Fatigue in multiple sclerosis: can we measure it and can we treat it?

Fatigue is a common and debilitating symptom in multiple sclerosis (MS). However, after over 100 years of inquiry its definition, measurement and understanding remains elusive. This paper describes the challenges clinicians and researchers face when assessing and treating MS patients, as well as our understanding of neural mechanisms involved in fatigue. Challenges for the future are discussed.

Effect of methylphenidate on oculomotor function in individuals with multiple sclerosis: a pilot randomized placebo-controlled trial.

Introduction: Individuals with multiple sclerosis (MS) frequently experience visual and oculomotor symptoms that may impact and confound neuropsychological assessments of information processing speed (IPS). In this study, we examined the effect of the psychostimulant methylphenidate on oculomotor function and the association between change in oculomotor speed and change in information processing speed. Methods: We used a repeated measures crossover design in which a sample of 11 participants with MS were randomly assigned to one of two treatment arms: one that received methylphenidate for 4 weeks and another that received a placebo for 4 weeks. After a 7-day washout period, the treatments were crossed over. The King Devick test, the Symbol Digit Modalities Test, and the Paced Auditory Serial Addition Test were administered at baseline and after each of the two study arms. Results: We found a significant improvement in oculomotor speed in the methylphenidate condition as compared to placebo. This improvement was significantly correlated with improvement on a visuomotor assessment of IPS (Symbol Digit Modalities Test), but no such association was found for an auditory-verbal assessment of IPS (Paced Auditory Serial Addition Test). Discussion: These findings suggest that individuals with MS experience improved oculomotor speed while taking methylphenidate, which may, in turn, improve performance on assessments of IPS with visuomotor demands.

Exploring the Efficacy of a Remote Strategy-Based Intervention for People With Multiple Sclerosis With Everyday Memory Impairments: A Pilot Study.

IMPORTANCE: This pilot study evaluates a remote strategy-based intervention for individuals with multiple sclerosis who experience everyday memory impairments. The intervention can potentially inform cognitive rehabilitation for this population. OBJECTIVE: To investigate the feasibility and efficacy of an intervention (TELE-Self-GEN) to determine whether it can alleviate everyday memory impairments of individuals with multiple sclerosis. DESIGN: Pretest-posttest. SETTING: Community. PARTICIPANTS: Ten adults with multiple sclerosis. INTERVENTION: Six synchronous treatment sessions were delivered online via Zoom. The treatment protocol embedded a memory strategy (self-generated learning) within a metacognitive framework, including self-awareness and self-management strategies. The treatment emphasizes when and how self-generation should be used. OUTCOME: Measurements assessed feasibility and participants' satisfaction with the intervention and its delivery method, as well as memory, everyday memory, and functional performance. RESULTS: Participants expressed high satisfaction with the virtual treatment, highlighting its convenience as a key factor. Treatment resulted in improvements in memory performance, perceived memory ability in daily life, and functional performance. CONCLUSIONS AND RELEVANCE: Results provide initial proof of concept in the utilization of a remotely delivered, strategy-based treatment approach to improve memory performance and functional abilities. The pilot data support a larger randomized clinical trial of the TELE-self-GEN. Plain-Language Summary: The results of this pilot study highlight the promising potential of TELE-self-GEN for people with multiple sclerosis (MS), who face memory challenges every day. This remotely delivered, strategy-based occupational therapy treatment approach, TELE-self-GEN, has the potential to significantly improve functional memory. The study participants reported improvements in their memory performance, perceived memory ability in daily life, and functional performance. These encouraging results serve as a foundation for more extensive clinical trials using TELE-self-GEN for people with MS.

Cognitive rehabilitation effects on grey matter volume and Go-NoGo activity in progressive multiple sclerosis: results from the CogEx trial.

