Brain age as a surrogate marker for cognitive performance in multiple sclerosis.

BACKGROUND AND PURPOSE: Data from neuro-imaging techniques allow us to estimate a brain's age. Brain age is easily interpretable as 'how old the brain looks' and could therefore be an attractive communication tool for brain health in clinical practice. This study aimed to investigate its clinical utility by investigating the relationship between brain age and cognitive performance in multiple sclerosis (MS). METHODS: A linear regression model was trained to predict age from brain magnetic resonance imaging volumetric features and sex in a healthy control dataset (HC_train, n = 1673). This model was used to predict brain age in two test sets: HC_test (n = 50) and MS_test (n = 201). Brain-predicted age difference (BPAD) was calculated as BPAD = brain age minus chronological age. Cognitive performance was assessed by the Symbol Digit Modalities Test (SDMT). RESULTS: Brain age was significantly related to SDMT scores in the MS_test dataset (r = -0.46, p < 0.001) and contributed uniquely to variance in SDMT beyond chronological age, reflected by a significant correlation between BPAD and SDMT (r = -0.24, p < 0.001) and a significant weight (-0.25, p = 0.002) in a multivariate regression equation with age. CONCLUSIONS: Brain age is a candidate biomarker for cognitive dysfunction in MS and an easy to grasp metric for brain health.

The role of hippocampal theta oscillations in working memory impairment in multiple sclerosis.

Working memory (WM) problems are frequently present in people with multiple sclerosis (MS). Even though hippocampal damage has been repeatedly shown to play an important role, the underlying neurophysiological mechanisms remain unclear. This study aimed to investigate the neurophysiological underpinnings of WM impairment in MS using magnetoencephalography (MEG) data from a visual-verbal 2-back task. We analysed MEG recordings of 79 MS patients and 38 healthy subjects through event-related fields and theta (4-8 Hz) and alpha (8-13 Hz) oscillatory processes. Data was source reconstructed and parcellated based on previous findings in the healthy subject sample. MS patients showed a smaller maximum theta power increase in the right hippocampus between 0 and 400 ms than healthy subjects (p = .014). This theta power increase value correlated negatively with reaction time on the task in MS (r = -.32, p = .029). Evidence was provided that this relationship could not be explained by a 'common cause' confounding relationship with MS-related neuronal damage. This study provides the first neurophysiological evidence of the influence of hippocampal dysfunction on WM performance in MS.

Spatiotemporal and spectral dynamics of multi-item working memory as revealed by the n-back task using MEG.

Multi-item working memory (WM) is a complex cognitive function thought to arise from specific frequency band oscillations and their interactions. While some theories and consistent findings have been established, there is still a lot of unclarity about the sources, temporal dynamics, and roles of event-related fields (ERFs) and theta, alpha, and beta oscillations during WM activity. In this study, we performed an extensive whole-brain ERF and time-frequency analysis on n-back magnetoencephalography data from 38 healthy controls. We identified the previously unknown sources of the n-back M300, the right inferior temporal and parahippocampal gyrus and left inferior temporal gyrus, and frontal theta power increase, the orbitofrontal cortex. We shed new light on the role of the precuneus during n-back activity, based on an early ERF and theta power increase, and suggest it to be a crucial link between lower-level and higher-level information processing. In addition, we provide strong evidence for the central role of the hippocampus in multi-item WM behavior through the dynamics of theta and alpha oscillatory changes. Almost simultaneous alpha power decreases observed in the hippocampus and occipital fusiform gyri, regions known to be involved in letter processing, suggest that these regions together enable letter recognition, encoding and storage in WM. In summary, this study offers an extensive investigation into the spatial, temporal, and spectral characteristics of n-back multi-item WM activity.

Neuraxial analgesia is not associated with an increased risk of post-partum relapses in MS.

BACKGROUND: Obstetrical analgesia remains a matter of controversy because of the fear of neurotoxicity of local anesthetics on demyelinated fibers or their potential relationship with subsequent relapses. OBJECTIVE: To assess the impact of neuraxial analgesia on the risk of relapse during the first 3 months post-partum, with a focus on women who experienced relapses during pregnancy. METHODS: We analyzed data of women followed-up prospectively during their pregnancies and at least 3 months post-partum, collected in the Pregnancy in Multiple Sclerosis (PRIMS) and Prevention of Post-Partum Relapses with Progestin and Estradiol in Multiple Sclerosis (POPARTMUS) studies between 1992-1995 and 2005-2012, respectively. The association of neuraxial analgesia with the occurrence of a post-partum relapse was estimated by logistic regression analysis. RESULTS: A total of 389 women were included, 215 from PRIMS and 174 from POPARTMUS. In total, 156 women (40%) had neuraxial analgesia. Overall, 24% experienced a relapse during pregnancy and 25% in the 3 months post-partum. Women with a pregnancy relapse were more likely to have a post-partum relapse (odds ratio (OR) = 1.83, p = 0.02), independently of the use of neuraxial analgesia. There was no association between neuraxial analgesia and post-partum relapse (OR = 1.08, p = 0.78). CONCLUSION: Neuraxial analgesia was not associated with an increased risk of post-partum relapses, whatever multiple sclerosis (MS) activity during pregnancy.

