Use, tolerability, benefits and side effects of orthotic devices in Charcot-Marie-Tooth disease.

BACKGROUND: Shoe inserts, orthopaedic shoes, ankle-foot orthoses (AFOs) are important devices in Charcot-Marie-Tooth disease (CMT) management, but data about use, benefits and tolerance are scanty. METHODS: We administered to Italian CMT Registry patients an online ad hoc questionnaire investigating use, complications and perceived benefit/tolerability/emotional distress of shoe inserts, orthopaedic shoes, AFOs and other orthoses/aids. Patients were also asked to fill in the Quebec User Evaluation of Satisfaction with assistive Technology questionnaire, rating satisfaction with currently used AFO and related services. RESULTS: We analysed answers from 266 CMT patients. Seventy per cent of subjects were prescribed lower limb orthoses, but 19% did not used them. Overall, 39% of subjects wore shoe inserts, 18% orthopaedic shoes and 23% AFOs. Frequency of abandonment was high: 24% for shoe inserts, 28% for orthopaedic shoes and 31% for AFOs. Complications were reported by 59% of patients and were more frequently related to AFOs (69%). AFO users experienced greater emotional distress and reduced tolerability as compared with shoe inserts (p<0.001) and orthopaedic shoes (p=0.003 and p=0.045, respectively). Disease severity, degree of foot weakness, customisation and timing for customisation were determinant factors in AFOs' tolerability. Quality of professional and follow-up services were perceived issues. CONCLUSIONS: The majority of CMT patients is prescribed shoe inserts, orthopaedic shoes and/or AFOs. Although perceived benefits and tolerability are rather good, there is a high rate of complications, potentially inappropriate prescriptions and considerable emotional distress, which reduce the use of AFOs. A rational, patient-oriented and multidisciplinary approach to orthoses prescription must be encouraged.

Identifying definite patterns of unmet needs in patients with multiple sclerosis using unsupervised machine learning.

INTRODUCTION: People with multiple sclerosis (PwMS) exhibit a spectrum of needs that extend beyond solely disease-related determinants. Investigating unmet needs from the patient perspective may address daily difficulties and optimize care. Our aim was to identify patterns of unmet needs among PwMS and their determinants. METHODS: We conducted a cross-sectional multicentre study. Data were collected through an anonymous, self-administered online form. To cluster PwMS according to their main unmet needs, we performed agglomerative hierarchical clustering algorithm. Principal component analysis (PCA) was applied to visualize cluster distribution. Pairwise comparisons were used to evaluate demographics and clinical distribution among clusters. RESULTS: Out of 1764 mailed questionnaires, we received 690 responses. Access to primary care was the main contributor to the overall unmet need burden. Four patterns were identified: cluster C1, 'information-seekers with few unmet needs'; cluster C2, 'high unmet needs'; cluster C3, 'socially and assistance-dependent'; cluster C4, 'self-sufficient with few unmet needs'. PCA identified two main components in determining the patterns: the 'public sphere' (access to information and care) and the 'private sphere' (need for assistance and social life). Older age, lower education, longer disease duration and higher disability characterized clusters with more unmet needs in the private sphere. However, demographic and clinical factors failed in explaining the four identified patterns. CONCLUSION: Our study identified four unmet need patterns among PwMS, emphasizing the importance of personalized care. While clinical and demographic factors provide some insight, additional variables warrant further investigation to fully understand unmet needs in PwMS.

Comparing Natural History of Early and Late Onset Pediatric Multiple Sclerosis.

OBJECTIVE: This study was undertaken to describe and compare disease course and prognosis of early (ie, disease onset before age 11 years) and late (ie, disease onset after age 11 years) onset pediatric multiple sclerosis. METHODS: Prospectively collected clinical information from Italian Multiple Sclerosis Register of 1993 pediatric multiple sclerosis patients, of whom 172 had early onset, was analyzed. Cox models adjusted for sex, baseline Expanded Disability Status Scale score, and disease-modifying treatments and stratified for diagnostic criteria adopted (Poser vs McDonald) were used to assess the risk of reaching irreversible Expanded Disability Status Scale scores of 3, 4, and 6, and conversion to secondary progressive phenotype in early versus late onset pediatric patients. Prognostic factors were also evaluated. RESULTS: A greater proportion of males, isolated brainstem involvement, and longer time interval between first and second clinical episode were observed in early versus late onset pediatric patients. Compared to late onset, early onset pediatric patients took longer from disease onset to convert to secondary progressive phenotype and to reach all disability milestones. Recovery from first demyelinating event, time to first relapse, annualized relapse rate during the first 3 years of disease, and disease-modifying treatment exposure were independent predictors for long-term disability in early onset pediatric patients. In late onset pediatric patients, isolated optic neuritis, multifocal symptoms, and progressive course at disease onset were additional predictors for long-term disability. INTERPRETATION: These findings point toward the existence of a different natural history in early versus late onset pediatric multiple sclerosis patients. ANN NEUROL 2022;91:483-495.