BACKGROUND: Research on cognitive rehabilitation (CR) and aerobic exercise (EX) to improve cognition in progressive multiple sclerosis (PMS) remains limited. CogEx trial investigated the effectiveness of CR and EX in PMS: here, we present MRI substudy volumetric and task-related functional MRI (fMRI) findings. METHODS: Participants were randomised to: 'CR plus EX', 'CR plus sham EX (EX-S)', 'EX plus sham CR (CR-S)' and 'CR-S plus EX-S' and attended 12-week intervention. All subjects performed physical/cognitive assessments at baseline, week 12 and 6 months post intervention (month 9). All MRI substudy participants underwent volumetric MRI and fMRI (Go-NoGo task). RESULTS: 104 PMS enrolled at four sites participated in the CogEx MRI substudy; 84 (81%) had valid volumetric MRI and valid fMRI. Week 12/month 9 cognitive performances did not differ among interventions; however, 25-62% of the patients showed Symbol Digit Modalities Test improvements. Normalised cortical grey matter volume (NcGMV) changes at week 12 versus baseline were heterogeneous among interventions (p=0.05); this was mainly driven by increased NcGMV in 'CR plus EX-S' (p=0.02). Groups performing CR (ie, 'CR plus EX' and 'CR plus EX-S') exhibited increased NcGMV over time, especially in the frontal (p=0.01), parietal (p=0.04) and temporal (p=0.04) lobes, while those performing CR-S exhibited NcGMV decrease (p=0.008). In CR groups, increased NcGMV (r=0.36, p=0.01) at week 12 versus baseline correlated with increased California Verbal Learning Test (CVLT)-II scores. 'CR plus EX-S' patients exhibited Go-NoGo activity increase (p<0.05, corrected) at week 12 versus baseline in bilateral insula. CONCLUSIONS: In PMS, CR modulated grey matter (GM) volume and insular activity. The association of GM and CVLT-II changes suggests GM plasticity contributes to cognitive improvements. TRIAL REGISTRATION NUMBER: NCT03679468.

Prevalence and Associated Clinical Characteristics of Walking-Related Motor, Cognitive, and Fatigability in Progressive Multiple Sclerosis: Baseline Results From the CogEx Study.

BACKGROUND: People with progressive multiple sclerosis (PMS) present motor (eg, walking) and cognitive impairments, and report fatigue. Fatigue encompasses fatigability which is objectively measured by the capacity to sustain a motor or cognitive task. OBJECTIVE: To investigate the prevalence of walking and cognitive fatigability (CF) and the associated clinical characteristics in a large sample of PMS patients. METHODS: PMS patients (25-65 years old) were included from 11 sites (Europe and North America), having cognitive impairment (1.28 standard deviation below normative data for the symbol digit modality test [SDMT]). Walking fatigability (WF) was assessed using the distance walk index (DWI) and CF using the SDMT (scores from the last 30 seconds compared to the first 30 seconds). Additional measures were: cognitive assessment-Brief International Cognitive Assessment for multiple sclerosis (MS), cardiorespiratory fitness, 6-minute walk, physical activity, depressive symptoms, perceived fatigue-Modified Fatigue Impact Scale (MFIS), MS impact-MSIS-29, and walking ability. RESULTS: Of 298 participants, 153 (51%) presented WF (DWI = -28.9 ± 22.1%) and 196 (66%) presented CF (-29.7 ± 15%). Clinical characteristics (EDSS, disease duration, and use of assistive device) were worse in patients with versus without WF. They also presented worse scores on MSIS-29 physical, MFIS total and physical and reduced physical capacity. CF patients scored better in the MSIS-29 physical and MFIS psychosocial, compared to non-CF group. Magnitude of CF and WF were not related. CONCLUSIONS: Half of the cognitively-impaired PMS population presented WF which was associated with higher disability, physical functions, and fatigue. There was a high prevalence of CF but without strong associations with clinical, cognitive, and physical functions. TRIAL REGISTRATION NUMBER: The "CogEx-study," www.clinicaltrial.gov identifier number: NCT03679468.

An Examination of Positive and Negative Outcomes During the COVID-19 Pandemic Among Persons With Multiple Sclerosis.

