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.

Evidence for interhemispheric imbalance in stroke patients as revealed by combining transcranial magnetic stimulation and electroencephalography.

Interhemispheric interactions in stroke patients are frequently characterized by abnormalities, in terms of balance and inhibition. Previous results showed an impressive variability, mostly given to the instability of motor-evoked potentials when evoked from the affected hemisphere. We aim to find reliable interhemispheric measures in stroke patients with a not-evocable motor-evoked potential from the affected hemisphere, by combining transcranial magnetic stimulation (TMS) and electroencephalography. Ninteen stroke patients (seven females; 61.26 ± 9.8 years) were studied for 6 months after a first-ever stroke in the middle cerebral artery territory. Patients underwent four evaluations: clinical, cortical, corticospinal, and structural. To test the reliability of our measures, the evaluations were repeated after 3 weeks. To test the sensitivity, 14 age-matched healthy controls were compared to stroke patients. In stroke patients, stimulation of the affected hemisphere did not result in any inhibition onto the unaffected. The stimulation of the unaffected hemisphere revealed a preservation of the inhibition mechanism onto the affected. This resulted in a remarkable interhemispheric imbalance, whereas this mechanism was steadily symmetric in healthy controls. This result was stable when cortical evaluation was repeated after 3 weeks. Importantly, patients with a better recovery of the affected hand strength were the ones with a more stable interhemispheric balance. Finally, we found an association between microstructural integrity of callosal fibers, suppression of interhemispheric TMS-evoked activity and interhemispheric connectivity. We provide direct and sensitive cortical measures of interhemispheric imbalance in stroke patients. These measures offer a reliable means of distinguishing healthy and pathological interhemispheric dynamics.

Introducing axonal myelination in connectomics: A preliminary analysis of g-ratio distribution in healthy subjects.

Microstructural imaging and connectomics are two research areas that hold great potential for investigating brain structure and function. Combining these two approaches can lead to a better and more complete characterization of the brain as a network. The aim of this work is characterizing the connectome from a novel perspective using the myelination measure given by the g-ratio. The g-ratio is the ratio of the inner to the outer diameters of a myelinated axon, whose aggregated value can now be estimated in vivo using MRI. In two different datasets of healthy subjects, we reconstructed the structural connectome and then used the g-ratio estimated from diffusion and magnetization transfer data to characterize the network structure. Significant characteristics of g-ratio weighted graphs emerged. First, the g-ratio distribution across the edges of the graph did not show the power-law distribution observed using the number of streamlines as a weight. Second, connections involving regions related to motor and sensory functions were the highest in myelin content. We also observed significant differences in terms of the hub structure and the rich-club organization suggesting that connections involving hub regions present higher myelination than peripheral connections. Taken together, these findings offer a characterization of g-ratio distribution across the connectome in healthy subjects and lay the foundations for further investigating plasticity and pathology using a similar approach.

Whole brain white matter histogram analysis of diffusion tensor imaging data detects microstructural damage in mild cognitive impairment and alzheimer's disease patients.

