Unraveling the gut-brain connection: The association of microbiota-linked structural brain biomarkers with behavior and mental health.

AIM: The gut microbiota can influence human behavior. However, due to the massive multiple-testing problem, research into the relationship between microbiome ecosystems and the human brain faces drawbacks. This problem arises when attempting to correlate thousands of gut bacteria with thousands of brain voxels. METHODS: We performed brain magnetic resonance imaging (MRI) scans on 133 participants and applied machine-learning algorithms (Ridge regressions) combined with permutation tests. Using this approach, we were able to correlate specific gut bacterial families with brain MRI signals, circumventing the difficulties of massive multiple testing while considering sex, age, and body mass index as confounding factors. RESULTS: The relative abundance (RA) of the Selenomonadaceae, Clostridiaceae, and Veillonellaceae families in the gut was associated with altered cerebellar, visual, and frontal T2-mapping and diffusion tensor imaging measures. Conversely, decreased relative abundance of the Eubacteriaceae family was also linked to T2-mapping values in the cerebellum. Significantly, the brain regions associated with the gut microbiome were also correlated with depressive symptoms and attentional deficits. CONCLUSIONS: Our analytical strategy offers a promising approach for identifying potential brain biomarkers influenced by gut microbiota. By gathering a deeper understanding of the microbiota-brain connection, we can gain insights into the underlying mechanisms and potentially develop targeted interventions to mitigate the detrimental effects of dysbiosis on brain function and mental health.

Obesity-associated deficits in inhibitory control are phenocopied to mice through gut microbiota changes in one-carbon and aromatic amino acids metabolic pathways.

BACKGROUND: Inhibitory control (IC) is critical to keep long-term goals in everyday life. Bidirectional relationships between IC deficits and obesity are behind unhealthy eating and physical exercise habits. METHODS: We studied gut microbiome composition and functionality, and plasma and faecal metabolomics in association with cognitive tests evaluating inhibitory control (Stroop test) and brain structure in a discovery (n=156), both cross-sectionally and longitudinally, and in an independent replication cohort (n=970). Faecal microbiota transplantation (FMT) in mice evaluated the impact on reversal learning and medial prefrontal cortex (mPFC) transcriptomics. RESULTS: An interplay among IC, brain structure (in humans) and mPFC transcriptomics (in mice), plasma/faecal metabolomics and the gut metagenome was found. Obesity-dependent alterations in one-carbon metabolism, tryptophan and histidine pathways were associated with IC in the two independent cohorts. Bacterial functions linked to one-carbon metabolism (thyX,dut, exodeoxyribonuclease V), and the anterior cingulate cortex volume were associated with IC, cross-sectionally and longitudinally. FMT from individuals with obesity led to alterations in mice reversal learning. In an independent FMT experiment, human donor's bacterial functions related to IC deficits were associated with mPFC expression of one-carbon metabolism-related genes of recipient's mice. CONCLUSION: These results highlight the importance of targeting obesity-related impulsive behaviour through the induction of gut microbiota shifts.

Resting-State Functional Connectivity Magnetic Resonance Imaging and Outcome After Acute Stroke.

Background and Purpose- Physiological effects of stroke are best assessed over entire brain networks rather than just focally at the site of structural damage. Resting-state functional magnetic resonance imaging can map functional-anatomic networks by analyzing spontaneously correlated low-frequency activity fluctuations across the brain, but its potential usefulness in predicting functional outcome after acute stroke remains unknown. We assessed the ability of resting-state functional magnetic resonance imaging to predict functional outcome after acute stroke. Methods- We scanned 37 consecutive reperfused stroke patients (age, 69±14 years; 14 females; 3-day National Institutes of Health Stroke Scale score, 6±5) on day 3 after symptom onset. After imaging preprocessing, we used a whole-brain mask to calculate the correlation coefficient matrices for every paired region using the Harvard-Oxford probabilistic atlas. To evaluate functional outcome, we applied the modified Rankin Scale at 90 days. We used region of interest analyses to explore the functional connectivity between regions and graph-computation analysis to detect differences in functional connectivity between patients with good functional outcome (modified Rankin Scale score ≤2) and those with poor outcome (modified Rankin Scale score >2). Results- Patients with good outcome had greater functional connectivity than patients with poor outcome. Although 3-day National Institutes of Health Stroke Scale score was the most accurate independent predictor of 90-day modified Rankin Scale (84.2%), adding functional connectivity increased accuracy to 94.7%. Preserved bilateral interhemispheric connectivity between the anterior inferior temporal gyrus and superior frontal gyrus and decreased connectivity between the caudate and anterior inferior temporal gyrus in the left hemisphere had the greatest impact in favoring good prognosis. Conclusions- These data suggest that information about functional connectivity from resting-state functional magnetic resonance imaging may help predict 90-day stroke outcome.

