less use of disease-modifying drugs, but not OCT metrics in PwMS within 5 years of onset. A pRFNL≤88 µm was associated with earlier cognitive disability (3.7 vs 9.9 years) and higher risk of cognitive deterioration (HR=1.64, p=0.022). A GCIPL≤77 µm was not associated with a higher risk of cognitive decline, but a trend was observed at ≤91.5 µm in PwMS with longer disease (HR=1.81, p=0.061).

CONCLUSIONS

The progressive retinal thinning is related to cognitive decline, indicating that cognitive dysfunction is a late manifestation of accumulated neuroaxonal damage. Quantifying the pRFNL aids in identifying individuals at risk of cognitive dysfunction.

Can Glatiramer Acetate Prevent Cognitive Impairment by Modulating Oxidative Stress in Patients with Multiple Sclerosis?

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination and neuroinflammation, often accompanied by cognitive impairment. This study aims (1) to investigate the potential of glatiramer acetate (GA) as a therapy for preventing cognitive decline in patients with MS (pwMS) by modulating oxidative stress (OS) and (2) to seek out the differences in cognition between pwMS in a cohort exhibiting good clinical evolution and control subjects (CS). An exploratory, prospective, multicentre, cross-sectional case-control study was conducted, involving three groups at a 1:1:1 ratio-41 GA-treated pwMS, 42 untreated pwMS, and 42 CS. The participants performed a neuropsychological battery and underwent venepuncture for blood sampling. The inclusion criteria required an Expanded Disability Status Scale score of ≤3.0 and a minimum of 5 years of MS disease. Concerning cognition, the CS had a better performance than the pwMS (p = <0.0001), and between those treated and untreated with GA, no statistically significant differences were found. Regarding oxidation, no statistically significant differences were detected. Upon categorizing the pwMS into cognitively impaired and cognitively preserved groups, the lactate was elevated in the pwMS with cognitive preservation (p = 0.038). The pwMS exhibited a worse cognitive performance than the CS. The pwMS treated with GA did not show an improvement in oxidation. Lactate emerged as a potential biomarker for cognitive preservation.

COVID-19 has no impact on disease activity, progression and cognitive performance in people with multiple sclerosis: a 2-year study

BACKGROUND

Sequelae of COVID-19 in people with multiple sclerosis (PwMS) have not been characterised. We explored whether COVID-19 is associated with an increased risk of disease activity, disability worsening, neuropsychological distress and cognitive dysfunction during the 18-24 months following SARS-COV-2 infection.

METHODS

We enrolled 174 PwMS with history of COVID-19 (MS-COVID) between March 2020 and March 2021 and compared them to an age, sex, disease duration, Expanded Disability Status Scale (EDSS), and a line of treatment-matched group of 348 PwMS with no history of COVID-19 in the same period (MS-NCOVID). We collected clinical, MRI data and SARS-CoV2 immune response in the 18-24 months following COVID-19 or baseline evaluation. At follow-up, PwMS also underwent a complete neuropsychological assessment with brief repeatable battery of neuropsychological tests and optimised scales for fatigue, anxiety, depression and post-traumatic stress symptoms.

RESULTS

136 MS-COVID and 186 MS-NCOVID accepted the complete longitudinal evaluation. The two groups had similar rate of EDSS worsening (15% vs 11%, p=1.00), number of relapses (6% vs 5%, p=1.00), disease-modifying therapy change (7% vs 4%, p=0.81), patients with new T2-lesions (9% vs 11%, p=1.00) and gadolinium-enhancing lesions (7% vs 4%, p=1.00) on brain MRI. 22% of MS-COVID and 23% MS-NCOVID were cognitively impaired at 18-24 months evaluation, with similar prevalence of cognitive impairment (p=1.00). The z-scores of global and domain-specific cognitive functions and the prevalence of neuropsychiatric manifestations were also similar. No difference was detected in terms of SARS-CoV2 cellular immune response.

CONCLUSIONS

In PwMS, COVID-19 has no impact on disease activity, course and cognitive performance 18-24 months after infection.

Cognition as a parameter in monitoring the effect of multiple sclerosis relapse treatment: A prospective controlled study

BACKGROUND

Cognitive evaluation was considered to be very important in the relapse period, on the basis of the presence of isolated cognitive attacks and the necessity of monitoring the patient both physically and cognitively.

MATERIALS AND METHODS

People with MS (pwMS) who were hospitalized during relapse were included in the study. All MS patients were evaluated by the neurologist with Expanded Disability Status Scale (EDSS), The 9 Hole Peg Test (9HPT) and the Timed 25-Foot Walk Test (T25-FWT). Additionally, all participants were examined cognitively with the Turkish version of the Brief International Cognitive Assessment for MS (BICAMS) battery. Also, schedules were indicated as during relapse before the treatment (pre-treatment) and the first month after relapse (1-month follow-up).

RESULTS

A total of 140 MS patients (mean age; 34.98±10.09, mean disease duration; 6.05±5.29 years) and 86 healthy controls (mean age; 36.94±10.83) were included to the present study. The mean EDSS scores in pre-treatment in MS patients was 2.74±1.14 and decreased significantly in the 1-month follow-up (1.74±1.24; p<0.001). The mean SDMT score was lower by 8.76 points in MS patients than in HCs) in pre-treatment and 7.66 points in 1-month follow-up (p<0.001). The mean SDMT scores of all participants increased with measurement time gradually (p<0.001).

CONCLUSION

In this study, it was detected which cognitive domains were affected after relapse treatment and cognitive changes in pwMS during relapse and remission periods compared to the healthy controls. All three BICAMS test scores significantly increased in one-month follow-up than the pre-treatment period. The results showed that CVLT-II and BVMT-R scores improved more in pwMS than in HCs, and also SDMT scores of pwMS showed a trend of increase, but was not a significant improvement.

Cognitive rehabilitation program in patients with multiple sclerosis: A pilot study

INTRODUCTION

In recent years, there has been an increase of studies dedicated to cognitive rehabilitation in patients with multiple sclerosis (MS); however, few of these analyze the impact on such variables as cognitive reserve. The study aims to explore the effects of a cognitive rehabilitation program comprising a combination of cognitive and physical exercises, as well as group sessions to improve cognitive performance, emotional state, and cognitive reserve index.

METHOD

Fifty patients with MS were subdivided into 2 groups: the control group, which performed aerobic exercise (n=25), and the experimental group (n=25), which participated in the integrated cognitive rehabilitation program (ICRP). All participants were evaluated 3 times (baseline, post-treatment, and long-term) with the Brief Repeatable Battery of Neuropsychological Tests, Cognitive Reserve Scale, Beck Depression Inventory, and a scale evaluating trait and state anxiety.

RESULTS

Compared with the control group, patients in the experimental group showed improvements in cognitive function, with significant changes in measures of information processing speed, attention, memory, cognitive reserve index, and long-term mood.

CONCLUSIONS

The ICRP was effective in improving cognitive and emotional function in MS, and increased the cognitive reserve index.

Association of the BDNF rs6265 Polymorphism with Cognitive Impairment in Multiple Sclerosis: A Case-Control Study in Mexican Patients

Cognition is a set of brain processes that allow the individual to interact with their environment. Multiple sclerosis (MS) is a chronic inflammatory disease that affects the cerebral white matter of the brain cortex and spinal cord, leading to cognitive impairment (CI) in 40-60% of the patients. Many studies have determined that CI is linked to genetic risk factors. We aimed to evaluate the association between BDNF gene rs6265 polymorphism and cognitive impairment in Mexican patients with MS by performing a case-control study. Mestizo-Mexican patients diagnosed with MS based on McDonald's criteria were enrolled. Cases were MS patients with CI (n = 31) while controls were MS patients without CI (n = 31). To measure cognitive functioning in MS patients, a neuropsychological screening battery for MS (NSB-MS) was used. Genotyping of the rs6265 gene variant was performed using quantitative real-time PCR (qPCR) with TaqMan probes. The results showed no statistically significant differences in sociodemographic and disease variables between case and control groups. qPCR analysis showed that there were 68% Val/Val wild-type homozygotes, 29% Val/Met polymorphic heterozygotes, and 3% Met/Met polymorphic homozygotes. The presence of BDNF gene rs6265 polymorphism showed an increased probability (3.6 times) of global cognitive impairment.

Cognitive impairment and health-related quality of life amongst older Australians: evidence from a longitudinal investigation

INTRODUCTION

Australia's population is steadily growing older, with older persons expected to make up over 20% of the population by 2066. Ageing is strongly associated with a significant drop in cognitive ability, ranging from mild cognitive impairment to severe cognitive impairment (dementia). This study examined the association between cognitive impairment and health-related quality of life (HRQoL) in older Australians.

METHODS

Two waves of longitudinal data from the nationally representative Household, Income and Labour Dynamics in Australia (HILDA) survey were utilised, with the age cut-off for older Australians defined as above 50. The final analysis included 10,737 person-year observations from 6892 unique individuals between 2012 and 2016. This study utilised the Backwards Digit Span (BDS) test and Symbol Digit Modalities test (SDMT) to assess cognitive function. HRQoL was measured using the physical and mental component summary scores of the SF-36 Health Survey (PCS and MCS). Additionally, HRQoL was measured using health state utility values (SF-6D score). A longitudinal random-effects GLS regression model was used to analyse the association between cognitive impairment and HRQoL.

