The neural substrates of social cognition deficits in newly diagnosed multiple sclerosis patients

OBJECTIVE

Cognitive and affective symptoms in multiple sclerosis (MS) can be independently impaired and have different pathways of progression. Cognitive alterations have been described since the earliest MS stages; by contrast, the social cognition (SC) domain has never been investigated in the first year from MS diagnosis. We aimed to evaluate SC and unravel its neural bases in newly diagnosed MS patients.

METHODS

Seventy MS patients underwent at diagnosis a 3 T-MRI and a neuropsychological/SC assessment (median time between diagnosis and MRI/cognitive evaluation = 0 months). We tested two matched reference samples: 31 relapsing-remitting MS patients with longer course (mean ± SD disease duration = 7.0 ± 4.5 years) and 38 healthy controls (HCs). Cortical thicknesses (CTh) and volumes of brain regions were calculated.

RESULTS

Newly diagnosed MS patients performed significantly lower than HCs in facial emotion recognition (global: p < 0.001; happiness: p = 0.041, anger: p = 0.007; fear: p < 0.001; disgust: p = 0.004) and theory of mind (p = 0.005), while no difference was found between newly diagnosed and longer MS patients. Compared to lower performers, higher performers in facial emotion recognition showed greater volume of amygdala (p = 0.032) and caudate (p = 0.036); higher performers in theory of mind showed greater CTh in lingual gyrus (p = 0.006), cuneus (p = 0.024), isthmus cingulate (p = 0.038), greater volumes of putamen (p = 0.016), pallidum (p = 0.029), and amygdala (p = 0.032); patients with higher empathy showed lower cuneus CTh (p = 0.042) and putamen volume (p = 0.007).

INTERPRETATIONS

SC deficits are present in MS patients since the time of diagnosis and remain persistent along the disease course. Specific basal, limbic, and occipital areas play a significant role in the pathogenesis of these alterations.

Purmorphamine, a Smo-Shh/Gli Activator, Promotes Sonic Hedgehog-Mediated Neurogenesis and Restores Behavioural and Neurochemical Deficits in Experimental Model of Multiple Sclerosis

Multiple sclerosis (MS) is a pathological condition characterized by the demyelination of nerve fibers, primarily attributed to the destruction of oligodendrocytes and subsequent motor neuron impairment. Ethidium bromide (EB) is a neurotoxic compound that induces neuronal degeneration, resulting in demyelination and symptoms resembling those observed in experimental animal models of multiple sclerosis (MS). The neurotoxic effects induced by EB in multiple sclerosis (MS) are distinguished by the death of oligodendrocytes, degradation of myelin basic protein (MBP), and deterioration of axons. Neurological complications related to MS have been linked to alterations in the signaling pathway known as smo-shh. Purmorphine (PUR) is a semi-synthetic compound that exhibits potent Smo-shh agonistic activity. It possesses various pharmacological properties, including antioxidant, anti-inflammatory, anti-apoptotic, and neuromodulatory effects. Hence, the current investigation was conducted to assess the neuroprotective efficacy of PUR (at doses of 5 and 10 mg/kg, administered intraperitoneally) both individually and in conjunction with Fingolimod (FING) (at a dose of 0.5 mg/kg, administered intraperitoneally) in the experimental model of MS induced by EB. The administration of EB was conducted via the intracerebropeduncle route (ICP) over a period of seven days in the brain of rats. The Wistar rats were allocated into six groups using randomization, each consisting of eight rats (n = 8 per group). The experimental groups in this study were categorized as follows: (I) Sham Control, (II) Vehicle Control, (III) PUR per se, (IV) EB, (V) EB + PUR5, (VI) EB + PUR10, (VII) EB + FING 0.5, and (VIII) EB + PUR10 + FING 0.5. On the final day of the experimental timeline, all animal subjects were euthanized, and subsequent neurochemical estimations were conducted on cerebrospinal fluid, blood plasma, and brain tissue samples. In addition, we conducted neurofilament (NFL) analysis and histopathological examination. We utilized the luxol myelin stain to understand better the degeneration associated with MS and its associated neurological complications. The findings of our study indicate that the activation of SMO-Shh by PUR has a mitigating effect on neurobehavioral impairments induced by EB, as well as a restorative effect on cellular and neurotransmitter abnormalities in an experimental model of MS.

Investigating the relationship of theory of mind and empathy with neuroimaging, neuropsychological, and neuropsychiatric data in persons with multiple sclerosis

Theory of Mind (ToM) is understanding others' minds. Empathy is an insight into emotions and feelings of others. Persons with multiple sclerosis (pwMS) may experience impairment in ToM and empathy. To investigate ToM, empathy, and their relationship with neuroimaging, neuropsychological, and neuropsychiatric data. 41 pwMS and 41 HC were assessed using RMET for ToM, EQ, BICAMS, HADS. Cortical and subcortical gray matter volumes were calculated with Freesurfer from 3T MRI scans. pwMS showed lower EQ scores (44.82 ± 11.9 vs 51.29 ± 9.18, p = 0.02) and worse RMET performance (22.37 ± 4.09 vs 24,47 ± 2.93, p = 0.011). Anxiety and depression were higher in pwMS. EQ correlated with subcortical (amygdala) and cortical (anterior cingulate) volumes. RMET correlated with cortical volumes (posterior cingulate, lingual). In regression analysis, amygdala volume was the single predictor of empathy performance (p = 0.041). There were no significant correlations between social cognitive tests and general cognition. A weak negative correlation was found between EQ and the level of anxiety (r = -0.342, p = 0.038) The present study indicates that pwMS have impairment on ToM and empathy. The performance of ToM and empathy in MS is linked to the volumes of critical brain areas involved in social cognition.

A systematic review and meta-analysis of socio-cognitive impairments in multiple sclerosis

Socio-cognitive impairment is frequent in multiple sclerosis (MS). However, little is known about the relationship between other potentially relevant clinical symptoms (i.e., cognition, depression, fatigue) and the degree of socio-cognitive impairment, and neural mechanisms underlying socio-cognitive deficits in MS. Therefore, we meta-analytically quantified socio-cognitive impairment in MS. A systematic literature search in MEDLINE Ovid, Web of Science Core Collection, CENTRAL, and PsycInfo was conducted until December 2022. Studies investigating affective or cognitive theory of mind (a/cToM), visual perspective taking (VPT) and social decision making (SDM) in MS patients relative to healthy controls were included. Risk-of-bias (RoB) was assessed using the CLARITY group "Tool for Assessing RoB in Cohort Studies". Mediation analysis investigated the contribution of clinical symptoms to socio-cognitive impairment. In total, n = 8534 studies were screened, 58 were included in the systematic review, 27 in the meta-analyses. Most studies were rated with a moderate RoB. Meta-analyses confirmed impairment of both aToM and cToM in MS patients, with larger effect sizes for aToM. Mediation analysis demonstrated that higher levels of fatigue selectively predicted the degree of cToM impairment. There was insufficient data available to quantify impairment in other socio-cognitive domains. Fourteen structural and functional imaging studies were identified and characterized by substantial heterogeneity. Summarized, this study confirmed substantial socio-cognitive impairment in MS and highlights the potential exacerbating role of comorbid clinical symptoms. We identify several evidence gaps that need to be addressed in future large-scale studies using comprehensive and coordinated assessments of socio-cognitive parameters, potential mediators, and neural correlates.Trial registration: The pre-registered review protocol can be assessed at www.crd.york.ac.uk/PROSPERO/ (ID: CRD42020206225).

Theory of mind, emotion recognition and emotional reactivity factors in early multiple sclerosis: Results from a South American cohort

OBJECTIVES

To study different components of social cognition and quality of life in patients with early multiple sclerosis and low Expanded Disability Status Scale and to test the influence of cognitive performance, fatigue and neuropsychiatric symptoms on social cognition performance.

METHODS

Thirty-four patients with relapsing-remitting MS, with ≤2 years of disease duration and scores ≤2 on the EDSS and 30 healthy controls underwent neuropsychological assessment with the Brief Repeatable Neuropsychological Test Battery. Components of social cognition, such as emotion recognition, theory of mind, empathy, and emotional reactivity, were assessed with the Reading the Mind in the Eyes test, the Faux Pas task, the International Affective Imagery System, and the Empathy Quotient. Anxiety, depression, fatigue and quality of life were measured.

