Fatigue in multiple sclerosis patients with different clinical phenotypes: a clinical and magnetic resonance imaging study.

BACKGROUND AND PURPOSE: The prevalence of fatigue and its relation with clinical, neuropsychological and brain magnetic resonance imaging (MRI) variables in a large cohort of multiple sclerosis (MS) patients was investigated. METHOD: The Modified Fatigue Impact Scale and its subdomains were collected from 725 healthy controls and 366 MS patients [238 relapsing-remitting (RRMS) and 128 progressive (PMS)]. For the Modified Fatigue Impact Scale global and subdomains, MS patients were classified as fatigued (F-MS) or non-fatigued (NF-MS) according to cut-off values provided by logistic regression models with a specificity of 90% (i.e. a 10% false-positive rate in classifying healthy controls). MS patients underwent neurological, neuropsychological and MRI evaluations. Clinical and MRI measures were compared between F-MS and NF-MS patients using age-, sex- and phenotype-adjusted linear models. Heterogeneities between phenotypes were tested with specific interaction terms. RESULTS: Global fatigue affected 174 (47.5%) MS patients, being more prevalent in PMS (PMS 64.1% vs. RRMS 38.7%, P < 0.001). For all dichotomizations, F-MS were older (P from <0.001 to 0.012) and more depressed (P < 0.001) than NF-MS patients. Compared to NF-MS, cognitive F-MS patients had lower education (P = 0.035). Compared to NF-MS, patients with global and physical fatigue had higher Expanded Disability Status Scale only for RRMS (P < 0.001). Only RRMS patients with physical fatigue had lower brain (P = 0.05), white matter (P = 0.039) and thalamic volumes (P = 0.022) compared to NF-MS patients. CONCLUSIONS: In MS, fatigue is associated with older age, lower education and higher depression. Only in RRMS, fatigue is associated with Expanded Disability Status Scale and brain atrophy. A plateauing effect of disability and structural damage can explain the lack of associations in PMS.

Structural and functional brain connectomes in patients with systemic lupus erythematosus.

BACKGROUND AND PURPOSE: Systemic lupus erythematosus (SLE) is an immune-mediated disease that may affect the nervous system. We explored the topographical organization of structural and functional brain connectivity in patients with SLE and its correlation with neuropsychiatric (NP) involvement and autoantibody profiles. METHODS: Graph theoretical analysis was applied to diffusion tensor magnetic resonance imaging (MRI) and resting-state functional MRI data from 32 patients with SLE and 32 age- and sex-matched healthy controls. Structural and functional connectivity matrices between 116 cortical/subcortical brain regions were estimated using a bivariate correlation analysis, and global and nodal network metrics were calculated. RESULTS: Structural, but not functional, global network properties (strength, transitivity, global efficiency and path length) were abnormal in patients with SLE versus controls (P < 0.0001), especially in patients with anti-double-stranded DNA (ADNA) autoantibodies (P = 0.03). No difference was found according to NP involvement or anti-phospholipid autoantibody status. Patients with SLE and controls shared identical structural hubs and the majority of functional hubs. In patients with SLE, all structural hubs showed reduced strength and clustering coefficient compared with controls (P from 0.001 to <0.0001), especially in patients with ADNA autoantibodies. Only a few differences in functional hub properties were found between patients with SLE and controls. Structural and functional hub measures did not differ according to NP involvement or anti-phospholipid autoantibody status. Significant correlations were found between clinical, MRI and network measures (r from -0.56 to 0.60, P from 0.0003 to 0.05). CONCLUSIONS: Abnormalities of global and nodal structural connectivity occur in patients with SLE, especially with ADNA autoantibodies, with a diffuse disruption of structural integrity. Functional network integrity may contribute to preserve clinical functions.

Fronto-temporal vulnerability to disconnection in paediatric moderate and severe traumatic brain injury.