BACKGROUND: Amnestic mild cognitive impairment (MCI) is a transitional stage between normal aging and Alzheimer's disease (AD). However, the clinical conversion from MCI to AD is unpredictable. Hence, identification of noninvasive biomarkers able to detect early changes induced by dementia is a pressing need. PURPOSE: To explore the added value of histogram analysis applied to measures derived from diffusion tensor imaging (DTI) for detecting brain tissue differences between AD, MCI, and healthy subjects (HS). STUDY TYPE: Prospective. POPULATION/SUBJECTS: A local cohort (57 AD, 28 MCI, 23 HS), and an Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort (41 AD, 58 MCI, 41 HS). FIELD STRENGTH: 3T. Dual-echo turbo spin echo (TSE); fluid-attenuated inversion recovery (FLAIR); modified-driven-equilibrium-Fourier-transform (MDEFT); inversion-recovery spoiled gradient recalled (IR-SPGR); diffusion tensor imaging (DTI). ASSESSMENT: Normal-appearing white matter (NAWM) masks were obtained using the T1 -weighted volumes for tissue segmentation and T2 -weighted images for removal of hyperintensities/lesions. From DTI images, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AXD), and radial diffusivity (RD) were obtained. NAWM histograms of FA, MD, AXD, and RD were derived and characterized estimating: peak height, peak location, mean value (MV), and quartiles (C25, C50, C75), which were compared between groups. Receiver operating characteristic (ROC) and area under ROC curves (AUC) were calculated. To confirm our results, the same analysis was repeated on the ADNI dataset. STATISTICAL TESTS: One-way analysis of variance (ANOVA), post-hoc Student's t-test, multiclass ROC analysis. RESULTS: For the local cohort, C25 of AXD had the maximum capability of group discrimination with AUC of 0.80 for "HS vs. patients" comparison and 0.74 for "AD vs. others" comparison. For the ADNI cohort, MV of AXD revealed the maximum group discrimination capability with AUC of 0.75 for "HS vs. patients" comparison and 0.75 for "AD vs. others" comparison. DATA CONCLUSION: AXD of NAWM might be an early marker of microstructural brain tissue changes occurring during the AD course and might be useful for assessing disease progression. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017.

CSF ß-amyloid as a putative biomarker of disease progression in multiple sclerosis.

BACKGROUND: Neurodegeneration plays a major role in determining disability in multiple sclerosis (MS) patients. Hence, there is increasing need to identify reliable biomarkers, which could serve as prognostic measure of disease progression. OBJECTIVES: To assess whether cerebrospinal fluid (CSF) tau and ß-amyloid (Aß) levels were altered in newly diagnosed MS patients and correlated with disability. Moreover, we investigated whether these CSF biomarkers associate with macroscopic brain tissue damage measures. METHODS: CSF Aß and tau levels were determined by enzyme-linked immunosorbent assay in CSF samples from 48 newly diagnosed MS patients, followed-up clinically for 3 years by recording their Expanded Disability Status Scale score at 6-month intervals, and 45 controls. All patients underwent magnetic resonance imaging at baseline and at the end of follow-up to quantify their lesion load (LL). RESULTS: CSF Aß levels were significantly reduced in patients compared to controls ( p < 0.001). Lower CSF Aß levels at baseline were a disability predictor at 3-year follow-up ( p = 0.009). CSF tau levels correlated with T2- and T1-LL ( p < 0.001). CONCLUSION: CSF Aß reduction is a promising biomarker of neurodegeneration and may predict patients' clinical outcome. Therefore, CSF Aß should be considered as a potential biomarker of prognostic value.

Brain Connectomics' Modification to Clarify Motor and Nonmotor Features of Myotonic Dystrophy Type 1.

The adult form of myotonic dystrophy type 1 (DM1) presents with paradoxical inconsistencies between severity of brain damage, relative preservation of cognition, and failure in everyday life. This study, based on the assessment of brain connectivity and mechanisms of plasticity, aimed at reconciling these conflicting issues. Resting-state functional MRI and graph theoretical methods of analysis were used to assess brain topological features in a large cohort of patients with DM1. Patients, compared to controls, revealed reduced connectivity in a large frontoparietal network that correlated with their isolated impairment in visuospatial reasoning. Despite a global preservation of the topological properties, peculiar patterns of frontal disconnection and increased parietal-cerebellar connectivity were also identified in patients' brains. The balance between loss of connectivity and compensatory mechanisms in different brain networks might explain the paradoxical mismatch between structural brain damage and minimal cognitive deficits observed in these patients. This study provides a comprehensive assessment of brain abnormalities that fit well with both motor and nonmotor clinical features experienced by patients in their everyday life. The current findings suggest that measures of functional connectivity may offer the possibility of characterizing individual patients with the potential to become a clinical tool.

