Performance In Multiple Sclerosis Patients Research Articles

COGNITIVE IMPAIRMENT IN MULTIPLE SCLEROSIS: ASSOCIATION WITH THE ACTIVITY OF INFLAMMATORY PROCESS AND SEVERITY OF DISABILITY

Background: Multiple sclerosis is the most common neurological disease leading to disability in young and productive patients. One of available methods of control over the course of the disease and detection of its progression is neuropsychological testing. However, selection of the most informative tests, as well as the search for interpretation of their results is still ongoing. Aim: To study cognitive functions in multiple sclerosis patients depending on the disease activity and degree of disability. Materials and methods: Fifty patients with multiple sclerosis were evaluated during their remissions and 15 of them were additionally assessed during an exacerbation. During neuropsychological testing a computer test “Selection of figures” was used for assessment of attention, productivity, frontal functions and visual neglect. We studied potential dependency of the parameters obtained from degree of disability and disease stage (exacerbation or remission). The control group comprised 12 healthy subjects. Results: Compared to healthy subjects, the multiple sclerosis patients had a prolonged time of test performance, decreased learning, and statistically significant decrease of the working efficacy (p < 0.05). During an attack, there was a decreased conceptualization (48 answers compared to 51.5 at remission stage); more than 3-fold (from 1,3 to 4,4) increase in the number of figures missed in one visual field, that could indirectly indicate visual neglect. Also, changes in frontal functions were noted as a tendency to almost 2-fold higher numbers of perseverative answers, more frequent categorical escape and learning abnormality. There was a positive correlation between expanded disability scale score (EDSS) and working efficacy (r = 0.453, p = 0.001), and a negative correlation between EDSS and mental stability (r = 0.4055, p = 0.0035). Conclusion: Patients with multiple sclerosis had abnormal rate and accuracy of test performance, compared to those in healthy subjects. During an exacerbation of the disease, there was a deterioration of the parameters compared to those registered in the remission. Also, a negative association with disease severity assessed by EDSS, was found. The data obtained documents feasibility of the computer test “Selection of figures” for dynamic control in multiple sclerosis patients.

General Mathematical Ability Predicts PASAT Performance in MS Patients: Implications for Clinical Interpretation and Cognitive Reserve.

The Paced Auditory Serial Addition Test (PASAT) is used to assess cognitive status in multiple sclerosis (MS). Although the mathematical demands of the PASAT seem minor (single-digit arithmetic), cognitive psychology research links greater mathematical ability (e.g., algebra, calculus) to more rapid retrieval of single-digit math facts (e.g., 5+6=11). The present study evaluated the hypotheses that (a) mathematical ability is related to PASAT performance and (b) both the relationship between intelligence and PASAT performance as well as the relationship between education and PASAT performance are both mediated by mathematical ability. Forty-five MS patients were assessed using the Wechsler Test of Adult Reading, PASAT and Calculation Subtest of the Woodcock-Johnson-III. Regression based path analysis and bootstrapping were used to compute 95% confidence intervals and test for mediation. Mathematical ability (a) was related to PASAT (β=.61; p<.001) and (b) fully mediated the relationship between Intelligence and PASAT (β=.76; 95% confidence interval (CI95)=.28, 1.45; direct effect of Intelligence, β=.42; CI95=-.39, 1.23) as well as the relationship between Education and PASAT (β=2.43, CI95=.81, 5.16, direct effect of Education, β=.83, CI95=-1.95, 3.61). Mathematical ability represents a source of error in the clinical interpretation of cognitive decline using the PASAT. Domain-specific cognitive reserve is discussed.

Effects of Yoga on Physiological Indices, Anxiety and Social Functioning in Multiple Sclerosis Patients: A Randomized Trial.