RESULTS

This study found that approximately 89% of Australian adults aged 50 or older had no cognitive impairment, 10.16% had moderate cognitive impairment, and 0.72% had severe cognitive impairment. This study also found that moderate and severe cognitive impairment were both negatively associated with HRQoL. Older Australians with moderate cognitive impairment scored worse on the PCS (β = - 1.765, SE = 0.317), MCS (β = - 1.612, SE = 0.326), and SF-6D (β = - 0.024, SE = 0.004) than peers without cognitive impairment given other covariates reference categories remain constant. Older adults experiencing severe cognitive had lower PCS (β = - 3.560, SE = 1.103), and SF-6D (β = - 0.034, SE = 0.012) scores compared to their counterparts with no cognitive impairment given other covariates reference categories remain constant.

CONCLUSION

We found evidence that HRQoL is negatively associated with cognitive impairment. Our findings will be beneficial for the future cost-effectiveness intervention targeted at reducing cognitive impairment since it provides information on the disutility associated with moderate and severe cognitive impairment.

Cognitive function in primary and secondary progressive multiple sclerosis: A multiparametric magnetic resonance imaging study

BACKGROUND AND PURPOSE

The differences in cognitive function between primary progressive and secondary progressive multiple sclerosis (MS) remain unclear. We compared cognitive performance between primary progressive multiple sclerosis (PPMS) and secondary progressive multiple sclerosis (SPMS), and explored the structural and functional magnetic resonance imaging (MRI) correlates of their cognitive functions.

METHODS

Seventy-five healthy controls and 183 MS patients (60 PPMS and 123 SPMS) underwent 3.0-T MRI. MS patients were administered the Brief Repeatable Battery of Neuropsychological Tests; cognitive domain z-scores were calculated and then averaged to obtain a measure of global cognition. Using hierarchical linear regression analysis, the contribution of lesion volumes, normalized brain volumes, white matter (WM) fractional anisotropy (FA) and mean diffusivity abnormalities, and resting state (RS) functional connectivity (FC) alterations to global cognition in PPMS and SPMS was investigated.

RESULTS

PPMS and SPMS had similar z-scores in all investigated cognitive domains. Poor global cognitive function was associated with decreased FA of the medial lemniscus (ΔR 2  = 0.11, p = 0.011) and lower normalized gray matter volume (ΔR 2  = 0.29, p < 0.001) in PPMS, and with decreased FA of the fornix (ΔR 2  = 0.35, p < 0.001) and lower normalized WM volume (ΔR 2  = 0.05; p = 0.034) in SPMS.

CONCLUSIONS

PPMS and SPMS had similar neuropsychological performance. Cognitive dysfunction in PPMS and SPMS was related to distinct patterns of structural MRI abnormalities and involvement of different WM tracts, whereas RS FC alterations did not contribute to explaining their global cognitive functioning.

Functional and structural brain MRI changes associated with cognitive worsening in multiple sclerosis: a 3-year longitudinal study

BACKGROUND

Heterogeneous processes may contribute to cognitive impairment in multiple sclerosis (MS).

OBJECTIVE

To apply a longitudinal multiparametric MRI approach to identify mechanisms associated with cognitive worsening in MS patients.

METHODS

3 T brain functional and structural MRI scans were acquired at baseline and after a median follow-up of 3.4 years in 35 MS patients and 22 healthy controls (HC). Associations between cognitive worsening (reliable change index score < - 1.25 at the Rao's battery) and longitudinal changes in regional T2-hyperintense white matter (WM) lesions, diffusion tensor microstructural WM damage, gray matter (GM) atrophy and resting state (RS) functional connectivity (FC) were explored.

RESULTS

At follow-up, HC showed no clusters of significant microstructural WM damage progression, GM atrophy or changes in RS FC. At follow-up, 10 MS patients (29%) showed cognitive worsening. Compared to cognitively stable, cognitively worsened MS patients showed more severe GM atrophy of the right anterior cingulate cortex and bilateral supplementary motor area (p < 0.001). Cognitively worsened vs cognitively stable MS patients showed also decreased RS FC in the right hippocampus of the right working memory network and in the right insula of the default mode network. Increased RS FC in the left insula of the executive control network was found in the opposite comparison (p < 0.001). No significant regional accumulation of focal WM lesions nor microstructural WM abnormalities occurred in both patients' groups.

CONCLUSIONS

GM atrophy progression in cognitively relevant brain regions combined with functional impoverishment in networks involved in cognitive functions may represent the substrates underlying cognitive worsening in MS.

Differences in metacognition between multiple sclerosis phenotypes: cognitive impairment and fatigue are key factors

Background

Cognitive impairment is present in 40-65% of patients with multiple sclerosis (pwMS). Objectively measured cognitive performance often does not match patients' subjective perception of their own performance.

Objective

We aimed to compare cognitive performance and subjective perception of cognitive deficits between pwMS and healthy controls (HCs), as well as the accuracy of subjective perception.

Methods

In total, 54 HC and 112 pwMS (relapsing-remitting, RRMS, and progressive PMS) underwent neuropsychological evaluation and completed perceived deficit, fatigue, and anxiety-depression scales. Participants were classified according to their consistency between subjective self-evaluation of cognitive abilities and objective cognitive performance to assess accuracy. Regression models were used to compare cognitive performance between groups and explore factors explaining inaccuracy in the estimation of cognitive performance.

Results

PMS showed greater and more widespread cognitive differences with HC than RRMS. No differences were found between pwMS and HC in the perception of deficit. PMS had higher ratios of overestimators. In explaining inaccuracy, fatigue and cognitive preservation were found to be risk factors for underestimation, whereas physical disability and cognitive impairment were risk factors for overestimation.

Conclusion

PwMS have metacognitive knowledge impairments. This study provides new information about metacognition, data on the prevalence of impairments over a relatively large sample of PwMS, and new insights into factors explaining it. Anosognosia, related to cognitive impairment, may be present in pwMS. Fatigue is a key factor in underestimating cognition.

Multiple Sclerosis and Depression: Translation and Adaptation of the Spanish Version of the Chicago Multiscale Depression Inventory and the Study of Factors Associated with Depressive Symptoms

OBJECTIVE

Depressive disorder occurs in up to 50% of persons with Multiple Sclerosis (PwMS). Accurate assessment of depression in MS is essential in clinical settings because depressive symptomatology can affect the clinical course of the disease.

METHODS

We translated, adapted, and tested the Spanish version of the Chicago Multiscale Depression Inventory (CMDI), a specific test to assess depression in neurological disorders. We compare our results with those obtained with previous versions of the questionnaire (English and Italian). Finally, we also analyze the relationship between the results obtained on the CMDI and demographic, clinical, and cognitive variables.

RESULTS

The results obtained with the Spanish version of the CMDI were similar to those observed in previous published versions. We also observed higher depression scores in PwMS (especially in progressive forms) compared with healthy controls. Moreover, depression symptomatology was related to higher disability and fatigue and worse cognitive performance in PwMS.

CONCLUSIONS

The results support the validity of the CDMI in the Spanish population, as well as the association between depression and other characteristic symptoms of MS. These findings also emphasize the importance of good assessment and multidisciplinary treatment of depression in PwMS.

Pre-training working memory/information processing capabilities and brain atrophy limit the improving effects of cognitive training

Background

Computerized training in persons with multiple sclerosis (PwMS) seems to enhance working memory (WM)/information processing (IP), but factors associated with the efficacy of the treatment have not been sufficiently explored. Objective: To identify clinical and radiological characteristics associated with positive WM/IP training responses.

Methods

Radiological and neuropsychological assessments were carried out on a sample of 35 PwMs who were divided into "WM/IP-impaired" and "WM/IP-preserved." All participants underwent adaptive n-back training for 10 days and were assessed post-training. Between-group differences ("WM/IP-impaired" vs. "WM/IP-preserved") in training-induced cognitive improvement were assessed and exploratory correlational/ regression-based methods were employed to assess the relationship between cognitive improvement and clinical and radiological variables.

Results

All PwMS exhibited WM/IP benefits after training, but those with preserved WM/IP functions showed greater positive effects as well as transfer effects to other WM/IP tests when compared to the impaired group. Additional analyses revealed that positive response to treatment was associated with WM/IP baseline capabilities and greater gray matter volume (GMVOL) in relevant areas such as the thalamus.

Conclusions

Restorative cognitive training is suitable to improve cognition in PwMS but its effective outcome differs depending on the baseline WM/IP capabilities and GMVOL.

Optical coherence tomography (OCT) measurements and cognitive performance in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Several studies report mixed associations between the retinal nerve fiber layer (RNFL) thickness with cognitive and physical disability in persons with multiple sclerosis (PwMS). Systematic synthesis of these findings is crucial in deriving credible conclusions.

