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.

H - 25 A Pilot Study of Coping and Cognition: Examining the Influence of Executive Functioning on Coping Strategies among Diverse Persons Living with Multiple Sclerosis

OBJECTIVE

Coping style has been identified as a potential strategy to lessen the impact of negative symptoms in persons with MS (pwMS). Prior work demonstrates that individuals with executive dysfunction are less likely to use effective coping strategies. Much remains unknown about the relationship between executive functioning (EF) and coping style, however, especially in diverse pwMS. The current pilot study aims to examine this relationship further.

METHODS

Eighteen middle aged pwMS (10 = Latino/a, 6 = African American, 1 = Asian, 1 = Biracial) underwent evaluations for EF and coping styles. EF was assessed using the Stroop Color-Word (SCW), Oral Trail Making Test B, and Controlled Oral Word Association Test. Coping was assessed using the three subscales of the Brief-COPE: problem-focused, positive emotion-focused, and avoidant coping.

RESULTS

Given the small sample size, data were interpreted in terms of effect size rather than p-values. Bivariate correlations were conducted between each EF test and coping subscale. Results demonstrated a medium-high effect size (r = 0.447) between SCW and problem-focused coping, such that better performance on the SCW was associated with greater problem-focused coping. Similarly, there was a moderate effect size (r = 0.326) between SCW and positive emotion-focused coping, with better performance on SCW related to greater positive emotion-focused coping. There were no notable relationships between EF and avoidant coping.

CONCLUSIONS

This study is among the first to demonstrate a relationship between EF and coping style in a sample of diverse pwMS. These results have implications for interventions that may improve coping, particularly among diverse groups who face unique challenges in coping with their disease.

H - 37 Impact of Barriers to Healthcare Access on Cognition and Accelerated Brain Aging in Diverse Persons with Multiple Sclerosis: Preliminary Pilot Data

OBJECTIVE

Racially/ethnically diverse persons with multiple sclerosis (pwMS) have worse outcomes than their white counterparts. Barriers to healthcare access may contribute to these disparities, though much remains unknown. The current pilot study investigates the impact of barriers to healthcare on cognition and accelerated brain aging in diverse pwMS. We hypothesize that greater barriers to healthcare will be associated with poorer cognitive performance and increased brain aging.

METHOD

Eighteen middle-aged pwMS (40-60 years) were included. Barriers to healthcare access was evaluated using total and subscale (skills, marginalization, expectations, knowledge, and pragmatics) scores of the modified Barriers to Care Questionnaire. Cognition was measured using raw scores from the Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), and California Verbal Learning Test-II (CVLT-II). Accelerated brain aging was calculated by subtracting chronological age from predicted brain age based on the brainageR paradigm.

RESULTS

Given established directional hypotheses, one tailed correlations were conducted. Greater marginalization-related barriers to healthcare were associated with poorer performance on the SDMT (r = -0.409, p = 0.046). Greater knowledge-based barriers to healthcare were associated with increased brain aging (r = -0.615, p = 0.004). Lastly, brain age was significantly related to immediate (r = -0.653, p = 0.003) and delayed (r = -0.549, p = 0.014) visual memory, such that increased brain age was associated with poorer visual memory.

CONCLUSION

To the authors' knowledge, this is among the first studies to examine the impact of barriers to healthcare on cognition and brain health in diverse pwMS. It demonstrates the importance of sociocultural determinants when examining outcomes in MS. This work has implications for culturally informed research and clinical care.

Internet-delivered cognitive behavioural therapy programme to reduce depressive symptoms in patients with multiple sclerosis: a multicentre, randomised, controlled, phase 3 trial

BACKGROUND

Depression is three to four times more prevalent in patients with neurological and inflammatory disorders than in the general population. For example, in patients with multiple sclerosis, the 12-month prevalence of major depressive disorder is around 25% and it is associated with a lower quality of life, faster disease progression, and higher morbidity and mortality. Despite its clinical relevance, there are few treatment options for depression associated with multiple sclerosis and confirmatory trials are scarce. We aimed to evaluate the safety and efficacy of a multiple sclerosis-specific, internet-based cognitive behavioural therapy (iCBT) programme for the treatment of depressive symptoms associated with the disease.