BACKGROUND: In patients with moderate and severe paediatric traumatic brain injury (TBI), we investigated the presence and severity of white matter (WM) tract damage, cortical lobar and deep grey matter (GM) atrophies, their interplay and their correlation with outcome rating scales. METHODS: Diffusion tensor (DT) and 3D T1-weighted MRI scans were obtained from 22 TBI children (13 boys; mean age at insult = 11.6 years; 72.7% in chronic condition) and 31 age-matched healthy children. Patients were tested with outcome rating scales and the Wechsler Intelligence Scale for Children (WISC). DT MRI indices were obtained from several supra- and infra-tentorial WM tracts. Cortical lobar and deep GM volumes were derived. Comparisons between patients and controls, and between patients in acute (<6 months from the event) vs. chronic (≥6 months) condition were performed. RESULTS: Patients showed a widespread pattern of decreased WM FA and GM atrophy. Compared to acute, chronic patients showed severer atrophy in the right frontal lobe and reduced FA in the left inferior longitudinal fasciculus and corpus callosum (CC). Decreased axial diffusivity was observed in acute patients versus controls in the inferior fronto-occipital fasciculus and CC. Chronic patients showed increased axial diffusivity in the same structures. Uncinate fasciculus DT MRI abnormalities correlated with atrophy in the frontal and temporal lobes. Hippocampal atrophy correlated with reduced WISC scores, whereas putamen atrophy correlated with lower functional independence measure scores. CONCLUSIONS: The study isolated a distributed fronto-temporal network of structures particularly vulnerable to axonal damage and atrophy that may contribute to cognitive deficits following TBI.

Basal vitamin D levels and disease activity in multiple sclerosis patients treated with fingolimod.

BACKGROUND: Several studies have shown an association between 25-hydroxyvitamin D (25[OH]D) levels and multiple sclerosis (MS) susceptibility and/or level of disease activity in patients treated with first line drugs. AIMS: To investigate whether baseline 25[OH]D values could influence disease activity also during treatment with the second-line drug fingolimod (FTY). PATIENTS AND METHODS: We enrolled 176 MS patients who started FTY at the San Raffaele Hospital (OSR) MS center with available 25[OH]D measurement at the time of treatment start. We then prospectively followed them for 2 years with periodic clinical examinations and MRI scans. RESULTS: We found no linear correlation between baseline 25[OH]D levels and annualized relapse rate (ARR) or time to first relapse. However, we observed that patients with serum 25[OH]D ≥ 100 nmol/l showed a lower number of Gd+ and combined unique activity (CUA) lesions at baseline compared to patients with the lowest 25[OH]D levels (less than 50 nmol/l, p value < 0.05). Moreover, they showed fewer CUA lesions at 2-year follow-up also when accounting for baseline level of disease activity (p value < 0.05). CONCLUSIONS: In patients treated with FTY, those with the highest baseline 25(OH)D levels had a significantly lower number of active lesions at baseline; the same effect, even if weaker, was observed also at 2-year follow-up when adjusting for baseline disease activity. Given Vitamin D supplementation safety profile, also if a causal effect has not yet been shown, most of MS patients could probably benefit from 25[OH]D levels above those currently considered to be sufficient.

The Italian Neuroimaging Network Initiative (INNI): enabling the use of advanced MRI techniques in patients with MS.

Magnetic resonance imaging (MRI) is an important paraclinical tool to diagnose and monitor multiple sclerosis (MS). Conventional MRI measures lack of pathological specificity and are weakly correlated with MS clinical manifestations. Advanced MRI techniques are improving the understanding of the mechanisms underlying tissue injury, repair, and functional adaptation in MS; however, they require careful standardization. The definition of standardized methods for the collection and analysis of advanced MRI techniques is central not only to improve the understanding of disease pathophysiology and evolution, but also to generate research hypotheses, monitor treatment, increase cost-effectiveness and power of clinical trials. We promoted the Italian Neuroimaging Network Initiative (INNI), involving centers and investigators with an International recognized expertise, with the major goal to determine and validate novel MRI biomarkers to be utilized as predictors and/or outcomes in future MS studies. The INNI initiative supported the creation of a centralized repository, where advanced structural and functional MRI scans available at the participating sites, with the related clinical and neuropsychological data, are collected. These data will be used to perform research studies to identify clinical, neuropsychological and imaging biomarkers characteristics of the entire spectrum of MS. INNI will be instrumental to help to define standardized MRI and clinical protocols towards an increasing uptake of personalized interventions for people with MS at a national and international level. Upon approval of the INNI Steering Committee, the data collected in the online database will be shared with any research center detailing specific research proposals on disease pathophysiology or treatment effects.