METHODS

Five databases were searched from their inception to March 2022. The inclusion criteria for studies were MS-specific and required RNFL and cognitive performance data in order to be analyzed. The selection processes followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

The systematic review yielded 31 studies that investigated the association between RNFL thickness and cognitive performance. Twenty-two studies reported positive associations, and nine did not. The meta-analysis included 11 studies with a total of 782 PwMS with mean age of 40.5 years, mean Expanded Disability Status Scale (EDSS) of 2.7, and disease duration of 11.3 years. RNFL thickness was significantly associated Symbol Digit Modalities Test (pooled r = 0.306, p < 0.001), Paced Auditory Serial Addition Test (pooled r = 0.374, p < 0.001) and Word List Generation (WLG, pooled r = 0.177, p < 0.001). RNFL was also significantly correlated with visuospatial learning and memory tests (pooled r = 0.148, p = 0.042) and verbal learning and memory tests (pooled r = 0.245, p = 0.005). Within three eligible studies, no significant association between ganglion cell inner-plexiform layer and SDMT 0.083 (95% CI - 0.186, 0.352) was noted. The heterogeneity was high in all correlation studies (I² > 63% and p < 0.008) except for the WLG and visuospatial memory findings.

CONCLUSION

RNFL thickness is associated with cognitive processing speed, verbal learning and memory, visual learning and memory, as well as verbal fluency in PwMS. The number of studies included in the meta-analyses were limited due to non-standardized reporting.

Regional white matter and gray matter damage and cognitive performances in multiple sclerosis according to sex

In this study, we investigated whether regional distribution of white matter (WM) lesions, normal-appearing [NA] WM microstructural abnormalities and gray matter (GM) atrophy may differently contribute to cognitive performance in multiple sclerosis (MS) patients according to sex. Using the same scanner, brain 3.0T MRI was acquired for 287 MS patients (females = 173; mean age = 42.1 [standard deviation, SD = 12.7] years; relapsing-remitting = 196, progressive = 91; median Expanded Disability Status Scale = 2.5 [interquartile range, IQR = 1.5-5.0]; median disease duration = 12.1 [IQR = 6.3-19.0] years; treatment: none = 70, first-line = 130, second-line = 87) and 172 healthy controls (HC) (females = 92; mean age = 39.3 [SD = 14.8] years). MS patients underwent also Rao's neuropsychological battery. Using voxel-wise analyses, we investigated in patients sex-related differences in the association of cognitive performances with WM lesions, NAWM fractional anisotropy (FA) and GM volumes (p < 0.01, family-wise error [FWE]). Sixty-six female (38%) and 48 male (42%) MS patients were cognitively impaired, with no significant between-group difference (p = 0.704). However, verbal memory performance was worse in males (p = 0.001), whereas verbal fluency performance was worse in females (p = 0.004). In both sexes, a higher T2-hyperintense lesion prevalence in cognitively-relevant WM tracts was significantly associated with worse cognitive performance (p ≤ 0.006), with stronger associations in females than males in global cognition (p ≤ 0.004). Compared to sex-matched HC, male and female MS patients had widespread lower NAWM FA and GM volume (p < 0.01). In both sexes, worse cognitive performance was associated with widespread reduced NAWM FA (p < 0.01), with stronger associations in females than males in global cognition and verbal memory (p ≤ 0.009). Worse cognitive performance was significantly associated with clusters of cortical GM atrophy in males (p ≤ 0.007) and mainly with deep GM atrophy in females (p ≤ 0.006). In this study, only limited differences in cognitive performances were found between male and female MS patients. A disconnection syndrome due to focal WM lesions and diffuse NAWM microstructural abnormalities seems to be more relevant in female MS patients to explain cognitive impairment.

Oligoclonal IgM bands are a promising biomarker for long-term cognitive outcomes in multiple sclerosis

BACKGROUND

The presence of lipid-specific oligoclonal IgM bands (LS-OCMB) in cerebrospinal fluid is associated with a more severe clinical multiple sclerosis (MS) course.

OBJECTIVE

To investigate LS-OCMB as a prognostic biomarker of cognitive long-term outcomes in MS.

METHODS

Ninety-nine patients underwent neuropsychological assessment. Cognitive performance between LS-OCMB- and LS-OCMB+ patients was compared adjusting by age, education, anxiety-depression, disease duration, and disability.

RESULTS

LS-OCMB+ patients of ∼13 years of disease duration performed worse on Symbol Digit Modalities Test (SDMT) (p = 0.005).

CONCLUSION

LS-OCMB+ perform worse on information processing speed and working memory (SDMT), suggesting that LS-OCMB could be a useful biomarker for long-term cognitive outcomes.

Possible evidence of near transfer effects after adaptive working memory training in persons with multiple sclerosis

BACKGROUND

Cognitive deficits, especially in working memory (WM) and information processing (IP) efficiency, are common in people with multiple sclerosis (PwMS). Few studies have examined the efficacy of n-back training in improving these two cognitive functions in PwMS. In the present study, we examined the effects of an intensive n-back training program by measuring the gains on the trained task (2- and 3-back tasks), but we also studied possible near transfer effects to other tests that assess WM and IP, as well as far transfer effects or improvements in other cognitive functions.

METHODS

A sample consisting of 35 PwMS with different cognitive statuses. All the participants underwent an adaptive n-back training for 10 days (60 min/day), and they were neuropsychologically assessed at baseline (D1) and after training (D10). The effectiveness of the training was tested: (1) by using mean-based comparisons and Cohen's d values; (2) by estimating and comparing the quartile values of the D1 and D10 distributions. Two indexes of improvement in individual performance were calculated, the net score improvement index (NSI) and the percent of maximum possible individualized improvement (PMPI).

RESULTS

Repeat practice improves 2- and 3-back performance, showing more correct responses (CR) and lower reaction times (RT) on D10 compared to D1. These results were corroborated by the NSI and PMPI scores, but the gains after training were more statistically significant for the 3-back (observing higher CR and lower RT after training) than for the 2-back (observing gains in CR, but not in RT). We also observed a possible transference of this improvement on the n-back task to other WM/IPS tests. Specifically, statistically significant pre-post training differences were found in the values in three quartiles of the Paced Auditory Serial Addition Test (PASAT; q25, p < 0.03; q50, p < 0.001; q75, p < 0.002) and of the Symbol Digit Modalities Test (SDMT; q25, p < 0.03; q50, p < 0.001; q75, p < 0.001) as well as in two quartiles of the Letter-Number Sequencing Task (LNST; q50, p < 0.004; q75 p < 0.001), and in one quartile of the Digit Backwards Span Test (DSBT; q75, p < 0.001). Reliable change analyses confirmed these performance improvements on the PASAT, SDMT, and LNST.

CONCLUSIONS

This study confirmed that the intensive and adaptive n-back training produced improvements in the trained task in PwMS with different cognitive statuses. Furthermore, these gains were not only observed on the trained task, but they seemed to be also transferred to other tests that measured WM and IP functions.

Strengthening Mental Abilities with Relational Training (SMART) in multiple sclerosis (MS): study protocol for a feasibility randomised controlled trial

Background

Multiple sclerosis (MS) is a chronic condition of the central nervous system, affecting around 1 in every 600 people in the UK, with 130 new diagnoses every week. Cognitive difficulties are common amongst people with MS, with up to 70% experiencing deficits in higher-level brain functions—such as planning and problem-solving, attention, and memory. Cognitive deficits make it difficult for people with MS to complete everyday tasks and limit their abilities to work, socialise, and live independently. There is a clear need—and recognised research priority—for treatments that can improve cognitive functioning in people with MS. The absence of effective cognitive interventions exacerbates burdens on the services accessed by people with MS—requiring these services to manage sequelae of untreated cognitive deficits, including reduced quality of life, greater disability and dependence, and poorer adherence to disease-modifying treatments. Our planned research will fill the evidence gap through developing—and examining the feasibility of trialling—a novel online cognitive rehabilitation programme for people with MS (SMART). The SMART programme directly trains relational skills (the ability to flexibly relate concepts to one another) based on theory that these skills are critical to broader cognitive functioning.

Methods

The primary objective of this study aims to conduct a feasibility study to inform the development of a definitive trial of SMART for improving cognitive functioning in people with MS. The secondary objective is to develop the framework for a cost-effectiveness analysis alongside a definitive trial, and the exploratory objective is to assess the signal of efficacy.

Discussion

As a feasibility trial, outcomes are unlikely to immediately effect changes to NHS practice. However, this is a necessary step towards developing a definitive trial—and will give us a signal of efficacy, a prerequisite for progression to a definitive trial. If found to be clinically and cost-effective, the latter trial could create a step-change in MS cognitive rehabilitation—improving service delivery and optimising support with limited additional resources.

Trial registration

Registration ID: ClnicalTrials.gov: NCT04975685—registered on July 23rd, 2021.

Protocol version: 2.0, 25 November 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01152-7.