METHODS

This parallel-group, randomised, controlled, phase 3 trial of an iCBT programme to reduce depressive symptoms in patients with multiple sclerosis was carried out at five academic centres with large outpatient care units in Germany and the USA. Patients with a neurologist-confirmed diagnosis of multiple sclerosis and depressive symptoms were randomly assigned (1:1:1; automated assignment, concealed allocation, no stratification, no blocking) to receive treatment as usual plus one of two versions of the iCBT programme Amiria (stand-alone or therapist-guided) or to a control condition, in which participants received treatment as usual and were offered access to the iCBT programme after 6 months. Masking of participants to group assignment between active treatment and control was not possible, although raters were masked to group assignment. The predefined primary endpoint, which was analysed in the intention-to-treat population, was severity of depressive symptoms as measured by the Beck Depression Inventory-II (BDI-II) at week 12 after randomisation. This trial is registered at ClinicalTrials.gov, NCT02740361, and is complete.

FINDINGS

Between May 3, 2017, and Nov 4, 2020, we screened 485 patients for eligibility. 279 participants were enrolled, of whom 101 were allocated to receive stand-alone iCBT, 85 to receive guided iCBT, and 93 to the control condition. The dropout rate at week 12 was 18% (50 participants). Both versions of the iCBT programme significantly reduced depressive symptoms compared with the control group (BDI-II between-group mean differences: control vs stand-alone iCBT 6·32 points [95% CI 3·37-9·27], p<0·0001, effect size d=0·97 [95% CI 0·64-1·30]; control vs guided iCBT 5·80 points [2·71-8·88], p<0·0001, effect size d=0·96 [0·62-1·30]). Clinically relevant worsening of depressive symptoms was observed in three participants in the control group, one in the stand-alone iCBT group, and none in the guided iCBT group. No occurrences of suicidality were observed during the trial and there were no deaths.

INTERPRETATION

This trial provides evidence for the safety and efficacy of a multiple sclerosis-specific iCBT tool to reduce depressive symptoms in patients with the disease. This remote-access, scalable intervention increases the therapeutic options in this patient group and could help to overcome treatment barriers.

FUNDING

National Multiple Sclerosis Society (USA).

An Examination of Racial/Ethnic Differences on the Neurobehavioral Symptom Inventory Among Veterans Completing the Comprehensive Traumatic Brain Injury Evaluation: A Veterans Affairs Million Veteran Program Study

OBJECTIVE

The purpose of this study was to explore racial/ethnic differences in neurobehavioral symptom reporting and symptom validity testing among military veterans with a history of traumatic brain injury (TBI).

METHOD

Participants of this observational cross-sectional study (N = 9,646) were post-deployed Iraq-/Afghanistan-era veterans enrolled in the VA's Million Veteran Program with a clinician-confirmed history of TBI on the Comprehensive TBI Evaluation (CTBIE). Racial/ethnic groups included White, Black, Hispanic, Asian, Multiracial, Another Race, American Indian or Alaska Native, and Native Hawaiian or Other Pacific Islander. Dependent variables included neurobehavioral symptom domains and symptom validity assessed via the Neurobehavioral Symptom Inventory (NSI) and Validity-10, respectively.

RESULTS

Chi-square analyses showed significant racial/ethnic group differences for vestibular, somatic/sensory, and affective symptoms as well as for all Validity-10 cutoff scores examined (≥33, ≥27, ≥26, >22, ≥22, ≥13, and ≥7). Follow-up analyses compared all racial/ethnic groups to one another, adjusting for sociodemographic- and injury-related characteristics. These analyses revealed that the affective symptom domain and the Validity-10 cutoff of ≥13 revealed the greatest number of racial/ethnic differences.

CONCLUSIONS

Results showed significant racial/ethnic group differences on neurobehavioral symptom domains and symptom validity testing among veterans who completed the CTBIE. An enhanced understanding of how symptoms vary by race/ethnicity is vital so that clinical care can be appropriately tailored to the unique needs of all veterans. Results highlight the importance of establishing measurement invariance of the NSI across race/ethnicity and underscore the need for ongoing research to determine the most appropriate Validity-10 cutoff score(s) to use across racially/ethnically diverse veterans.

Geopolitical Considerations for Working with Medically Complex Patients: A Case Illustration

OBJECTIVE

Becoming culturally competent healthcare providers depends on the ability of practitioners to acquire knowledge, awareness, and skills related to other cultures. In building these areas of competence, it is essential to consider geopolitical factors that may influence health and health-seeking behaviors, particularly when working with immigrant populations. When care is sought, they are likely to experience significant barriers to effective care, including lack of providers who speak their language and failure of practitioners to integrate cultural beliefs into treatment plans. This is further complicated by the presence of geopolitical issues, including immigration status, war/conflict in the patient's country of origin, and/or human rights violations.