IMPORTANCE: This study provides information to clinicians about how persons with MS coped in both positive and negative ways during a potentially traumatic experience (the coronavirus disease 2019 [COVID-19] pandemic), which will help clinicians to provide better services to this population in the face of stressful events. OBJECTIVE: To describe both positive and negative outcomes among persons with multiple sclerosis (MS) and to examine whether resilience and social support were related to positive and negative outcomes during the peak of the pandemic. DESIGN: An online survey administered during the COVID-19 pandemic. PARTICIPANTS: Participants were 74 individuals with MS and 104 healthy controls (HCs) recruited through social media and community support groups. OUTCOMES AND MEASURES: The survey included questionnaires that assessed both positive and negative responses to the pandemic, including benefit finding, loneliness, and distress. Resilience and social support were also assessed. RESULTS: Differences were noted between persons with MS and HCs on negative but not positive outcomes. Better social support and resilience were related to positive outcomes. CONCLUSIONS AND RELEVANCE: Both persons with MS and HCs were similar in benefit finding and stress management. However, negative outcomes were worse in the MS group. Our findings shed light on the importance of individuals with MS adopting a positive outlook to help during times of adversity. What This Article Adds: Among persons with disabilities such as multiple sclerosis, finding benefits during stressful times can be a potential coping mechanism. Furthermore, resilience and social support should be taken into account to moderate the effects of adverse events.

Evaluating the effects of brain injury, disease and tasks on cognitive fatigue.

Because cognitive fatigue (CF) is common and debilitating following brain injury or disease we investigated the relationships among CF, behavioral performance, and cerebral activation within and across populations by combining the data from two cross-sectional studies. Individuals with multiple sclerosis (MS) were included to model CF resulting from neurological disease; individuals who had sustained a traumatic brain injury (TBI) were included to model CF resulting from neurological insult; both groups were compared with a control group (Controls). CF was induced while neuroimaging data was acquired using two different tasks. CF significantly differed between the groups, with the clinical groups reporting more CF than Controls-a difference that was statistically significant for the TBI group and trended towards significance for the MS group. The accrual of CF did not differ across the three groups; and CF ratings were consistent across tasks. Increasing CF was associated with longer response time for all groups. The brain activation in the caudate nucleus and the thalamus was consistently correlated with CF in all three groups, while more dorsally in the caudate, activation differed across the groups. These results suggest the caudate and thalamus to be central to CF while more dorsal aspects of the caudate may be sensitive to damage associated with particular types of insult.

Cognitive rehabilitation and aerobic exercise for cognitive impairment in people with progressive multiple sclerosis (CogEx): a randomised, blinded, sham-controlled trial.

BACKGROUND: Cognitive dysfunction in people with relapsing-remitting multiple sclerosis can improve with cognitive rehabilitation or exercise. Similar effects have not been clearly shown in people with progressive multiple sclerosis. We aimed to investigate the individual and synergistic effects of cognitive rehabilitation and exercise in patients with progressive multiple sclerosis. METHODS: CogEx was a randomised, sham-controlled trial completed in 11 hospital clinics, universities, and rehabilitation centres in Belgium, Canada, Denmark, Italy, UK, and USA. Patients with progressive multiple sclerosis were eligible for inclusion if they were aged 25-65 years and had an Expanded Disability Status Scale (EDSS) score of less than 7. All had impaired processing speed defined as a performance of 1·282 SD or greater below normative data on the Symbol Digit modalities Tests (SDMT). Participants were randomly assigned (1:1:1:1), using an interactive web-response system accessed online from each centre, to cognitive rehabilitation plus exercise, cognitive rehabilitation plus sham exercise, exercise plus sham cognitive rehabilitation, or sham exercise plus sham cognitive rehabilitation. The study statistician created the randomisation sequence that was stratified by centre. Participants, outcome assessors, and investigators were blinded to group allocation. The study statistician was masked to treatment during analysis only. Interventions were conducted two times per week for 12 weeks: cognitive rehabilitation used an individualised, computer-based, incremental approach to improve processing speed; sham cognitive rehabilitation consisted of internet training provided individually; the exercise intervention involved individualised aerobic training using a recumbent arm-leg stepper; and the sham exercise involved stretching and balance tasks without inducing cardiovascular strain. The primary outcome measure was processing speed measured by SDMT at 12 weeks; least squares mean differences were compared between groups using linear mixed model in all participants who had a 12-week assessment. The trial is registered with ClinicalTrials.gov, NCT03679468, and is completed. FINDINGS: Between Dec 14, 2018, and April 2, 2022, 311 people with progressive multiple sclerosis were enrolled and 284 (91%) completed the 12-week assessment (117/311 [38%] male and 194/311 [62%] female). The least squares mean group differences in SDMT at 12 weeks did not differ between groups (p=0·85). Compared with the sham cognitive rehabilitation and sham exercise group (n=67), differences were -1·30 (95% CI -3·75 to 1·16) for the cognitive rehabilitation plus exercise group (n=70); -2·78 (-5·23 to -0·33) for the sham cognitive rehabilitation plus exercise group (n=71); and -0·71 (-3·11 to 1·70) for the cognitive rehabilitation plus sham exercise group (n=76). 11 adverse events possibly related to the interventions occurred, six in the exercise plus sham cognitive rehabilitation group (pain, dizziness, and falls), two in the cognitive rehabilitation plus sham exercise group (headache and pain), two in the cognitive rehabilitation and exercise group (increased fatigue and pain), and one in the dual sham group (fall). INTERPRETATION: Combined cognitive rehabilitation plus exercise does not seem to improve processing speed in people with progressive multiple sclerosis. However, our sham interventions were not inactive. Studies comparing interventions with a non-intervention group are needed to investigate whether clinically meaningful improvements in processing speed might be attainable in people with progressive multiple sclerosis. FUNDING: MS Canada.