Resting state effective connectivity abnormalities of the Papez circuit and cognitive performance in multiple sclerosis

The Papez circuit is central to memory and emotional processes. However, little is known about its involvement in multiple sclerosis (MS). We aimed to investigate abnormalities of resting state (RS) effective connectivity (EC) between regions of the Papez circuit in MS and their relationship with cognitive performances. Sixty-two MS patients and 64 healthy controls (HC) underwent neuropsychological assessment, 3D T1-weighted, and RS functional MRI. RS EC analysis was performed using SPM12 and dynamic causal modeling. RS EC abnormalities were investigated using parametric empirical Bayes models and were correlated with cognitive scores. Compared to HC, MS patients showed (posterior probability > 0.95) higher EC between the right entorhinal cortex and right subiculum, and lower EC from the anterior cingulate cortex (ACC) to the posterior cingulate cortex (PCC), from left to right subiculum, from left anterior thalamus to ACC, and within ACC and PCC. Lower RS EC from the ACC to the PCC correlated with worse global cognitive scores (rho = 0.19; p = 0.03), worse visuospatial memory (rho = 0.19; p = 0.03) and worse semantic fluency (rho = 0.21; p = 0.02). Lower RS EC from the left to the right subiculum correlated with worse verbal memory (rho = 0.20; p = 0.02), lower RS EC within the ACC correlated with worse attention (rho = -0.19; p = 0.04) and more severe brain atrophy (rho = -0.26; p = 0.003). Higher EC from the right entorhinal cortex to right subiculum correlated with worse semantic fluency (rho = 0.21; p = 0.02). In conclusion, MS patients showed altered RS EC within the Papez circuit. Abnormal RS EC involving cingulate cortices and hippocampal formation contributed to explain cognitive deficits.

The longitudinal relationship between fatigue, depression, anxiety, disability, and adherence with cognitive status in patients with early multiple sclerosis treated with interferon beta-1a

Background

Cognitive dysfunction is common in multiple sclerosis and may worsen with reduced treatment adherence. We examined longitudinal relationships between anxiety, depression, fatigue, disability and adherence with cognitive status in patients with relapsing-remitting multiple sclerosis (MS) treated with interferon beta-1a in four countries.

Methods

The Confidence study is a prospective study in 165 people with MS with four visits (baseline/12/24/36 months). Physical and psychological symptoms were assessed using standardized questionnaires. Adherence was calculated as the number of injections divided by number of expected injections. Cognitive status was assessed by the Brief Repeatable Battery of Neuropsychological Tests and converted to a global Z-score.

Results

At baseline, mean age was 35.7 ± 11 years and 66% were female (n = 109). Adherence to treatment was very high throughout the study (>99%). A depression score ≥ 8 was significantly associated with a higher risk of low cognitive status compared with a lower score (0–7): relative risk 1.79 (1.14–2.83) adjusted for education and time since diagnosis. The P-value-for-time was not significant (P = 0.304) meaning that associations existed since baseline and remained stable during follow-up.

Conclusion

Our findings provide evidence for a longitudinal association between depression and low cognitive status in patients treated with interferon beta-1a in routine medical practice.

•

Long-term effects of adherence to treatment and MS symptoms with cognition are largely unknown.

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Depression was longitudinally associated with a higher risk of low cognitive status in a real-world population.

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Clinical consideration and additional investigation in the treatment of depression for cognitive benefits should be considered.

Cognitive impairment in multiple sclerosis phenotypes: Neuropsychological assessment in a portuguese sample

BACKGROUND

Cognitive impairment affects 40-65% of MS patients, encompassing all disease stages and types of clinical courses. This estimation is based on different instruments used and population normative data.

OBJECTIVE

This study aims to assess the cognitive function in a hospital-based cohort of Portuguese MS patients, to allow estimating the prevalence of cognitive impairment in different phenotypes.

METHODS

Three hundred and thirteen patients with Multiple Sclerosis (MS) underwent neuropsychological assessment with the brief repeatable battery of neuropsychological tests (BRBN-T) and the brief international cognitive assessment for multiple sclerosis (BICAMS).

RESULTS

Differences were observed in the cognitive impairment profile of different disease phenotypes and of the different disease severity stages. RRMS patients performed better in the cognitive test of the BRBN-T and BICAMS than those with progressive disease phenotypes. Relationships between cognitive impairment and disability and professional status were relevant. Although similarities could be observed in the cognitive profile of the MS phenotypes, with predominant involvement of verbal memory, verbal fluency, and information processing speed, the latter was found to be more frequent as the disease progressed.

CONCLUSION

This study contributes to improve knowledge about the cognitive profile of the different MS phenotypes and understand the cognitive characteristics of Portuguese patients.

Innate immune cells and myelin profile in multiple sclerosis: a multi-tracer PET/MR study

PURPOSE

Neuropathological studies have demonstrated distinct profiles of microglia activation and myelin injury among different multiple sclerosis (MS) phenotypes and disability stages. PET imaging using specific tracers may uncover the in vivo molecular pathology and broaden the understanding of the disease heterogeneity.

METHODS

We used the 18-kDa translocator protein (TSPO) tracer (R)-[¹¹C]PK11195 and [¹¹C]PIB PET images acquired in a hybrid PET/MR 3 T system to characterize, respectively, the profile of innate immune cells and myelin content in 47 patients with MS compared to 18 healthy controls (HC). For the volume of interest (VOI)-based analysis of the dynamic data, (R)-[¹¹C]PK11195 distribution volume (V_T) was determined for each subject using a metabolite-corrected arterial plasma input function while [¹¹C]PIB distribution volume ratio (DVR) was estimated using a reference region extracted by a supervised clustering algorithm. A voxel-based analysis was also performed using Statistical Parametric Mapping. Functional disability was evaluated by the Expanded Disability Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC), and Symbol Digit Modality Test (SDMT).

RESULTS

In the VOI-based analysis, [¹¹C]PIB DVR differed between patients and HC in the corpus callosum (P = 0.019) while no differences in (R)-[¹¹C]PK11195 V_T were observed in patients relative to HC. Furthermore, no correlations or associations were observed between both tracers within the VOI analyzed. In the voxel-based analysis, high (R)-[¹¹C]PK11195 uptake was observed diffusively in the white matter (WM) when comparing the progressive phenotype and HC, and lower [¹¹C]PIB uptake was observed in certain WM regions when comparing the relapsing-remitting phenotype and HC. None of the tracers were able to differentiate phenotypes at voxel or VOI level in our cohort. Linear regression models adjusted for age, sex, and phenotype demonstrated that higher EDSS was associated with an increased (R)-[¹¹C]PK11195 V_T and lower [¹¹C]PIB DVR in corpus callosum (P = 0.001; P = 0.023), caudate (P = 0.015; P = 0.008), and total T₂ lesion (P = 0.007; P = 0.012), while better cognitive scores in SDMT were associated with higher [¹¹C]PIB DVR in the corpus callosum (P = 0.001), and lower (R)-[¹¹C]PK11195 V_T (P = 0.013).

CONCLUSIONS

Widespread innate immune cells profile and marked loss of myelin in T₂ lesions and regions close to the ventricles may occur independently and are associated with disability, in both WM and GM structures.

A tractometry principal component analysis of white matter tract network structure and relationships with cognitive function in relapsing-remitting multiple sclerosis

Understanding the brain changes underlying cognitive dysfunction is a key priority in multiple sclerosis (MS) to improve monitoring and treatment of this debilitating symptom. Functional connectivity network changes are associated with cognitive dysfunction, but it is less well understood how changes in normal appearing white matter relate to cognitive symptoms. If white matter tracts have network structure it would be expected that tracts within a network share susceptibility to MS pathology. In the present study, we used a tractometry approach to explore patterns of variance in white matter metrics across white matter (WM) tracts, and assessed how such patterns relate to neuropsychological test performance across cognitive domains. A sample of 102 relapsing-remitting MS patients and 27 healthy controls underwent MRI and neuropsychological testing. Tractography was performed on diffusion MRI data to extract 40 WM tracts and microstructural measures were extracted from each tract. Principal component analysis (PCA) was used to decompose metrics from all tracts to assess the presence of any co-variance structure among the tracts. Similarly, PCA was applied to cognitive test scores to identify the main cognitive domains. Finally, we assessed the ability of tract co-variance patterns to predict test performance across cognitive domains. We found that a single co-variance pattern which captured microstructure across all tracts explained the most variance (65% variance explained) and that there was little evidence for separate, smaller network patterns of pathology. Variance in this pattern was explained by effects related to lesions, but one main co-variance pattern persisted after this effect was regressed out. This main WM tract co-variance pattern contributed to explaining a modest degree of variance in one of our four cognitive domains in MS. These findings highlight the need to investigate the relationship between the normal appearing white matter and cognitive impairment further and on a more granular level, to improve the understanding of the network structure of the brain in MS.

Predominant domains and associated demographic and clinical characteristics in multiple sclerosis-related cognitive impairment in mildly disabled patients

Background

Cognitive impairment (CI) is a common finding in multiple sclerosis (MS); however, there is a limited information about its prevalence in mildly disabled cases. We aimed to determine the most affected domains, and also the relation between the demographic factors and cognitive outcomes in mildly disabled relapsing–remitting MS (RRMS).