Multiple sclerosis (MS) as a chronic disease could affect patients' various domains of life. This study was conducted to study the effect of yoga on the physiological indices, anxiety and social functioning of patients with MS in southwest, Iran. In this clinical trial study, 60 MS patients were enrolled according to inclusion criteria and randomly assigned to two groups of 30 each. Prior to and after intervention, the patients' vital signs were measured. For case group yoga exercises were performed three sessions a week for 12 weeks while control group performed no exercise. The data were gathered by questionnaire and analysed by descriptive and analytical statistics in SPSS. Prior to intervention, there was no significant difference in fatigue severity and pain between the two groups but the mean fatigue severity and pain in case group decreased compared to the control group after the intervention. Prior to intervention, there was no significant difference in mean physiological indices between the two groups but the mean physiological indices in case group decreased significantly after the intervention (p<0.05). Yoga is likely to increase self-efficacy of MS patients through enhancing physical activity, increasing the strength of lower limbs and balance, and decreasing fatigue and pain, and finally to promote social functioning and to relieve stress and anxiety in these patients.

Role of executive functions in prospective memory in multiple sclerosis: Impact of the strength of cue–action association

ABSTRACTObjectives: Patients diagnosed with multiple sclerosis (MS) often report prospective memory (PM) deficits. Although PM is important for daily functioning, it is not formally assessed in clinical practice. The aim of this study was to examine the role of executive functions in MS patients’ PM revealed by the effect of strength of cue–action association on PM performance. Method: Thirty-nine MS patients were compared to 18 healthy controls matched for age, gender, and education on a PM task modulating the strength of association between the cue and the intended action. Results: Deficits in MS patients affecting both prospective and retrospective components of PM were confirmed using 2 × 2 × 2 mixed analyses of variance (ANOVAs). Among patients, multiple regression analyses revealed that the impairment was modulated by the efficiency of executive functions, whereas retrospective memory seemed to have little impact on PM performance, contrary to expectation. More specifically, results of 2 × 2 × 2 mixed-model analyses of covariance (ANCOVAs) showed that low-executive patients had more difficulty detecting and, especially, retrieving the appropriate action when the cue and the action were unrelated, whereas high-executive patients’ performance seemed to be virtually unaffected by the cue–action association. Conclusions: Using an objective measure, these findings confirm the presence of PM deficits in MS. They also suggest that such deficits depend on executive functioning and can be reduced when automatic PM processes are engaged through semantic cue–action association. They underscore the importance of assessing PM in clinical settings through a cognitive evaluation and offer an interesting avenue for rehabilitation.

Anxiety and Depressive Symptoms Are Associated With Worse Performance on Objective Cognitive Tests in MS.

Cognitive impairment, anxiety, and depressive symptoms are common in multiple sclerosis (MS) and are known to interact in non-MS populations. This retrospective chart review examined this relationship in a relapsing-remitting MS population. A significant difference on measures of processing speed/working memory and visual-spatial memory was found in MS patients with anxiety compared with nonanxious MS patients, while a significant difference was found on measures of processing speed, visual-spatial memory and executive function in MS patients with depressive symptoms compared with those without. Further research is needed to determine the causal relationship between anxiety and depressive symptoms and cognitive impairment.

Deficits in tongue motor control are linked to microstructural brain damage in multiple sclerosis: a pilot study.

BackgroundDeterioration of fine motor control of the tongue is common in Multiple Sclerosis (MS) and has a major impact on quality of life. However, the underlying neuronal substrate is largely unknown. Here, we aimed to explore the association of tongue motor dysfunction in MS patients with overall clinical disability and structural brain damage.MethodsWe employed a force transducer based quantitative-motor system (Q-Motor) to objectively assess tongue function in 33 patients with MS. The variability of tongue force output (TFV) and the mean applied tongue force (TF) were measured during an isometric tongue protrusion task. Twenty-three age and gender matched healthy volunteers served as controls. Correlation analyses of motor performance in MS patients with individual disease burden as expressed by the Expanded Disability Status Scale (EDSS) and with microstructural brain damage as measured by the fractional anisotropy (FA) on Diffusion Tensor Imaging were performed.ResultsMS patients showed significantly increased TFV and decreased TF compared to controls (p < 0.02). TFV but not TF was correlated with the EDSS (p < 0.04). TFV was inversely correlated with FA in the bilateral posterior limb of the internal capsule expanding to the brain stem (p < 0.001), a region critical to tongue function. TF showed a weaker, positive and unilateral correlation with FA in the same region (p < 0.001).ConclusionsChanges in TFV were more robust and correlated better with disease phenotype and FA changes than TF. TFV might serve as an objective and non-invasive outcome measure to augment the quantitative assessment of motor dysfunction in MS.