RESULTS

Patients showed significant differences in verbal memory, executive functions and social cognition, especially emotion recognition and ToM. Regarding emotional reactivity, patients showed a positive bias in the interpretation of the valence of neutral images.

CONCLUSIONS

Patients with early MS showed impairments in several components of social cognition independent of cognitive performance, neuropsychiatric symptoms and fatigue. Social cognition deficits may be present in MS even in the early stages.

Understanding the spectrum of non-motor symptoms in multiple sclerosis: insights from animal models

Multiple sclerosis is a chronic autoimmune disease of the central nervous system and is generally considered to be a non-traumatic, physically debilitating neurological disorder. In addition to experiencing motor disability, patients with multiple sclerosis also experience a variety of non-motor symptoms, including cognitive deficits, anxiety, depression, sensory impairments, and pain. However, the pathogenesis and treatment of such non-motor symptoms in multiple sclerosis are still under research. Preclinical studies for multiple sclerosis benefit from the use of disease-appropriate animal models, including experimental autoimmune encephalomyelitis. Prior to understanding the pathophysiology and developing treatments for non-motor symptoms, it is critical to characterize the animal model in terms of its ability to replicate certain non-motor features of multiple sclerosis. As such, no single animal model can mimic the entire spectrum of symptoms. This review focuses on the non-motor symptoms that have been investigated in animal models of multiple sclerosis as well as possible underlying mechanisms. Further, we highlighted gaps in the literature to explain the non-motor aspects of multiple sclerosis in experimental animal models, which will serve as the basis for future studies.

Neural and behavioral effects of parent training on emotion recognition in mothers rearing children with attention-deficit/hyperactivity disorder

This randomized controlled study examined neurological changes in socioemotional processing skills through parent training in caregivers of children with attention-deficit/hyperactivity disorder. Thirty mothers of children with attention-deficit/hyperactivity disorder were stratified into parent training and non-parent training groups. Functional magnetic resonance imaging was performed during the "Reading the Mind in the Eyes" test, and parenting difficulties were evaluated using the Parenting Stress Index and the Parenting Scale, twice (before and after parent training). Only mothers in the parent training group showed a significant decrease in Parenting Stress Index and Parenting Scale scores. They also demonstrated increased activity in the left occipital fusiform gyrus during the task of estimating emotions from facial pictures. We presumed that these changes might reflect the potential impact of enrollment in parent training in reducing stress, which might have increased activation of the fusiform gyrus.

Patterns of brain atrophy in recently-diagnosed relapsing-remitting multiple sclerosis

Recurrent neuroinflammation in relapsing-remitting MS (RRMS) is thought to lead to neurodegeneration, resulting in progressive disability. Repeated magnetic resonance imaging (MRI) of the brain provides non-invasive measures of atrophy over time, a key marker of neurodegeneration. This study investigates regional neurodegeneration of the brain in recently-diagnosed RRMS using volumetry and voxel-based morphometry (VBM). RRMS patients (N = 354) underwent 3T structural MRI <6 months after diagnosis and 1-year follow-up, as part of the Scottish multicentre 'FutureMS' study. MRI data were processed using FreeSurfer to derive volumetrics, and FSL for VBM (grey matter (GM) only), to establish regional patterns of change in GM and normal-appearing white matter (NAWM) over time throughout the brain. Volumetric analyses showed a decrease over time (q<0.05) in bilateral cortical GM and NAWM, cerebellar GM, brainstem, amygdala, basal ganglia, hippocampus, accumbens, thalamus and ventral diencephalon. Additionally, NAWM and GM volume decreased respectively in the following cortical regions, frontal: 14 out of 26 regions and 16/26; temporal: 18/18 and 15/18; parietal: 14/14 and 11/14; occipital: 7/8 and 8/8. Left GM and NAWM asymmetry was observed in the frontal lobe. GM VBM analysis showed three major clusters of decrease over time: 1) temporal and subcortical areas, 2) cerebellum, 3) anterior cingulum and supplementary motor cortex; and four smaller clusters within the occipital lobe. Widespread GM and NAWM atrophy was observed in this large recently-diagnosed RRMS cohort, particularly in the brainstem, cerebellar GM, and subcortical and occipital-temporal regions; indicative of neurodegeneration across tissue types, and in accord with limited previous studies in early disease. Volumetric and VBM results emphasise different features of longitudinal lobar and loco-regional change, however identify consistent atrophy patterns across individuals. Atrophy measures targeted to specific brain regions may provide improved markers of neurodegeneration, and potential future imaging stratifiers and endpoints for clinical decision making and therapeutic trials.

Correlation of brain segmental volume changes with clinical parameters: a longitudinal study in multiple sclerosis patients

OBJECTIVE

 To measure the cranial volume differences from 15 different parts in the follow-up of relapsing-remitting multiple sclerosis (RRMS) patients and correlate them with clinical parameters.

METHODS

 Forty-seven patients with RRMS were included in the study. Patients were grouped into two categories; low Expanded Disability Status Scale (EDSS) (< 3; group 1), and moderate-high EDSS (≥ 3; group 2). Patients were evaluated with Beck Depression Inventory (BDI), Montreal Cognitive Assessment (MOCA), Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), and calculated Annualized Relapse Rate (ARR) scores. Magnetic resonance imaging (MRI) was performed with a 1.5T MRI device (Magnetom AERA, Siemens, Erlangen, Germany) twice in a 1-year period. Volumetric analysis was performed by a free, automated, online MRI brain volumetry software. The differences in volumetric values between the two MRI scans were calculated and correlated with the demographic and clinical parameters of the patients.

RESULTS

 The number of attacks, disease duration, BDI, and FSS scores were higher in group 2; SDMT was higher in group 1. As expected, volumetric analyses have shown volume loss in total cerebral white matter in follow-up patients (p < 0.001). In addition, putaminal volume loss was related to a higher number of attacks. Besides, a negative relation between FSS with total amygdala volumes, a link between atrophy of globus pallidus and ARR, and BDI scores was found with the aid of network analysis.

CONCLUSIONS

 Apart from a visual demonstration of volume loss, cranial MRI with volumetric analysis has a great potential for revealing covert links between segmental volume changes and clinical parameters.

Facial emotion impairment in multiple sclerosis is linked to modifying observation strategies of emotional faces

BACKGROUND

Facial emotion recognition (FER) may be impaired in patients with multiple sclerosis (MS). Nevertheless, the literature is heterogeneous, with studies not highlighting this kind of impairment. Moreover, most studies have not explored differences between MS spectrum disorders (radiologically isolated syndrome (RIS), clinically-isolated syndrome (CIS), relapsing-remitting (RRMS), and progressive (primary - (PPMS) and secondary - (SPMS)). One hypothesis would be that FER impairment results from an alteration of eye-gaze strategies while observing emotional faces. Consequently, a FER deficit would be found in MS patients for whom these observation strategies would be disturbed and more frequent in the progressive forms.

METHODS

We prospectively enroled 52 patients (10 RIS, 10 CIS, 12RRMS, 10 SPMS, 10 PPMS) and 23 healthy controls (HC) to assess FER using Ekman Faces Test. Eye movements (number and duration of fixations) were recorded with an eye-tracking device.

RESULTS

21% of the MS participants had significant FER impairment. This impairment was observed in all phenotypes. In progressive forms, FER impairment was more frequent, more severe, and associated with modified emotional face observation strategies. MS participants with significant FER impairment had significantly more modification of eye-gaze strategies during observation of expressive faces than MS participants without FER impairment.

CONCLUSION

FER impairment seems to be linked to a deficit of attention orientation in MS. Remediation of eye-gaze strategies during observation of emotional faces could be beneficial, as observed in other neurological diseases.

Analysis of the extent of limbic system changes in multiple sclerosis using FreeSurfer and voxel-based morphometry approaches

Background and purpose

The limbic brain is involved in diverse cognitive, emotional, and autonomic functions. Injury of the various parts of the limbic system have been correlated with clinical deficits in MS. The purpose of this study was to comprehensively examine different regions of the subcortical limbic system to assess the extent of damage within this entire system as it may be pertinent in correlating with specific aspects of cognitive and behavioral dysfunction in MS by using a fully automated, unbiased segmentation approach.