Frequency, entity and determinants of fatigue in Charcot-Marie-Tooth disease.

BACKGROUND AND PURPOSE: Fatigue, a disabling symptom in many neuromuscular disorders, has been reported also in Charcot-Marie-Tooth disease (CMT). The presence of fatigue and its correlations in CMT was investigated. METHODS: The Modified Fatigue Impact Scale (MFIS) was administered to CMT patients from the Italian Registry and a control group. An MFIS score >38 indicated abnormal fatigue. The correlation with disease severity and clinical characteristics, the Hospital Anxiety and Depression Scale and Epworth Sleepiness Scale scores, and drug use was analysed. RESULTS: Data were collected from 251 CMT patients (136 women) and 57 controls. MFIS total (mean ± standard deviation 32 ± 18.3, median 33), physical (18.9 ± 9.7, 20) and psychosocial (2.9 ± 2.4, 3) scores in CMT patients were significantly higher than controls. Abnormal fatigue occurred in 36% of the patients who, compared to patients with normal scores, had more severe disease (median CMT Examination Score 9 vs. 7), more frequent use of foot orthotics (22% vs. 11%), need of support for walking (21% vs. 8%), hand disability (70% vs. 52%) and positive sensory symptoms (56% vs. 36%). Patients with abnormal fatigue had significantly increased frequency of anxiety/depression/general distress (Hospital Anxiety and Depression Scale), somnolence (Epworth Sleepiness Scale), obesity (body mass index ≥ 30) and use of anxiolytic/antidepressant or anti-inflammatory/analgesic drugs. CONCLUSIONS: Fatigue is a relevant symptom in CMT as 36% of our series had scores indicating abnormal fatigue. It correlated with disease severity but also with anxiety, depression, sleepiness and obesity, indicating different components in the generation of fatigue. CMT patients' management must include treatment of fatigue and of its different generators, including general distress, sleepiness and obesity.

Clinical spectrum and frequency of Charcot-Marie-Tooth disease in Italy: Data from the National CMT Registry.

BACKGROUND AND PURPOSE: Data are reported from the Italian CMT Registry. METHODS: The Italian CMT Registry is a dual registry where the patient registers and chooses a reference center where the attending clinician collects a minimal dataset of information and administers the Charcot-Marie-Tooth (CMT) Examination/Neuropathy Score. Entered data are encrypted. RESULTS: Overall, 1012 patients had registered (535 females) and 711 had received a genetic diagnosis. Demyelinating CMT (65.3%) was more common than axonal CMT2 (24.6%) and intermediate CMT (9.0%). The PMP22 duplication was the most frequent mutation (45.2%), followed by variants in GJB1 and MPZ (both ~10%) and MFN2 (3.3%) genes. A relatively high mutation rate in some "rare" genes (HSPB1 1.6%, NEFL 1.5%, SH3TC2 1.5%) and the presence of multiple mutation clusters across Italy was observed. CMT4A was the most disabling type, followed by CMT4C and CMT1E. Disease progression rate differed depending on the CMT subtype. Foot deformities and walking difficulties were the main features. Shoe inserts and orthotic aids were used by almost one-half of all patients. Scoliosis was present in 20% of patients, especially in CMT4C. Recessive forms had more frequently walking delay, walking support need and wheelchair use. Hip dysplasia occurred in early-onset CMT. CONCLUSIONS: The Italian CMT Registry has proven to be a powerful data source to collect information about epidemiology and genetic distribution, clinical features and disease progression of CMT in Italy and is a useful tool for recruiting patients in forthcoming clinical trials.

Progression is independent of relapse activity in early multiple sclerosis: a real-life cohort study.

