Is the Symbol Digit Modalities Test a useful outcome in secondary progressive multiple sclerosis?

Digital outcome measures are associated with brain atrophy in patients with multiple sclerosis

BACKGROUND

Digital monitoring of people with multiple sclerosis (PwMS) using smartphone-based monitoring tools is a promising method to assess disease activity and progression.

OBJECTIVE

To study cross-sectional and longitudinal associations between active and passive digital monitoring parameters and MRI volume measures in PwMS.

METHODS

In this prospective study, 92 PwMS were included. Clinical tests [Expanded Disability Status Scale (EDSS), Timed 25 Foot Walk test (T25FW), 9-Hole Peg Test (NHPT), and Symbol Digit Modalities Test (SDMT)] and structural MRI scans were performed at baseline (M0) and 12-month follow-up (M12). Active monitoring included the smartphone-based Symbol Digit Modalities Test (sSDMT) and 2 Minute Walk Test (s2MWT), while passive monitoring was based on smartphone keystroke dynamics (KD). Linear regression analyses were used to determine cross-sectional and longitudinal relations between digital and clinical outcomes and brain volumes, with age, disease duration and sex as covariates.

RESULTS

In PwMS, both sSDMT and SDMT were associated with thalamic volumes and lesion volumes. KD were related to brain, ventricular, thalamic and lesion volumes. No relations were found between s2MWT and MRI volumes. NHPT scores were associated with lesion volumes only, while EDSS and T25FW were not related to MRI. No longitudinal associations were found for any of the outcome measures between M0 and M12.

CONCLUSION

Our results show clear cross-sectional correlations between digital biomarkers and brain volumes in PwMS, which were not all present for conventional clinical outcomes, supporting the potential added value of digital monitoring tools.

Correlation between cognitive changes and neuroradiological changes over time in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

While many studies have examined relationships of neuroimaging variables to cognitive measures in multiple sclerosis (MS), longitudinal studies are lacking. The relationship of cognitive changes to neuroradiological changes in MS is thus incompletely understood. The present study systematically reviews all studies reporting a relationship between MRI changes and cognitive changes after at least one year of follow-up.

METHOD

An extensive and methodical search of online databases was conducted to identify qualified studies until August 2023. Among various cognitive tests and magnetic resonance imaging (MRI) measures, Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), verbal fluency, T2 lesion volume (T2LV), white matter lesion volume (WML), and grey matter volume (GMV) qualified for inclusion in a meta-analysis investigating the association of cognitive changes to neuroradiological changes.

RESULTS

We identified 35 studies that explored the link between MRI changes and changes in cognitive outcomes. Of these, twenty studies (57.14%) investigated the association between SDMT/PASAT and MRI metrics. Eleven studies (31.42%) focused on the relationship between MRI metrics and verbal learning and memory, while ten studies (28.57%) reported associations with visuospatial learning and memory. Furthermore, eight studies (22.85%) analyzed the correlation between verbal fluency and MRI measures. Only 5 were eligible for inclusion in the meta-analysis. The meta-analysis evaluated correlations between SDMT/PASAT and GMV (rs = 0.67, 95% CI 0.44-0.91), and verbal fluency and T2LV (rs = 0.35, 95% CI 0.09-0.60).

CONCLUSION

In this rigorously conducted systematic review, we found a significant association of cognitive changes, specifically SDMT/PASAT and verbal fluency, to changes in T2LV and atrophy in individuals with MS. Findings should be interpreted cautiously due to the limited amount of high-quality research, small sample sizes, and variability in study methodologies.

Impact of Cognitive Impairment on Quality of Life in Multiple Sclerosis Patients-A Comprehensive Review

Multiple sclerosis (MS) is characterized by a variety of symptoms that have a major impact on quality of life (QoL) even in early stages. In addition to individual motor, sensory, visual disturbances, and brainstem and sphincter disorders, which are expressed through the widely used Expanded Disability Status Scale (EDSS), other manifestations of MS have a detrimental effect on overall functioning and quality of life, such as cognitive impairment, depression, anxiety, fatigue, and pain. However, when talking about QoL, categorical definitions cannot be used because although the concept is generally understood, it is highly nuanced. Suffering from MS can significantly reduce QoL. Numerous research studies have focused on trying to identify and assess which are the elements that most affect the loss of QoL in MS people. However, in addition to the fact that the measurement of QoL can be subjective, it is very difficult to consider these elements in isolation, as they are interrelated. One such limiting factor of QoL that has been investigated is cognitive impairment (CI). This has been shown to have an impact on the lives of MS people, although the different approaches that have been taken to assess CI have evident limitations.

Biomarkers of disability worsening in inactive primary progressive multiple sclerosis

OBJECTIVE

To investigate serum biomarkers of progression in inactive primary progressive multiple sclerosis (PPMS).

METHODS

We measured protein biomarkers (growth differentiation factor-15 (GDF-15), dickkopf-1 (DKK-1), neuron specific enolase (NSE) and cathepsin-D) in serum samples from 39 patients with inactive PPMS included in a clinical trial enrolling people with PPMS (clinicaltrials.gov identifier NCT02913157) and investigated the association of these biomarker levels with clinical disability at baseline and during follow-up. We then performed a meta-analysis of publicly available transcriptomic datasets to investigate the gene expression of these biomarkers in the CNS in progressive MS.