METHOD

The current study uses a sample case of a Burmese-speaking, Myanmar national to illustrate a culturally informed approach to the assessment of neurobehavioral changes within complex geopolitical circumstances. The sample represents an amalgam of several patients, designed to represent common presentations, sociodemographic situations, and concerns that arise during the neuropsychological assessment process.

RESULTS

Description of relevant case information including background, clinical observations, and performance on testing is provided.

DISCUSSION

Awareness of the impact of these life experiences not only has the potential to deepen our understanding of our patients but also results in a more holistic, accurate, and culturally competent conceptualization of their physical and mental health needs.

Thalamic atrophy moderates associations among aerobic fitness, cognitive processing speed, and walking endurance in persons with multiple sclerosis

BACKGROUND AND OBJECTIVES

Thalamic atrophy (TA) represents a biomarker of neurodegeneration and associated dysfunction/decline in physical and cognitive functioning among persons with multiple sclerosis (MS). Aerobic fitness, as an end point of exercise training, represents a promising target for restoring function in MS, but it is unknown if such effects differ by TA. This cross-sectional study examined whether aerobic fitness was differentially associated with cognitive processing speed and walking endurance in persons with MS who present with and without TA.

METHODS

44 fully ambulatory persons with MS completed a graded exercise test for measuring aerobic fitness (VO_2peak) and underwent 3T MRI for measuring TA, the Symbol Digit Modalities Test (SDMT), and the 6-min walk (6MW). We performed Spearman correlations (r_s) among VO_2peak, SDMT, and 6MW scores overall, and in persons with and without TA. We applied Fisher's z-test for comparing correlations based on TA status.

RESULTS

When controlling for age, EDSS score, and global MRI measures of atrophy, VO_2peak was strongly associated with SDMT scores (pr_s = 0.74, p < 0.01) and 6MW performance (pr_s = 0.77, p < 0.01) in persons with TA, whereas VO_2peak was not associated with SDMT scores (pr_s =  - 0.01, p = 0.99) or 6MW performance (pr_s = 0.25, p = 0.38) in those without TA. The correlations between VO_2peak and SDMT (z = 2.86, p < 0.01) and VO_2peak and 6MW (z = 2.33, p = 0.02) were significantly stronger in the TA group.

DISCUSSION

This study provides initial evidence of strong, selective associations among aerobic fitness, cognitive processing speed, and walking endurance in persons with TA as a biomarker for MS-related neurodegeneration. Such data support TA as a moderator of the association among aerobic fitness, cognitive processing speed, and walking endurance in persons with MS. Future research should carefully consider the role of TA when designing trials of aerobic exercise, cognition, and mobility in MS.

Associations of White Matter and Basal Ganglia Microstructure to Cognitive Fatigue Rate in Multiple Sclerosis

Fatigue, including cognitive fatigue, is one of the most debilitating symptoms reported by persons with multiple sclerosis (pwMS). Cognitive fatigue has been associated with disruptions in striato-thalamo-cortical and frontal networks, but what remains unknown is how the rate at which pwMS become fatigued over time relates to microstructural properties within the brain. The current study aims to fill this gap in knowledge by investigating how cognitive fatigue rate relates to white matter and basal ganglia microstructure in a sample of 62 persons with relapsing-remitting MS. Participants rated their level of cognitive fatigue at baseline and after each block (x7) of a within-scanner cognitive fatigue inducing task. The slope of the regression line of all eight fatigue ratings was designated as “cognitive fatigue rate.” Diffusional kurtosis imaging maps were processed using tract-based spatial statistics and regional analyses (i.e., basal ganglia) and associated with cognitive fatigue rate. Results showed cognitive fatigue rate to be related to several white matter tracts, with many having been associated with basal ganglia connectivity or the previously proposed “fatigue network.” In addition, cognitive fatigue rate was associated with the microstructure within the putamen, though this did not survive multiple comparisons correction. Our approach of using cognitive fatigue rate, rather than trait fatigue, brings us closer to understanding how brain pathology may be impacting the experience of fatigue in the moment, which is crucial for developing interventions. These results hold promise for continuing to unpack the complex construct that is cognitive fatigue.