Diffusion tensor magnetic resonance imaging in very early onset pediatric multiple sclerosis.

OBJECTIVES: Active myelination during childhood may influence the impact of multiple sclerosis (MS) on brain structural integrity. We studied normal-appearing white matter (NAWM) in children with MS onset before age 12 years using diffusion tensor (DT) magnetic resonance imaging (MRI). METHODS: DT MRI scans were obtained from 22 MS children with their first attack before age 12 years, and 31 healthy controls from two referral centers. Using probabilistic tractography, brain tissue integrity within interhemispheric, intrahemispheric, and projection tracts was compared between patients and site-matched controls. The impact of disease and age at MRI on tract NAWM fractional anisotropy (FA) and mean diffusivity (MD) values was evaluated using linear models. RESULTS: Compared to controls, pediatric MS patients had reduced FA and increased MD of the bilateral superior longitudinal fasciculus and corpus callosum (CC), without center-by-group interaction. CC NAWM average FA was correlated with brain T2 lesion volume. In controls, the majority of the tracts analyzed showed a significant increase of FA and decrease of MD with age. Such a linear correlation was lost in patients. CONCLUSIONS: In very young pediatric MS patients, DT MRI abnormalities affect brain WM tracts differentially, and are only partially correlated with focal WM lesions. Impaired maturation of WM tracts with age may be an additional factor contributing to these findings.

Regional cortical thinning in multiple sclerosis and its relation with cognitive impairment: A multicenter study.

OBJECTIVES: The objectives of this paper are to compare in a multicenter setting patterns of regional cortical thickness in patients with relapsing-remitting multiple sclerosis (RRMS) and cognitive impairment (CI) and those cognitively preserved (CP), and explore the relationship between cortical thinning and cognitive performance. METHODS: T1-weighted isotropic brain scans were collected at 3T from seven European centers in 60 RRMS patients and 65 healthy controls (HCs). Patients underwent clinical and neuropsychological examinations. Cortical thickness (CTh) measures were calculated using FreeSurfer (failing in four) and both lobar and vertex-based general linear model (GLM) analyses were compared between study groups. RESULTS: Twenty (36%) MS patients were classified as CI. Mean global CTh was smaller in RRMS patients compared to HCs (left 2.43 vs. 2.53 mm, right 2.44 vs. 2.54 mm, p < 0.001). Multivariate GLM regional analysis showed significantly more temporal thinning in CI compared to CP patients. Verbal memory scores correlated to regional cortical thinning in the insula whereas visual memory scores correlated to parietal thinning. CONCLUSIONS: This multicenter study showed mild global cortical thinning in RRMS. The extent of thinning is less pronounced than previously reported. Only subtle regional differences between CI and CP patients were observed, some of which related to specific cognitive domains.

Searching for the neural basis of reserve against memory decline: intellectual enrichment linked to larger hippocampal volume in multiple sclerosis.

BACKGROUND AND PURPOSE: Active engagement in intellectually enriching activities (e.g. reading, hobbies) builds 'reserve' against memory decline in elders and persons with multiple sclerosis (MS), but the neural basis for this protective influence of enrichment is unknown. Herein the neuroanatomical basis of reserve against memory decline in MS patients is investigated. METHODS: Relapse-onset MS patients (N = 187) underwent 3.0 T magnetic resonance imaging of the brain to quantify T2 lesion volume (T2LV) and normalized volumes of total brain, total white, total grey (using SIENAX) and thalamus, caudate, putamen, pallidum, amygdala and hippocampus (using FIRST). Patients completed a survey quantifying their engagement in early life intellectual enrichment (i.e. reading, hobbies). Verbal and visuospatial episodic memory was assessed with neuropsychological tasks in a representative subsample (N = 97). RESULTS: Controlling for demographics and T2LV, intellectual enrichment was specifically linked to larger normalized hippocampal volume (r(p) = 0.213, P = 0.004), with no link to other brain volumes/structures. Moreover, greater intellectual enrichment moderated/attenuated the negative relationship between normalized total brain volume (i.e. overall cerebral atrophy) and normalized hippocampal volume (i.e. hippocampal atrophy; P = 0.001) whereby patients who engaged in more early life intellectual enrichment better maintained hippocampal volume in the face of worse overall cerebral atrophy. Finally, the link between greater intellectual enrichment and better memory was partially mediated through larger hippocampal volume. CONCLUSIONS: These findings support larger hippocampal volume as one key component of the neuroanatomical basis of reserve against memory decline in MS. These findings are consistent with previous literature on experience-dependent neuroplasticity within the hippocampus.