Functional Anatomy of the Thalamus as a Model of Integrated Structural and Functional Connectivity of the Human Brain In Vivo.

While methods of measuring non-invasively both, functional and structural brain connectivity are available, the degree of overlap between them is still unknown. In this paper this issue is addressed by investigating the connectivity pattern of a brain structure with many, well characterized structural connections, namely the thalamus. Diffusion-weighted and resting state (RS) functional MRI (fMRI) data were collected in a group of 38 healthy participants. Probabilistic tractography was performed to parcellate the thalamus into regions structurally connected to different cortical areas. The resulting regions were used as seeds for seed-based analysis of RS fMRI data. The tractographic parcellation was thus cross-validated against functional connectivity data by evaluating the overlap between the functional and structural thalamo-cortical connections originating from the parcellated regions. Our data show only a partial overall correspondence between structural and functional connections, in the same group of healthy individuals, thus suggesting that the two approaches provide complementary and not overlapping information. Future studies are warranted to extend the results we obtained in the thalamus to other structures, and to confirm that the mechanisms behind functional connectivity are more complex than just expressing structural connectivity.

Phenotypic variability of PINK1 expression: 12 Years' clinical follow-up of two Italian families.

BACKGROUND: Mutations in the PINK1 gene are the second most frequent cause of autosomal recessive early-onset parkinsonism. METHODS: We evaluated five affected PINK1 homozygous and 14 heterozygous mutation carriers from two large Italian families over a 12-year follow-up period. Motor, nonmotor, cognitive, psychiatric, and behavioral profiles were systematically assessed. Four homozygotes and eight heterozygotes underwent magnetic resonance imaging. RESULTS: All homozygotes showed a mild progression of motor signs and a persistent excellent response to levodopa. All but one patient complained of nonmotor symptoms and sleep impairment. Three presented impulse control disorders and two anxiety and apathy. All obtained abnormal scores at Montreal Cognitive Assessment (MoCA) and in tests sensitive to frontal functions; one presented a global cognitive impairment. Three heterozygotes showed motor signs and were diagnosed as possibly affected. They had nonmotor symptoms and cognitive impairment, and two of them showed mild bilateral temporal atrophy. Five unaffected heterozygotes reported abnormal scores at MoCA and low performances at tests sensitive to frontal functions. CONCLUSION: We expanded the phenotypic profile of PINK1-related parkinsonism, including psychiatric and cognitive features as part of clinical presentation.

Correction: Spanò et al. Effect of Dual-Task Motor-Cognitive Training in Preventing Falls in Vulnerable Elderly Cerebrovascular Patients: A Pilot Study. Brain Sci. 2022, 12, 168.

In the original publication [...].

Brain tissue modifications induced by cholinergic therapy in Alzheimer's disease.

A previous preliminary investigation based on a novel MRI approach to map anatomical connectivity revealed areas of increased connectivity in Alzheimer's disease (AD) but not in mild cognitive impairment patients. This prompted the hypothesis tested here, that these areas might reflect phenomena of brain plasticity driven by acetylcholinesterase inhibitors (AChEIs). Thirty-eight patients with probable AD (19 under medication with AChEIs and 19 drug-naïve) were recruited together with 11 healthy controls. All subjects had MRI scanning at 3T, including volumetric and diffusion-weighted scans. Probabilistic tractography was used to initiate streamlines from all parenchymal voxels, and anatomical connectivity maps (ACMs) were obtained by counting, among the total number of streamlines initiated, the fraction passing through each brain voxel. After normalization into standard space, ACMs were used to test for between-group comparisons, and for interactions between the exposure to AChEIs and global level of cognition. Patients with AD had reduced ACM values in the fornix, cingulum, and supramarginal gyri. The ACM value was strongly associated with the AChEI dosage-x-duration product in the anterior limb (non-motor pathway) of the internal capsule. Tractography from this region identified the anterior thalamic radiation as the main white matter (WM) tract passing through it. The reduced connectivity in WM bundles connecting the hippocampi with the rest of the brain (fornix/cingulum) suggests a possible mechanism for the spread of AD pathology. An intriguing explanation for the interaction between AChEIs and ACM is related to the mechanisms of brain plasticity, partially driven by neurotrophic properties of acetylcholine replacement.