Methods

Sixty-seven subjects were included in this study, including 52 with multiple sclerosis (MS) and 15 healthy controls. Only patients with stable MS disease, without any relapses, MRI activity, or disability progression were included. Subcortical limbic system segmentation was performed using the FreeSurfer pipeline ScLimbic, which provides volumes for fornix, mammillary bodies, hypothalamus, septal nuclei, nucleus accumbens, and basal forebrain. Hippocampus and anterior thalamic nuclei were added as additional components of the limbic circuitry, also segmented through FreeSurfer. Whole limbic region mask was generated by combining these structures and used for Voxel-based morphometry (VBM) analysis.

Results

The mean [95% confidence interval] of the total limbic system volume was lower (0.22% [0.21–0.23]) in MS compared to healthy controls (0.27%, [0.25–0.29], p < .001). Pairwise comparisons of individual limbic regions between MS and controls was significant in the nucleus accumbens (0.046%, [0.043–0.050] vs. 0.059%, [0.051–0.066], p = .005), hypothalamus (0.062%, [0.059–0.065] vs. 0.074%, [0.068–0.081], p = .001), basal forebrain (0.038%, [0.036–0.040] vs. 0.047%, [0.042–0.051], p = .001), hippocampus (0.47%, [0.45–0.49] vs. 0.53%, [0.49–0.57], p = .004), and anterior thalamus (0.077%, [0.072–0.082] vs. 0.093%, [0.084–0.10], p = .001) after Bonferroni correction. Volume of several limbic regions was significantly correlated with T2 lesion burden and brain parenchymal fraction (BPF). Multiple regression model showed minimal influence of BPF on limbic brain volume and no influence of other demographic and disease state variables. VBM analysis showed cluster differences in the fornix and anterior thalamic nuclei at threshold p < 0.05 after adjusting for covariates but the results were insignificant after family-wise error corrections.

Conclusions

The results show evidence that brain volume loss is fairly extensive in the limbic brain. Given the significance of the limbic system in many disease states including MS, such volumetric analyses can be expanded to studying cognitive and emotional disturbances in larger clinical trials. FreeSurfer ScLimbic pipeline provided an efficient and reliable methodology for examining many of the subcortical structures related to the limbic brain.

Perspective taking deficits and their relationship with theory of mind abilities in patients with relapsing-remitting multiple sclerosis (RRMS)

Introduction and objectives: In recent years, research has reported that between 45% and 70% of patients with Multiple Sclerosis (MS) have cognitive deficits, the most prominent being those associated with the frontal lobe. Among these deficits, we can find Theory of Mind (ToM), which is the ability to infer feelings and thoughts of others. Although it has been suggested that ToM relies on more basic skills, such as perspective taking (PT), no studies have investigated this association in patients with MS. The aim of this study was to investigate PT abilities in patients with MS and to establish their relationship with ToM deficits. Material and methods: 36 patients with relapsing-remitting multiple sclerosis (RRMS) and 42 healthy controls matched by age, sex and educational level were evaluated. Both groups were tested to estimate premorbid and current intellectual capacity, PT, ToM (Reading the Mind in the Eyes Test -RMET- and Faux Pas) and complementary scales (fatigue, depression and disability). Results: Patients with RRMS presented significant differences from controls in both PT and ToM tests. The PT test showed positive correlation with RMET, one of our ToM tests. Conclusion: The results show that there is a relationship between ToM and PT abilities. Our findings are of clinical and academic relevance to both the assessment and interpretation as well as the rehabilitation of social deficits in MS.

The Anatomy of Friendship: Neuroanatomic Homophily of the Social Brain among Classroom Friends

Homophily refers to the tendency to like similar others. Here, we ask if homophily extends to brain structure. Specifically: do children who like one another have more similar brain structures? We hypothesized that neuroanatomic similarity tied to friendship is most likely to pertain to brain regions that support social cognition. To test this hypothesis, we analyzed friendship network data from 1186 children in 49 classrooms. Within each classroom, we identified "friendship distance"-mutual friends, friends-of-friends, and more distantly connected or unconnected children. In total, 125 children (mean age = 7.57 years, 65 females) also had good quality neuroanatomic magnetic resonance imaging scans from which we extracted properties of the "social brain." We found that similarity of the social brain varied by friendship distance: mutual friends showed greater similarity in social brain networks compared with friends-of-friends (β = 0.65, t = 2.03, P = 0.045) and even more remotely connected peers (β = 0.77, t = 2.83, P = 0.006); friends-of-friends did not differ from more distantly connected peers (β = -0.13, t = -0.53, P = 0.6). We report that mutual friends have similar "social brain" networks, adding a neuroanatomic dimension to the adage that "birds of a feather flock together."

Amygdala network reorganization mediates the theory of mind performances in multiple sclerosis

Theory of mind (ToM) seems to be affected in multiple sclerosis (MS). MRI studies suggested a role of the amygdala in social cognitive performances. Therefore, we explored the role of the amygdala network in ToM using a multimodal MRI approach. In MS, patients with impaired ToM showed contradictory dysexecutive neuropsychological profile. Therefore, we compared neural networks involved in ToM and executive functions (EFs). Twenty patients with relapsing-remitting MS and 15 matched healthy controls were selected. ToM (Faux Pas test and mind stories) and EFs were assessed within and outside the scanner. All subjects underwent a battery of neuropsychological tests. Multimodal MRI with structural (diffusion imaging) and functional (resting-state and task-based) sequences was used to analyze the role and connections of the amygdala in ToM functioning. Cognitive and ToM performances were similar between patients and controls. Resting-state data revealed decreased connectivity of the left amygdala with frontal areas in patients compared to controls (p < 0.0001). During the task-based functional MRI, patients demonstrated increased connectivity between the amygdala and several cerebellar and left temporal regions (all p < 0.05). The microstructural alterations between the left amygdala and left temporal regions were associated with increased functional connectivity within the same pathway (r = 0.74; p < 0.01). No overlap was observed between functional networks involved in ToM and EFs. Our study demonstrates more connectivity recruitment between the amygdala and cerebellar and temporal regions in MS patients to reach preserved ToM performance. Microstructural abnormalities have been related to this compensatory network. Finally, different networks were involved in EFs and ToM.

Resting-State Functional Brain Connectivity for Human Mentalizing: Biobehavioral Mechanisms of Theory of Mind in Multiple Sclerosis

Although neural hubs of mentalizing are acknowledged, the brain mechanisms underlying mentalizing deficit, characterizing different neurological conditions, are still a matter of debate. To investigate the neural underpinning of Theory of Mind (ToM) deficit in Multiple Sclerosis (MS), a region of interest (ROI)-based resting-state fMRI study was proposed. 37 MS patients (23 females, mean age=54.08±11.37 years, median Expanded Disability Status Scale=6.00) underwent an MRI and a neuro-psychosocial examination, and were compared with 20 sex-age-education matched healthy subjects. A neuroanatomical ToM model was constructed deriving 11 bilateral ROI, then between and within-functional connectivity (FC) were assessed to test for group differences. Correlation with psychosocial scores was also investigated. Lower ToM performance was registered for MS both in cognitive and affective ToM, significantly associated with processing speed. A disconnection between limbic-paralimbic network and prefrontal execution loops was observed. A trend of aberrant intrinsic connectivity in MS within the anterior cingulate cortex (ACC) was also reported. Finally, a correlation between cognitive ToM and intrinsic FC was detected in ACC and dorsal striatum, belonging to the limbic-paralimbic network, likely explaining the behavioral deficit in MS. The results suggest that aberrant intrinsic and extrinsic connectivity constitutes a crucial neural mechanism underlying ToM deficit in MS.

Relapsing-remitting and secondary-progressive multiple sclerosis patients differ in decoding others' emotions by their eyes

BACKGROUND AND PURPOSE

Difficulties in emotion processing and social cognition identified in multiple sclerosis (MS) patients have a potential impact on their adaptation to the social environment. We aimed to explore the neural correlates of emotion recognition in MS and possible differences between relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS) patients by the Reading the Mind in the Eyes test (RMEt).

