The Complex Interplay Between Trait Fatigue and Cognition in Multiple Sclerosis

peer reviewedCognitive impairments are frequent in patients with Multiple Sclerosis (MS). Yet, the influence of MS-related symptoms on cognitive status is not clear. Studies investigating the impact of trait fatigue along with anxio-depressive symptoms on cognition are seldom, and even less considered fatigue as multidimensional. Moreover, these studies provided conflicting results. Twenty-nine MS patients and 28 healthy controls, matched on age, gender and education underwent a full comprehensive neuropsychological assessment. Anxio-depressive and fatigue symptoms were assessed using the HAD scale and the MFIS, respectively. Six composite scores were derived from the neuropsychological assessment, reflecting the cognitive domains of working memory, verbal and visual learning, executive functions, attention and processing speed. Stepwise regression analyses were conducted in each group to investigate if trait cognitive and physical fatigue, depression and anxiety are relevant predictors of performance in each cognitive domain. In order to control for disease progression, patient’s EDSS score was also entered as predictor variable. In the MS group, trait physical fatigue was the only significant predictor of working memory score. Cognitive fatigue was a predictor for executive functioning performance and for processing speed (as well as EDSS score for processing speed). In the healthy controls group, only an association between executive functioning and depression was observed. Fatigue predicted cognition in MS patients only, beyond anxio-depressive symptoms and disease progression. Considering fatigue as a multidimensional symptom is paramount to better understand its association with cognition, as physical and cognitive fatigue are predictors of different cognitive processes

MRI Multiparameter measures as relevant explanatory variables of cognitive but not physical fatigue in Multiple Sclerosis

Introduction: Fatigue symptoms are highly frequent in patients with multiple sclerosis (MS). However, the underlying brain and clinical mechanisms associated specifically to feeling of cognitive and physical fatigue remain largely misunderstood. Aim of study: To investigate whether subjective cognitive and physical fatigue depend on different sets of brain and clinical variables in MS. Methods: Multiparameter mapping (MPM) MRI data (R1 parameter in central grey matter (GM), R2 in cortical and central GM, R2 in cortical white matter (WM), PD in central GM and in cortical WM), and clinical data (age, depression, anxiety, cognitive and physical fatigue scores at the M-FIS; disease duration and EDSS score for patients) were collected among MS patients (n=35) and healthy controls (n=28). Stepwise regression analysis for the cognitive and physical sub-scores of the M-FIS were performed in each group, using clinical and MRI variables. Results: Variance of cognitive M-FIS score for patients was explained with a model taking into account anxiety, depression and measures of cortical and central grey matter (R² = 0.5397, p < .0001). For controls, the model included age, depression and R2 parameter in cortical white matter (R²=0.4137, p = 0.0045). The model with physical M-FIS score included EDSS and anxiety for patients (R² = 0.3834, p = 0.0004), but age and depression for controls (R²= 0.4908, p = 0.0002). Conclusions: These results suggest (1) that the determinants of subjective fatigue vary between MS and control participants; (2) that only cognitive fatigue is linked to brain characteristics. These results stress the need to study cognitive and physical fatigue as two separate entities in MS.Etude de la fatigue mentale dans la Sclérose en Plaques: approche cognitive et par imagerie cérébral

Facilitating the use of an alternative pointing system for patients with multiple sclerosis with motor and cognitive impairments through procedural learning

We show that it's possible for people with MS with cognitive and motor impairments to use an alternative pointing system for their computer

Cognitive reserve in post-morbid Multiple Sclerosis: Maintenance of leisure activities might not be critical for disease progression.

Introduction: It has been largely proposed that premorbid engagement in leisure activities (LA) might have protective effects against multiple sclerosis (MS) related cognitive impairments. Yet, it is not clear whether maintaining those activities after the disease outbreak is critical for disease progression. Aim of the study: To assess (i) whether MS patients tend to disengage from LA after both disease outbreak and diagnosis, and (ii) if post-morbid LA are related to current cognitive status. Methods: 25 MS patients filled-in a LA questionnaire and underwent a neuropsychological assessment. Cognitive enrichment scores were calculated for the 5 years preceding and following the first symptom’s outbreak as well as the age of diagnosis, and were compared using Wilcoxon signed-rank tests. To test the relationship between post-morbid LA engagement and current cognitive status, Pearson’s correlations were performed between cognitive enrichment scores and performance in four cognitive tests (verbal and visual episodic learning, processing speed and working memory). Results: Wilcoxon tests did not reach significance (p < 0.05) when comparing pre and post-symptom cognitive enrichment scores, suggesting that MS patients did not show a decrease in LA following the first symptom. This was also true when considering diagnosis age rather than symptom’s outbreak. Pearson’s correlations between cognitive scores and post-morbid LA were not significant. Conclusion: These results suggest that MS patients maintain their engagements in LA following the disease outbreak. Nevertheless, there were no evidence for a link between post-morbid LA engagement and cognitive status, suggesting that continuation of activities does not affect disease progression