A randomized, controlled, single-blind, 6-month pilot study to evaluate the efficacy of MS-Line!: a cognitive rehabilitation programme for patients with multiple sclerosis.

BACKGROUND: MS-Line! was created to provide an effective treatment for cognitive impairment in multiple sclerosis (MS) patients. OBJECTIVE: To assess the efficacy of MS-Line!. METHODS: A randomized, controlled, single-blind, 6-month pilot study. Patients were randomly assigned to an experimental group (cognitive rehabilitation with the programme) or to a control group (no cognitive rehabilitation). Randomization was stratified by cognitive impairment level. Cognitive assessment included: selective reminding test, 10/36 spatial recall test (10/36 SPART), symbol digit modalities test, paced auditory serial addition test, word list generation (WLG), FAS test, subtests of WAIS-III, Boston naming test (BNT), and trail making test (TMT). RESULTS: Forty-three patients (22 in the experimental group, 21 in the control group) were analyzed. Covariance analysis showed significant differences in 10/36 SPART (P=0.0002), 10/36 SPART delayed recall (P=0.0021), WLG (P=0.0123), LNS (P=0.0413), BNT (P=0.0007) and TMT-A (P=0.010) scores between groups. CONCLUSIONS: The study showed a significant improvement related to learning and visual memory, executive functions, attention and information processing speed, and naming ability in those patients who received cognitive rehabilitation. The results suggest that MS-Line! is effective in improving cognitive impairment in MS patients.

A new cognitive rehabilitation programme for patients with multiple sclerosis: the 'MS-line! Project'.

BACKGROUND: Cognitive rehabilitation is often delayed in multiple sclerosis (MS). OBJECTIVE: To develop a free and specific cognitive rehabilitation programme for MS patients to be used from early stages that does not interfere with daily living activities. METHODS: MS-line!, cognitive rehabilitation materials consisting of written, manipulative and computer-based materials with difficulty levels developed by a multidisciplinary team. RESULTS: Mathematical, problem-solving and word-based exercises were designed. Physical materials included spatial, coordination and reasoning games. Computer-based material included logic and reasoning, working memory and processing speed games. CONCLUSIONS: Cognitive rehabilitation exercises that are specific for MS patients have been successfully developed.

Multidisciplinary management of multiple sclerosis symptoms.

BACKGROUND: Effective management of multisymptomatic chronic diseases such as multiple sclerosis (MS) requires a multimodal, interdisciplinary approach. At MS clinics, numerous healthcare specialties are coordinated to provide patients with quality clinical care for all aspects of their disease. Settings and resource availability may vary between countries. Four specific specialty services from different EU countries are examined in more detail. SUMMARY: The multidisciplinary neurorehabilitation team in Rennes, France, provides specialized consultations (e.g. spasticity, urodynamic unit, devices), inpatient and outpatient intensive rehabilitation programs and therapeutic education. Management approaches are based on a patient's level of impairment as assessed by the Expanded Disability Status Scale. In Girona, Spain, neuropsychologists perform assessments as part of the neurological protocol for all patients with MS. Depending on the level of impairment and patients' characteristics (e.g. working or not working), cognitive deficits may be treated at home or at a neurorehabilitation center. In Barcelona, Spain, neuro-ophthalmologists are involved in the differential diagnosis and follow-up care of MS patients with visual disturbances; particular attention is given to patients' vision-related quality of life. Pain specialists at the Marianne Strauß Klinik in Berg, Germany, have developed a system for classifying MS pain syndromes and differentiating MS-related pain from non MS-related pain. Chronic pain management involves numerous disciplines and requires active engagement by patients in developing treatment plans. Key Messages: MS affects several body systems and patients invariably require specialized interdisciplinary support. Insight into services provided by various specialties and their fit within multidisciplinary care models at MS centers may facilitate the design or refinement of care models in other locations.

The nature of memory impairment in multiple sclerosis: understanding different patterns over the course of the disease.