The effects of cognitive rehabilitation combined with aerobic exercise or stretching-and-toning on new learning and memory in persons with moderate-to-severe TBI: Protocol for a randomized controlled trial.

This paper describes the protocol for a Phase I/II, parallel-group, blinded randomized controlled trial that compares the effects of 12-weeks of combined learning and memory rehabilitation with either aerobic cycling exercise or stretching on cognitive, neuroimaging, and everyday life outcomes in 60 persons with moderate-to-severe traumatic brain injury (TBI) who demonstrate impairments in new learning. Briefly, participants will undergo baseline testing consisting of neuropsychological testing, neuroimaging, daily life measures, and cardiorespiratory fitness. Following baseline testing, participants will be randomized to one of 2 conditions (30 participants per condition) using concealed allocation. Participants will be masked as to the intent of the conditions. The conditions will both involve supervised administration of an enhanced, 8-week version of the Kessler Foundation modified Story Memory Technique, embedded within either 12-weeks of supervised and progressive aerobic cycling exercise training (experimental condition) or 12-weeks of supervised stretching-and-toning (active control condition). Following the 12-week intervention period, participants will complete the same measures as at baseline that will be administered by treatment-blinded assessors. The primary study outcome is new learning and memory impairment based on California Verbal Learning Test (CVLT)-III slope, the secondary outcomes include neuroimaging measures of hippocampal volume, activation, and connectivity, and the tertiary outcomes involve measures of daily living along with other cognitive outcomes. We further will collect baseline sociodemographic data for examining predictors of response heterogeneity. If successful, this trial will provide the first Class I evidence supporting combined memory rehabilitation and aerobic cycling exercise training for treating TBI-related new learning and memory impairment.

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

BACKGROUND: There is considerable evidence that persons with multiple sclerosis (PwMS) who experience cognitive impairments (CIs) are at risk of having significant limitations in activities of daily living (ADLs). However, ADL assessment often consists of proxies or self-report of ADLs. This study examined whether the performance of instrumental ADLs (I-ADL) is impaired in PwMS with and without CI. METHODS: Participants included 72 PwMS and 48 matched healthy controls (HCs). PwMS were divided into MS-CI (n = 25) and MS-not-impaired (n = 47) groups based on the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) scores. All participants performed the Actual RealityTM (AR) test, measuring I-ADL using authentic websites. RESULTS: The MS-CI performed significantly worse on AR compared with HC and MS-not-impaired. In addition, the MS-not-impaired performed significantly worse than HC on AR. AR differentiates well between PwMS with and without CI. CONCLUSIONS: While CI in MS results in significant limitations in the performance of I-ADL, PwMS who do not show evidence of CI can have limitations in I-ADL. AR assessment is a valid and reliable tool sensitive to CI. It should be used in addition to traditional cognitive assessments to detect early functional deterioration through the course of MS.