Functional MRI in investigating cognitive impairment in multiple sclerosis.

There is increasing evidence that the severity of the clinical manifestations of multiple sclerosis (MS) does not simply result from the extent of tissue destruction, but it rather represents a complex balance between tissue damage, tissue repair, and cortical reorganization. Functional magnetic resonance imaging (fMRI) provides information about the plasticity of the human brain. Therefore, it has the potential to provide important pieces of information about brain reorganization following MS-related structural damage. When investigating cognitive systems, fMRI changes have been described in virtually all patients with MS and different clinical phenotypes. These functional changes have been related to the extent of brain damage within and outside T2-visible lesions as well as to the involvement of specific central nervous system structures. It has also been suggested that a maladaptive recruitment of specific brain regions might be associated with the appearance of clinical symptoms in MS, such as fatigue and cognitive impairment. fMRI studies from clinically (and cognitively) impaired MS patients may be influenced by different task performances between patients and controls. As a consequence, new strategies have been introduced to assess the role, if any, of brain reorganization in severely impaired patients, including the analysis of resting-state networks. The enhancement of any beneficial effects of this brain adaptive plasticity should be considered as a potential target of therapy for MS.

A review of recent literature on functional MRI and personal experience in two cases of definite vestibular migraine.

The pathophysiology of vestibular migraine (VM) is at present poorly understood. Functional magnetic resonance imaging (fMRI), a technique that measures brain activity by detecting changes associated with blood flow oxygenation, has been used to study neural pathways involved in VM pathophysiology. In this study, we summarize results of previous fMRI studies in VM patients, both during and between vertigo attacks. Moreover, we report our experience in two patients with definite VM, who underwent fMRI during a visual stimulation in a vertigo-free period. Compared with 15 matched healthy controls, fMRI demonstrated activation of brain areas related to integration of visual and vestibular cues (increased activation of the paracentral lobule and bilateral inferior parietal lobule and decreased activation of the left superior frontal gyrus, head of the caudate nucleus, left superior temporal gyrus, left parahippocampal gyrus, and right lingual gyrus). Our results partially confirm those of other authors, reporting increased activation of multimodal association brain areas (BA 40, BA 31/5) and decreased activation of occipital regions In addition, we also found a decreased activation of fronto-temporal areas, such as the parahippocampal region, functionally involved in space memory and navigation.

Influence of the topography of brain damage on depression and fatigue in patients with multiple sclerosis.

OBJECTIVES: Involvement of selected central nervous system (CNS) regions has been associated with depression and fatigue in MS. We assessed whether specific regional patterns of lesion distribution and atrophy of the gray (GM) and white matter (WM) are associated with these symptoms in MS. METHODS: Brain dual-echo and 3D T1-weighted images were acquired from 123 MS patients (69 depressed (D), 54 non-depressed (nD), 64 fatigued, 59 non-fatigued) and 90 controls. Lesion distribution, GM and WM atrophy were estimated using VBM and SPM8. RESULTS: Gender, age, disease duration and conventional MRI characteristics did not differ between D-MS and nD-MS patients. Fatigued patients experienced higher EDSS and depression than non-fatigued ones. Lesion distribution and WM atrophy were not related to depression and fatigue. Atrophy of regions in the frontal, parietal and occipital lobes had a combined effect on depression and fatigue. Atrophy of the left middle frontal gyrus and right inferior frontal gyrus were selectively related to depression. No specific pattern of GM atrophy was found to be related to fatigue. CONCLUSIONS: Depression in MS is linked to atrophy of cortical regions located in the bilateral frontal lobes. A distributed pattern of GM atrophy contributes to the concomitant presence of depression and fatigue in these patients.