Disability accrual in multiple sclerosis may occur as relapse-associated worsening or progression independent of relapse activity. The role of progression independent of relapse activity in early multiple sclerosis is yet to be established. The objective of this multicentre, observational, retrospective cohort study was to investigate the contribution of relapse-associated worsening and progression independent of relapse activity to confirmed disability accumulation in patients with clinically isolated syndrome and early relapsing-remitting multiple sclerosis, assessed within one year from onset and with follow-up ≥5 years (n = 5169). Data were extracted from the Italian Multiple Sclerosis Register. Confirmed disability accumulation was defined by an increase in Expanded Disability Status Scale score confirmed at 6 months, and classified per temporal association with relapses. Factors associated with progression independent of relapse activity and relapse-associated worsening were assessed using multivariable Cox regression models. Over a follow-up period of 11.5 ± 5.5 years, progression independent of relapse activity occurred in 1427 (27.6%) and relapse-associated worsening in 922 (17.8%) patients. Progression independent of relapse activity was associated with older age at baseline [hazard ratio (HR) = 1.19; 95% confidence interval (CI) 1.13-1.25, P < 0.001], having a relapsing-remitting course at baseline (HR = 1.44; 95% CI 1.28-1.61, P < 0.001), longer disease duration at baseline (HR = 1.56; 95% CI 1.28-1.90, P < 0.001), lower Expanded Disability Status Scale at baseline (HR = 0.92; 95% CI 0.88-0.96, P < 0.001) and lower number of relapses before the event (HR = 0.76; 95% CI 0.73-0.80, P < 0.001). Relapse-associated worsening was associated with younger age at baseline (HR = 0.87; 95% CI 0.81-0.93, P < 0.001), having a relapsing-remitting course at baseline (HR = 1.55; 95% CI 1.35-1.79, P < 0.001), lower Expanded Disability Status Scale at baseline (HR = 0.94; 95% CI 0.89-0.99, P = 0.017) and a higher number of relapses before the event (HR = 1.04; 95% CI 1.01-1.07, P < 0.001). Longer exposure to disease-modifying drugs was associated with a lower risk of both progression independent of relapse activity and relapse-associated worsening (P < 0.001). This study provides evidence that in an early relapsing-onset multiple sclerosis cohort, progression independent of relapse activity was an important contributor to confirmed disability accumulation. Our findings indicate that insidious progression appears even in the earliest phases of the disease, suggesting that inflammation and neurodegeneration can represent a single disease continuum, in which age is one of the main determinants of disease phenomenology.

The Selective Agonist for Sphingosine-1-Phosphate Receptors Siponimod Increases the Expression Level of NR4A Genes in Microglia Cell Line.

Fingolimod (FTY720) and siponimod (BAF312) are selective agonists for sphingosine-1-phosphate (S1P) receptors approved for the treatment of relapsing-remitting (RR) and secondary progressive (SP) multiple sclerosis (MS), respectively. BAF312 exerts pro-myelination and neuro-protective functions on CNS resident cells, although the underlying molecular mechanism is not yet fully understood. NR4A2 is an anti-inflammatory gene, belonging to the NR4A family, whose expression is reduced in blood from treatment-naïve patients with RRMS, but is restored in patients treated with FTY720 for more than two years. We performed an in vitro study to investigate the potential involvement of the NR4A genes in the protective and restorative effects of BAF312. We showed that BAF312 enhances the expression of NR4A1 and NR4A2 in the N9 microglial cell line, but has no effect in the peripheral blood mononuclear cells and oligodendrocytes. This study suggests a novel molecular mechanism of action for the selective agonists for S1P receptors within the CNS.

The impact of pre-freezing storage time and temperature on gene expression of blood collected in EDTA tubes.

BACKGROUND: Blood is a common source of RNA for gene expression studies. However, it is known to be vulnerable to pre-analytical variables. Although RNA stabilization systems have been shown to reduce such influence, traditional EDTA tubes are still widely used since they are less expensive and enable to study specific leukocyte populations. This study aimed to assess the influence of storage time and temperature between blood sampling and handling on RNA from peripheral blood mononuclear cells (PBMCs). METHODS AND RESULTS: Nine blood samples were collected in EDTA tubes from 10 healthy donors. One tube from each donor was immediately processed for PBMC isolation, while the others were first incubated at either 4 degrees Celsius (°C) or room temperature for 2, 4, 6 and 24 h. RNA yield and quality and the expression level of fourt housekeeping (B2M, CASC3, GAPDH, HPRT1) and 8 target genes (CD14, CD19, CD20, IL10, MxA, TNF, TNFAIP3, NR4A2) were compared between samples. RNA yield, quality and integrity did not vary significantly with time and temperature. B2M was the most stable housekeeping gene, while the others were increasingly influenced by storing time, especially at 4 °C. Even when normalized to B2M, the expression level of some target genes, particularly TNFAIP3 and NR4A2, was highly affected by delays in blood processing at either temperature, already from 2 h. CONCLUSION: Pre-analytical processing has a great impact on transcript expression from blood collected in EDTA tubes, especially on genes related to inflammation. Standardized procedure of blood handling are needed to obtain reliable results.