Associations between Social Support and Cognitive Performance among Persons with MS.

BACKGROUND: Social support is a protective factor against cognitive decline in the general population. However, the relationship between social support and cognitive functioning among persons with multiple sclerosis (MS) is not well understood. OBJECTIVE: The present study aimed to investigate the associations between different aspects of social support and cognitive performance among persons with MS. METHODS: A volunteer sample of 60 persons with MS completed the Medical Outcomes Study Support Social Survey 5-item short form (MSSS-5) and the Social Network Index (SNI). Cognitive functioning was assessed through a virtually-administered neuropsychological battery. Multiple linear regressions were conducted to examine the associations between social support measures and cognitive performance. RESULTS: In models adjusting for level of premorbid functioning, both perceived social support (i.e., to what extent one receives assistance from their social network; p = .002) and total size of social network (i.e., total number of people one regularly talks to; p = .002) were significant predictors of processing speed/executive functioning with moderate effect sizes. However, when we accounted for employment status in a post hoc analysis, the association between social network size and processing speed/executive functioning became statistically insignificant, while the relationship between perceived social support and processing speed/executive functioning remained significant (p = .002). CONCLUSIONS: Greater perceived social support is associated with better performance on processing speed/executive functioning measures among persons with MS, independent of effects from premorbid functioning and employment status. Maintaining a strong social support network may be an important factor in optimizing cognitive health in MS.

The influence of information processing speed on benefit from learning and memory rehabilitation in TBI: a sub-analysis of the TBI-MEM trial.

OBJECTIVE: This study examined the influence of processing speed (PS) on benefit from treatment with the Kessler Foundation modified Story Memory Technique® (KF-mSMT®), a cognitive rehabilitation intervention shown to improve new learning and memory in traumatic brain injury (TBI). SETTING: Non-profit research center. PARTICIPANTS: 62 participants with moderate-to-severe TBI were included, 31 assigned to the treatment group and 31 to the placebo-control group. DESIGN: Double-blind, placebo-controlled, randomized clinical trial. The present study represents a post-hoc analysis to examine the role of PS on treatment efficacy. MAIN MEASURES: Baseline and follow-up neuropsychological assessment including the California Verbal Learning Test, Second Edition (CVLT-II), Memory Assessment Scales - Prose Memory (MAS-PM) and the Symbol Digit Modalities Test (SDMT). RESULTS: A treatment effect was not observed on the CVLT-II learning slope in the treatment group relative to the placebo group post-treatment, after co-varying for education, baseline CVLT slope and PS performance. However, performance on a measure of PS, the SDMT, was a significant predictor of post-treatment change following KF-mSMT® treatment. PS was not a significant predictor of benefit from treatment as documented by the MAS-PM immediate or delayed recall score, both of which showed a significant treatment effect. CONCLUSION: Performance on measures of cognitive dysfunction aside from learning and memory impact the benefit from KF-mSMT® treatment. Implications for cognitive rehabilitation for individuals with TBI are discussed.

Longitudinal assessment of neurocognitive function in people with relapsing multiple sclerosis initiating alemtuzumab in routine clinical practice: LEM-COG study results.