Forceps minor damage and co-occurrence of depression and fatigue in multiple sclerosis.

OBJECTIVE: Using diffusion tensor magnetic resonance imaging (DT MRI), we analyzed the architectural integrity of the brain white matter (WM) from a large cohort of MS patients to identify the structural substrates of the concomitant presence of depression and fatigue. METHODS: Brain dual-echo, 3D T1-weighted and DT MRI scans were acquired from 147 MS patients and 90 gender- and age-matched healthy controls (HCs). Patients were stratified by the presence of depression (92 depressed (D), 55 not depressed (nD)) and fatigue (81 fatigued (F), 66 not fatigued (nF)). Sixty-five patients had co-occurrence of depression and fatigue (DF). Whole-brain voxel-wise comparisons of WM DT MRI abnormalities were performed using tract-based-spatial-statistics (TBSS). Tract-specific analyses were run in brain WM tracts using standard-space templates. RESULTS: Whole-brain voxel-wise analysis yielded no significant differences between patient subgroups. At tract-specific analysis, DF patients had reduced fractional anisotropy (FA) of the forceps minor. Reduced FA of the right anterior thalamic radiation and right uncinate fasciculus was found in F-MS vs not F-MS patients after correcting for depression. No significant differences were found between D vs not D-MS patients, after correcting for fatigue. CONCLUSIONS: This study provides evidence for partially overlapping damage to frontal and fronto-temporal pathways underlying depression and fatigue in MS.

Magnetic resonance imaging correlates of physical disability in relapse onset multiple sclerosis of long disease duration.

BACKGROUND: Understanding long-term disability in multiple sclerosis (MS) is a key goal of research; it is relevant to how we monitor and treat the disease. OBJECTIVES: The Magnetic Imaging in MS (MAGNIMS) collaborative group sought to determine the relationship of brain lesion load, and brain and spinal cord atrophy, with physical disability in patients with long-established MS. METHODS: Patients had a magnetic resonance imaging (MRI) scan of their brain and spinal cord, from which we determined brain grey (GMF) and white matter (WMF) fractional volumes, upper cervical spinal cord cross-sectional area (UCCA) and brain T2-lesion volume (T2LV). We assessed patient disability using the Expanded Disability Status Scale (EDSS). We analysed associations between EDSS and MRI measures, using two regression models (dividing cohort by EDSS into two and four sub-groups). RESULTS: In the binary model, UCCA (p < 0.01) and T2LV (p = 0.02) were independently associated with the requirement of a walking aid. In the four-category model UCCA (p < 0.01), T2LV (p = 0.02) and GMF (p = 0.04) were independently associated with disability. CONCLUSIONS: Long-term physical disability was independently linked with atrophy of the spinal cord and brain T2 lesion load, and less consistently, with brain grey matter atrophy. Combinations of spinal cord and brain MRI measures may be required to capture clinically-relevant information in people with MS of long disease duration.

Microstructural magnetic resonance imaging of cortical lesions in multiple sclerosis.

BACKGROUND: Pathologic and magnetic resonance imaging (MRI) studies have shown that cortical lesions (CLs) are a frequent finding in multiple sclerosis (MS). OBJECTIVE: To quantify microstructural damage in CLs and normal appearing (NA) cortex in relapse-onset MS patients at different stages of the disease. METHODS: Brain double inversion recovery (DIR), diffusion tensor (DT) MRI and 3D T 1-weighted scans were acquired from 35 relapsing-remitting (RR) patients, 23 secondary progressive (SP) patients, 12 benign (B) MS patients and 41 healthy controls (HC). Diffusivity values in CLs, cortex, white matter (WM) lesions and normal-appearing white matter (NAWM) were assessed. RESULTS: Compared to HC, MS patients had a significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) in the cortex and NAWM. CLs had higher FA vs HC cortex and vs patients' cortex. Compared to RRMS patients, SPMS patients had higher WM lesion volume, higher MD in the cortex, and more severe damage to the NAWM and WM lesions. Compared to SPMS patients, BMS patients had lower MD and FA of CLs. Damage in other compartments was similar between SPMS and BMS patients. Damage in CLs had a high power to discriminate BMS from SPMS (area under the curve: 79-91%), with high specificity (85%), sensitivity (100%) and accuracy (90%). CONCLUSIONS: Microstructural imaging features of CLs differ from those of WM lesions and are likely to reflect neuronal damage and microglial activation. The nature and extent of CL damage can be used to help distinguish the different MS clinical phenotypes.