RESULTS

When compared with healthy controls, people with PPMS had higher serum levels of GDF-15, DKK-1 and cathepsin-D at baseline. These findings match those in our meta-analysis which found increased expression of GDF-15 and cathepsin-D in the CNS in progressive MS. At baseline, elevated serum DKK-1 was associated with worse Expanded Disability Status Scale (EDSS) and nine-hole peg test (9HPT) scores. None of the other biomarkers levels significantly correlated with EDSS, Timed 25-Foot Walk Test (T25FWT), 9HPT, or cognitive measures. However, serum GDF-15 and cathepsin-D were higher at baseline in participants who developed worsening disability. Our receiver operating characteristic curve showed that higher serum GDF-15 and cathepsin-D at baseline significantly discriminated between participants who worsened in T25FWT and 9HPT and those who remained stable.

CONCLUSIONS

Patients with PPMS have altered levels of GDF-15, DKK-1 and cathepsin-D in serum, and GDF-15 and cathepsin-D may have predictive value in progression free of inflammatory activity in PPMS.

Neurodegeneration and its potential markers in the diagnosing of secondary progressive multiple sclerosis. A review

Approximately 70% of relapsing-remitting multiple sclerosis (RRMS) patients will develop secondary progressive multiple sclerosis (SPMS) within 10-15 years. This progression is characterized by a gradual decline in neurological functionality and increasing limitations of daily activities. Growing evidence suggests that both inflammation and neurodegeneration are associated with various pathological processes throughout the development of MS; therefore, to delay disease progression, it is critical to initiate disease-modifying therapy as soon as it is diagnosed. Currently, a diagnosis of SPMS requires a retrospective assessment of physical disability exacerbation, usually over the previous 6-12 months, which results in a delay of up to 3 years. Hence, there is a need to identify reliable and objective biomarkers for predicting and defining SPMS conversion. This review presents current knowledge of such biomarkers in the context of neurodegeneration associated with MS, and SPMS conversion.

Longitudinal Changes in Cognitive Test Scores in Patients With Relapsing-Remitting Multiple Sclerosis: An Analysis of the DECIDE Dataset

BACKGROUND AND OBJECTIVES

Cognitive impairment is a common and impactful symptom of relapsing-remitting multiple sclerosis (RRMS). Cognitive outcome measures are often used in cross-sectional studies, but their performance as longitudinal outcome measures in clinical trials is not widely researched. In this study, we used data from a large clinical trial to describe change on the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT) over up to 144 weeks of follow-up.

METHODS

We used the data set from DECIDE (clinicaltrials.gov identifier NCT01064401), a large randomized controlled RRMS trial to describe change on the SDMT and PASAT over 144 weeks of follow-up. We compared change on these cognitive outcomes with change on the timed 25-foot walk (T25FW), a well-established physical outcome measure. We investigated several definitions for clinically meaningful change: any change, 4-point change, 8-point change, and 20% change for the SDMT, any change, 4-point change, and 20% change for the PASAT, and 20% change for the T25FW.

RESULTS

DECIDE included 1,814 trial participants. SDMT and PASAT scores steadily improved throughout follow-up: the SDMT from a mean 48.2 (SD, 16.1) points at baseline to 52.6 (SD 15.2) at 144 weeks and the PASAT from 47.0 (SD 11.3) at baseline to 50.0 (SD 10.8) at 144 weeks. This improvement in scores is most likely due to a practice effect. Throughout the trial, participants were more likely to experience improvement than worsening of their SDMT and PASAT performance, whereas the number of worsening events on the T25FW steadily increased. Changing the definition of clinically meaningful change for the SDMT and PASAT or using a 6-month confirmation changed the overall number of worsening or improvement events but did not affect the overall behavior of these measures.

DISCUSSION

Our findings suggest that the SDMT and PASAT scores do not accurately reflect the steady cognitive decline that people with RRMS experience. Both outcomes show postbaseline increases in scores, which complicates the interpretation of these outcome measures in clinical trials. More research into the size of these changes is needed before recommending a general threshold for clinically meaningful longitudinal change.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Consensus for the Early Identification of Secondary Progressive Multiple Sclerosis in Portugal: a Delphi Panel

INTRODUCTION

Multiple sclerosis is a disease with a heterogeneous evolution. The early identification of secondary progressive multiple sclerosis is a clinical challenge, which would benefit from the definition of biomarkers and diagnostic tools applicable in the transition phase from relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis. We aimed to reach a Portuguese national consensus on the monitoring of patients with multiple sclerosis and on the more relevant clinical variables for the early identification of its progression.

MATERIAL AND METHODS

A Delphi panel which included eleven Portuguese Neurologists participated in two rounds of questions between July and August of 2021. In the first round, 39 questions which belonged to the functional, cognitive, imaging, biomarkers and additional evaluations were included. Questions for which no consensus was obtained in the first round (less than 80% of agreement), were appraised by the panel during the second round.