BACKGROUND: Alemtuzumab is effective in reducing relapse rate and disability, but limited data exist on its effect on cognitive function in relapsing multiple sclerosis (RMS). The present study assessed neurocognitive function and safety associated with alemtuzumab treatment in RMS. METHODS: This longitudinal, single-arm, prospective study included people with RMS (aged 25-55 years) who were treated with alemtuzumab in clinical practice in the United States of America and Canada. The first participant was enrolled in December 2016. The primary endpoint was the change from baseline to post-baseline (month [M] 12/24) in MS-COGnitive (MS-COG) composite score. Secondary endpoints included Paced Auditory Serial Addition Test (PASAT), Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), Selective Reminding Test (SRT), Controlled Oral Word Association Test (COWAT), and Automated Neuropsychological Assessment Metrics (ANAM) scores. Depression and fatigue were assessed using Hamilton Rating Scale-Depression (HAM-D) and Fatigue Severity Scale (FSS)/Modified Fatigue Impact Scale (MFIS), respectively. Magnetic resonance imaging (MRI) parameters were assessed when available. Safety was assessed throughout the study. Descriptive statistics were used for the pre-specified statistical analyses. Since the study was terminated early (November 2019) because of operational and resource difficulties, post hoc analyses for statistical inference were performed among participants who had a baseline value and at least one complete post-baseline assessment for cognitive parameters, fatigue, or depression. RESULTS: Of the 112 participants enrolled, 39 were considered as the primary analysis population at M12. At M12, a mean change of 0.25 (95% confidence interval [CI]: 0.04, 0.45; p = 0.0049; effect size [ES]: 0.39) was observed in the MS-COG composite score. Improvements were observed in processing speed (based on PASAT and SDMT; p < 0.0001; ES: 0.62), as well as in individual PASAT, SDMT and COWAT scores. An improvement was also noted in HAM-D (p = 0.0054; ES: -0.44), but not in fatigue scores. Among MRI parameters, decreases in burden of disease volume (BDV; ES: -0.12), new gadolinium-enhancing lesions (ES: -0.41) and newly active lesions (ES: -0.07) were observed at M12. About 92% of participants showed stable or improved cognitive status at M12. There were no new safety signals reported in the study. The most common adverse events (≥10% of participants) were headache, fatigue, nausea, insomnia, urinary tract infection, pain in extremity, chest discomfort, anxiety, dizziness, arthralgia, flushing, and rash. Hypothyroidism (3.7%) was the most frequent adverse event of special interest. CONCLUSION: The findings from this study suggest that alemtuzumab has a positive impact on cognitive function with significant improvements in processing speed and depression in people with RMS over a period of 12 months. The safety profile of alemtuzumab was consistent with previous studies.

A virtual reality program to assess cognitive function in multiple sclerosis: A pilot study.

Introduction: Cognitive impairment is a debilitating symptom in people with multiple sclerosis (MS). Most of the neuropsychological tasks have little resemblance to everyday life. There is a need for ecologically valid tools for assessing cognition in real-life functional contexts in MS. One potential solution would involve the use of virtual reality (VR) to exert finer control over the task presentation environment; however, VR studies in the MS population are scarce. Objectives: To explore the utility and feasibility of a VR program for cognitive assessment in MS. Methods: A VR classroom embedded with a continuous performance task (CPT) was assessed in 10 non-MS adults and 10 people with MS with low cognitive functioning. Participants performed the CPT with distractors (i.e., WD) and without distractors (i.e., ND). The Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II), and a feedback survey on the VR program was administered. Results: People with MS exhibited greater reaction time variability (RTV) compared to non-MS participants, and greater RTV in both WD and ND conditions was associated with lower SDMT. Conclusions: VR tools warrant further research to determine their value as an ecologically valid platform for assessing cognition and everyday functioning in people with MS.

Abnormal thalamic functional connectivity correlates with cardiorespiratory fitness and physical activity in progressive multiple sclerosis.