Natalizumab in pediatric multiple sclerosis: results of a cohort of 55 cases.

BACKGROUND: Limited information is available on the use of natalizumab (NA) in pediatric multiple sclerosis (ped-MS) patients. OBJECTIVE: The purpose of this study was to describe the long-term effects of NA in a large cohort of active ped-MS patients. METHODS: Patients with definite ped-MS were treated with NA if in the previous year they had experienced at least two relapses or a severe relapse with incomplete recovery while on immunomodulating treatment, or at least two relapses and new magnetic resonance imaging (MRI) lesions regardless of any prior treatment. RESULTS: The study included 55 patients (mean age: 14.4 years, mean number of relapses: 4.4, pre-treatment mean disease duration: 25.5 months). They received a median number of 26 infusions. Three relapses occurred during the follow-up, one female patient continued to deteriorate in cognitive functioning. Mean Expanded Disability Status Scale (EDSS) scores decreased from 2.7 to 1.9 at the last visit (p<0.001). During the follow-up the majority of patients remained free from MRI activity. Transient and mild clinical adverse events occurred in 20 patients. Mild hematological abnormalities occurred in seven patients. Anti-JCV antibodies were detected in 20/51 tested patients. CONCLUSIONS: NA was well tolerated in all patients. A strong suppression of disease activity was observed in the majority of patients during the follow-up.

Analysis of "task-positive" and "task-negative" functional networks during the performance of the Symbol Digit Modalities Test in patients at presentation with clinically isolated syndrome suggestive of multiple sclerosis.

An abnormal pattern of brain activations has been shown in patients with multiple sclerosis during the performance of several cognitive tasks. The aim of this study is to investigate abnormalities of the patterns of activation/deactivation in the functional networks related to "task-positive" and "task-negative" events during the execution of the Symbol Digit Modalities Test (SDMT) in patients with clinically isolated syndromes (CIS) and preserved cognitive abilities. Eighteen CIS patients within 3 months from their first clinical attack and 15 healthy controls (HC) underwent neuropsychological assessment and performed an adapted functional magnetic resonance imaging (fMRI) version of the SDMT. "Task-positive" responses to task execution and "task-negative" activity of the default mode network were compared between groups. A regression analysis was performed to investigate the correlation between fMRI results and T2 lesion load (T2 LL) and brain atrophy. Neuropsychological performance did not differ between groups. Compared to HC, CIS patients exhibited an enhanced deactivation of the "task-negative" network at the level of the posterior cingulate cortex, whereas no differences between groups were found when the patterns of "task-positive" events were compared. A regression analysis detected a correlation (p < 0.001,r ranging from 0.62 to 0.73) between T2 LL and "task-positive" activations of areas that are part of the attention network, comprising the anterior cingulate gyrus, left prefrontal gyrus and inferior parietal lobe. No correlation was found between patterns of functional modifications and brain atrophy. CIS patients experience an enhanced pattern of brain deactivations during cognitive performances, which might contribute to their normal neuropsychological status.

Contribution of magnetic resonance imaging to the diagnosis and monitoring of multiple sclerosis.