A multicenter retrospective study of charcot-marie-tooth disease type 4B (CMT4B) associated with mutations in myotubularin-related proteins (MTMRs).

OBJECTIVE: Charcot-Marie-Tooth (CMT) disease 4B1 and 4B2 (CMT4B1/B2) are characterized by recessive inheritance, early onset, severe course, slowed nerve conduction, and myelin outfoldings. CMT4B3 shows a more heterogeneous phenotype. All are associated with myotubularin-related protein (MTMR) mutations. We conducted a multicenter, retrospective study to better characterize CMT4B. METHODS: We collected clinical and genetic data from CMT4B subjects in 18 centers using a predefined minimal data set including Medical Research Council (MRC) scores of nine muscle pairs and CMT Neuropathy Score. RESULTS: There were 50 patients, 21 of whom never reported before, carrying 44 mutations, of which 21 were novel and six representing novel disease associations of known rare variants. CMT4B1 patients had significantly more-severe disease than CMT4B2, with earlier onset, more-frequent motor milestones delay, wheelchair use, and respiratory involvement as well as worse MRC scores and motor CMT Examination Score components despite younger age at examination. Vocal cord involvement was common in both subtypes, whereas glaucoma occurred in CMT4B2 only. Nerve conduction velocities were similarly slowed in both subtypes. Regression analyses showed that disease severity is significantly associated with age in CMT4B1. Slopes are steeper for CMT4B1, indicating faster disease progression. Almost none of the mutations in the MTMR2 and MTMR13 genes, responsible for CMT4B1 and B2, respectively, influence the correlation between disease severity and age, in agreement with the hypothesis of a complete loss of function of MTMR2/13 proteins for such mutations. INTERPRETATION: This is the largest CMT4B series ever reported, demonstrating that CMT4B1 is significantly more severe than CMT4B2, and allowing an estimate of prognosis. ANN NEUROL 2019.

Nabiximols discontinuation rate in a large population of patients with multiple sclerosis: a 18-month multicentre study.

INTRODUCTION: Delta-δ-tetrahydrocannabinol and cannabidiol (THC:CBD) oromucosal spray is used as an add-on therapy option for moderate to severe multiple sclerosis (MS) spasticity resistant to other medications. Aims of this study were to provide real-life data on long-term clinical outcomes in a large population of Italian patients treated with THC:CBD and to evaluate predictors of THC:CBD therapy continuation. MATERIALS AND METHODS: This prospective observational multicentre Italian study screened all patients with MS consecutively included in the Agenzia Italiana del Farmaco e-registry at the start of THC:CBD treatment (baseline), after 4 weeks (T1), 12±3 weeks (T2), 24±3 weeks (T3), 48±3 weeks (T4) and 72±3 weeks (T5) from baseline. RESULTS: A total of 1845 patients were recruited from 32 MS Italian centres. At T1, 1502 (81.4%) of patients reached a Numerical Rating Scale (NRS) improvement of ≥20%, with an NRS reduction of 26.9% at T1 and of 34.4% at T5. At T5, 725 patients (48.3% of 1502) discontinued treatment with highest discontinuation rate at T2 and T3. Daily number of puffs was generally stable through the observation period. The multivariate analysis showed that higher NRS scores at baseline (OR 2.28, 95% CI 1.15 to 6.36, p<0.01) and higher differences of NRS between T0 and T1 (OR 2.11, 95% CI 1.08 to 8.26, p<0.05) were associated with an increased probability to continue therapy after 18 months. DISCUSSION: THC:CBD effects were sustained for 18 months with a relatively stable number of puffs per day. About 50% of patients abandoned THC:CBD therapy for loss of efficacy or adverse events.

Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients.