METHODS

A total of 43 MS patients (27 RRMS, 16 SPMS) and 25 matched healthy controls (HC) underwent clinical assessments, RMEt, and a high-resolution T1-weighted 3-T magnetic resonance imaging (MRI) scan. The number of correct answers on the RMEt was compared between groups. T1-weighted volumes were processed according to an optimized voxel-based morphometry (VBM) protocol to obtain gray matter (GM) maps. Voxelwise analyses were run to assess potential associations between RMEt performance and regional GM volumes.

RESULTS

Taken altogether, MS patients reported significantly lower performance on the RMEt compared to HC. When dividing the patients into those with RRMS and those with SPMS, only the latter group was found to perform significantly worse than HC on the RMEt. VBM analysis revealed significant association between RMEt scores and GM volumes in several cortical (temporoparieto-occipital cortex) and subcortical (hippocampus, parahippocampus, and basal ganglia) brain regions, and in the cerebellum in SPMS patients only.

CONCLUSIONS

Results suggest that, in addition to other clinical differences between RRMS and SPMS, the ability to recognize others' emotional states may be affected in SPMS more significantly than RRMS patients. This is supported by both behavioral and MRI data.

Relationship Between Interpersonal Depressive Symptoms and Reduced Amygdala Volume in People with Multiple Sclerosis: Considerations for Clinical Practice

Background

The lifetime prevalence of depression in people with multiple sclerosis (MS) is approximately 50% compared with around 15% in the general population. There is a relationship between depression and quality of life in people with MS and evidence that depression may contribute to disease progression.

Methods

This cross-sectional pilot study assessed the association between depression and regional brain atrophy, including amygdala and hippocampal volume. Forty-nine participants with MS recruited through a hospital MS clinic were administered the Center for Epidemiological Studies Depression Scale Revised (CESD-R) to investigate whether higher endorsements on the items depressive affect and interpersonal symptoms were associated with volumetric magnetic resonance imaging measurements of hippocampal and amygdala atrophy.

Results

Regression analysis revealed an association between depression-related interpersonal symptoms and right amygdala volume. No association was found between depression and hippocampal volume.

Conclusions

These results provide preliminary support for a unilateral, biologically based relationship between the right amygdala and characteristic interpersonal depressive symptoms expressed by people with MS and add to the growing body of literature implicating regional brain atrophy in MS-associated depression. Given that the interpersonal subcomponent of the CESD-R measures social functioning, and the neural networks in the amygdala are known to be implicated in processing social stimuli, this research suggests that targeted diagnosis and treatments for depression in people with MS may be particularly beneficial. Further confirmatory research of this relationship is required.

Theory of mind and its neuroanatomical correlates in people with multiple sclerosis

Background Theory of mind (ToM) is one of the several different concepts in social cognition and is defined as the ability to access the mental states of others or to adopt the point of view of others. Although studies have shown that ToM is impaired in people with multiple sclerosis (MS), the results based on individual ToM tasks are conflicting; some studies have shown deficits only in the 'Reading the Mind in the Eyes' Test (RMET), while others have reported poor performance in the Faux Pas Test (FPT) as well as RMET. Furthermore, little is known about the relationship between ToM performance and neuroanatomical characteristics in MS. This study investigated ToM impairment and its relationship to regional brain volume or cortical thickness in people with MS. Methods This cross-sectional study included 20 participants with relapse-onset MS and 27 age- and sex-matched volunteers as healthy controls (HC). All the participants underwent neuropsychological (NP) tests as well as ToM tasks, including RMET and FPT. Participants with MS underwent brain MRI within 6 months before and after undergoing the NP and ToM tests. Regional volume of subcortical structures or cortical thickness were analysed based on 3D T1-weighted images using FreeSurfer software. Results Both RMET and FPT scores were significantly lower in participants with MS than in HC (p = 0.0049, p = 0.0071, respectively). Imaging analyses showed that FPT scores, but not RMET scores, were positively correlated with the right thalamus (R² = 0.26, p = 0.012) and left pallidum (R² = 0.39, p = 0.0021) volumes after adjusting for age. Furthermore, surface-based morphometry revealed significant correlation between age-adjusted cortical thickness of ten cortical areas, including the fusiform gyrus, orbitofrontal cortex, temporal-parietal junction, and superior temporal gyrus, and FPT scores. Conclusions These study findings showed that both RMET and FPT performances are impaired in participants with MS. Furthermore, FPT deficits, but not RMET deficits, were significantly associated with the volume of two subcortical structures as well as the thickness of ten cortical areas, suggesting that FPT is an appropriate task to access ToM performance in MS.

Development, Spanish Normative Data, and Validation of a Social Cognition Battery in Prodromal Alzheimer's Disease and Multiple Sclerosis

OBJECTIVES

The assessment of social cognition changes may be challenging, especially in the earliest stages of some neurodegenerative diseases. Our objective was to validate a social cognition battery from a multidomain perspective. In this regard, we aimed to adapt several tests, collect normative data, and validate them in prodromal Alzheimer's disease (AD) and multiple sclerosis (MS).

METHODS

A total of 92 healthy controls, 25 prodromal AD, and 39 MS patients were enrolled. Age-, gender-, and education-matched control groups were created for comparisons. Social cognition battery was composed of an emotion-labeling task developed from FACES database, the Story-based Empathy test (SET), the Faux Pas test, and the Interpersonal Reactivity Index. Patients were also evaluated with a comprehensive cognitive battery to evaluate the other cognitive domains. Automatic linear modeling was used to predict each social cognition test's performance using the neuropsychological tests examining other cognitive domains.

RESULTS

The reliability of the battery was moderate-high. Significant intergroup differences were found with medium-large effect sizes. Moderate correlations were found between social cognition battery and neuropsychological tests. The emotion labeling task and SET showed moderate correlations with age and education, and age, respectively. Regression-based norms were created considering the relevant demographic variables. Linear regression models including other neuropsychological tests explained between 7.7% and 68.8% of the variance of the social cognition tests performance.

CONCLUSIONS

Our study provides a battery for the assessment of social cognition in prodromal AD and MS with Spanish normative data to improve the evaluation in clinical and research settings.

Memory, processing of emotional stimuli, and volume of limbic structures in pediatric-onset multiple sclerosis

OBJECTIVE

The limbic system is involved in memory and in processing of emotional stimuli. We measured volume of the hippocampus, amygdala, and thalamus, and assessed their relative contribution to episodic memory and emotion identification in POMS.

METHOD

Sixty-five POMS participants (Mage = 18.3 ± 3.9 years; 48 female (73.8%)), average disease duration = 3.8 ± 3.8 years) and 76 age- and sex-matched controls (Mage = 18.1 ± 4.6 years; 49 female (64.5%)) completed the Penn Computerized Neurocognitive Battery (PCNB); 59 of 65 POMS participants and 69 out of 76 controls underwent 3 T MRI scanning. We derived age-adjusted Z-scores on accuracy and response time (RT) measures of episodic memory and emotion identification of the PCNB. Magnetic resonance imaging (MRI) volumetrics were normalized using the scaling factor computed by SIENAx. On PCNB tests that differed between groups, we used multiple linear regression to assess relationships between regional brain volumes and either episodic memory or emotion identification outcomes controlling for age, sex, accuracy/RT, and parental education.

RESULTS

POMS participants were slower and less accurate than controls on the episodic memory domain but did not differ from controls on emotion outcomes. At the subtest level, POMS participants showed reduced accuracy on Word Memory (p = .002) and slower performance on Face Memory (p = .04) subtests. POMS participants had smaller total and regional brain volumes of the hippocampus, amygdala, and thalamus (p values ≤ 0.01). Collapsing across groups, both hippocampal and thalamic volume were significant predictors of Word Memory accuracy; hippocampal volume (B = 0.24, SE = 0.10, p = .02) was more strongly associated with Word Memory performance than thalamic volume (B = 0.16, SE = 0.05, p = .003), though the estimate with was less precise.

CONCLUSIONS

POMS participants showed reduced episodic memory performance compared to controls. Aspects of episodic memory performance were associated with hippocampal and thalamic volume. Emotion identification was intact, despite volume loss in the amygdala.