RESULTS

The response rate was 100% in both rounds and consensus was reached for a total of 33 questions (84.6%). Consensus was reached for monitoring time, evaluation scales and clinical variables such as the degree of brain atrophy and mobility reduction, changes suggestive of secondary progressive multiple sclerosis. Additionally, digital devices were considered tools with potential to identify disease progression. Most questions for which no consensus was obtained referred to the cognitive assessment and the remaining referred to both functional and imaging domains.

CONCLUSION

Consensus was obtained for the determination of the monitorization interval and for most of the clinical variables. Most questions that did not reach consensus were related with the confirmation of progression taking into account only one test/domain, reinforcing the multifactorial nature of multiple sclerosis.

Are we ready to define cognitive worsening in MS? How different cutoffs detect future cognitive worsening after six years of follow-up

BACKGROUND

Although cognitive evaluation has been incorporated in recent MS clinical trials, the definition of cognitive progression is not clear and recent data are questioning the 4-point cutoff using the SDMT at the individual level. We aimed to evaluate the behavior of cognitive performance over time using different cutoffs.

METHODS

Cognitive performance over six years was analyzed in a cohort of 42 relapsing-remitting MS patients and 30 controls using verbal/visual memory and information processing speed tests. Fixed cutoffs were: 10% and 20% change (all tests) and a 4- and 8-point change (SDMT). The relative cutoff established by regression-based models was a 1SD change.

RESULTS

The distributions of "worsening", "stability", and "improvement" showed low concordance rates across the cutoffs (p < 0.001 for most comparisons). Most patients classified with worsening initially using fixed cutoffs had subsequent improvement in all cognitive tests, yielding a low sensitivity to predict later cognitive worsening. Using the relative cutoff, the proportion of patients with subsequent improvement was noticeably smaller.

CONCLUSIONS

Fixed cutoffs classify a high proportion of patients with cognitive improvement. Most patients categorized with worsening initially presented subsequent improvement. Instead, the relative cutoff generally had a better performance. These data raise concerns about how we are defining cognitive worsening so far, especially at the individual level.

Clinical and Paraclinical Biomarkers and the Hitches to Assess Conversion to Secondary Progressive Multiple Sclerosis: A Systematic Review

Conversion to secondary progressive (SP) course is the decisive factor for long-term prognosis in relapsing multiple sclerosis (MS), generally considered the clinical equivalent of progressive MS-associated neuroaxonal degeneration. Evidence is accumulating that both inflammation and neurodegeneration are present along a continuum of pathologic processes in all phases of MS. While inflammation is the prominent feature in early stages, its quality changes and relative importance to disease course decreases while neurodegenerative processes prevail with ongoing disease. Consequently, anti-inflammatory disease-modifying therapies successfully used in relapsing MS are ineffective in SPMS, whereas specific treatment for the latter is increasingly a focus of MS research. Therefore, the prevention, but also the (anticipatory) diagnosis of SPMS, is of crucial importance. The problem is that currently SPMS diagnosis is exclusively based on retrospectively assessing the increase of overt physical disability usually over the past 6–12 months. This inevitably results in a delay of diagnosis of up to 3 years resulting in periods of uncertainty and, thus, making early therapy adaptation to prevent SPMS conversion impossible. Hence, there is an urgent need for reliable and objective biomarkers to prospectively predict and define SPMS conversion. Here, we review current evidence on clinical parameters, magnetic resonance imaging and optical coherence tomography measures, and serum and cerebrospinal fluid biomarkers in the context of MS-associated neurodegeneration and SPMS conversion. Ultimately, we discuss the necessity of multimodal approaches in order to approach objective definition and prediction of conversion to SPMS.

MRI brain volume loss, lesion burden, and clinical outcome in secondary progressive multiple sclerosis

BACKGROUND

Magnetic resonance imaging (MRI) of brain volume measures are widely used outcomes in secondary progressive multiple sclerosis (SPMS), but it is unclear whether they are associated with physical and cognitive disability.

OBJECTIVE

To investigate the association between MRI outcomes and physical and cognitive disability worsening in people with SPMS.

METHODS

We used data from ASCEND, a large randomized controlled trial (n = 889). We investigated the association of change in whole brain and gray matter volume, contrast enhancing lesions, and T2 lesions with significant worsening on the Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25FW), Nine-Hole Peg Test (NHPT), and Symbol Digit Modalities Test (SDMT) with logistic regression models.

RESULTS

We found no association between MRI measures and EDSS or SDMT worsening. T25FW worsening at 48 and 96 weeks, and NHPT worsening at 96 weeks were associated with cumulative new or newly enlarging T2 lesions at 96 weeks. NHPT worsening at 48 and 96 weeks was associated with normalized brain volume loss at 48 weeks, but not with other MRI outcomes.

CONCLUSION

The association of standard MRI outcomes and disability was noticeably weak and inconsistent over 2 years of follow-up. These MRI outcomes may not be useful surrogates of disability measures in SPMS.