Illness intrusiveness: A key part of the cognition-mood link in multiple sclerosis.

PURPOSE: The current study attempted to expand the literature on cognition and mood in MS by determining if illness intrusiveness may potentially serve as an intermediary factor in the well-established cognition-mood relationship in people with MS. METHOD: This study employed a retrospective cross-sectional design to answer this question. Baseline neuropsychological test data and mood questionnaires from 199 participants with clinically definite MS were used in this study. The sample was middle-aged (M = 48.4, SD = 11.8), highly educated (M = 14.6, SD = 2.2), majority female (76.9%) and majority White (74.5%). Assumptions for parametric statistics and ordinary least squares regression were met. Conditional process models evaluated whether illness intrusiveness mediated the relationship between cognitive functioning and psychiatric symptoms. RESULTS: In total, 33.2% of the sample met criteria for clinically significant anxiety, 41.7% met criteria for depression, and 27.8% of the sample met criteria for processing speed impairment, consistent with other MS samples. Illness intrusiveness was found to mediate the relationship between processing speed and depression, ab = -.07, 95% CI [-.15, -.002], processing speed and anxiety, ab = -.06, 95% CI [-.12, -.02], and processing speed and more general mood disturbance, ab = -.08, 95% CI [-.13, -.0005]. CONCLUSIONS: Illness intrusiveness was found to be a potential important intermediary mechanism by which the primary cognitive impairment in MS, processing speed, impacts mood in this disease population. Conclusions, treatment implications, and directions for future research in light of these findings were discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Handedness and Cognition in Multiple Sclerosis: Potential Indications for Hemispheric Vulnerability.

BACKGROUND: Multiple sclerosis (MS) affects over 2.5 million individuals worldwide, yet much of the disease course is unknown. Hemispheric vulnerability in MS may elucidate part of this process but has not yet been studied. The current study assessed neuropsychological functioning as it relates to hemispheric vulnerability in MS. METHODS: Verbal IQ, as measured by verbal comprehension index (VCI), nonverbal IQ, as measured by perceptual reasoning index (PRI) and memory acquisition were compared in right-handed (dextral) and non-right-handed (non-dextral) persons with MS (PwMS). RESULTS: Linear mixed-effects modeling indicated a significant main effect of handedness, F(1, 195.35) = 3.95, p = .048, for a composite measure of VCI, PRI, and memory acquisition, with better performance for dextral PwMS. In examining differences for specific neuropsychological measures, the largest effect size between dextral and non-dextral participants was seen in PRI (d = 0.643), F(1,341) = 12.163, p = .001. No significant interaction effect between handedness and IQ was found, F(3, 525.60) = 0.75, p = .523. CONCLUSIONS: Dextral PwMS perform better than non-dextral PwMS when assessing neuropsychological performance for memory and IQ combined. Results are suggestive of increased vulnerability in the left brain to the pathological process of MS.

A closer look at the influence of mood and disability on illness intrusiveness in multiple sclerosis.

PURPOSE: Multiple sclerosis (MS) patients often report high levels of illness intrusiveness. The direct and indirect effects of disability and psychological symptoms on illness intrusiveness remain largely unknown, despite their pervasiveness. The present study aimed to examine how depression and anxiety can serve as mechanisms through which disability may impact illness intrusiveness in 3 life domains-instrumental activities, intimacy, and relationships and personal development. METHOD: Participants (N = 72) were adults (Mage = 47.86, SD = 11.79), predominantly female (73.6%) and diagnosed relapse-remitting MS (81.9%). The data was used from an archival neuropsychological database. Data on self-report measures were analyzed to examine the relationship between disability and illness intrusiveness, with depression and anxiety as mediators. Mediation models were run for total illness intrusiveness and the subscales. RESULTS: Depression and anxiety were significant mediators through which disability may impact overall illness intrusiveness. When examining life domains, depression was a significant mediator in all domains. Anxiety was only a significant mediator between disability and relationships/personal development. CONCLUSIONS: Results suggest that greater disability both directly and indirectly interferes with illness intrusiveness via depression and anxiety. However, life domains are differentially impacted. Thus, this study helps to guide interventions on the best symptoms to target to improve illness intrusiveness and overall quality of life. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The influence of trait mindfulness on depression in multiple sclerosis: potential implications for treatment.