Innate immunity impacts social-cognitive functioning in people with multiple sclerosis and healthy individuals: Implications for IL-1ra and urinary immune markers

Social-cognitive difficulties can negatively impact interpersonal communication, shared social experience, and meaningful relationships. This pilot investigation examined the relationship between social-cognitive functioning and inflammatory markers in people with multiple sclerosis (MS) and demographically-matched healthy individuals. Additionally, we compared the immune marker profile in serum and urine-matched samples. Social cognitive functioning was objectively assessed using The Awareness of Social Inference Test - Short (TASIT-S) and subjectively assessed using self-reports of abilities in emotion recognition, emotional empathy, and cognitive theory of mind. In people with MS and healthy individuals, there were moderate-to-large negative relationships between pro-inflammatory biomarkers (serum IL-1β, IL-17, TNF-α, IP-10, MIP-1α, and urine IP-10, MIP-1β) of the innate immune system and social-cognitive functioning. In MS, a higher serum concentration of the anti-inflammatory marker IL-1ra was associated with better social-cognitive functioning (i.e., self-reported emotional empathy and TASIT-S sarcasm detection performance). However, there were mixed findings for anti-inflammatory serum markers IL-4 and IL-10. Overall, our findings indicate a relationship between pro-inflammatory cytokines and social-cognitive abilities. Future studies may provide greater insight into biologically-derived inflammatory processes, sickness behaviour, and their connection with social cognition.

Outcomes on Social and Classic Cognition in adults with Pediatric-onset Multiple Sclerosis

BACKGROUND

Cognitive impairment affecting classic and social domains has been consistently reported in patients with Multiple Sclerosis (MS). However, little is known about the cognitive outcomes, particularly on social cognition, in adults with pediatric-onset multiple sclerosis (POMS).

OBJECTIVES

To compare the performance in classic and social cognitive domains between adults with POMS and adult-onset MS (AOMS).

METHODS

A group of 30 patients with POMS (age onset <18 years) was compared with age-matched (AOAMS, n=30) and disease duration-matched (AODMS, n= 30) patients who developed MS after the age of 18 years. Cognitive performance was assessed using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) and Theory of Mind (ToM) tests.

RESULTS

Cognitive impairment was more prevalent in POMS patients (40% vs. 16.7%, p=0.045), independently of age or disease duration, affecting more severely information-processing speed and visual memory domains. No statistically significant differences were found in ToM performance between patients with POMS and AOMS. When analyzing ToM performance according to age of disease onset (≤15 years; 15-20 years; ≥20 years), patients with disease onset ≤15 years old had significantly lower scores on ToM tests when compared to the other groups.

CONCLUSION

Patients with POMS were more prone to develop impairment on classic cognitive domains than on ToM ability, when compared with AOMS patients. The interference of POMS with critical neurodevelopmental periods, specific for each cognitive domain, may explain different outcomes at adulthood on social and classic cognition.

Social cognition in multiple sclerosis and its subtypes: A meta-analysis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated demyelinating disease that disrupts several social cognitive abilities, including the theory of mind (ToM) and facial emotion recognition (FER). It is unclear how specific ToM subcomponents, including cognitive and affective ToM, are affected in patients with MS and the social cognitive abilities in MS subtypes.

METHODS

A search of PubMed, Web of Science, and Embase databases was conducted until June 2020. Effect sizes were calculated using Hedges g with a random-effects model.

RESULTS

A total of 45 studies were included. Relative to health controls (HCs), patients with MS and its subtypes (including relapsing-remitting MS [RRMS] and progressive MS) exhibited impairments in ToM (g = -0.77, g = -0.70, g = -0.75, respectively), cognitive ToM (g = -0.72, g = -0.83, g = -0.73, respectively), affective ToM (g = -0.84, g = -0.63, g = -0. 50, respectively), and FER (g = -0.62, g = -0.53, g = -1.07, respectively). In addition, there was no difference between progressive primary MS and secondary progressive MS in overall ToM, cognitive ToM, affective ToM, and FER. Compared to patients with RRMS, patients with progressive MS showed no difference in overall ToM, cognitive ToM, and affective ToM but had more serious defects in FER (g = -0.57).

CONCLUSIONS

These quantitative results indicate that patients with MS and its subtypes have a differential impairment of the core aspects of social cognitive processing (including ToM and FER), which may help develop the structured social cognitive interventions in MS.

Social Cognition in Multiple Sclerosis: A 3-Year Follow-Up MRI and Behavioral Study

Social cognition (SC) has become a topic of widespread interest in the last decade. SC deficits were described in multiple sclerosis (MS) patients, in association with amygdala lesions, even in those without formal cognitive impairment. In this 3-year follow-up study, we aimed at longitudinally investigating the evolution of SC deficits and amygdala damage in a group of cognitive-normal MS patients, and the association between SC and psychological well-being. After 3 years (T3) from the baseline examination (T0), 26 relapsing-remitting MS patients (RRMS) were retested with a neuropsychological battery and SC tasks (theory of mind, facial emotion recognition, empathy). A SC composite score (SCcomp) was calculated for each patient. Emotional state, fatigue, and quality of life (QoL) were also evaluated. RRMS patients at T3 underwent a 3T-MRI as performed at T0, from which were calculated both volume and cortical lesion volume (CLV) of the amygdalae. Compared to T0, at T3 all RRMS patients were still cognitive-normal and remained stable in their global SC impaired performance. At T0, SCcomp correlated with amygdala CLV (p = 0.002) while, at T3, was more associated with amygdala volume (p = 0.035) rather than amygdala CLV (p = 0.043). SCcomp change T3-T0 correlated with global emotional state (p = 0.043), depression (p = 0.046), anxiety (p = 0.034), fatigue (p = 0.025), and QoL-social functioning (p = 0.033). We showed the longitudinal stability of SC deficits in cognitive-normal RRMS patients, mirroring the amygdala structural damage and the psychological well-being. These results highlight that SC exerts a key role in MS.

Neurocognitive impairment and social cognition in multiple sclerosis

PURPOSE/AIM OF THE STUDY

The impairment of neurocognitive functions occurs in all subtypes of multiple sclerosis, even from the earliest stages of the disease. Commonly reported manifestations of cognitive impairment include deficits in attention, conceptual reasoning, processing efficiency, information processing speed, memory (episodic and working), verbal fluency (language), and executive functions. Multiple sclerosis patients also suffer from social cognition impairment, which affects their social functioning. The objective of the current paper is to assess the effect of neurocognitive impairment and its potential correlation with social cognition performance and impairment in multiple sclerosis patients.

MATERIALS AND METHODS

An overview of the available-to-date literature on neurocognitive impairment and social cognition performance in multiple sclerosis patients by disease subtype was performed.

RESULTS

It is not clear if social cognition impairment occurs independently or secondarily to neurocognitive impairment. There are associations of variable strengths between neurocognitive and social cognition deficits and their neural basis is increasingly investigated.

CONCLUSIONS

The prompt detection of neurocognitive predictors of social cognition impairment that may be applicable to all multiple sclerosis subtypes and intervention are crucial to prevent further neural and social cognition decline in multiple sclerosis patients.

Empathy and Theory of Mind in Multiple Sclerosis: A Meta-Analysis

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system. Studies have shown that MS disrupts several social cognitive abilities [including empathy and theory of mind (ToM)]. Overall ToM deficits in MS are well documented, but how the specific ToM subcomponents and empathic capacity are affected remains unclear. For this meta-analysis, we searched PubMed, Web of Science, and Embase from inception to July 2020. Effect sizes were calculated using Hedges g with a random-effects model. Thirty-three studies were included. Relative to healthy controls (HCs), patients with MS were moderately impaired in overall empathy (g = -0.67), overall ToM (g = -74), cognitive ToM (g = -0.72), and the overlapping domains of cognitive empathy/affective ToM (g = -0.79); no group differences were identified for affective empathy (g = -0.19). Compared with HCs, patients with relapsing-remitting MS (RRMS) and progressive MS were impaired in overall empathy, overall ToM, cognitive ToM, and cognitive empathy/affective ToM, without significant RRMS-progressive MS differences in impairment degree. We conducted the first meta-analytic review investigating the empathy and ToM functioning patterns in patients with MS and examined the overlapping and distinct subcomponents of these constructs. The findings suggest differential impairment of the core aspects of social cognitive processing in patients with MS, which may importantly inform the development of structured social cognitive MS interventions.

Protective effects of cognitive and brain reserve in multiple sclerosis: Differential roles on social cognition and 'classic cognition'

BACKGROUND

According to cognitive reserve (CR) and brain reserve (BR) theories, lifetime intellectual enrichment and maximal brain volume protect against cognitive decline.