A metformin add-on clinical study in multiple sclerosis to evaluate brain remyelination and neurodegeneration (MACSiMiSE-BRAIN): study protocol for a multi-center randomized placebo controlled clinical trial.

Introduction: Despite advances in immunomodulatory treatments of multiple sclerosis (MS), patients with non-active progressive multiple sclerosis (PMS) continue to face a significant unmet need. Demyelination, smoldering inflammation and neurodegeneration are important drivers of disability progression that are insufficiently targeted by current treatment approaches. Promising preclinical data support repurposing of metformin for treatment of PMS. The objective of this clinical trial is to evaluate whether metformin, as add-on treatment, is superior to placebo in delaying disease progression in patients with non-active PMS. Methods and analysis: MACSiMiSE-BRAIN is a multi-center two-arm, 1:1 randomized, triple-blind, placebo-controlled clinical trial, conducted at five sites in Belgium. Enrollment of 120 patients with non-active PMS is planned. Each participant will undergo a screening visit with assessment of baseline magnetic resonance imaging (MRI), clinical tests, questionnaires, and a safety laboratory assessment. Following randomization, participants will be assigned to either the treatment (metformin) or placebo group. Subsequently, they will undergo a 96-week follow-up period. The primary outcome is change in walking speed, as measured by the Timed 25-Foot Walk Test, from baseline to 96 weeks. Secondary outcome measures include change in neurological disability (Expanded Disability Status Score), information processing speed (Symbol Digit Modalities Test) and hand function (9-Hole Peg test). Annual brain MRI will be performed to assess evolution in brain volumetry and diffusion metrics. As patients may not progress in all domains, a composite outcome, the Overall Disability Response Score will be additionally evaluated as an exploratory outcome. Other exploratory outcomes will consist of paramagnetic rim lesions, the 2-minute walking test and health economic analyses as well as both patient- and caregiver-reported outcomes like the EQ-5D-5L, the Multiple Sclerosis Impact Scale and the Caregiver Strain Index. Ethics and dissemination: Clinical trial authorization from regulatory agencies [Ethical Committee and Federal Agency for Medicines and Health Products (FAMHP)] was obtained after submission to the centralized European Clinical Trial Information System. The results of this clinical trial will be disseminated at scientific conferences, in peer-reviewed publications, to patient associations and the general public. Trial registration: ClinicalTrials.gov Identifier: NCT05893225, EUCT number: 2023-503190-38-00.

Increased brain atrophy and lesion load is associated with stronger lower alpha MEG power in multiple sclerosis patients.

In multiple sclerosis, the interplay of neurodegeneration, demyelination and inflammation leads to changes in neurophysiological functioning. This study aims to characterize the relation between reduced brain volumes and spectral power in multiple sclerosis patients and matched healthy subjects. During resting-state eyes closed, we collected magnetoencephalographic data in 67 multiple sclerosis patients and 47 healthy subjects, matched for age and gender. Additionally, we quantified different brain volumes through magnetic resonance imaging (MRI). First, a principal component analysis of MRI-derived brain volumes demonstrates that atrophy can be largely described by two components: one overall degenerative component that correlates strongly with different cognitive tests, and one component that mainly captures degeneration of the cortical grey matter that strongly correlates with age. A multimodal correlation analysis indicates that increased brain atrophy and lesion load is accompanied by increased spectral power in the lower alpha (8-10 Hz) in the temporoparietal junction (TPJ). Increased lower alpha power in the TPJ was further associated with worse results on verbal and spatial working memory tests, whereas an increased lower/upper alpha power ratio was associated with slower information processing speed. In conclusion, multiple sclerosis patients with increased brain atrophy, lesion and thalamic volumes demonstrated increased lower alpha power in the TPJ and reduced cognitive abilities.

Correction to: Detecting neurodegenerative pathology in multiple sclerosis before irreversible brain tissue loss sets in.

[This corrects the article DOI: 10.1186/s40035-019-0178-4.].

Detecting neurodegenerative pathology in multiple sclerosis before irreversible brain tissue loss sets in.