PURPOSE: This study seeks to add to existing literature on depression and illness intrusiveness in chronic disorders by examining, (1) how the perceived intrusiveness of multiple sclerosis (MS) leads to depression, (2) and the mediating role trait mindfulness plays in this relationship METHODS: Participants (N = 755) were persons with MS (PwMS) recruited through the North American Research Committee on MS (NARCOMS) registry (a larger study). Participants completed the Illness Intrusiveness Ratings Scale, the Hospital Anxiety and Depression Scale and the Mindful Attention Awareness Scale. A mediation model assessed if trait mindfulness mediates the relationship between illness intrusiveness and depression RESULTS: Illness intrusiveness predicted trait mindfulness (a = - 4.54; p < .001), trait mindfulness predicted depression (b = - .04; p < .001); there was a direct effect of illness intrusiveness on depression (c' = 2.53; p < .001) and an indirect effect on depression (ab = .17, 95% BCa CI [.10, .25]) when trait mindfulness was in the model, which represented a medium size effect, R2med = .10 [95% CI .07, .14] CONCLUSION: Trait mindfulness mediates the relationship between illness intrusiveness and depression in PwMS. Providers could provide psychoeducation on the benefits of mindfulness and mindfulness-based interventions.

Relationship Between Anxiety and Cognition in Multiple Sclerosis: Implications for Treatment.

BACKGROUND: Anxiety, which is very prevalent in multiple sclerosis (MS) but understudied, has been shown to negatively affect cognition in many different populations. Slowed information processing speed underlies most cognitive impairments in MS, including verbal learning. The aim of this study was to look at how anxiety influences cognition-specifically processing speed and verbal learning-in MS. METHODS: Eligibility criteria were adults (≥18 years) who had a diagnosis of clinically definite MS and had participated in neuropsychological research projects. A retrospective medical record review was conducted on the neuropsychological testing data. Two hierarchical multiple regressions were conducted to determine the unique contributions of processing speed and anxiety on verbal learning in MS, after adjusting for demographic and disability variables. Two separate mediation analyses were conducted to determine the relationship between processing speed, verbal learning, and anxiety. RESULTS: Participants (N = 141) ranged in age from 18-91 years. Based on the multiple regression analyses, processing speed (ß = 0.55, ΔR 2 = 0.27, P < .001) and anxiety (ß = -0.34, ΔR 2 = 0.11, P < .001) were uniquely significant predictors of verbal learning. Based on the mediation analyses, there was a significant indirect effect of anxiety on verbal learning through processing speed (ab = -0.31, 95% CI = -0.60 to -0.09). There was also a significant indirect effect of processing speed on verbal learning through anxiety (ab = -0.05, 95% CI = 0.01 to 0.12). CONCLUSIONS: Results suggest a bidirectional relationship of anxiety and processing speed on verbal learning in MS. Anxiety has a significant effect on cognition and should not be overlooked. Interventions targeting anxiety may improve cognition in MS.

Motivation in multiple sclerosis cognitive fatigue: An experimental approach.

Introduction: Cognitive fatigue is a common symptom in multiple sclerosis (MS). Recent research has implicated dopaminergic pathways originating in the basal ganglia as neurological correlates of cognitive fatigue in MS. This same system has long been associated with goal-directed behavior and reward-based motivation. While researchers have demonstrated that reward has a reliable impact on performance in tasks of sustained attention in healthy individuals, the effect of reward on fatigue is less clear, as prior research has not adequately controlled for desensitization to reward in a sustained attention task. The primary aims of this study were to examine the effect of reward on attention in MS patients, and to examine the effect of reward on objective cognitive fatigue. Method: The study employed a 3 × 3 repeated measures design to evaluate performance of N = 64 patients with definite MS on a measure of cognitive fatigue across several reward conditions. The study utilized a novel delayed-reward paradigm to better control the measured effect of reward on fatigue. Results: Reward (main effect) displayed a significant effect on overall performance (F = 3.050, p < .05). Reward was also shown to affect fatigue trajectory (Reward × Interval, F = 2.433, p < .05). However, this effect was dependent on the method of reward administration. Conclusions: Study findings support the role of motivation in MS cognitive performance, particularly in objective cognitive fatigue, a behavioral finding that is consistent with current neuropsychological theory. Study findings support the delayed-reward paradigm as an effective method for measuring reward effect on tasks of sustained attention.