OBJECTIVE

To examine the effects of CR and BR on social cognition in multiple sclerosis (MS), and compare it with 'classic cognition'.

METHODS

We included 60 MS patients and 60 healthy controls matched on age, sex, and education. Education was used has a proxy of CR and intracranial volume (ICV) as a proxy of BR. Participants underwent Theory of Mind (ToM) testing (Eyes Test, Videos Test), comprehensive neuropsychological assessment and 3Tesla brain MRI. Cortical and subcortical grey matter (GM) volumes were calculated.

RESULTS

We found positive effects of education and ICV on general cognitive status and ToM performance, respectively. Higher education moderated the impact of subcortical GM atrophy on 'classic' cognitive status (R2=0.219, p=<0.001). Conversely, greater ICV attenuated the impact of cortical GM atrophy on Eyes Test (R²=0.158, p=0.002) and Videos Test (R²=0.198, p=0.001). Stratification for disease duration showed that the protective effect of education/ICV occurred in early stages of disease (<10 years).

CONCLUSION

CR and BR have differential protective roles in MS, with BR having a positive effect on social cognition and CR on 'classic' cognitive domains.

A Scope of the Social Brain in Multiple Sclerosis: Insights From Neuroimaging Studies

Multiple sclerosis (MS) is the most common inflammatory neurologic disease in young adults. Its pathological mechanisms include demyelination, neurodegeneration, and synaptopathy. Cognitive deficits occur in up to 65% of individuals with MS and affect both nonsocial (eg, information processing speed, memory, and executive functions) and social (ie, emotion recognition, theory of mind, and empathy) cognitive domains. In the last 3 decades, there has been a growing interest in social cognition and its relationship with neuropsychological, sociodemographic, and disease characteristics in individuals with MS. Uncovering the neuropathological correlates of social cognitive deficits is now a crucial aim that would also help us better understand the underlying mechanisms of social cognition. We reviewed 11 neuroimaging studies to investigate social cognition in MS. These studies focused mainly on facial emotion recognition and theory of mind, with the findings suggesting that a disrupted cortico-subcortical network forms the basis of social deficits involving both domains. We then interpreted these results in the context of multiple disconnection syndrome, which occurs as a result of axonal demyelination and degeneration within the connexome of several neural hubs devoted to social cognition. Heterogeneity in social cognitive performance, observed among our study participants, is discussed with reference to the cognitive reserve and brain reserve hypotheses. These reserves may explain why individuals with comparable clinical characteristics of MS may exhibit different cognitive profiles. Further research is required to generalize these findings to the MS population and to inform the development of effective interventions to improve psychosocial functioning in individuals with MS.

The impact of deep grey matter volume on cognition in multiple sclerosis

BACKGROUND

Cognitive dysfunctions are very frequent in people living with multiple sclerosis (MS). Several studies have previously indicated grey matter (GM) atrophy as useful predictor of patients' cognitive impairment. However, considerable uncertainty exists about the possible impact of deep grey matter volumes on cognition. This study aimed to evaluate the relationship of the subcortical (sc) GM volumes with the presence and severity of global and selective cognitive impairment in MS.

METHODS

A group of MS patients with relapsing remitting course were enrolled. Patients underwent a neuropsychological evaluation by using the Brief Repeatable Battery of Neuropsychological Tests (BRBN) and the Delis-Kaplan Executive Function System Sorting Test (D-KEFST); z scores were estimated and items with z score below 2 standard deviation were considered failed. Thus, brain MRIs images were acquired and measurements of whole brain (WB), white matter (WM), and cortical grey matter (GM) were obtained by SIENAX. After FIRST tool segmentation, volumes of subcortical GM structures were also estimated.

RESULTS

The sample included 50 MS patients, of which 16/50 (32%) subjects were cognitively impaired. Multiple regression analyses found a significant association of severity of cognitive impairment, defined as number of failed neuropsychological tests, with lower volumes of cortex (p=0.003), thalamus (p=0.009), caudate (p=0.011), putamen (p=0.020), pallidus (p=0.012) and hippocampus (p=0.045), independently from other MS features. In addition, an association between accumbens volume and D-KEFS ST FSC and D-KEFS ST FSD z scores was observed (p<0.03).

CONCLUSIONS

Our results indicated that volumes of several scGM structures, and in particular of thalamus, contribute to determine cognitive dysfunctions in MS, mainly influencing the executive functioning. Further investigations in larger MS cohorts with cognitive impairment are necessary to better understand the structural brain damage underlying this "invisible disability".

Distinct Functional Connectivity Signatures of Impaired Social Cognition in Multiple Sclerosis

Objective: Multiple sclerosis (MS) is characterized by impairments in basic cognitive functions such as information processing speed as well as in more complex, higher-order domains such as social cognition. However, as these deficits often co-occur, it has remained challenging to determine whether they have a specific pathological basis or are driven by shared biology.

Methods: To identify neural signatures of social cognition deficits in MS, data were analyzed from n = 29 patients with relapsing–remitting MS and n = 29 healthy controls matched for age, sex, and education. We used neuropsychological assessments of information processing speed, attention, learning, working memory, and relevant aspects of social cognition (theory of mind, emotion recognition (ER), empathy) and employed neuroimaging of CNS networks using resting-state functional connectivity.

Results: MS patients showed significant deficits in verbal learning and memory, as well as implicit ER. Performance in these domains was uncorrelated. Functional connectivity analysis identified a distinct network characterized by significant associations between poorer ER and lower connectivity of the fusiform gyrus (FFG) with the right lateral occipital cortex, which also showed lower connectivity in patients compared to controls. Moreover, while ER was correlated with MS symptoms such as fatigue and motor/sensory functioning on a behavioral level, FFG connectivity signatures of social cognition deficits showed no overlap with these symptoms.

Conclusions: Our analyses identify distinct functional connectivity signatures of social cognition deficits in MS, indicating that these alterations may occur independently from those in other neuropsychological functions.

Cognitive Impairment and Brain Reorganization in MS: Underlying Mechanisms and the Role of Neurorehabilitation

Multiple sclerosis (MS) is a chronic, immune-mediated, inflammatory, and degenerative disease of the central nervous system (CNS) that affects both white and gray matter. Various mechanisms throughout its course, mainly regarding gray matter lesions and brain atrophy, result in cognitive network dysfunction and can cause clinically significant cognitive impairment in roughly half the persons living with MS. Altered cognition is responsible for many negative aspects of patients' lives, independently of physical disability, such as higher unemployment and divorce rates, reduced social activities, and an overall decrease in quality of life. Despite its devastating impact it is not included in clinical ratings and decision making in the way it should be. It is interesting that only half the persons with MS exhibit cognitive dysfunction, as this implies that the other half remain cognitively intact. It appears that a dynamic balance between brain destruction and brain reorganization is taking place. This balance acts in favor of keeping brain systems functioning effectively, but this is not so in all cases, and the effect does not last forever. When these systems collapse, functional brain reorganization is not effective anymore, and clinically apparent impairments are evident. It is therefore important to reveal which factors could make provision for the subpopulation of patients in whom cognitive impairment occurs. Even if we manage to detect this subpopulation earlier, effective pharmaceutical treatments will still be lacking. Nevertheless, recent evidence shows that cognitive rehabilitation and neuromodulation, using non-invasive techniques such as transcranial magnetic or direct current stimulation, could be effective in cognitively impaired patients with MS. In this Mini Review, we discuss the mechanisms underlying cognitive impairment in MS. We also focus on mechanisms of reorganization of cognitive networks, which occur throughout the disease course. Finally, we review theoretical and practical issues of neurorehabilitation and neuromodulation for cognition in MS as well as factors that influence them and prevent them from being widely applied in clinical settings.

