Isolated Cognitive Decline in Neurologically Stable Patients with Multiple Sclerosis

Cognitive progression independent of relapse in multiple sclerosis

BACKGROUND

Substantial physical-disability worsening in relapsing-remitting multiple sclerosis (RRMS) occurs outside of clinically recorded relapse. This phenomenon, termed progression independent of relapse activity (PIRA), is yet to be established for cognitive decline.

METHODS

Retrospective analysis of RRMS patients. Cognitive decline was defined using reliable-change-index cut-offs for each test (Symbol Digit Modalities Test, Brief Visuospatial Memory Test-Revised, California Verbal Learning Test-II). Decline was classified as PIRA if the following conditions were met: no relapse observed between assessments nor within 9 months of cognitive decline.

RESULTS

The study sample (n = 336) was 80.7% female with a mean (standard deviation (SD)) age, disease duration, and observation period of 43.1 (9.5), 10.8 (8.4), and 8.1 (3.1) years, respectively. A total of 169 (50.3%) subjects were cognitively impaired at baseline relative to age-, sex-, and education-matched HCs. Within subjects who experienced cognitive decline (n = 167), 89% experienced cognitive PIRA. A total of 141 (68.1%) cognitive decline events were observed independent of EDSS worsening. Cognitive PIRA was more likely to be observed with increased assessments (p < 0.001) and lower assessment density (p < 0.001), accounting for baseline clinical factors.

CONCLUSION

These results establish the concept of cognitive PIRA and further our understanding of progressive cognitive decline in RRMS.

Determinants and Biomarkers of Progression Independent of Relapses in Multiple Sclerosis

Clinical, pathological, and imaging evidence in multiple sclerosis (MS) suggests that a smoldering inflammatory activity is present from the earliest stages of the disease and underlies the progression of disability, which proceeds relentlessly and independently of clinical and radiological relapses (PIRA). The complex system of pathological events driving "chronic" worsening is likely linked with the early accumulation of compartmentalized inflammation within the central nervous system as well as insufficient repair phenomena and mitochondrial failure. These mechanisms are partially lesion-independent and differ from those causing clinical relapses and the formation of new focal demyelinating lesions; they lead to neuroaxonal dysfunction and death, myelin loss, glia alterations, and finally, a neuronal network dysfunction outweighing central nervous system (CNS) compensatory mechanisms. This review aims to provide an overview of the state of the art of neuropathological, immunological, and imaging knowledge about the mechanisms underlying the smoldering disease activity, focusing on possible early biomarkers and their translation into clinical practice. ANN NEUROL 2024;96:1-20.

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.

Lexical and syntactic deficits analyzed via automated natural language processing: the new monitoring tool in multiple sclerosis

Background

Impairment of higher language functions associated with natural spontaneous speech in multiple sclerosis (MS) remains underexplored.

Objectives

We presented a fully automated method for discriminating MS patients from healthy controls based on lexical and syntactic linguistic features.

Methods

We enrolled 120 MS individuals with Expanded Disability Status Scale ranging from 1 to 6.5 and 120 age-, sex-, and education-matched healthy controls. Linguistic analysis was performed with fully automated methods based on automatic speech recognition and natural language processing techniques using eight lexical and syntactic features acquired from the spontaneous discourse. Fully automated annotations were compared with human annotations.

Results

Compared with healthy controls, lexical impairment in MS consisted of an increase in content words (p = 0.037), a decrease in function words (p = 0.007), and overuse of verbs at the expense of noun (p = 0.047), while syntactic impairment manifested as shorter utterance length (p = 0.002), and low number of coordinate clause (p < 0.001). A fully automated language analysis approach enabled discrimination between MS and controls with an area under the curve of 0.70. A significant relationship was detected between shorter utterance length and lower symbol digit modalities test score (r = 0.25, p = 0.008). Strong associations between a majority of automatically and manually computed features were observed (r > 0.88, p < 0.001).

Conclusion

Automated discourse analysis has the potential to provide an easy-to-implement and low-cost language-based biomarker of cognitive decline in MS for future clinical trials.

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.

Fitts' Tapping Task as a New Test for Cognition and Manual Dexterity in Multiple Sclerosis: Validation Study

Introduction. Studies suggest that people with multiple sclerosis (pwMS) experience continuous and subclinical physical worsening, even as early as their disease diagnosis. Validating sensitive and reproducible tests that can capture subclinical disease activity early in the disease are clinically useful and highly warranted. We aimed at validating the utility of Fitts’ Tapping Task (FTT) as reproducible measure of psychomotor performance in pwMS. Materials and Methods. Thirty newly-diagnosed pwMS (within 2 years of diagnosis and Expanded Disability Status Scale; EDSS ≤ 2.0), 30 people with migraine (pwMig), and 30 healthy controls (HCs) underwent a psychomotor assessment using the FTT, O’Connor hand dexterity test, and Visual Reaction Time Test (VRTT). Hand strength was measured using a hand-grip dynamometer. Subjects also provided patient-reported outcomes (PROs) using the 36-Item Short Form Survey (SF-36). Intrarater and interrater reproducibility was acquired on 5 HCs by two independent operators. Test−retest reproducibility was determined in 5 pwMS over a 1-week follow-up. Eight pwMS returned for the same test procedures 2 years after the baseline assessment. Bland−Altman plots were used to determine the minimally detectable change (MDC) and logistic regression models determined the ability to differentiate between newly-diagnosed pwMS and HCs. Results. FTT exhibited a high intrarater and interrater reproducibility (interclass correlation coefficient of 0.961, p < 0.001). The test−retest demonstrated an MDC of the average FTT at > 15%. PwMS had significantly a slower FTT time and O’Connor dexterity time when compared to pwMig and HCs (p < 0.001 for both). Higher Fitts’ difficulty levels (4th and 6th difficulty) and average performance on the O’Connor test were able to differentiate newly-diagnosed pwMS from HCs with 80% accuracy (p < 0.01). Slower FTT performance was correlated with worse PROs due to physical health. Over the 2-year follow-up, and despite being clinically stable (no change in EDSS), 6 out of 8 (75%) pwMS had more than a 15% worsening in their average FTT time. Conclusions. FTT is a highly-reproducible test for measuring psychomotor performance in newly-diagnosed pwMS. FTT can capture insidious worsening in psychomotor performance and cognitive function in early stages of MS.