BACKGROUND: Altered thalamic volumes and resting state (RS) functional connectivity (FC) might be associated with physical activity (PA) and cardiorespiratory fitness (CRF) in people with progressive multiple sclerosis (PMS). OBJECTIVES: To assess thalamic structural and functional alterations and investigate their correlations with PA/CRF levels in people with PMS. METHODS: Seven-day accelerometry and cardiopulmonary exercise testing were used to assess PA/CRF levels in 91 persons with PMS. They underwent 3.0 T structural and RS fMRI acquisition with 37 age/sex-matched healthy controls (HC). Between-group comparisons of MRI measures and their correlations with PA/CRF variables were assessed. RESULTS: PMS people had lower volumes compared to HC (all p < 0.001). At corrected threshold, PMS showed decreased intra- and inter-thalamic RS FC, and increased RS FC between the thalamus and the hippocampus, bilaterally. At uncorrected threshold, decreased thalamic RS FC with caudate nucleus, cerebellum and anterior cingulate cortex (ACC), as well as increased thalamic RS FC with occipital regions, were also detected. Lower CRF, measured as peak oxygen consumption (VO2peak), correlated with lower white matter volume (r = 0.31, p = 0.03). Moreover, lower levels of light PA correlated with increased thalamic RS FC with the right hippocampus (r = - 0.3, p = 0.05). DISCUSSION: People with PMS showed widespread brain atrophy, as well as pronounced intra-thalamic and thalamo-hippocampal RS FC abnormalities. White matter atrophy correlated with CRF, while increased thalamo-hippocampal RS FC was associated to worse PA levels. Thalamic RS FC might be used to monitor physical impairment and efficacy of rehabilitative and disease-modifying treatments in future studies.

The Efficacy of the Speed of Processing Training Program in Improving Functional Outcome: From Restoration to Generalization.

OBJECTIVE: To examine the efficacy of Speed of Processing Training (SOPT) in improving everyday functional outcomes in persons with multiple sclerosis (MS). DESIGN: Randomized controlled trial. SETTING: A nonprofit rehabilitation research institution and the community. PARTICIPANTS: In total, 60 participants with MS with impaired processing speed were randomly assigned to SOPT (n=33) or an active control group (n=27). INTERVENTION: SOPT, a restorative computerized cognitive intervention involving 10 treatment sessions consisting of visual tasks designed to improve speed and accuracy of information processing MAIN OUTCOME MEASURES: Outcomes included performance on the Timed Instrumental Activities of Daily Living (TIADL) and self-report of functional behavior, quality of life, and affect. RESULTS: The treatment group showed improvement in the total TIADL score and 2 subtests compared with the active control group. Participants in the treatment group who demonstrated improved cognitive performance after the intervention also showed improved performance on one TIADL subtest. Quality of life, affective symptomatology, and self-reported functional status were not changed after the intervention. CONCLUSIONS: Improvement in underlying cognitive or perceptual deficits is thought to promote recovery and everyday performance as per the restorative approach to cognitive rehabilitation. However, this study showed only selected improvements in everyday functional outcomes for persons with MS.

Bridging Big Data: Procedures for Combining Non-equivalent Cognitive Measures from the ENIGMA Consortium.

Investigators in neuroscience have turned to Big Data to address replication and reliability issues by increasing sample sizes, statistical power, and representativeness of data. These efforts unveil new questions about integrating data arising from distinct sources and instruments. We focus on the most frequently assessed cognitive domain - memory testing - and demonstrate a process for reliable data harmonization across three common measures. We aggregated global raw data from 53 studies totaling N = 10,505 individuals. A mega-analysis was conducted using empirical bayes harmonization to remove site effects, followed by linear models adjusting for common covariates. A continuous item response theory (IRT) model estimated each individual's latent verbal learning ability while accounting for item difficulties. Harmonization significantly reduced inter-site variance while preserving covariate effects, and our conversion tool is freely available online. This demonstrates that large-scale data sharing and harmonization initiatives can address reproducibility and integration challenges across the behavioral sciences.

Slowing processing speed is associated with cognitive fatigue in newly diagnosed multiple sclerosis patients.

OBJECTIVE: To further investigate objective measures of cognitive fatigue (CF), defined as the inability to sustain performance over time, in newly diagnosed multiple sclerosis (MS) patients, by conducting a performance analysis on the Paced Auditory Serial Addition Test (PASAT) based on the type of errors (omissions vs. incorrect responses) committed. METHOD: Sixty-two newly diagnosed patients with MS (pwMS) and 41 healthy controls (HC) completed the PASAT. Analysis of the change in performance during the test was performed by comparing the number of correct responses, incorrect responses, and omissions in the 1st versus the 3rd tertile of the PASAT. RESULTS: A significant decline in accuracy over time was observed to be related to an increment in the number of omissions, significantly more pronounced in pwMS than in HC. No change in the number of incorrect responses throughout the PASAT was observed for either group. CONCLUSIONS: CF can be detected even in newly diagnosed pwMS and might objectively manifest as a progressive increase in omissions during a sustained highly demanding task (i.e., PASAT). This pattern may reflect slowed processing speed and increased fatigue in pwMS. Focusing on omissions on the PASAT instead of correct responses only may improve its specificity as an objective measure of CF.