Sensation de fatigue et performances cognitives: un lien spécifique dans la Sclérose en Plaques

Introduction. La fatigue constitue un des symptômes les plus fréquents et invalidants des patients atteints de sclérose en plaques (SEP). Toutefois, le lien entre sensation subjective de fatigue et déficits cognitifs reste actuellement peu clair. L'objectif de cette étude était donc d'investiguer la présence d'associations entre performances cognitives et mesures subjectives de fatigue physique et mentale. Des analyses de régression multiples stepwise ont été réalisées afin de déterminer la contribution respective des scores de fatigue physique et mentale, de dépression et d'anxiété aux performances cognitives des patients. Méthode: 38 patients SEP (EDSS : 1 à 6) et 29 sujets de contrôle appariés au niveau de l'âge et du sexe ont été inclus. Les scores de fatigue mentale et physique ont été obtenus sur base de la Modified-Fatigue Impact Scale (M-FIScog et M-FISphys) et les niveaux d'anxiété et de dépression au moyen de l'échelle HAD. Les performances cognitives ont été évaluées via des mesures de mémoire de travail (Indice de Mémoire de Travail (IMT) de la WAIS III), de mémoire épisodique verbale (total des 5 essais d¿apprentissage du CVLT) et visuelle (score de rappel immédiat au test 10/36), de vitesse de traitement (Indice de Vitesse de Traitement (IVT) de la WAIS III, Symbol Digit Modality Test, vitesse de dénomination et de lecture à l'épreuve de Stroop), et de fonctionnement exécutif (indice d'interférence à l'épreuve de Stroop). Les scores cognitifs ont été convertis en notes standard afin de prendre en compte la distribution d'âge et de niveau d'étude des participants. Résultats: Chez les patients SEP, le score M-FIScog a été retenu comme explicateur de la performance à l'IVT (R² :0.12, p<0.05), aux conditions dénomination (R² : 0.17, p<0.05) et interférence (R² :0.32, p<0.0005) du test de Stroop. Pour le groupe contrôle, aucune variable étudiée n'était significative, pour les 8 scores cognitifs présentés. Discussion: Ces résultats soulignent l'importance de distinguer fatigue mentale et fatigue physique dans la SEP, seule la fatigue mentale apparaissant un explicateur de la performance cognitive. L'influence de la fatigue mentale semble spécifique à la SEP pour des tâches simples impliquant la vitesse de traitement, et se révélant accrue lorsqu'un contrôle exécutif est requit.Etude de la fatigue mentale dans la Sclérose en Plaques: approche cognitive et par imagerie cérébral

Subjective feeling of fatigue and cognitive performances: a specific link in Multiple Sclerosis

Introduction. Fatigue is one of the most frequent and debilitating symptom reported by patients with Multiple Sclerosis (MS). Yet, the link between cognitive impairments and subjective feeling of fatigue remains unclear. This study aims to investigate the associations between cognitive performance and subjective measures of both physical and mental fatigue. Stepwise regression analyses were conducted in order to determine, correspondingly, the contribution of physical and cognitive fatigue scores, as well as depression and anxiety scores, on patients' cognitive performance. Methods. 38 MS patients (EDSS: 1 to 6) and 28 healthy controls, matched on age and sex, were included in this study. Cognitive and physical fatigue scores were obtained from the Modified-Fatigue Impact Scale (M-FIScog and M-FISphys), and anxiety and depression level were determined from the HAD scale. Cognitive performance was assessed for working memory (Working Memory Index (WMI) from the WAIS III), verbal episodic memory (sum of the 5 learning trials of the CVLT), visual episodic memory (immediate recall score of the 10/36 test), processing speed (Processing Speed Index (PSI) from the WAIS-IV, Symbol Digit Modality Test (SDMT), denomination and reading speed at the Stroop task) and executive functioning (interference score of the Stroop task). In order to take participants' age distribution and education levels into account, cognitive scores were converted into standard scores. Results. For MS patients, M-FIScog scores explained variance in performance for PSI (R² :0.12, p<0.05), and for denomination (R² : 0.17, p<0.05) and interference (R² :0.32, p<0.0005) scores of the Stroop task. Regarding the control group, no variable was significant for each 8 cognitive scores. M-FISphys, depression and anxiety scores were retained by none of the significant model. Discussion. These results stress the need to dissociate cognitive and physical fatigue in MS. Only cognitive fatigue appeared as an explanatory variable of cognitive performance. Moreover, the influence of cognitive fatigue seems to be MS-specific for task relying on processing speed, and accentuated when the task requires executive control.Etude de la fatigue mentale dans la Sclérose en Plaques: approche cognitive et par imagerie cérébral