Dynamic walking features and improved walking performance in multiple sclerosis patients treated with fampridine (4-aminopyridine)

BackgroundImpaired walking capacity is a frequent confinement in Multiple Sclerosis (MS). Patients are affected by limitations in coordination, walking speed and the distance they may cover. Also abnormal dynamic walking patterns have been reported, involving continuous deceleration over time. Fampridine (4-aminopyridine), a potassium channel blocker, may improve walking in MS. The objective of the current study was to comprehensively examine dynamic walking characteristics and improved walking capacity in MS patients treated with fampridine.MethodsA sample of N = 35 MS patients (EDSS median: 4) underwent an electronic walking examination prior to (Time 1), and during treatment with fampridine (Time 2). Patients walked back and forth a distance of 25 ft for a maximum period of 6 min (6-minute 25-foot-walk). Besides the total distance covered, average speed on the 25-foot distance and on turns was determined separately for each test minute, at Time 1 and Time 2.ResultsPrior to fampridine administration, 27/35 patients (77 %) were able to complete the entire 6 min of walking, while following the administration, 34/35 patients (97 %) managed to walk for 6 min. In this context, walking distance considerably increased and treatment was associated with faster walking and turning across all six test minutes (range of effect sizes: partial eta squared = .34-.72). Importantly, previously reported deceleration across test minutes was consistently observable at Time 1 and Time 2.DiscussionFampridine administration is associated with improved walking speed and endurance. Regardless of a treatment effect of fampridine, the previously identified, abnormal dynamic walking feature, i.e. the linear decline in walking speed, may represent a robust feature.ConclusionsThe dynamic walking feature might hence be considered as a candidate for a new outcome measure in clinical studies involving interventions other than symptomatic treatment, such as immune-modulating medication.Trial registrationDRKS00009228 (German Clinical Trials Register). Date obtained: 25.08.2015.

Interferon-Beta Therapy of Multiple Sclerosis Patients Improves the Responsiveness of T Cells for Immune Suppression by Regulatory T Cells.

Multiple sclerosis (MS) is an inflammatory autoimmune disease characterized by imbalanced immune regulatory networks, and MS patient-derived T effector cells are inefficiently suppressed through regulatory T cells (Treg), a phenomenon known as Treg resistance. In the current study we investigated T cell function in MS patients before and after interferon-beta therapy. We compared cytokine profile, responsiveness for Treg-mediated suppression ex vivo and evaluated reactivity of T cells in vivo using a humanized mouse model. We found that CD4+ and CD8+ T cells of therapy-naive MS patients were resistant to Treg-mediated suppression. Treg resistance is associated with an augmented IL-6 production, enhanced IL-6 receptor expression, and increased PKB/c-Akt phosphorylation. These parameters as well as responsiveness of T cells to Treg-mediated suppression were restored after interferon-beta therapy of MS patients. Following transfer into immunodeficient mice, MS T cells induced a lethal graft versus host disease (GvHD) and in contrast to T cells of healthy volunteers, this aggressive T cell response could not be controlled by Treg, but was abolished by anti-IL-6 receptor antibodies. However, magnitude and lethality of GvHD induced by MS T cells was significantly decreased after interferon-beta therapy and the reaction was prevented by Treg activation in vivo. Our data reveals that interferon-beta therapy improves the immunoregulation of autoaggressive T effector cells in MS patients by changing the IL-6 signal transduction pathway, thus restoring their sensitivity to Treg-mediated suppression.