Results

Ninety-one mildly disabled RRMS patients with expanded disability status scale (EDSS) < 4 and literacy level above 9 years, were recruited. Based on Minimal Assessment of Cognitive Function in MS (MACFIMS) battery, CI was observed in 19.8% of the patients while 40.60% of the patients had at least one failure in cognitive tests. The most common impaired cognitive domain was information processing speed and working memory (27.5%). There was no significant difference between men and women in terms of CI in our sample (p-values > 0.05). Disease duration (p = 0.01), EDSS (p = 0.01), and education (p < 0.01) were significantly different between CI and non-CI patients, while age (p = 0.72), sex (p = 0.50), diagnostic gap (p = 0.89), and frequency of relapses (p = 0.22), did not differ considerably.

Conclusions

RRMS patients experience some degrees of CI that may present even before the onset of remarkable physical disability; nevertheless, a higher EDSS score and longer disease duration increases the risk of CI. These findings suggest routine cognitive assessment of MS patients.

Cognitive Performance and Health-Related Quality of Life in Patients with Neuromyelitis Optica Spectrum Disorder

Background: The frequency of cognitive impairment (CI) reported in neuromyelitis optica spectrum disorder (NMOSD) is highly variable, and its relationship with demographic and clinical characteristics is poorly understood. We aimed to describe the cognitive profile of NMOSD patients, and to analyse the cognitive differences according to their serostatus; furthermore, we aimed to assess the relationship between cognition, demographic and clinical characteristics, and other aspects linked to health-related quality of life (HRQoL). Methods: This cross-sectional study included 41 patients (median age, 44 years; 85% women) from 13 Spanish centres. Demographic and clinical characteristics were collected along with a cognitive z-score (Rao’s Battery) and HRQoL patient-centred measures, and their relationship was explored using linear regression. We used the Akaike information criterion to model which characteristics were associated with cognition. Results: Fourteen patients (34%) had CI, and the most affected cognitive domain was visual memory. Cognition was similar in AQP4-IgG-positive and -negative patients. Gender, mood, fatigue, satisfaction with life, and perception of stigma were associated with cognitive performance (adjusted R2 = 0.396, p < 0.001). Conclusions: The results highlight the presence of CI and its impact on HRQoL in NMOSD patients. Cognitive and psychological assessments may be crucial to achieve a holistic approach in patient care.

Computational basis of decision-making impairment in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is commonly associated with decision-making, neurocognitive impairments, and mood and motivational symptoms. However, their relationship may be obscured by traditional scoring methods.

OBJECTIVES

To study the computational basis underlying decision-making impairments in MS and their interaction with neurocognitive and neuropsychiatric measures.

METHODS

Twenty-nine MS patients and 26 matched control subjects completed a computer version of the Iowa Gambling Task (IGT). Participants underwent neurocognitive evaluation using an expanded version of the Brief Repeatable Battery. Hierarchical Bayesian Analysis was used to estimate three established computational models to compare parameters between groups.

RESULTS

Patients showed increased learning rate and reduced loss-aversion during decision-making relative to control subjects. These alterations were associated with: (1) reduced net gains in the IGT; (2) processing speed, executive functioning and memory impairments; and (3) higher levels of depression and current apathy.

CONCLUSION

Decision-making deficits in MS patients could be described by the interplay between latent computational processes, neurocognitive impairments, and mood/motivational symptoms.

Assessing the presence of oligoclonal IgM bands as a prognostic biomarker of cognitive decline in the early stages of multiple sclerosis

BACKGROUND

An association has been found between the presence of lipid-specific oligoclonal IgM bands (LS-OCMB) in cerebrospinal fluid and a more severe clinical multiple sclerosis course.

OBJECTIVE

To investigate lipid-specific oligoclonal IgM bands as a prognostic biomarker of cognitive impairment in the early stages of multiple sclerosis.

METHODS

Forty-four patients underwent neuropsychological assessment at baseline and 4 years. Cognitive performance at follow-up was compared adjusting by age, education, anxiety-depression, and baseline performance.

RESULTS

LS-OCMB+ patients only performed worse for Long-Term Storage in the Selective Reminding Test (p = .018).

CONCLUSION

There are no remarkable cognitive differences between LS-OCMB- and LS-OCMB+ patients in the early stages of MS.

Mechanisms of Network Changes in Cognitive Impairment in Multiple Sclerosis

Background and Objectives

Cognitive impairment in multiple sclerosis (MS) is associated with functional connectivity abnormalities. While there have been calls to use functional connectivity measures as biomarkers, there remains to be a full understanding of why they are affected in MS. In this cross-sectional study, we tested the hypothesis that functional network regions may be susceptible to disease-related “wear and tear” and that this can be observable on co-occurring abnormalities on other magnetic resonance metrics. We tested whether functional connectivity abnormalities in cognitively impaired patients with MS co-occur with (1) overlapping, (2) local, or (3) distal changes in anatomic connectivity and cerebral blood flow abnormalities.

Methods

Multimodal 3T MRI and assessment with the Brief Repeatable Battery of Neuropsychological tests were performed in 102 patients with relapsing-remitting MS and 27 healthy controls. Patients with MS were classified as cognitively impaired if they scored ≥1.5 SDs below the control mean on ≥2 tests (n = 55) or as cognitively preserved (n = 47). Functional connectivity was assessed with Independent Component Analysis and dual regression of resting-state fMRI images. Cerebral blood flow maps were estimated, and anatomic connectivity was assessed with anatomic connectivity mapping and fractional anisotropy of diffusion-weighted MRI. Changes in cerebral blood flow and anatomic connectivity were assessed within resting-state networks that showed functional connectivity abnormalities in cognitively impaired patients with MS.

Results

Functional connectivity was significantly decreased in the anterior and posterior default mode networks and significantly increased in the right and left frontoparietal networks in cognitively impaired relative to cognitively preserved patients with MS (threshold-free cluster enhancement corrected at p ≤ 0.05, 2 sided). Networks showing functional abnormalities showed altered cerebral blood flow and anatomic connectivity locally and distally but not in overlapping locations.

Discussion

We provide the first evidence that functional connectivity abnormalities are accompanied by local cerebral blood flow and structural connectivity abnormalities but also demonstrate that these effects do not occur in exactly the same location. Our findings suggest a possibly shared pathologic mechanism for altered functional connectivity in brain networks in MS.

Dynamics and Predictors of Cognitive Impairment along the Disease Course in Multiple Sclerosis

(1) Background: The evolution and predictors of cognitive impairment (CI) in multiple sclerosis (MS) are poorly understood. We aimed to define the temporal dynamics of cognition throughout the disease course and identify clinical and neuroimaging measures that predict CI. (2) Methods: This paper features a longitudinal study with 212 patients who underwent several cognitive examinations at different time points. Dynamics of cognition were assessed using mixed-effects linear spline models. Machine learning techniques were used to identify which baseline demographic, clinical, and neuroimaging measures best predicted CI. (3) Results: In the first 5 years of MS, we detected an increase in the z-scores of global cognition, verbal memory, and information processing speed, which was followed by a decline in global cognition and memory (p < 0.05) between years 5 and 15. From 15 to 30 years of disease onset, cognitive decline continued, affecting global cognition and verbal memory. The baseline measures that best predicted CI were education, disease severity, lesion burden, and hippocampus and anterior cingulate cortex volume. (4) Conclusions: In MS, cognition deteriorates 5 years after disease onset, declining steadily over the next 25 years and more markedly affecting verbal memory. Education, disease severity, lesion burden, and volume of limbic structures predict future CI and may be helpful when identifying at-risk patients.

Cortical Thickness and Serum NfL Explain Cognitive Dysfunction in Newly Diagnosed Patients With Multiple Sclerosis

Background and Objectives

To determine the relative importance of global or regional MRI and blood markers of neurodegeneration and neuroaxonal injury in predicting cognitive performance for recently diagnosed patients with multiple sclerosis (MS).

Methods

Thirty-five newly diagnosed patients with relapsing-remitting MS (RRMS) and 23 healthy controls (HCs) simultaneously completed a full clinical and neuropsychological assessment, structural brain MRI, and serum neurofilament light chain (sNfL) level test. Linear regression analyses were performed to determine which global or regional measures of gray matter (GM) atrophy and cortical thickness (CT), in combination with sNfL levels and clinical scores, are most strongly related to neuropsychological impairment.

Results

Compared with HCs, patients with MS showed bilateral thalamic GM atrophy (left, p = 0.033; right, p = 0.047) and diminished CT, particularly in the right superior and transverse temporal gyri (p = 0.045; p = 0.037). Regional atrophy failed to add predictive variance, whereas anxiety symptoms, sNfL, and global CT were the best predictors (R² = 0.404; p < 0.001) of cognitive outcomes, with temporal thickness accounting for greater variance in cognitive deficits than global CT.

Discussion

Thalamic GM atrophy and thinning in temporal regions represent a distinctive MRI trait in the early stages of MS. Although sNfL levels alone do not clearly differentiate HCs and patients with RRMS, in combination with global and regional CT, sNfL levels can better explain the presence of underlying cognitive deficits. Hence, cortical thinning and sNfL increases can be considered 2 parallel neurodegenerative markers in the pathogenesis of progression in newly diagnosed patients with MS.