BACKGROUND: Multiple sclerosis (MS) is a complex chronic inflammatory and degenerative disorder of the central nervous system. Accelerated brain volume loss, or also termed atrophy, is currently emerging as a popular imaging marker of neurodegeneration in affected patients, but, unfortunately, can only be reliably interpreted at the time when irreversible tissue damage likely has already occurred. Timing of treatment decisions based on brain atrophy may therefore be viewed as suboptimal. MAIN BODY: This Narrative Review focuses on alternative techniques with the potential of detecting neurodegenerative events in the brain of subjects with MS prior to the atrophic stage. First, metabolic and molecular imaging provide the opportunity to identify early subcellular changes associated with energy dysfunction, which is an assumed core mechanism of axonal degeneration in MS. Second, cerebral hypoperfusion has been observed throughout the entire clinical spectrum of the disorder but it remains an open question whether this serves as an alternative marker of reduced metabolic activity, or exists as an independent contributing process, mediated by endothelin-1 hyperexpression. Third, both metabolic and perfusion alterations may lead to repercussions at the level of network performance and structural connectivity, respectively assessable by functional and diffusion tensor imaging. Fourth and finally, elevated body fluid levels of neurofilaments are gaining interest as a biochemical mirror of axonal damage in a wide range of neurological conditions, with early rises in patients with MS appearing to be predictive of future brain atrophy. CONCLUSIONS: Recent findings from the fields of advanced neuroradiology and neurochemistry provide the promising prospect of demonstrating degenerative brain pathology in patients with MS before atrophy has installed. Although the overall level of evidence on the presented topic is still preliminary, this Review may pave the way for further longitudinal and multimodal studies exploring the relationships between the abovementioned measures, possibly leading to novel insights in early disease mechanisms and therapeutic intervention strategies.

The effect of task modality and stimulus frequency in paced serial addition tests on functional brain activity.

INTRODUCTION: The paced serial addition test (PSAT) is regularly used to assess cognitive deficits in various neuropsychiatric conditions. Being a complex test, it reflects the status of multiple cognitive domains such as working memory, information processing speed and executive functioning. Two versions of the PSAT exist. One uses auditory stimuli through spoken numbers and is known as the PASAT, while the other one presents patients with visual stimuli and is called PVSAT. The PASAT is considered more frustrating by patients, and hence the visual version is usually preferred. Research has suggested that an interference might exist between patients' verbal answers and the auditory presentation of stimuli. We therefore removed the verbal response in this study, and aimed to investigate differences in functional brain activity through functional magnetic resonance imaging. METHODS: Fifteen healthy controls performed the two test versions inside an MRI scanner-switching between stimulus modality (auditory vs. visual) as well as inter-stimulus frequency (3s vs. 2s). We extracted 11 independent components from the data: attentional, visual, auditory, sensorimotor and default mode networks. We then performed statistical analyses of mean network activity within each component, as well as inter-network connectivity of each component pair during the different task types. RESULTS: Unsurprisingly, we noted an effect of modality on activity in the visual and auditory components. However, we also describe bilateral frontoparietal, anterior cingulate and insular attentional network activity. An effect of frequency was noted only in the sensorimotor network. Effects were found on edges linking visual and auditory regions. Task modality influenced an attentional-sensorimotor connection, while stimulus frequency had an influence on sensorimotor-default mode connections. CONCLUSIONS: Scanner noise during functional MRI may interfere with brain activation-especially during tasks involving auditory pathways. The question whether to use PVSAT or PASAT for an fMRI study is, therefore, an important one. Specific effects of both modalities should be known to study designers. We conclude that both tests should not be considered interchangeable, as significant changes were brought to light during test performance in different modalities.

Does including the full CVLT-II and BVMT-R improve BICAMS? Evidence from a Belgian (Dutch) validation study.

BACKGROUND: The Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) is a fast, easy-to-administer and already widely validated neuropsychological battery for cognition in multiple sclerosis. OBJECTIVE: The goals of our study were to validate the BICAMS in a Belgian Dutch-speaking population and to investigate to what extent including extensive versions of two of the three BICAMS subtests improved its psychometric qualities. METHODS: Ninety-seven persons with MS and ninety-seven healthy controls were included and group-matched on age, education level and gender. All participants performed the BICAMS with an extensive version of the CVLT-II and BVMT-R. RESULTS: The SDMT and BVMT-R were able to dissociate between the MS and healthy control group, while the CVLT-II was not. Distributions of CVLT-II scores suggest learning effects in the MS group, indicating the need for alternative word lists or the construction of an adapted version fitted for repeated administration. Including the full CVLT-II and BVMT-R did not markedly improve the psychometric qualities of the BICAMS. CONCLUSION: This study validates the BICAMS in a Belgian Dutch-speaking population and facilitates the use of it in clinical practice, while providing evidence that including full versions of the CVLT-II and BVMT-R does not increase its psychometric qualities markedly.