Neuroenhancement through cognitive training and anodal tDCS in multiple sclerosis

Background: Cognitive training has been shown to improve cognitive function and quality of life in multiple sclerosis (MS) patients and is correlated with increased activity in the left dorsolateral prefrontal cortex (DLPFC). Objective: This study aims to test whether combining attention training with anodal transcranial direct current stimulation (a-tDCS) over the left DLPFC can improve training efficacy. Methods: Twenty patients impaired in attention/speed of information processing were randomly assigned to cognitive training during a-tDCS over the left DLPFC or cognitive training during sham tDCS for 10 daily sessions. Neuropsychological evaluations were conducted at baseline, after treatment and six months later. Results: When a-tDCS, rather than sham, was applied during the cognitive training, patients showed a significantly greater improvement in the Symbol Digit Modality Test (SDMT) and Wisconsin Card Sorting Test (WCST) after treatment (p < 0.05) and in the Paced Auditory Serial Addition Test (PASAT) 2” and WCST six months later (p < 0.05). They also had significantly shorter time to reach the most difficult exercise level, compared to sham treatment (6.3 vs. 7.4 sessions; p < 0.05). Conclusions: These results indicate that a-tDCS on the DLPFC during cognitive training fosters improvements in attention and executive function in MS patients and shortens treatment duration.

Neuromuscular taping versus sham therapy on muscular strength and motor performance in multiple sclerosis patients

Purpose: Purpose of this study is to evaluate differences in leg muscles strength and motor performance between neuromuscular taping (NT) and sham tape groups. Method: Relapsing-remitting (RR) multiple sclerosis (MS) patients were recruited and randomly assigned to NT or sham tape groups. All patients underwent the treatment 5 times at 5-d intervals. They were submitted to a 6-minute walk test and isokinetic test (peak torque) at the beginning (T0), at the end (T1) and 2 months after the end of the treatment (T2). Results: Forty MS patients (38 F; 2 M; mean age 45.5 ± 6.5 years) were assigned to NT group (n = 20) and to sham tape group (n = 20). Delta Peak Torque T1–T0 and T2–T0 between two groups were statistically significant in quadriceps (p = 0.007; 0.000) and hamstrings (p = 0.011; 0.007). The difference between the two groups according to 6-minute walk test was not statistically significant but in NT group it was noticed an increasing trend about the distance run. Conclusions: In this single-blind randomized controlled trial, NT seemed to increase strength in leg muscles, compared to a sham device, in RR MS patients. Further studies are needed to consider this therapy as a complement to classic physical therapy.Implications for RehabilitationNeuromuscular taping (NT) in multiple sclerosis:NT is well tolerated by multiple sclerosis patients and should be a complement to classic physical therapy.This technique normalizes muscular function, strengthens weakened muscles and assists the postural alignment.

A Pilot Study of Dalfampridine for Improving Upper Extremity Function in Multiple Sclerosis Patients (P1.124)

A Pilot Study of Dalfampridine for Improving Upper Extremity Function in Multiple Sclerosis Patients (P1.124)