Quantitative magnetization transfer provides information complementary to grey matter atrophy in Alzheimer's disease brains.

Preliminary studies, based on a region-of-interest approach, suggest that quantitative magnetization transfer (qMT), an extension of magnetization transfer imaging, provides complementary information to conventional magnetic resonance imaging (MRI) in the characterisation of Alzheimer's disease (AD). The aim of this study was to extend these findings to the whole brain, using a voxel-wise approach. We recruited 19AD patients and 11 healthy subjects (HS). All subjects had an MRI acquisition at 3.0T including a T(1)-weighted volume, 12 MT-weighted volumes for qMT, and data for computing T(1) and B(1) maps. The T(1)-weighted volumes were processed to yield grey matter (GM) volumetric maps, while the other sequences were used to compute qMT parametric maps of the whole brain. qMT maps were warped to standard space and smoothed, and subsequently compared between groups. Of all the qMT parameters considered, only the forward exchange rate, RM(0)(B), showed significant group differences. These images were therefore retained for the multimodal statistical analysis, designed to locate brain regions of RM(0)(B) differences between AD and HS groups, adjusting for local GM atrophy. Widespread areas of reduced RM(0)(B) were found in AD patients, mainly located in the hippocampus, in the temporal lobe, in the posterior cingulate and in the parietal cortex. These results indicate that, among qMT parameters, RM(0)(B) is the most sensitive to AD pathology. This quantity is altered in the hippocampus of patients with AD (as found by previous works) but also in other brain areas, that PET studies have highlighted as involved with both, reduced glucose metabolism and amyloid ß deposition. RM(0)(B) might reflect, through the measurement of the efficiency of MT exchange, some information with a specific pathological counterpart. Given previous evidence of a strict relationship between RM(0)(B) and intracellular pH, an intriguing speculation is that our findings might reflect metabolic changes related to mitochondrial dysfunction, which has been proposed as a contributor to neurodegeneration in AD.

Damage to the cingulum contributes to Alzheimer's disease pathophysiology by deafferentation mechanism.

This study investigates the differential contribution of gray matter (GM) atrophy and deafferentation through white matter (WM) damage in the clinical progression of Alzheimer's disease (AD). Thirty-one patients with probable AD, 23 with amnestic mild cognitive impairment (a-MCI), and 14 healthy subjects underwent MRI scanning at 3T. Voxel-based morphometry was used to assess regional GM atrophy in AD and a-MCI patients. Diffusion tensor-MRI tractography was used to reconstruct the cingulum bilaterally, and to quantify, voxel-by-voxel, its fractional anisotropy (FA) and mean diffusivity (MD) (measures of microscopic WM integrity). Atrophy of the cinguli was also assessed by means of jacobian determinants (JD) of local transformations. In AD patients, four clusters of reduced GM were found nearby the cinguli, in the posterior (PCC) and anterior cingulate cortex, and in the hippocampal/parahippocampal areas. Widespread areas of reduced FA and increased MD were found in the cinguli of both, AD and a-MCI patients. A region of macroscopic atrophy was detectable in AD patients only. Strong associations were found between local GM densities in the four identified clusters, and measures of micro- and (to a lesser extent) macroscopic damage of patients' cinguli. Linear regression analyses revealed that MD in the cinguli predicts patients' measures of episodic memory in combination with GM density of hippocampal/parahippocampal areas, and measures of global cognition in combination with GM density of the PCC. This study indicates that brain deafferentation though the cingulum is likely to play a remarkable role in progressive development of cognitive impairment in AD.