Regional grey matter microstructural changes and volume loss according to disease duration in multiple sclerosis patients

The spatio-temporal characteristics of grey matter (GM) impairment in multiple sclerosis (MS) are poorly understood. We used a new surface-based diffusion MRI processing tool to investigate regional modifications of microstructure, and we quantified volume loss in GM in a cohort of patients with MS classified into three groups according to disease duration. Additionally, we investigated the relationship between GM changes with disease severity. We studied 54 healthy controls and 247 MS patients classified regarding disease duration: MS1 (less than 5 years, n = 67); MS2 (5–15 years, n = 107); and MS3 (more than15 years, n = 73). We compared GM mean diffusivity (MD), fractional anisotropy (FA) and volume between groups, and estimated their clinical associations. Regional modifications in diffusion measures (MD and FA) and volume did not overlap early in the disease, and became widespread in later phases. We found higher MD in MS1 group, mainly in the temporal cortex, and volume reduction in deep GM and left precuneus. Additional MD changes were evident in cingulate and occipital cortices in the MS2 group, coupled to volume reductions in deep GM and parietal and frontal poles. Changes in MD and volume extended to more than 80% of regions in MS3 group. Conversely, increments in FA, with very low effect size, were observed in the parietal cortex and thalamus in MS1 and MS2 groups, and extended to the frontal lobe in the later group. MD and GM changes were associated with white matter lesion load and with physical and cognitive disability. Microstructural integrity loss and atrophy present differential spatial predominance early in MS and accrual over time, probably due to distinct pathogenic mechanisms that underlie tissue damage.

Neurocognitive performance in relapsing-remitting multiple sclerosis patients is associated with metabolic abnormalities of the thalamus but not the hippocampus- GABA-edited 1H MRS study

OBJECTIVES

Multiple sclerosis (MS) is an inflammatory demyelinating disease that may cause physical disabling as well as cognitive dysfunction. The presented study investigated how the neuropsychological status depends on the thalamus and hippocampus's metabolic processes, using γ-aminobutyric acid-edited magnetic resonance spectroscopy (GABA-edited ¹H MRS) in patients with early MS, and how the results differ from healthy volunteers.

METHODS

We recruited 36 relapsing-remitting (RRMS) MS patients and 22 controls (CON). In addition to common ¹H MRS metabolites, such as N-acetyl-aspartate (tNAA), myoinositol (mIns), total choline and creatine (tCr, tCho), we also evaluated GABA and glutamate/glutamine (Glx). Metabolite ratios were correlated with the results of Single-Digit Modality Test (SDMT) and Expanded Disability Status Score (EDSS).

RESULTS

In the thalamus, GABA ratios (GABA/tCr, GABA/tNAA) were significantly lower in RRMS patients than in CON. Both tCho- and mIns-ratios correlated with lower scores of SDMT but not with EDSS. Metabolic ratios in the hippocampus did not differ between RRMS and CON and did not correlate with any of performed tests.

DISCUSSION

This study is the first to provide GABA-edited ¹H MRS evidence for MS-related metabolic changes of the thalamus and hippocampus. The findings underline the importance of evaluating subcortical grey matter in MS patients to improve understanding of the clinical manifestations of MS and as a potential future target for treatment.

Cognitive rehabilitation program in patients with multiple sclerosis: A pilot study

INTRODUCTION

In recent years, there has been an increase of studies dedicated to cognitive rehabilitation in patients with multiple sclerosis (MS); however, few of these analyze the impact on such variables as cognitive reserve. The study aims to explore the effects of a cognitive rehabilitation program comprising a combination of cognitive and physical exercises, as well as group sessions to improve cognitive performance, emotional state, and cognitive reserve index.

METHOD

Fifty patients with MS were subdivided into 2 groups: the control group, which performed aerobic exercise (n=25), and the experimental group (n=25), which participated in the integrated cognitive rehabilitation program (ICRP). All participants were evaluated 3 times (baseline, post-treatment, and long-term) with the Brief Repeatable Battery of Neuropsychological Tests, Cognitive Reserve Scale, Beck Depression Inventory, and a scale evaluating trait and state anxiety.

RESULTS

Compared with the control group, patients in the experimental group showed improvements in cognitive function, with significant changes in measures of information processing speed, attention, memory, cognitive reserve index, and long-term mood.

CONCLUSIONS

The ICRP was effective in improving cognitive and emotional function in MS, and increased the cognitive reserve index.

Predicting Neuropsychological Impairment in Relapsing Remitting Multiple Sclerosis: The Role of Clinical Measures, Treatment, and Neuropsychiatry Symptoms

OBJECTIVE

This retrospective observational study aimed to define neuropsychological impairment (NI) profiles and determine the influence of clinical, demographic, and neuropsychiatric measures in specific cognitive domains in a cohort of relapsing-remitting multiple sclerosis (RRMS) patients.

METHODS

Ninety-one RRMS patients underwent a neurological examination and a brief neuropsychological assessment. Patients were classified according to the disease-modifying therapies (DMTs) received (platform or high-efficacy). Differences between groups and multiple regression analyses were performed to determine the predictive value of the assessed measures in cognitive performance.

RESULTS

More than two-thirds of the patients showed NI. Specifically, mild to moderate NI was presented in approximately half of the participants. Paced Auditory Serial Addition Test (PASAT-3) and Symbol Digit Modalities Test (SDMT) were the most frequently impaired cognitive tests (45.3% and 41.3%, respectively) followed by phonemic verbal fluency (PVF) (27.8%). Expanded Disability Status Scale (EDSS), age, depressive symptoms, and disease duration were the best predictors of SDMT (R2 = .34; p < .01), whereas disease duration, EDSS, and anxiety-state levels predicted PASAT-3 (R2 = .33, p < .01). Educational level, age, EDSS, and depressive symptoms demonstrated the strongest association with PVF (R2 = .31, p < .01).

CONCLUSIONS

Our results indicated a significant prevalence of NI in RRMS patients that was not dependent on the DMT type. In addition to the meaningful working memory (PASAT-3) and information processing speed (SDMT) impairments found, PVF deficits may also be an important marker of cognitive impairment in RRMS patients. This study supports the relevance of standard clinical measures and reinforces the importance of quantifying clinical and neuropsychiatric symptoms to predict subsequent cognitive performance on a similar multiple sclerosis phenotype and disease stage.

Group cognitive rehabilitation to reduce the psychological impact of multiple sclerosis on quality of life: the CRAMMS RCT

BACKGROUND

People with multiple sclerosis have problems with memory and attention. The effectiveness of cognitive rehabilitation has not been established.

OBJECTIVES

The objectives were to assess the clinical effectiveness and cost-effectiveness of a cognitive rehabilitation programme for people with multiple sclerosis.

DESIGN

This was a multicentre, randomised controlled trial in which participants were randomised in a ratio of 6 : 5 to receive cognitive rehabilitation plus usual care or usual care alone. Participants were assessed at 6 and 12 months after randomisation.

SETTING

The trial was set in hospital neurology clinics and community services.

PARTICIPANTS

Participants were people with multiple sclerosis who had cognitive problems, were aged 18-69 years, could travel to attend group sessions and gave informed consent.

INTERVENTION

The intervention was a group cognitive rehabilitation programme delivered weekly by an assistant psychologist to between four and six participants for 10 weeks.

MAIN OUTCOME MEASURES

The primary outcome was the Multiple Sclerosis Impact Scale - Psychological subscale at 12 months. Secondary outcomes included results from the Everyday Memory Questionnaire, the 30-Item General Health Questionnaire, the EuroQol-5 Dimensions, five-level version and a service use questionnaire from participants, and the Everyday Memory Questionnaire - relative version and the Modified Carer Strain Index from a relative or friend of the participant.

RESULTS

Of the 449 participants randomised, 245 were allocated to cognitive rehabilitation (intervention group) and 204 were allocated to usual care (control group). Of these, 214 in the intervention group and 173 in the control group were included in the primary analysis. There was no clinically important difference in the Multiple Sclerosis Impact Scale - Psychological subscale score between the two groups at the 12-month follow-up (adjusted difference in means -0.6, 95% confidence interval -1.5 to 0.3; p = 0.20). There were no important differences between the groups in relation to cognitive abilities, fatigue, employment, or carer strain at follow-up. However, there were differences, although small, between the groups in the Multiple Sclerosis Impact Scale - Psychological subscale score at 6 months (adjusted difference in means -0.9, 95% confidence interval -1.7 to -0.1; p = 0.03) and in everyday memory on the Everyday Memory Questionnaire as reported by participants at 6 (adjusted difference in means -5.3, 95% confidence interval -8.7 to -1.9) and 12 months (adjusted difference in means -4.4, 95% confidence interval -7.8 to -0.9) and by relatives at 6 (adjusted difference in means -5.4, 95% confidence interval -9.1 to -1.7) and 12 months (adjusted difference in means -5.5, 95% confidence interval -9.6 to -1.5) in favour of the cognitive rehabilitation group. There were also differences in mood on the 30-Item General Health Questionnaire at 6 (adjusted difference in means -3.4, 95% confidence interval -5.9 to -0.8) and 12 months (adjusted difference in means -3.4, 95% confidence interval -6.2 to -0.6) in favour of the cognitive rehabilitation group. A qualitative analysis indicated perceived benefits of the intervention. There was no evidence of a difference in costs (adjusted difference in means -£574.93, 95% confidence interval -£1878.93 to £729.07) or quality-adjusted life-year gain (adjusted difference in means 0.00, 95% confidence interval -0.02 to 0.02). No safety concerns were raised and no deaths were reported.