Multiple sclerosis (MS) is an autoimmune pathology leading to neurodegeneration. Because of the complexity and heterogenic etiology of this disease, diagnosis and treatment for individual patients are challenging. Exosome-associated microRNAs (miRNAs) have recently emerged as a new class of diagnostic biomarkers involved in both autoimmune and neurologic disorders. Interesting new evidence has emerged showing that circulating miRNAs are dysregulated in MS body fluids, including serum, plasma, and cerebrospinal fluid. We hypothesized that exosome-associated miRNAs could present a readily accessible blood-based assay for MS disease. We detected expression of miRNAs by quantitative PCR on a small cohort of MS patients. We analyzed circulating exosome-associated miRNAs of MS patients before and after therapy and found that 14 exosome-associated miRNAs were significantly down-regulated, while 2 exosome-associated miRNAs were significantly up-regulated in IFN-ß-treated relapsing-remitting MS patients with response to therapy compared to those without response. We identified a serum miRNA panel that could be used to monitor the response to IFN-ß therapy. Overall, these data suggest that circulating exosome-associated miRNA profiling could represent an easily detectable biomarker of disease and treatment response.-Manna, I., Iaccino, E., Dattilo, V., Barone, S., Vecchio, E., Mimmi, S., Filippelli, E., Demonte, G., Polidoro, S., Granata, A., Scannapieco, S., Quinto, I., Valentino, P., Quattrone, A. Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients.

Assessment of the Corticospinal Tract Profile in Pure Lower Motor Neuron Disease: A Diffusion Tensor Imaging Study.

AIM: The aim of this study was to evaluate the corticospinal tract (CST) diffusion profile in pure lower motor neuron disease (pLMND) patients who at baseline did not show any clinical or electrophysiological involvement of upper motor neurons (UMN), and in amyotrophic lateral sclerosis (ALS) patients. MATERIALS AND METHODS: Fifteen ALS patients with delayed central motor conduction time (CMCT) and 14 pLMND patients with normal CMCT were enrolled together with 15 healthy controls. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) maps were obtained. The tract profile of CST was reconstructed with the automated fiber quantification tool and its diffusion properties were quantified voxel-by-voxel and then compared pairwise between groups. Moreover, a random forest (RF) classifier was trained to evaluate the ability of CST diffusion metrics in distinguishing pairwise the groups from the controls. RESULTS: ALS patients presented wide microstructural abnormalities in the entire CST as assessed by FA decrease and RD increase while pLMND patients showed focal FA decrease and a larger AD increase in the cerebral peduncle and posterior limb of the internal capsule in comparison with controls. RF revealed that diffusion tensor imaging (DTI) metrics accurately distinguished ALS patients and pLMND patients from controls (96.67 and 95.71% accuracy, respectively). CONCLUSIONS: Our study demonstrates that the CST was impaired in both ALS and pLMND patients, thus suggesting that DTI metrics are a reliable tool in detecting subtle changes of UMN in pLMND patients, also in the absence of clinical and CMCT abnormalities.

Impairment of acquired color vision in multiple sclerosis: an early diagnostic sign linked to the greatness of disease.

OBJECTIVE: To assess the type and degree of both red-green and blue-yellow color vision deficiencies of Calabrian males affected by multiple sclerosis. MATERIAL: Eighty Calabrian male patients were enrolled (age range 18-70 years; mean age 40.6 ± 12.4 years) showing a disease duration mean of 10.6 ± 8.2 years (range = 0.5-46 years) coming from the Institute of Neurology, Magna Graecia University, Catanzaro. Optic neuritis present in the medical histories of the 21 patients does not influence color vision. Excluding seven colorblind subjects and one affected by a bilateral maculopathy, the analyzed sample group was 72. Seventy controls were matched for age and sex. METHOD: An ophthalmologist examined all patients and controls in order to rule out diabetic retinopathy, cataracts, senile maculopathy, or ocular fundus' anomalies. The Ishihara test identified the colorblind patients. The City University Test screened for people with abnormal color vision by grading the severity of color vision deficiency. The second part of the City University Test as well as the Farnsworth Test confirmed both the color vision deficiency type and degree. RESULTS: Fifty-one percentage (37/72) of the patients showing a color vision deficiency were subdivided into two subgroups: subgroup one showed red-green deficiency (57%, 21/37); subgroup two showed a coupled red-green and blue-yellow deficiency (43%, 16/37). Furthermore, we found two distinct curves showing a groove within the first 10 years of the disease. Both monocular and binocular analyses allowed us to identify the patients showing the monocular color vision deficiency, but they were well compensated by binocular vision. CONCLUSION: We think that the majority of the patients with the red-green deficiency will develop the coupled red-green and blue-yellow deficiency in the latter years of multiple sclerosis.