Effect of Early Radial Shock Wave Treatment on Spasticity in Subacute Stroke Patients: A Pilot Study.

Background: Spasticity is a complication that can start immediately after stroke. Radial extracorporeal shock wave therapy (rESWT) is a physical therapy tool used to manage chronic spasticity. However, the effect of rESWT's early use to treat spasticity after stroke is still not clearly investigated. The aim of this study is to evaluate the efficacy of rESWT in improving poststroke spasticity of the upper limb in patients with a recent onset of spasticity compared to conventional physiotherapy alone. Methods: 40 stroke patients were randomly assigned to experimental (EG) or control group (CG). Both groups underwent two daily sessions of conventional rehabilitation therapy (CRT) 5 days per week; the EG underwent one rESWT session a week for 4 weeks. The modified Ashworth scale (MAS) tested at the shoulder, elbow, and wrist was used as outcome measure. MAS was evaluated at baseline, after 2 and 4 rESWT session, and one month after the last session (follow-up). Results: No significant differences between groups were found at baseline in terms of age, days from onset of spasticity after stroke, and MAS at each body segment. The sample lost eight drop-out patients. Except for the shoulder MAS values, the EG showed statistically significant lower MAS values already after the second rESWT session compared to CG. This significant difference was maintained until the follow-up. The CG showed a significant increase of wrist spasticity after the second evaluation, while the EG maintained constant MAS values throughout the observational period. The elbow spasticity was significantly higher in the CG at the follow-up evaluation. Conclusion: The rESWT combined with CRT seems to be effective in avoiding the increasing progression of spasticity after stroke.

Left egocentric neglect in early subacute right-stroke patients is related to damage of the superior longitudinal fasciculus.

A typical consequence of stroke in the right hemisphere is unilateral spatial neglect. Distinct forms of neglect have been described, such as space-based (egocentric) and object-based (allocentric) neglect. However, the relationship between these two forms of neglect is still far from being understood, as well as their neural substrates. Here, we further explore this issue by using voxel lesion symptoms mapping (VLSM) analyses on a large sample of early subacute right-stroke patients assessed with the Apples Cancellation Test. This is a sensitive test that simultaneously measures both egocentric and allocentric neglect. Behaviourally, we found no correlation between egocentric and allocentric performance, indicating independent mechanisms supporting the two forms of neglect. This was confirmed by the VLSM analysis that pointed out a link between a damage in the superior longitudinal fasciculus and left egocentric neglect. By contrast, no association was found between brain damage and left allocentric neglect. These results indicate a higher probability to observe egocentric neglect as a consequence of white matter damages in the superior longitudinal fasciculus, while allocentric neglect appears more "globally" related to the whole lesion map. Overall, these findings on early subacute right-stroke patients highlight the role played by white matter integrity in sustaining attention-related operations within an egocentric frame of reference.

Effect of Dual-Task Motor-Cognitive Training in Preventing Falls in Vulnerable Elderly Cerebrovascular Patients: A Pilot Study.

Falling is a frequent and major clinical problem among older adults, as well as in patients with chronic cerebrovascular diseases (CVD). At present, sequential (mixed) and simultaneously (dual-task) motor-cognitive trainings are the best approaches to affording patients more autonomy in their everyday motor independence while reducing fall risks and consequences. The objective of this study was to evaluate the efficacy of an advanced and innovative dual-task motor-cognitive rehabilitation program on fall risks in vulnerable older persons with chronic CVD. To this purpose, 26 consecutive older fallers with chronic CVD were recruited, and completed a mixed motor-cognitive or a dual-task motor-cognitive training program. Each patient also underwent two test evaluations to assess balance, gait, fear of falling, and walking performance at pre-and post-intervention. We found that our experimental motor-cognitive dual-task rehabilitation program could be an effective method to improve walking balance, gait, walking speed, and fear of falling, while reducing the risk of falls in older people with chronic CVD. Furthermore, results show that the simultaneous motor-cognitive training is more effective than the sequential motor-cognitive training. Therefore, our study brings innovative data, which can contribute positively to the management of this population.