Subclinical MRI disease activity influences cognitive performance in MS patients

BackgroundThe pathological mechanisms underlying cognitive dysfunction in multiple sclerosis (MS) are not yet fully understood and, in addition to demyelinating lesions and gray-matter atrophy, subclinical disease activity may play a role. ObjectiveTo evaluate the contribution of asymptomatic gadolinium-enhancing lesions to cognitive dysfunction along with gray-matter damage and callosal atrophy in relapsing-remitting MS (RRMS) patients. MethodsForty-two treated RRMS and 30 controls were evaluated. MRI (3T) variables of interest were brain white-matter and cortical lesion load, cortical and deep gray-matter volumes, corpus callosum volume and presence of gadolinium-enhancing lesions. Outcome variables included EDSS, MS Functional Composite (MSFC) subtests and the Brief Repeatable Battery of Neuropsychological tests. Cognitive dysfunction was classified as deficits in two or more cognitive subtests. Multivariate regression analyses assessed the contribution of MRI metrics to outcomes. ResultsPatients with cognitive impairment (45.2%) had more cortical lesions and lower gray-matter and callosal volumes. Patients with subclinical MRI activity (15%) had worse cognitive performance. Clinical disability on MSFC was mainly associated with putaminal atrophy. The main independent predictors for cognitive deficits were high burden of cortical lesions and number of gadolinium-enhancing lesions. ConclusionsCognitive dysfunction was especially related to high burden of cortical lesions and subclinical disease activity. Cognitive studies in MS should look over subclinical disease activity as a potential contributor to cognitive impairment.

Fingolimod treatment promotes regulatory phenotype and function of B cells.

ObjectiveTo evaluate the influence of Fingolimod treatment on B-cell subset composition and function in multiple sclerosis patients and its potential clinical relevance.MethodsSubset composition and cytokine production of B cells derived from peripheral blood mononuclear cells from multiple sclerosis patients under Fingolimod treatment, untreated multiple sclerosis patients and healthy controls were analyzed by flow cytometry and ELISA. Migration of lymphocyte subsets across primary human brain microvascular endothelial cells was assessed in an in vitro transmigration assay. Cell numbers and composition of B-cell subsets in cerebrospinal fluid and peripheral blood were determined by flow cytometry. Regulatory B-cell frequencies were correlated with parameters of disease stability.ResultsWithin the peripheral B-cell compartment of Fingolimod-treated patients, the proportion of regulatory B cells (CD38+CD27−CD24+CD5+) was significantly increased as compared to treatment-naïve multiple sclerosis patients and to healthy controls, and significantly more regulatory B cells produced Interleukin-10. Fingolimod treatment enhanced the capacity of regulatory B cells to transmigrate across brain endothelial cells in an in vitro model of the blood-brain-barrier. In line with these findings, the cerebrospinal fluid/blood ratio of total B cells and regulatory B cells was strongly increased by Fingolimod treatment, and patients exhibited increased regulatory B-cell frequencies in the cerebrospinal fluid. Finally, elevated regulatory B-cell percentages in the periphery significantly correlated with clinical and paraclinical disease stability.InterpretationThese data suggest a novel and as yet unrecognized role of Fingolimod in correction of the imbalance between regulatory and effector B-cell functions in multiple sclerosis both by direct effects and indirect partitioning effects on B-cell subpopulations.

Impact of depression, fatigue, and global measure of cortical volume on cognitive impairment in multiple sclerosis.

Objective. To investigate the influence of demographic and clinical variables, such as depression, fatigue, and quantitative MRI marker on cognitive performances in a sample of patients affected by multiple sclerosis (MS). Methods. 60 MS patients (52 relapsing remitting and 8 primary progressive) underwent neuropsychological assessments using Rao's Brief Repeatable Battery of Neuropsychological Tests (BRB-N), the Beck Depression Inventory-second edition (BDI-II), and the Fatigue Severity Scale (FSS). We performed magnetic resonance imaging to all subjects using a 3 T scanner and obtained tissue-specific volumes (normalized brain volume and cortical brain volume). We used Student's t-test to compare depressed and nondepressed MS patients. Finally, we performed a multivariate regression analysis in order to assess possible predictors of patients' cognitive outcome among demographic and clinical variables. Results. 27.12% of the sample (16/59) was cognitively impaired, especially in tasks requiring attention and information processing speed. From between group comparison, we find that depressed patients had worse performances on BRB-N score, greater disability and disease duration, and brain volume decrease. According to multiple regression analysis, the BDI-II score was a significant predictor for most of the neuropsychological tests. Conclusions. Our findings suggest that the presence of depressive symptoms is an important determinant of cognitive performance in MS patients.