Paced visual serial addition test in multiple sclerosis.

The paced auditory serial addition test (PASAT), a subtest of the multiple sclerosis functional composite score (MSFC), is increasingly used in the evaluation of cognitive function in multiple sclerosis (MS). While patient acceptance for the PASAT is low, its visual version, the paced visual serial addition test (PVSAT), is perceived to be better tolerated. The aim of this study was to investigate the interchangeability of PVSAT and PASAT in the evaluation of cognitive function in MS. Twenty-one normal controls and 50 patients with clinically definite MS were tested with PASAT and PVSAT. Both for PASAT and PVSAT, 3 and 2-second versions of two parallel test forms were used. In the PVSAT, the PASAT stimuli were shown on a computer screen. Patients were also tested with the other two MSFC subtests, i.e. the nine-hole pegboard test and timed 25-foot walk test, to calculate MSFC scores. PASAT-3 correlated highly with both PVSAT-3 and PVSAT-2. MSFC-v scores calculated with PVSAT-2 and PVSAT-3 values correlated highly with MSFC scores calculated with PASAT-3 results. The results suggest that the PVSAT can be used as an alternative for the PASAT in the MSFC.

Impact of a 5-day expedition to machu picchu on persons with multiple sclerosis.

Persons with multiple sclerosis (MS) are less physically active than nondiseased persons and often report low self-efficacy levels. In the context of an awareness project to promote physical activity and participation in MS, we addressed the impact of training for and participation in a unique expedition. Medical events, relapses, and self-reported neurological worsening were followed from 6 months before and up to 4 months afterwards. Validated patient-reported outcome measures were used to assess fatigue, self-efficacy in exercising, walking abilities, and illness perception. Nine participants completed the training, expedition, and observational study. Minor events, relapses, and/or neurological worsening were reported in six participants. The three participants with mild disability and no cardiovascular risk factors or comorbidities were free of medical and neurological events. We found a significant reduction of motor fatigue at last when compared with the first assessment. The reduction tended to be more evident in participants with mild disability (Expanded Disability Status Scale (EDSS) <4 at baseline). Cognitive fatigue, self-efficacy, and self-reported walking abilities did not change significantly. Illness perceptions tended to be reduced over time in the domains of consequences, identity, and concerns. Overall, no major adverse events occurred.

Self-reported health promotion and disability progression in multiple sclerosis.

BACKGROUND: Health behavior may be associated with disability progression in multiple sclerosis (MS). OBJECTIVES: To investigate health-promoting behavior as measured by the Health-Promoting Lifestyle Profile II, which includes the subscales of health responsibility, physical activity, nutrition, spiritual growth, interpersonal relationships and stress management. METHODS: We conducted a cross-sectional survey among individuals with MS, registered by the Flemish MS society, Belgium. Scores for the total scale and subscales were categorized into quintiles. A time-to-event analysis and Cox proportional hazard regression were performed with time to Expanded Disability Status Score (EDSS) of 6 (requires a cane) as an outcome measure. Hazard ratios for the time from onset and the time from birth were adjusted for gender, age at onset and immunomodulatory treatment. The first category was the reference group (first quintile). RESULTS: Data on 1372 respondents with definite MS were collected. Subjects with relapsing onset MS and higher scores for overall health-promoting behavior, and the subscales of physical activity, nutrition and spiritual growth, had a reduced risk of reaching EDSS 6 compared to the reference group. No associations were found for the subscales of health responsibility, stress management and interpersonal relations. In progressive onset MS, no significant associations were obtained. CONCLUSION: Our study shows an association of self-reported health promoting behavior with disability progression in subjects with relapsing onset MS.

Consensus guidelines on the neurologist's role in the management of neurogenic lower urinary tract dysfunction in multiple sclerosis.

OBJECTIVE: To review current management of neurogenic lower urinary tract dysfunction (NLUTD) in MS patients and give recommendations on the joint role of the neurologist and urologist in NLUTD management. METHODS: An algorithm for evaluation and referral of MS patients to urologists was created. It is an outcome of discussions about current knowledge, existing guidelines, and key issues during two Belgian consensus meetings attended by neurologists, urologists and other stakeholders involved in MS management. At these meetings, updated information on management of NLUTD in MS was exchanged and the neurologists' opinion on how to integrate this in the other aspects of care in MS patients was explored. RESULTS: Short evaluation of NLUTD in MS patients by neurologists and appropriate referral to urologists could accelerate proper diagnosis and treatment. Neurologists can play a central role in the inter-disciplinary communication on interactions between disease manifestations of MS and their treatments. CONCLUSION: The coordinating role of neurologists in NLUTD management may considerably improve QoL in MS patients. More research is needed to evaluate outcomes of urological assessments and treatment.