The Effect of Dual-Task Motor-Cognitive Training in Adults with Neurological Diseases Who Are at Risk of Falling.

Falls are common in patients with neurological diseases and can be very problematic. Recently, there has been an increase in fall prevention research in people with neurological diseases; however, these studies are usually condition-specific (e.g., only MS, PD or stroke). Here, our aim was to evaluate and compare the efficacy of an advanced and innovative dual-task, motor-cognitive rehabilitation program in individuals with different neurological diseases who are at risk of falling. We recruited 95 consecutive adults with neurological diseases who are at risk of falling and divided them into four groups: 31 with cerebrovascular disease (CVD), 20 with Parkinson's disease (PD), 23 with traumatic brain injury (TBI) and 21 with other neurological diseases (OND). Each patient completed a dual-task, motor-cognitive training program and underwent two test evaluations to assess balance, gait, fear of falling and walking performance at the pre-and post-intervention. We found that our experimental motor-cognitive, dual-task rehabilitation program was an effective method for improving walking balance, gait, walking endurance and speed, and fear of falling, and that it reduced the risk of falls in patients with different neurological diseases. This study presents an alternative approach for people with chronic neurological diseases and provides innovative data for managing this population.

Pursuit ocular movements in multiple sclerosis: a video-based eye-tracking study.

Multiple sclerosis (MS) patients frequently develop some form of ocular motor dysfunction during the disease. In previous studies, ocular motor abnormalities were found to correlate with clinical disability and with impaired cognitive performance. The objective of this study was to assess the pursuit ocular movement (POM) frequency in relapsing-remitting (RR) and secondary progressive (SP) MS patients by using a vision-based non-intrusive eye tracker. POM frequency was significantly lower (p < 0.001) in MS patients compared to normal controls. No differences between RR and SP-MS patients and no correlation between POM and expanded disability status scale (EDSS) score were found. This exploratory study suggests that our vision-based system is a new simple non-intrusive method showing impairment of POM values in MS patients, even in the absence of association with clinical disability (EDSS). Future works on larger cohorts of MS patients might validate this eye tracking in MS clinical practice.

Dual-Task Performance in Multiple Sclerosis' Patients: Cerebellum Matters?

OBJECTIVE: Gait, cognitive impairments, and their mutual influence in dual tasking (cognitive-motor dual tasking, CM-DT) are important to address therapeutic approaches in patients with multiple sclerosis (PMS). CM-DT correlates have been widely investigated with variable and dissimilar results, due to differences in methods. However, although the cerebellum has recently shown to be involved in both motor and cognitive functions, few studies have explored its role in the integration of the concurrent execution of gait and cognition. This case-control study aims to explore the effects of adding a cognitive task to walking in PMS and to investigate the role of the cerebellum in the interfering process. METHODS: In total, 20 patients and 18 healthy controls (HC) underwent clinical assessments, dual task (DT), and 3 T magnetic resonance imaging (MRI). DT was composed by three 2-min trials requiring fast walking. In 2 of them 2 different cognitive tasks were added. RESULTS: Both groups evidenced the presence of cognitive-motor interference (CMI) for both cognitive conditions with a greater effect of word list generation task in PMS. Analysis of variance between HC and patients with high or low performances showed a significantly increased volume in Vermis lobules VIIIa and IX of high performers compared with HC. CONCLUSION: Our results show that CMI is also present in healthy individuals but is significantly more disabling in PMS. Furthermore, MRI data point to the existence of an initial mechanism of cerebellar reorganization in PMS with lower interference. Subsequently, the failure of this mechanism due to the progression of disability leads to a more evident expression of symptoms.