Signal Detection Theory as a Novel Tool to Understand Cognitive Fatigue in Individuals With Multiple Sclerosis

Multiple Sclerosis (MS) affects 2.8 million persons worldwide. One of the most persistent, pervasive, and debilitating symptoms of MS is cognitive fatigue. While this has been known for over a century, cognitive fatigue has been difficult to study because patients' subjective (self-reported) cognitive fatigue has consistently failed to correlate with more objective measures, such as reaction time (RT) and accuracy. Here, we investigated whether more nuanced metrics of performance, specifically the metrics of Signal Detection Theory (SDT), would show a relationship to cognitive fatigue even if RT and accuracy did not. We also measured brain activation to see whether SDT metrics were related to activation in brain areas that have been shown to be sensitive to cognitive fatigue. Fifty participants (30 MS, 20 controls) took part in this study and cognitive fatigue was induced using four blocks of a demanding working memory paradigm. Participants reported their fatigue before and after each block, and their performance was used to calculate SDT metrics (Perceptual Certainty and Criterion) and RT and accuracy. The results showed that the SDT metric of Criterion (i.e., response bias) was positively correlated with subjective cognitive fatigue. Moreover, the activation in brain areas previously shown to be related to cognitive fatigue, such as the striatum, was also related to Criterion. These results suggest that the metrics of SDT may represent a novel tool with which to study cognitive fatigue in MS and other neurological populations. These results hold promise for characterizing cognitive fatigue in MS and developing effective interventions in the future.

A much needed metric: Defining reliable and statistically meaningful change of the oral version Symbol Digit Modalities Test (SDMT)

BACKGROUND

The Symbol Digit Modalities Test (SDMT) has been recommended for use in clinical trials and outcome studies to monitor cognitive change. However, defining what is a meaningful change has been elusive for several years.

OBJECTIVE

The present investigation aimed to develop methods for assessing individual-level statistically significant change on the SDMT - reliable change indices (RCIs) and standardized regression-based (SRB) equations.

METHODS

A total of 219 healthy individuals completed the oral version SDMT at baseline, 6-month and 1-year follow-up.

RESULTS

The SDMT demonstrated high reliability across all time points (r's = 0.83 to 0.86). Reliable change scores of 7, 8, and 10 points for the 6-month intervals represented statistically meaningful change at the 0.70, 0.80, and 0.90 confidence intervals, respectively. Over 1-year, a difference of 8, 10, and 12 was statistically meaningful at the 0.70, 0.80, and 0.90 confidence intervals, respectively. SRB equations are also provided taking into account additional factors found to be predictive of SDMT scores over time.

CONCLUSION

Clinicians frequently denote a decline of 4 points on the SDMT as meaningful. Results in this large normative sample show that higher cut-points are needed to demonstrate statistically significant decline at the individual level. RCIs are provided for 6 month and one year assessment, which is typical in clinical practice and trials. SRB equations are also provided for use when applicable and may provide a more precise assessment of meaningful change.

A-50 Representation and Generalizability in Neuropsychologically-Focused Multiple Sclerosis Research: Who Are we Studying and Who Does it Apply to?

Objective

MS impacts individuals from diverse racial/ethnic groups, yet they are not always well represented in research. The objectives of the current study are to examine how often neuropsychologically-focused MS research (NFMSR) studies: (1) include diverse populations; (2) explicitly describe the race/ethnicity of their participants; and (3) discuss generalizability/cultural implications.

Methods

A sample of NFMSR studies (defined here as studies examining cognitive functioning, mood, neuroimaging, fatigue, and quality of life) published within major journals between 2017–2020 were identified. Articles focusing on clinically isolated syndrome or pediatric populations were excluded. Variables of interest included sample size, sex/gender, race/ethnicity, age, education, socioeconomic status (SES), generalizability/cultural limitations, discussion of racism/disparities, and recruitment procedures. Data were coded and analyzed in IBM’s Statistical Package for the Social Sciences (SPSS; version 27).

Results

Race/ethnicity was not often reported in NFMSR studies, and when described, the representation of diverse individuals with MS was low (i.e., samples were mostly Caucasian). In addition, specific information about recruitment methods and SES was lacking. Generalizability/cultural implications or disparities were not discussed in the majority of studies. Report of education was variable, while sex, age, disease course, and EDSS were more often reported.

Conclusions

To the authors’ knowledge, this is the first study to highlight the significant gaps in representation in NFMSR. These results have significant implications for how we should be using the current literature to characterize patients or guide treatments. In addition, the current study serves as a call to action for MS researchers to work toward more inclusive and generalizable studies.