Introduction: Memory deficit is one of the most common and severe cognitive impairments in patients with multiple sclerosis and can greatly affect their quality of life. However, there is currently no agreement as to the nature of memory deficit in multiple sclerosis. Methods: This cross-sectional study, carried out at the Dr. Josep Trueta and Santa Caterina hospitals in Girona (Spain), was designed to determine the semiology of verbal memory deficit in the different stages of the disease. To this end, a modification of Rey's verbal auditory test was created by introducing two recognition trials between the five learning trials, thus monitoring what happens in terms of acquisition versus the retrieval of information during the learning phase. Linear regression models were used to evaluate verbal episodic memory performance between-groups adjusting results by age, sex, educational level, and the presence of anxiety and/or depressive symptoms. Results: 133 patients with multiple sclerosis, clinically isolated syndrome, and radiologically isolated syndrome and 55 healthy controls aged 18-65 years were assessed. It was observed that the memory processes of multiple sclerosis patients worsen with the progression of the disease. In this respect, patients in pre-diagnostic phases (radiologically isolated syndrome and clinically isolated syndrome) show no differences in verbal episodic memory compared to the healthy controls. Patients in the inflammatory stage (relapsing-remitting multiple sclerosis) show a previously learned information retrieval deficit, while patients in progressive stages (secondary progressive multiple sclerosis and primary progressive multiple sclerosis) do not even correctly acquire information. Discussion: These results provide significant information to assist in understanding the nature of memory deficits in multiple sclerosis over the course of the disease. These results are discussed in terms of possible cognitive rehabilitation strategies depending on the evolutive stage and are related to neuropathological mechanisms involved in the progression of the disease.

Differences in metacognition between multiple sclerosis phenotypes: cognitive impairment and fatigue are key factors.

Background: Cognitive impairment is present in 40-65% of patients with multiple sclerosis (pwMS). Objectively measured cognitive performance often does not match patients' subjective perception of their own performance. Objective: We aimed to compare cognitive performance and subjective perception of cognitive deficits between pwMS and healthy controls (HCs), as well as the accuracy of subjective perception. Methods: In total, 54 HC and 112 pwMS (relapsing-remitting, RRMS, and progressive PMS) underwent neuropsychological evaluation and completed perceived deficit, fatigue, and anxiety-depression scales. Participants were classified according to their consistency between subjective self-evaluation of cognitive abilities and objective cognitive performance to assess accuracy. Regression models were used to compare cognitive performance between groups and explore factors explaining inaccuracy in the estimation of cognitive performance. Results: PMS showed greater and more widespread cognitive differences with HC than RRMS. No differences were found between pwMS and HC in the perception of deficit. PMS had higher ratios of overestimators. In explaining inaccuracy, fatigue and cognitive preservation were found to be risk factors for underestimation, whereas physical disability and cognitive impairment were risk factors for overestimation. Conclusion: PwMS have metacognitive knowledge impairments. This study provides new information about metacognition, data on the prevalence of impairments over a relatively large sample of PwMS, and new insights into factors explaining it. Anosognosia, related to cognitive impairment, may be present in pwMS. Fatigue is a key factor in underestimating cognition.

Long-term clinical and radiological evolution in one case of Susac's syndrome.

Susac's syndrome is a rare idiopathic microangiopathy affecting the precapillary arterioles of the brain, retina and cochlea leading to the clinical triad of encephalopathy, retinopathy and hearing loss. The objective of this study is to describe a new case of Susac's syndrome reactivated after a 12-year period with a good response to immunosuppressive therapy. The patient was a 32-year-old woman, complaining of diplopia, right blurred vision, progressive gait disturbance, tinnitus, attention deficit, and slight memory loss. The patient was diagnosed as having Susac's syndrome and discharged with steroid therapy. After a 12-year period of clinical stability she had a relapse. Immunosuppressive therapy resulted in significant clinical and radiological improvement. Early clinical identification of Susac's syndrome is crucial for the initiation of immunosuppressive therapy and differential diagnosis. In our case, the combined use of corticosteroids and azathioprine was key in the relapse management.

Oligoclonal IgM bands are a promising biomarker for long-term cognitive outcomes in multiple sclerosis.

BACKGROUND: The presence of lipid-specific oligoclonal IgM bands (LS-OCMB) in cerebrospinal fluid is associated with a more severe clinical multiple sclerosis (MS) course. OBJECTIVE: To investigate LS-OCMB as a prognostic biomarker of cognitive long-term outcomes in MS. METHODS: Ninety-nine patients underwent neuropsychological assessment. Cognitive performance between LS-OCMB- and LS-OCMB+ patients was compared adjusting by age, education, anxiety-depression, disease duration, and disability. RESULTS: LS-OCMB+ patients of ∼13 years of disease duration performed worse on Symbol Digit Modalities Test (SDMT) (p = 0.005). CONCLUSION: LS-OCMB+ perform worse on information processing speed and working memory (SDMT), suggesting that LS-OCMB could be a useful biomarker for long-term cognitive outcomes.