Synaptic Elimination in Neurological Disorders

Synapses are well known as the main structures responsible for transmitting information through the release and recognition of neurotransmitters by pre- and post-synaptic neurons. These structures are widely formed and eliminated throughout the whole lifespan via processes termed synaptogenesis and synaptic pruning, respectively. Whilst the first pro-cess is needed for ensuring proper connectivity between brain regions and also with the periphery, the second phenomenon is important for their refinement by eliminating weaker and unnecessary synapses and, at the same time, maintaining and fa-voring the stronger ones, thus ensuring proper synaptic transmission. It is well-known that synaptic elimination is modulated by neuronal activity. However, only recently the role of the classical complement cascade in promoting this phenomenon has been demonstrated. Specifically, microglial cells recognize activated complement component 3 (C3) bound to synapses tar-geted for elimination, triggering their engulfment. As this is a highly relevant process for adequate neuronal functioning, dis-ruptions or exacerbations in synaptic pruning could lead to severe circuitry alterations that could underlie neuropathological alterations typical of neurological and neuropsychiatric disorders. In this review, we focus on discussing the possible in-volvement of excessive synaptic elimination in Alzheimer’s disease, as it has already been reported dendritic spine loss in post-synaptic neurons, increased association of complement proteins with its synapses and, hence, augmented microglia-mediated pruning in animal models of this disorder. In addition, we briefly discuss how this phenomenon could be related to other neurological disorders, including multiple sclerosis and schizophrenia.

Resting-State Functional Correlates of Social Cognition in Multiple Sclerosis: An Explorative Study

Social cognition includes mental operations essential for functional social interactions, and several studies revealed an impairment of social cognition abilities in patients with Multiple Sclerosis (MS). These deficits have been related to global and focal gray matter atrophy as well as microstructural white matter damage. Although some studies reveal a correlation between social cognition and task-based functional magnetic resonance imaging (MRI), no studies to date have explored the association between brain resting-state functional connectivity (RS-FC) abnormalities and several measures of social cognition in MS. The aim of this explorative study was to assess the contribution of RS-FC abnormalities of major brain networks to social cognition in MS patients. Clinical, neuropsychological, and MRI data were collected from 41 non-depressed and cognitively preserved relapsing-remitting MS patients (mean disease duration = 8.8 ± 8.2 years; median Expanded Disability Status Scale = 1.5, range 0–6.5) and 25 matched healthy controls (HCs). The ToM Pictures Sequencing Task (TMPS) and the Reading the Mind in the Eyes Task were employed to evaluate social cognition. All participants underwent a structural MRI and RS functional MRI 3T protocol. Regional gray matter atrophy was measured, and FCs of the default mode (DMN), right and left fronto-parietal, executive (EN), salience, cerebellar, and limbic (LN) networks were evaluated by independent component analysis (ICA). Differences on TMPS were found between MS patients and HC (MS < HC). In the MS group, associations were found between right middle temporal gyrus FC (in the DMN) and reciprocity subscale of TMPS, posterior cingulate cortex (PCC) FC (in the DMN) and first-order false-belief subscale of TMPS, cingulate gyrus FC (in the EN) and TMPS as well as reciprocity subscale of TMPS, and right superior temporal gyrus (in the LN) and reciprocity subscale of TMPS. All detected RS-FC changes did not co-localize with regional gray matter atrophy. The results suggest an association between social cognition and RS-FC changes of DMN, EN, and LN in MS. Future studies should further explore the possible adaptive or maladaptive mechanisms of these FC abnormalities in MS.

Multiple sclerosis and cognition: synaptic failure and network dysfunction

Cognitive impairment is increasingly recognized to be a core feature of multiple sclerosis (MS), with important implications for the everyday life of individuals with MS and for disease management. Unfortunately, the exact mechanisms that underlie this cognitive impairment are poorly understood and there are no effective therapeutic options for this aspect of the disease. During MS, focal brain inflammatory lesions, together with pathological changes of both CNS grey matter and normal-appearing white matter, can interfere with cognitive functions. Moreover, inflammation may alter the crosstalk between the immune and the nervous systems, modulating the induction of synaptic plasticity and neurotransmission. In this Review, we examine the CNS structures and cognitive domains that are affected by the disease, with a specific focus on hippocampal involvement in MS and experimental autoimmune encephalomyelitis, an experimental model of MS. We also discuss the hypothesis that, during MS, immune-mediated alterations of synapses' ability to express long-term plastic changes may contribute to the pathogenesis of cognitive impairment by interfering with the dynamics of neuronal networks.

Impaired Self-Other Distinction and Subcortical Gray-Matter Alterations Characterize Socio-Cognitive Disturbances in Multiple Sclerosis

Introduction: Recent studies of patients with multiple sclerosis (MS) have revealed disturbances in distinct components of social cognition, such as impaired mentalizing and empathy. The present study investigated this socio-cognitive profile in MS patients in more detail, by examining their performance on tasks measuring more fundamental components of social cognition and any associated disruptions to gray-matter volume (GMV). Methods: We compared 43 patients with relapse-remitting MS with 43 age- and sex-matched healthy controls (HCs) on clinical characteristics (depression, fatigue), cognitive processing speed, and three aspects of low-level social cognition; specifically, imitative tendencies, visual perspective taking, and emotion recognition. Using voxel-based morphometry, we then explored relationships between GMV and these clinical and behavioral measures. Results: Patients exhibited significantly slower processing speed, poorer perspective taking, and less imitation compared with HCs. These impairments were related to reduced GMV throughout the putamen, thalami, and anterior insula, predominantly in the left hemisphere. Surprisingly, differences between the groups in emotion recognition were not significant. Conclusion: Less imitation and poorer perspective taking indicate a cognitive self-bias when faced with conflicting self- and other-representations. This suggests that impaired self-other distinction, and an associated subcortical pattern of GM atrophy, might underlie the socio-cognitive disturbances observed in MS.

Assessment and Impact of Cognitive Impairment in Multiple Sclerosis: An Overview

Cognitive impairment affects 40⁻60% of patients with multiple sclerosis. It may be present early in the course of the disease and has an impact on a patient's employability, social interactions, and quality of life. In the last three decades, an increasing interest in diagnosis and management of cognitive impairment has arisen. Neuropsychological assessment and neuroimaging studies focusing on cognitive impairment are now being incorporated as primary outcomes in clinical trials. However, there are still key uncertainties concerning the underlying mechanisms of damage, neural basis, sensitivity and validity of neuropsychological tests, and efficacy of pharmacological and non-pharmacological interventions. The present article aimed to present an overview of the assessment, neural correlates, and impact of cognitive impairment in multiple sclerosis.

Moral Judgment: An Overlooked Deficient Domain in Multiple Sclerosis?

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system through which patients can suffer from sensory, motor, cerebellar, emotional, and cognitive symptoms. Although cognitive and behavioral dysfunctions are frequently encountered in MS patients, they have previously received little attention. Among the most frequently impaired cognitive domains are attention, information processing speed, and working memory, which have been extensively addressed in this population. However, less emphasis has been placed on other domains like moral judgment. The latter is a complex cognitive sphere that implies the individuals’ ability to judge others’ actions and relies on numerous affective and cognitive processes. Moral cognition is crucial for healthy and adequate interpersonal relationships, and its alteration might have drastic impacts on patients’ quality of life. This work aims to analyze the studies that have addressed moral cognition in MS. Only three works have previously addressed moral judgement in this clinical population compared to healthy controls, and none included neuroimaging or physiological measures. Although scarce, the available data suggest a complex pattern of moral judgments that deviate from normal response. This finding was accompanied by socio-emotional and cognitive deficits. Only preliminary data are available on moral cognition in MS, and its neurobiological foundations are still needing to be explored. Future studies would benefit from combining moral cognitive measures with comprehensive neuropsychological batteries and neuroimaging/neurophysiological modalities (e.g., functional magnetic resonance imaging, tractography, evoked potentials, electroencephalography) aiming to decipher the neural underpinning of moral judgement deficits and subsequently conceive potential interventions in MS patients.

The neural basis of fatigue in multiple sclerosis: A multimodal MRI approach

Background

Fatigue is a frequent disabling symptom in multiple sclerosis (MS), but its pathophysiology remains incompletely understood. This study aimed to explore the underlying neural basis of fatigue in patients with MS.

Methods

We enrolled 60 consecutive patients with MS and 60 healthy controls (HC) matched on age, sex, and education. Fatigue was assessed using the Portuguese version of the Modified Fatigue Impact Scale (MFIS). All participants underwent 3T brain MRI (conventional and diffusion tensor imaging [DTI] sequences). White matter (WM) focal lesions were identified and T1/T2 lesion volumes were computed. Tract-based spatial statistics were applied for voxel-wise analysis of DTI metrics fractional anisotropy and mean diffusivity (MD) on normal-appearing WM (NAWM). Using Freesurfer software, total and regional volumes of cortical and subcortical gray matter (GM) were calculated.