LIMITATIONS

The trial included a sample of participants who had relatively severe cognitive problems in daily life. The trial was not powered to perform subgroup analyses. Participants could not be blinded to treatment allocation.

CONCLUSIONS

This cognitive rehabilitation programme had no long-term benefits on quality of life for people with multiple sclerosis.

FUTURE WORK

Future research should evaluate the selection of those who may benefit from cognitive rehabilitation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN09697576.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 4. See the National Institute for Health Research Journals Library website for further project information.

Cortical diffusion kurtosis imaging and thalamic volume are associated with cognitive and walking performance in relapsing-remitting multiple sclerosis

BACKGROUND

In multiple sclerosis (MS), pronounced neurodegeneration manifests itself as cerebral gray matter (GM) atrophy, which is associated with cognitive and physical impairments. Microstructural changes in GM estimated by diffusion kurtosis imaging (DKI) may reveal neurodegeneration that is undetectable by conventional structural MRI and thus serve as a more sensitive marker of disease progression.

OBJECTIVE

The primary objective was to investigate the relationships between morphological and diffusional properties in cerebral GM and physical and cognitive performance in relapsing-remitting MS (RRMS) patients. A secondary objective was to investigate the relationship between GM microstructure and white matter (WM) injury, estimated by the volume of WM lesions.

METHODS

Sixty-seven RRMS patients performed the brief repeatable battery of neuropsychological tests (BRB-N), the 6-minute walk test (6MWT), the six spot step test (SSST), and underwent MRI scans using structural and DKI protocols. GM volumetrics and DKI measurements were analyzed in the cortex and deep GM structures using a general linear model with demographics, physical- and cognitive performance as covariates.

RESULTS

Mean diffusivity (MD) in the cortex was associated with the SSST, 6MWT, information processing, global cognitive performance, and volume of WM lesions. In addition, thalamic volume was associated with SSST (r² = 0.21, 6MWT (r² = 0.18), information processing (r² = 0.21), and WM lesion volume (r² = 0.60).

CONCLUSION

Cortical diffusion and thalamic volume are associated with walking and cognitive performance in RRMS patients and are highly affected by the presence of WM lesions.

Cognitive impairment in multiple sclerosis: diagnosis and monitoring

INTRODUCTION

Cognitive impairment (CI) has a prevalence of 45-70% in people with multiple sclerosis (MS), producing a negative impact on their quality of life, personal life, and work. Early detection of CI has become an important aspect to be considered for an adequate follow-up, to optimize social adaptation and to implement specific cognitive rehabilitation strategies. The aim of this work is to propose a suitable cognitive evaluation of patients with MS based on available and efficient tools for diagnosis and monitoring purposes well supported by literature review and clinical experience.

METHODS

A multidisciplinary panel of professionals from the field of neurology, neuropsychology, and neuroimaging performed a literature review of the topic of cognitive impairment assessment. This was combined and completed with their clinical experience to produce a set of recommendations.

RESULTS

Some limitations to cognitive evaluation are described: shortage of time and resources during the neurology consultation, scarceness or absence of specialized professionals' availability, importance of tests adaptation, and doubts about its use to define therapeutic efficiency. We recommend a baseline and annual screening evaluation, and we suggest a baseline and periodic neuropsychological assessment. The latter ought to change to a recommendation with the presence of either positive screening test, or subjective to cognitive complaints, screening-test results and patient or family report mismatch, or in specific social/work situations.

CONCLUSIONS

Cognitive evaluation should be performed on all patients diagnosed with MS and throughout follow-up. It is necessary to support the creation of multidisciplinary MS teams to optimize the evaluation and follow-up of MS patients.

Cognition in acute relapses: A psychometric evaluation and its correlation with event-related potential, P300 in multiple sclerosis

OBJECTIVE

During acute relapses of multiple sclerosis (MS), physical symptoms attract utmost care. However, cognitive impairment may constitute an substantial part of a new relapse. In this study, we evaluated the cognitive status of MS patients during acute relapses.

MATERIALS AND METHODS

We enrolled 35 definite MS patients and 21 healthy subjects. Neuropsychometric tests and the event-related potential, P300 were administered to the MS patients before corticosteroid treatment, and 3 months later. The control subjects were tested only once.

RESULTS

The differences between the scores of the Timed 25-Foot Walk test, the Brief Repeatable Battery subtests (10/36 SPART, SDMT, SRT, SRT-LTM) in the relapse and remission phases were statistically significant (p = .005, p = .007, p = .05, p = .029, p = .001, respectively). The latencies of P300 waves during the relapses were significantly prolonged than the ones in the remission and the controls' (p = .004, p < .001, respectively).

CONCLUSIONS

In this study, we observed a significant involvement of visual-spatial perception, remote memory, and recall, as well as P300 latencies in acute relapses. The inclusion of cognitive assessment during a relapse can provide accurate information on cognitive status for future treatment modalities.

Manual and automated tissue segmentation confirm the impact of thalamus atrophy on cognition in multiple sclerosis: A multicenter study

BACKGROUND AND RATIONALE

Thalamus atrophy has been linked to cognitive decline in multiple sclerosis (MS) using various segmentation methods. We investigated the consistency of the association between thalamus volume and cognition in MS for two common automated segmentation approaches, as well as fully manual outlining.

METHODS

Standardized neuropsychological assessment and 3-Tesla 3D-T1-weighted brain MRI were collected (multi-center) from 57 MS patients and 17 healthy controls. Thalamus segmentations were generated manually and using five automated methods. Agreement between the algorithms and manual outlines was assessed with Bland-Altman plots; linear regression assessed the presence of proportional bias. The effect of segmentation method on the separation of cognitively impaired (CI) and preserved (CP) patients was investigated through Generalized Estimating Equations; associations with cognitive measures were investigated using linear mixed models, for each method and vendor.

RESULTS

In smaller thalami, automated methods systematically overestimated volumes compared to manual segmentations [ρ=(-0.42)-(-0.76); p-values < 0.001). All methods significantly distinguished CI from CP MS patients, except manual outlines of the left thalamus (p = 0.23). Poorer global neuropsychological test performance was significantly associated with smaller thalamus volumes bilaterally using all methods. Vendor significantly affected the findings.

CONCLUSION

Automated and manual thalamus segmentation consistently demonstrated an association between thalamus atrophy and cognitive impairment in MS. However, a proportional bias in smaller thalami and choice of MRI acquisition system might impact the effect size of these findings.

Altered phase and nonphase EEG activity expose impaired maintenance of a spatial-object attentional focus in multiple sclerosis patients

Some of the anatomical and functional basis of cognitive impairment in multiple sclerosis (MS) currently remains unknown. In particular, there is scarce knowledge about modulations in induced EEG (nonphase activity) for diverse frequency bands related to attentional deficits in this pathology. The present study analyzes phase and nonphase alpha and gamma modulations in 26 remitting-relapsing multiple sclerosis patients during their participation in the attention network test compared with twenty-six healthy controls (HCs) matched in sociodemographic variables. Behavioral results showed that the MS group exhibited general slowing, suggesting impairment in alerting and orienting networks, as has been previously described in other studies. Time–frequency analysis of EEG revealed that the gamma band was related to the spatial translation of the attentional focus, and the alpha band seemed to be related to the expectancy mechanisms and cognitive processing of the target. Moreover, phase and nonphase modulations differed in their psychophysiological roles and were affected differently in the MS and HC groups. In summary, nonphase modulations can unveil hidden cognitive mechanisms for phase analysis and complete our knowledge of the neural basis of cognitive impairment in multiple sclerosis pathology.

Efficacy of high-intensity aerobic exercise on cognitive performance in people with multiple sclerosis: A randomized controlled trial

BACKGROUND

Cognitive impairment is highly prevalent in multiple sclerosis (MS). Progressive aerobic exercise (PAE) represents a promising approach toward preservation or even improvement of cognitive performance in people with MS (pwMS).

OBJECTIVE

To investigate the effects of PAE on the cognitive domains of information processing, learning and memory, and verbal fluency in pwMS.

METHODS

This randomized controlled trial included an exercise (n = 43, 24 weeks of supervised PAE, followed by self-guided physical activity) and a waitlist group (n = 43, 24 weeks of habitual lifestyle, followed by supervised PAE). Assessments included the Brief Repeatable Battery of Neuropsychological tests (BRB-N), self-reported mood, and cardiorespiratory fitness. Published reference data were used to compute Z-scores for BRB-N scores. Cognitive impairment was defined as one or more Z-scores ⩽ -1.5SD.

RESULTS

No between-group changes in the total group were observed in BRB-N scores following PAE. In the cognitively impaired subgroup (43% of the total group) the between-group point estimate suggested a potential clinical relevant improvement in the Symbol Digit Modalities Test (95% CI overlapping zero). Cardiorespiratory fitness increased in the total group and the cognitively impaired subgroup.