A Cohort Study of Cognitive Impairment in Patients of Multiple Sclerosis

Abstract Introduction:Multiple sclerosis (MS) is an inflammatory disease which disrupts the ability of nervous system to communicate, resulting in a wide range of signs and symptoms including physical, cognitive and psychiatric. Cognitive dysfunction is increasingly recognized as a critical factor in the quality of life of patients with MS. Remission of cognitive symptoms is uncommon, and cognitive decline may indicate progressive disease despite stable physical symptoms. Methods: A total of 30 patients of MS diagnosed by modified Mc Donald criterion 2010 had undergone MACFINS battery of Cognitive testing twice, first at the time of initial recruitement and then after a period of 6 months. Results: No significant cognitive decline was observed in patients after a mean follow up of 11 months. There was mild but not significant impairment in EDSS. There appears a strong direct correlation between all neuropsychological tests and physical disability. Most significant correlation of EDSS is seen with PASAT (P=0.002), BVMT1(P= 0.008), BVMT2(P=0.007), COWAT(P=0.0002) and Stroop B(P=0.009). Conclusion: Cognitive deterioration occurs probably insidiously and inconsistently in patients with MS. EDSS has significant direct correlation with cognitive impairment in these patients. A larger sample size study is required to conclusively establish cognitive performance in MS patients.

Relationship between urodynamic findings and sexual function in multiple sclerosis patients with lower urinary tract dysfunction.

Sexual dysfunction (SD) is prevalent in multiple sclerosis (MS) patients and affects quality of life. Furthermore, lower urinary tract dysfunction (LUTD) is common in MS patients. Our aim was to determine the relationship between urodynamic findings and SD in a cohort of MS patients with LUTD. From January 2011 to September 2013, 135 consecutive patients with MS in remission phase and LUTD underwent a first urodynamic examination, according to the International Continence Society criteria. Neurological impairment was assessed using the Expanded Disability Status Scale and SD was investigated with the Female Sexual Function Index (FSFI) or the International Index of Erectile Function (IIEF-15). Multivariate logistic regression analysis was performed to identify predictors of female SD (FSFI < 26.55) or moderate-severe erectile dysfunction (ED) (IIEF-EF ≤ 16), after adjusting for confounding factors including urodynamic findings. Subjects with maximum detrusor pressure during involuntary detrusor contraction (PdetmaxIDC) ≥20.0cmH2 O had lower IIEF-EF, IIEF overall satisfaction (IIEF-OS), FSFI-Arousal, FSFI-Lubrication and FSFI-Orgasm. Subjects with maximum cystometric capacity (MCC) ≥135 ml had higher IIEF-EF, intercourse satisfaction (IIEF-IS), orgasmic function (IIEF-OF), sexual desire (IIEF-SD), FSFI-Arousal, FSFI-Lubrication, FSFI-Orgasm, FSFI-Satisfaction and FSFI-Pain. On multivariate logistic regression analysis, PdetmaxIDC ≥20cmH2 O [odds ratio(OR) 6.7; P<0.05] and MCC <135ml (OR6.80; P<0.05) were predictors of moderate-severe ED. In a model including all previous variables, compliance ≤3ml/cmH2 O was an independent predictor of moderate-severe ED (OR 14.49; P<0.01). No relationship was found between the previous variables and FSFI <26.55. Neurogenic bladder is associated with SD in MS patients. The presence of PdetmaxIDC ≥20cmH2 O, MCC <135ml and compliance ≤3ml/cmH2 O may significantly predict the presence of moderate-severe ED.