The corticospinal tract profile in amyotrophic lateral sclerosis.

This work evaluates the potential in diagnostic application of a new advanced neuroimaging method, which delineates the profile of tissue properties along the corticospinal tract (CST) in amyotrophic lateral sclerosis (ALS), by means of diffusion tensor imaging (DTI). Twenty-four ALS patients and twenty-four demographically matched healthy subjects were enrolled in this study. The Automated Fiber Quantification (AFQ), a tool for the automatic reconstruction of white matter tract profiles, based on a deterministic tractography algorithm to automatically identify the CST and quantify its diffusion properties, was used. At a group level, the highest non-overlapping DTI-related differences were detected in the cerebral peduncle, posterior limb of the internal capsule, and primary motor cortex. Fractional anisotropy (FA) decrease and mean diffusivity (MD) and radial diffusivity (RD) increases were detected when comparing ALS patients to controls. The machine learning approach used to assess the clinical utility of this DTI tool revealed that, by combining all DTI metrics measured along tract between the cerebral peduncle and the corona radiata, a mean 5-fold cross validation accuracy of 80% was reached in discriminating ALS from controls. Our study provides a useful new neuroimaging tool to characterize ALS-related neurodegenerative processes by means of CST profile. We demonstrated that specific microstructural changes in the upper part of the brainstem might be considered as a valid biomarker. With further validations this method has the potential to be considered a promising step toward the diagnostic utility of DTI measures in ALS. Hum Brain Mapp 38:727-739, 2017. © 2016 Wiley Periodicals, Inc.

Individual differences in depression are associated with abnormal function of the limbic system in multiple sclerosis patients.

BACKGROUND: Depression is common in patients with multiple sclerosis (MS), although the brain mechanisms of this psychiatric condition in MS are poorly understood. Specifically, it remains to be determined whether depression in MS is related to altered activity and functional connectivity patterns within limbic circuits. METHODS: Seventy-seven MS patients with variable levels of depression (as assessed via the Beck Depression Inventory) underwent functional magnetic resonance imaging while performing an emotional processing task. To conduct the functional connectivity analyses, the bilateral amygdala and hippocampus, two areas critically involved in the pathophysiology of depression, were chosen as 'seed' regions. Multiple regression models were used to assess how depression in MS patients was correlated with the activity and functional connectivity patterns within the limbic system. RESULTS: Depression scores in MS patients were negatively correlated: (1) with the activity in the subgenual cingulate cortex; (2) with the functional connectivity between the hippocampus and orbitofrontal cortex as well as the dorsolateral prefrontal cortex, and (3) with the functional connectivity between the amygdala and dorsolateral prefrontal cortex. CONCLUSIONS: Our study showed that individual differences in depression in MS patients were significantly associated with altered regional activity and functional connectivity patterns within the limbic system.

Structural 'connectomic' alterations in the limbic system of multiple sclerosis patients with major depression.

BACKGROUND: Major depression (MD) is a common psychiatric disorder in multiple sclerosis (MS). Despite the negative impact of MD on the quality of life of MS patients, little is known about its underlying brain mechanisms. OBJECTIVE: We studied the whole-brain connectivity patterns that were associated with MD in MS. Alterations were mainly expected within limbic circuits. METHODS: Diffusion tensor imaging data were collected in 20 MS patients with MD, 22 non-depressed MS patients and 16 healthy controls. We used deterministic tractography and graph analysis to study the white-matter connectivity patterns that characterized MS patients with MD. RESULTS: We found that MD in MS was associated with increased local path length in the right hippocampus and right amygdala. Further analyses revealed that these effects were driven by an increased shortest distance between both the right hippocampus and right amygdala and a series of regions including the dorsolateral and ventrolateral prefrontal cortex, orbitofrontal cortex, sensory-motor cortices and supplementary motor area. CONCLUSION: Our data provide strong support for neurobiological accounts positing that MD in MS is mediated by abnormal 'communications' within limbic circuits. We also found evidence that MD in MS may be linked with connectivity alterations at the limbic-motor interface, a group of regions that translates emotions into survival-oriented behaviors.