Structural and functional magnetic resonance imaging correlates of fatigue and dual-task performance in progressive multiple sclerosis.

BACKGROUND: Frontal cortico-subcortical dysfunction may contribute to fatigue and dual-task impairment of walking and cognition in progressive multiple sclerosis (PMS). PURPOSE: To explore the associations among fatigue, dual-task performance and structural and functional abnormalities of frontal cortico-subcortical network in PMS. METHODS: Brain 3 T structural and functional MRI sequences, Modified Fatigue Impact Scale (MFIS), dual-task motor and cognitive performances were obtained from 57 PMS patients and 10 healthy controls (HC). The associations of thalamic, caudate nucleus and dorsolateral prefrontal cortex (DLPFC) atrophy, microstructural abnormalities of their connections and their resting state effective connectivity (RS-EC) with fatigue and dual-task performance were investigated using random forest. RESULTS: Thirty-seven PMS patients were fatigued (F) (MFIS ≥ 38). Compared to HC, non-fatigued (nF) and F-PMS patients had significantly worse dual-task performance (p ≤ 0.002). Predictors of fatigue (out-of-bag [OOB]-accuracy = 0.754) and its severity (OOB-R2 = 0.247) were higher Expanded Disability Status scale (EDSS) score, lower RS-EC from left-caudate nucleus to left-DLPFC, lower fractional anisotropy between left-caudate nucleus and left-thalamus, higher mean diffusivity between right-caudate nucleus and right-thalamus, and longer disease duration. Microstructural abnormalities in connections among thalami, caudate nuclei and DLPFC, mainly left-lateralized in nF-PMS and more bilateral in F-PMS, higher RS-EC from left-DLPFC to right-DLPFC in nF-PMS and lower RS-EC from left-caudate nucleus to left-DLPFC in F-PMS, higher EDSS score, higher WM lesion volume, and lower cortical volume predicted worse dual-task performances (OOB-R2 from 0.426 to 0.530). CONCLUSIONS: In PMS, structural and functional frontal cortico-subcortical abnormalities contribute to fatigue and worse dual-task performance, with different patterns according to the presence of fatigue.

Associations between smartphone keystroke dynamics and cognition in MS.

Objective: Examine the associations between smartphone keystroke dynamics and cognitive functioning among persons with multiple sclerosis (MS). Methods: Sixteen persons with MS with no self-reported upper extremity or typing difficulties and 10 healthy controls (HCs) completed six weeks of remote monitoring of their keystroke dynamics (i.e., how they typed on their smartphone keyboards). They also completed a comprehensive neuropsychological assessment and symptom ratings about fatigue, depression, and anxiety at baseline. Results: A total of 1,335,787 keystrokes were collected, which were part of 30,968 typing sessions. The MS group typed slower (P < .001) and more variably (P = .032) than the HC group. Faster typing speed was associated with better performance on measures of processing speed (P = .016), attention (P = .022), and executive functioning (cognitive flexibility: P = .029; behavioral inhibition: P = .002; verbal fluency: P = .039), as well as less severe impact from fatigue (P < .001) and less severe anxiety symptoms (P = .007). Those with better cognitive functioning and less severe symptoms showed a stronger correlation between the use of backspace and autocorrection events (P < .001). Conclusion: Typing speed may be sensitive to cognitive functions subserved by the frontal-subcortical brain circuits. Individuals with better cognitive functioning and less severe symptoms may be better at monitoring their typing errors. Keystroke dynamics have the potential to be used as an unobtrusive remote monitoring method for real-life cognitive functioning among persons with MS, which may improve the detection of relapses, evaluate treatment efficacy, and track disability progression.