Magnetic resonance (MR) imaging is an extremely sensitive modality for detecting focal changes to the white matter (WM) in patients with multiple sclerosis (MS). For this reason, it has become an integral part of the diagnostic workup of patients with clinically isolated syndromes who are at risk of developing definite MS, and it is always recommended in patients with definite MS to confirm the diagnosis and monitor the disease course. Crucial to the use of MR imaging for diagnostic purposes is the identification of lesion features - in terms of site, shape and size - that may be considered suggestive or typical for MS, and thus help in the differential diagnosis with other neurological diseases with similar clinical presentation to MS. This need has led to the publication of several guidelines for characterising MS lesions on both dual-echo (T2 and proton density) and T1-weighted sequences after administration of contrast material. Developments in clinical research into MS have highlighted the need to formulate a diagnosis as far as possible on the basis of objective and reproducible criteria. Currently, when making a clinical diagnosis and monitoring patients with suspected MS, neurologists and neuroradiologists make use of specific diagnostic criteria that have changed over the years and will probably continue to be updated. It is therefore crucial for radiologists to become familiar with these criteria in order to improve the quality of their diagnostic assessment. In patients with a definite diagnosis of MS, on the other hand, the main problem is to define standard procedures for monitoring the course of the disease and response to pharmacological treatments. even though no guidelines currently exist, it is possible to suggest some strategies to improve the assessment in this setting.

Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study.

BACKGROUND: Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown. OBJECTIVE: To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level. METHODS: Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01. RESULTS: Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039). CONCLUSION: Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Abnormal cervical cord function contributes to fatigue in multiple sclerosis.

UNLABELLED: BACKGROUND/OBJECTIVE We aimed to investigate whether cervical cord damage and dysfunction is associated with the presence and severity of fatigue in multiple sclerosis (MS) using a multiparametric magnetic resonance (MR) approach. METHODS: Cervical cord functional magnetic resonance imaging (fMRI) during a tactile stimulation of the right hand, and structural brain and cord MRI were acquired from 20 controls, 15 MS patients without fatigue (NF) and 20 MS patients with fatigue (F). Between-group differences in the extent of focal lesions and diffusivity abnormalities in the brain and cord, cord-normalized cross-sectional area (CSAn) and fMRI activity were assessed. RESULTS: All structural MRI measures differed significantly among groups, except for cord lesion number and CSAn. Compared with controls, NF-MS patients experienced higher cord recruitment (p=0.04). Compared with F-MS, NF-MS patients had a lower brain normal-appearing white matter average fractional anisotropy (p=0.001) and increased cord recruitment (p=0.02). In patients with MS, the extent of cord recruitment was correlated with the severity of fatigue (r=-0.34, p=0.04). Compared with the other two groups, F-MS patients had a more diffuse recruitment of cord quadrants on the axial and longitudinal planes. CONCLUSIONS: Abnormalities of function, but not of structure, of the cervical cord are likely to contribute to the pathogenesis of fatigue in MS.

Functional magnetic resonance imaging correlates of cognitive performance in patients with a clinically isolated syndrome suggestive of multiple sclerosis at presentation: an activation and connectivity study.

BACKGROUND/OBJECTIVE: To assess whether abnormalities on functional magnetic resonance imaging (fMRI) are related to cognitive function in patients at presentation with clinically isolated syndrome (CIS) suggestive of multiple sclerosis. METHODS: Eighteen patients with CIS and 15 healthy controls (HCs) performed an adapted fMRI version of the Paced Auditory Serial Addition Test (PASAT). According to their PASAT performance, CIS patients were divided into two groups: 10 with a low PASAT performance (<1 SD from the mean value of HCs) were considered 'cognitive impairment' (CI); eight patients were defined as 'cognitively preserved' (CP). Between-group differences in the patterns of brain activations and effective connectivity were assessed. RESULTS: During PASAT, compared to HCs, CIS patients showed increased activations of the bilateral inferior parietal lobe (IPL), bilateral precuneus, bilateral middle frontal gyrus (MFG), left anterior cingulate cortex (ACC), left claustrum, right thalamus and right caudate nucleus. When CIS patients were analyzed, the CI group had a more significant activation of the bilateral IPL than HCs and CP patients. Compared to CP patients, they also had more significant recruitment of the right superior parietal lobe, right cerebellum, left MFG and left ACC. The analysis of effective connectivity showed stronger connections between several regions of the right hemisphere involved in working memory function in CI patients versus CP and HC. CONCLUSIONS: During performance of the PASAT, CIS patients show abnormalities in the patterns of cortical recruitment and connectivity related to the level of their cognitive impairment.