Results

Compared to HC, patients with MS scored significantly higher on MFIS (33.8 ± 19.7 vs 16.5 ± 15.1, p < 0.001). MFIS scores were not significantly correlated with T1/T2 lesion volumes, total GM volume, or any regional volume of cortical and subcortical GM. Significant correlations were found between global scores of MFIS and MD increase of the NAWM skeleton, including corona radiata, internal capsule, external capsule, corticospinal tract, cingulum, corpus callosum, fornix, superior longitudinal fasciculus, superior fronto-occipital fasciculus, sagittal stratum, posterior thalamic radiation, cerebral peduncle, and uncinate fasciculus.

Conclusions

In this study, fatigue was associated with widespread NAWM damage but not with lesion load or GM atrophy. Functional disconnection, caused by diffuse microstructural WM damage, might be the main neural basis of fatigue in MS.

Involvement of the Amygdala in Memory and Psychosocial Functioning in Pediatric-Onset Multiple Sclerosis

Youth with multiple sclerosis (MS) often experience cognitive impairment and psychosocial disturbances. We describe the relationship between memory function, psychosocial skills, and brain volume in 32 patients with pediatric-onset MS and 30 controls. Amygdala volume was significantly lower in patients compared with controls. In general, poorer memory was associated with reduced functional communication skills and reduced amygdala volume. Greater amygdala volume in patients correlated with parent-reported functional communication and social skills. Adjusting for whole-brain volume, right amygdala volume was positively associated with visual memory; left amygdala volume was a stronger predictor of parent-reported social skills.

Future Brain and Spinal Cord Volumetric Imaging in the Clinic for Monitoring Treatment Response in MS

PURPOSE OF REVIEW

Volumetric analysis of brain imaging has emerged as a standard approach used in clinical research, e.g., in the field of multiple sclerosis (MS), but its application in individual disease course monitoring is still hampered by biological and technical limitations. This review summarizes novel developments in volumetric imaging on the road towards clinical application to eventually monitor treatment response in patients with MS.

RECENT FINDINGS

In addition to the assessment of whole-brain volume changes, recent work was focused on the volumetry of specific compartments and substructures of the central nervous system (CNS) in MS. This included volumetric imaging of the deep brain structures and of the spinal cord white and gray matter. Volume changes of the latter indeed independently correlate with clinical outcome measures especially in progressive MS. Ultrahigh field MRI and quantitative MRI added to this trend by providing a better visualization of small compartments on highly resolving MR images as well as microstructural information. New developments in volumetric imaging have the potential to improve sensitivity as well as specificity in detecting and hence monitoring disease-related CNS volume changes in MS.

Relationship between Social Cognition and traditional cognitive impairment in Progressive Multiple Sclerosis and possible implicated neuroanatomical regions

BACKGROUND

Cognitive impairment is a relevant contributor of the medical and social burden in Progressive MS. Social Cognition, the neurocognitive processes underlying social interaction, has been explored mainly in European and North American cohorts, influencing social aspects of quality of life (QOL) of early MS patients and families. Few studies have studied Social Cognition in Progressive MS and the literature on its neuroanatomical bases or brain atrophy measurements is still scarce.

OBJECTIVES

To explore the relationship between Social Cognition performance and its correlations with traditional cognitive domains, brain atrophy and QOL in primary and secondary Progressive MS patients.

METHODS

Cross-sectional analysis including: mini-Social-Cognition-and-Emotional-Assessment (mini-SEA), neuropsychological battery, disability, depression, fatigue, QOL, and brain volume.

RESULTS

Forty-three MS patients, 23 primary and 20 secondary Progressive, 65% women, mean age and disease duration of 57.2 and 15.7 years, respectively, with high levels of disability (median EDSS 6.0) and a widespread impairment in traditional domains (mostly episodic verbal/visual and working memories) were assessed. The Mini-SEA score was correlated with executive functions (cognitive shifts Rho:0.55; p = 0.001) analyzing the whole group, and with visual episodic memory (Rho:0.58, p = 0.009) in the primary Progressive MS group. Mini-SEA score was also correlated with total normalized grey matter volume (Rho:0.48; p = 0.004). Particularly, atrophy within bilateral cortical regions of orbitofrontal, insula and cerebellum, and right regions of fusiform gyrus and precuneus were significantly associated with higher Social Cognition impairment. In this cohort, QOL was not correlated with Social Cognition, but with EDSS, fatigue and depression.

CONCLUSIONS

In Progressive MS, Social Cognition is directly correlated with traditional cognitive domains such as executive function and episodic memory. It is also associated with global grey matter atrophy and regional atrophy within associative visual and executive cortical areas, but no correlations with QOL were found in this cohort. These findings may contribute to the understanding of the pathological bases behind Social Cognition in Progressive MS.

Theory of mind in multiple sclerosis: A neuropsychological and MRI study

OBJECTIVES

Social cognition stands among the most frequently affected yet the least studied cognitive domains in multiple sclerosis (MS). Theory of mind (ToM) is a social cognitive facet that implies the one's ability to predict others' mental states. The objective of this study was to assess the relationship between ToM and neuropsychological and neuroimaging data.

METHODS

Thirty-eight consecutive MS patients completed the Reading the Mind in the Eyes test (RMET). They underwent a neuropsychological evaluation and a 3T T1-weighted brain MRI. A fully automated volume-based morphometry algorithm (MorphoBox) was applied to calculate regional brain volumes. Correlation analysis was performed using Spearman's test.

RESULTS

Among the sociodemographic and clinical data, significant correlations were found between RMET scores and each of years of education (r=0.54; p<0.01) and the duration of the disease progressive phase (r=-0.46; p<0.01). Regarding neuropsychological measures, RMET scores were directly correlated with information processing speed (r=0.58; p<0.01) and empathy (r=0.46; p<0.01) scores. As for brain volumes, RMET scores were directly correlated with parietal (left: r=0.39; right: r=0.46; p<0.05) and temporal (left: r=0.36; right: r=0.40; p<0.05) white matter volumes, as well as with cingulate (left: r=0.32; right: r=0.44; p<0.05) gray matter volumes.

CONCLUSION

These results highlight the relationship between ToM and some of the disease characteristics and cognitive domains. Importantly, ToM performance in MS is associated with brain volumes of key areas in social cognitive networks. Further works are needed to enhance the current knowledge on the underlying mechanisms of ToM deficits in this population.

Disconnection as a mechanism for social cognition impairment in multiple sclerosis

Objective:

To assess the contribution of microstructural normal-appearing white matter (NAWM) damage to social cognition impairment, specifically in the theory of mind (ToM), in multiple sclerosis (MS).

Methods:

We enrolled consecutively 60 patients with MS and 60 healthy controls (HC) matched on age, sex, and education level. All participants underwent ToM testing (Eyes Test, Videos Test) and 3T brain MRI including conventional and diffusion tensor imaging sequences. Tract-based spatial statistics (TBSS) were applied for whole-brain voxel-wise analysis of fractional anisotropy (FA) and mean diffusivity (MD) on NAWM.

Results:

Patients with MS performed worse on both tasks of ToM compared to HC (Eyes Test 58.7 ± 13.8 vs 81.9 ± 10.4, p < 0.001, Hedges g −1.886; Videos Test 75.3 ± 9.3 vs 88.1 ± 7.1, p < 0.001, Hedges g −1.537). Performance on ToM tests was correlated with higher values of FA and lower values of MD across widespread white matter tracts. The largest effects (≥90% of voxels with statistical significance) for the Eyes Test were body and genu of corpus callosum, fornix, tapetum, uncinate fasciculus, and left inferior cerebellar peduncle, and for the Videos Test genu and splenium of corpus callosum, fornix, uncinate fasciculus, left tapetum, and right superior fronto-occipital fasciculus.

Conclusions:

These results indicate that a diffuse pattern of NAWM damage in MS contributes to social cognition impairment in the ToM domain, probably due to a mechanism of disconnection within the social brain network. Gray matter pathology is also expected to have an important role; thus further research is required to clarify the neural basis of social cognition impairment in MS.