CONCLUSION

In the present representative MS group, 24 weeks of supervised PAE had no effect on any cognitive domain in the total group but potentially improved processing speed in the cognitively impaired subgroup.

Impact of Cognitive Reserve and Structural Connectivity on Cognitive Performance in Multiple Sclerosis

Background: Cognitive reserve (CR) could attenuate the impact of the brain burden on the cognition in people with multiple sclerosis (PwMS).

Objective: To explore the relationship between CR and structural brain connectivity and investigate their role on cognition in PwMS cognitively impaired (PwMS-CI) and cognitively preserved (PwMS-CP).

Methods: In this study, 181 PwMS (71% female; 42.9 ± 10.0 years) were evaluated using the Cognitive Reserve Questionnaire (CRQ), Brief Repeatable Battery of Neuropsychological tests, and MRI. Brain lesion and gray matter volumes were quantified, as was the structural network connectivity. Patients were classified as PwMS-CI (z scores = −1.5 SD in at least two tests) or PwMS-CP. Linear and multiple regression analyses were run to evaluate the association of CRQ and structural connectivity with cognition in each group. Hedges's effect size was used to compute the strength of associations.

Results: We found a very low association between CRQ scores and connectivity metrics in PwMS-CP, while in PwMS-CI, this relation was low to moderate. The multiple regression model, adjusted for age, gender, mood, lesion volume, and graph metrics (local and global efficiency, and transitivity), indicated that the CRQ (β = 0.26, 95% CI: 0.17–0.35) was associated with cognition (adj R² = 0.34) in PwMS-CP (55%). In PwMS-CI, CRQ (β = 0.18, 95% CI: 0.07–0.29), age, and network global efficiency were independently associated with cognition (adj R² = 0.55). The age- and gender-adjusted association between CRQ score and global efficiency on having an impaired cognitive status was −0.338 (OR: 0.71, p = 0.036) and −0.531 (OR: 0.59, p = 0.002), respectively.

Conclusions: CR seems to have a marginally significant effect on brain structural connectivity, observed in patients with more severe clinical impairment. It protects PwMS from cognitive decline regardless of their cognitive status, yet once cognitive impairment has set in, brain damage and aging are also influencing cognitive performance.

Impact of chemerin, lipid profile, and insulin resistance on disease parameters in patients with multiple sclerosis

INTRODUCTION

Plasma chemerin, which has chemotactic and adipogenic functions, is increased in several inflammatory diseases. However, its relationship with multiple sclerosis (MS) has not been explored yet. In this study, we aimed to determine chemerin levels and their possible role in MS.

METHODS

Chemerin serum concentrations were evaluated by using ELISA kit in 91 clinically definite MS patients and 52 healthy controls. The mean serum chemerin, insulin, and cholesterol levels were compared. Patients were divided into two groups according to the body mass index (BMI), and the relationships between clinical and metabolic parameters were evaluated.

RESULTS

Serum chemerin levels were 10.46 ± 1.65 ng/mL in MS patients and 10.26 ± 2.14 ng/mL in the control group. No significant difference was found between patients and controls (p = 0.55). We found no difference regarding age, gender, and BMI between two groups (p = 0.053, p = 0.54, p = 0.41). However, female patients with MS had higher chemerin levels than male patients. There were no associations between serum chemerin levels and EDSS score, annualized relapse rate, BMI, insulin resistance, and serum cholesterol levels in MS patients.

CONCLUSION

In this study, we aimed to determine serum chemerin levels in patients with MS. However, in our study, there was no significant difference between serum chemerin levels of MS patients and healthy controls'. Additionally, chemerin levels were not associated with other metabolic parameters, as well as cognitive dysfunction. Further studies are needed to evaluate the role of chemerin in MS patients.

Backward Walking and Dual-Task Assessment Improve Identification of Gait Impairments and Fall Risk in Individuals with MS

Background

Individuals with multiple sclerosis (MS) experience deficits in motor and cognitive domains, resulting in impairment in dual-task walking ability. The goal of this study was to compare performance of forward walking and backward walking in single- and dual-task conditions in persons with MS to age- and sex-matched healthy controls. We also examined relationships between forward and backward walking to cognitive function, balance, and retrospective fall reports.

Methods

All measures were collected in a single session. A 2 × 2 × 2 mixed model ANOVA was used to compare differences in forward and backward walking in single- and dual-task conditions between MS and healthy controls. Spearman correlations were used to examine relationships between gait and cognitive function, falls, and balance.

Results

Eighteen individuals with relapsing-remitting MS and 14 age- and sex-matched healthy controls participated. Backward walking velocity revealed significant differences between groups for both single-task (p = 0.015) and dual-task (p = 0.014) conditions. Persons with MS demonstrated significant differences between single- and dual-task forward and backward walking velocities (p = 0.023; p = 0.004), whereas this difference was only apparent in the backward walking condition for healthy controls (p = 0.004). In persons with MS, there were significant differences in double support time between single- and dual-task conditions in both backward (p < 0.001) and forward (p = 0.001) directions. More falls at six months were significantly associated with shorter backward dual-task stride length (r = −0.490; p = 0.046) and slower velocity (r = −0.483; p = 0.050).

Conclusion

Differences in MS and age- and sex-matched healthy controls are more pronounced during backward compared to forward walking under single- and dual-task conditions. Future work with a larger sample size is needed to validate the clinical utility of backward walking and dual-task assessments and mitigate the limited sensitivity of the current dual-task assessments that primarily rely upon forward walking.

Characterization of multiple sclerosis lesions with distinct clinical correlates through quantitative diffusion MRI

Diffusion magnetic resonance imaging can reveal quantitative information about the tissue changes in multiple sclerosis. The recently developed multi-compartment spherical mean technique can map different microscopic properties based only on local diffusion signals, and it may provide specific information on the underlying microstructural modifications that arise in multiple sclerosis. Given that the lesions in multiple sclerosis may reflect different degrees of damage, we hypothesized that quantitative diffusion maps may help characterize the severity of lesions "in vivo" and correlate these to an individual's clinical profile. We evaluated this in a cohort of 59 multiple sclerosis patients (62% female, mean age 44.7 years), for whom demographic and disease information was obtained, and who underwent a comprehensive physical and cognitive evaluation. The magnetic resonance imaging protocol included conventional sequences to define focal lesions, and multi-shell diffusion imaging was used with b-values of 1000, 2000 and 3000 s/mm² in 180 encoding directions. Quantitative diffusion properties on a macro- and micro-scale were used to discriminate distinct types of lesions through a k-means clustering algorithm, and the number and volume of those lesion types were correlated with parameters of the disease. The combination of diffusion tensor imaging metrics (fractional anisotropy and radial diffusivity) and multi-compartment spherical mean technique values (microscopic fractional anisotropy and intra-neurite volume fraction) differentiated two type of lesions, with a prediction strength of 0.931. The B-type lesions had larger diffusion changes compared to the A-type lesions, irrespective of their location (P < 0.001). The number of A and B type lesions was similar, although in juxtacortical areas B-type lesions predominated (60%, P < 0.001). Also, the percentage of B-type lesion volume was higher (64%, P < 0.001), indicating that these lesions were larger. The number and volume of B-type lesions was related to the severity of disease evolution, clinical disability and cognitive decline (P = 0.004, Bonferroni correction). Specifically, more and larger B-type lesions were correlated with a worse Multiple Sclerosis Severity Score, cerebellar function and cognitive performance. Thus, by combining several microscopic and macroscopic diffusion properties, the severity of damage within focal lesions can be characterized, further contributing to our understanding of the mechanisms that drive disease evolution. Accordingly, the classification of lesion types has the potential to permit more specific and better-targeted treatment of patients with multiple sclerosis.

What Are the Minimal Detectable Changes in SDMT and Verbal Fluency Tests for Assessing Changes in Cognitive Performance in Persons with Multiple Sclerosis and Non-Multiple Sclerosis Controls?

INTRODUCTION

Cognitive impairment is frequent in persons with multiple sclerosis (PwMS) and can impact on activities of daily living. The capacity to differentiate real changes from background statistical noise induced by human, instrumentational, and environmental variations inherent to the evaluation would improve cognitive assessments.

OBJECTIVE

To assess the short-term reproducibility of cognitive tests in non-multiple sclerosis (non-MS) persons and PwMS.

METHODS

Sixty-two PwMS and 19 non-MS persons performed 2 measurements, 1 week apart, of the Symbol Digit Modalities Test (SDMT) and phonological and semantic verbal fluency. Test-retest reliability was evaluated by the intraclass correlation coefficients (ICC) and agreement by standard error of measurement (SEM) and minimum detectable change (MDC).

RESULTS

The reliability of the cognitive variables studied had moderate to high ICC values (ICC > 0.8) in both populations. The threshold to consider a significant cognitive modification evaluated by SEM and MDC was lower in PwMS compared with non-MS persons.

CONCLUSIONS

SDMT and verbal fluency have good short-term reproducibility in PwMS. Specific SEM and MDC cutoffs based on the same design of evaluation (especially retest timing) and to the targeted pathological population (MS vs. healthy) should systematically be used to consider cognitive modification as significant in research protocol as well as in clinical practice.