Reduced Dual-Task Performance in MS Patients Is Further Decreased by Muscle Fatigue

Background. Multiple sclerosis (MS) can be accompanied by motor, cognitive, and sensory impairments. Additionally, MS patients often report fatigue as one of their most debilitating symptoms. It is, therefore, expected that MS patients will have difficulties in performing cognitive-motor dual tasks (DTs), especially in a fatiguing condition. Objective. To determine whether MS patients are more challenged by a DT than controls in a fatiguing and less-fatiguing condition and whether DT performance is associated with perceived fatigue. Methods. A group of 19 MS patients and 19 age-, sex-, and education-matched controls performed a cognitive task (2-choice reaction time task) separately or concurrent with a low-force or a high-force motor task (index finger abduction at 10% or 30% maximal voluntary contraction). Results. MS patients performed less well on a cognitive task than controls. Cognitive task performance under DT conditions decreased more for MS patients. Moreover, under high-force DT conditions, cognitive performance declined in both groups but to a larger degree for MS patients. Besides a decline in cognitive task performance, MS patients also showed a stronger decrease in motor performance under high-force DT conditions. DT costs were positively related to perceived fatigue as measured by questionnaires. Conclusions. Compared with controls, MS patients performed less well on DTs as demonstrated by a reduction in both cognitive and motor performances. This performance decrease was stronger under fatiguing conditions and was related to the sense of fatigue of MS patients. These data illustrate problems that MS patients may encounter in daily life because of their fatigue.

Mechanism of action of interferon‐β in relapsing–remitting multiple sclerosis: Effects on Th17 and Th9 cells

AbstractInterferon‐β is the first‐line treatment to inhibit neuroinflammation of the central nervous system in patients with relapsing–remitting multiple sclerosis. The mechanism of action of interferon‐β is complex. The study of Doi et al. in the present issue provides a new mechanism of interferon‐β function in multiple sclerosis patients. Recent investigations of Th17 and Th9 cells in multiple sclerosis are summarized.

Default network connectivity is linked to memory status in multiple sclerosis.

Memory impairment affects 50% of multiple sclerosis (MS) patients. Altered resting-state functional connectivity (FC) has been observed in the default network (DN) of MS patients. No study to date has examined the association of DN FC to its behavioral concomitant, memory. The approach of the present study represents a methodological shift allowing straightforward interpretation of FC alterations in MS, as it presupposes specificity of a network to its paired cognitive function. We examined FC from fMRI collected during rest in the DN of 43 MS patients with and without memory-impairment. Memory-intact patients showed increased DN FC relative to memory-impaired patients. There were no regions of higher FC in memory-impaired patients. DN FC was positively correlated with memory function, such that higher FC was associated with better memory performance. Results were unchanged after controlling for cognitive efficiency, supporting specificity of the DN to memory and not cognitive status more generally. These findings support DN FC as a marker of memory function in MS patients that can be targeted by future treatment interventions. Pairing a functional network with its behavioral concomitant represents a straightforward method for interpreting FC alterations in patients with MS.

The influence of age and illness duration on cognitive impairment in aging patients with relapsing-remitting multiple sclerosis (RR-MS)

The aim of this study was to dissociate age and duration of illness effects on cognitive impairment of patients with relapsing-remitting multiple sclerosis. Cognitive impairment among patients with multiple sclerosis (MS) is well known. However, few studies were devoted to assess the respective role of disease duration and age on cognitive functions in MS patients. Therefore, two studies were carried out on relapsing-remitting MS (RR-MS) patients using some tests of the BCcogSEP--a French test battery evaluating cognitive functions in MS. The cognitive deficits of RR-MS patients aged 50 years and over and whose symptoms had been present for more than 20 years were more severe than those of MS patients with a shorter illness duration (less than 10 years) or matched-age control participants. The more impaired cognitive functions were information-processing speed, episodic memory, verbal fluency and attention. On the other hand, cognitive performances of young RR-MS patients were similar to those of older RR-MS patients when all patients had the same illness duration (8 years in this study). Older patients even achieved better performance than younger ones on verbal fluency. This can be partly explained by the theory of cognitive reserve, as reported in previous cognitive aging studies. In RR-MS patients, the influence of illness duration seems to be a predominant factor in the development of cognitive impairment.