Frailty and brain changes in older adults without cognitive impairment: A scoping review.

Little is known about changes in the brain associated with frailty, in particular, which brain areas could be related to frailty in older people without cognitive impairment. This scoping review mapped evidence on functional and/or structural brain changes in frail older adults without cognitive impairment. The methodology proposed by the JBI® was used in this study. The search in PubMed, PubMed PMC, BVS/BIREME, EBSCOHOST, Scopus, Web of Science, Embase, and PROQUEST was conducted up to January 2023. Studies included following the population, concepts, context and the screening and data extraction were performed by two independent reviewers. A total of 9,912 records were identified, 5,676 were duplicates and were excluded. The remaining articles were screened; 31 were read in full and 17 articles were included. The results showed that lesions in white matter hyperintensities, reduced volume of the hippocampus, cerebellum, middle frontal gyrus, low gray matter volume, cortical atrophy, decreased connectivity of the supplementary motor area, presence of amyloid-beta peptide (aß) in the anterior and posterior putamen and precuneus regions were more frequently observed in frail older adults, compared with non-frail individuals. Studies have suggested that such findings may be of neurodegenerative or cerebrovascular origin. The identification of these brain alterations in frail older adults through neuroimaging studies contributes to our understanding of the underlying mechanisms of frailty. Such findings may have implications for the early detection of frailty and implementation of intervention strategies.

Current clinical and research practices on frontotemporal dementia in Brazil: a national survey.

BACKGROUND: Frontotemporal dementia (FTD) is a frequent cause of young-onset dementia and represents a major challenge for the diagnosis and clinical management. It is essential to evaluate the difficulties faced by physicians on the diagnostic workup and on patient care. OBJECTIVE: The aim of this study was to investigate the current practices and the local limits on the diagnosis and management of FTD in Brazil. METHODS: We elaborated an online survey, composed of 29 questions and divided in four parts, comprising questions about existing health facilities, clinical practices related to FTD, and suggestions to increment the national research on FTD. The invitation to participate was sent by email to all neurologists affiliated to the Brazilian Academy of Neurology (n = 3658), and to all physicians who attended the XII Meeting of Researchers on Alzheimer's disease, in 2019 (n = 187). The invitation was also diffused through social media. RESULTS: 256 Brazilian physicians answered the questionnaire. The three most relevant disorders for the differential diagnosis of FTD were Alzheimer's disease (AD) (n = 211), bipolar disorder (n = 117) and dementia with Lewy bodies (n = 92). Most respondents (125/256) reported the difficulty in performing genetic testing as the main limit in the diagnostic of FTD. 93% and 63% of participants considered that the assessment of social cognition and AD CSF biomarkers are useful for the diagnosis of FTD, respectively. CONCLUSIONS: The present study may provide valuable insights for the medical education and clinical training of physicians, and to foster future research on FTD in Brazil.

ANTECEDENTES: A demência frontotemporal (DFT) é causa frequente de demência pré-senil e representa um desafio em termos de diagnóstico e de manejo clínico. É essencial avaliar as dificuldades existentes na propedêutica e nos cuidados médicos. OBJETIVO: Investigar as práticas médicas e as dificuldades para diagnóstico e manejo da DFT no Brasil. MéTODOS: Elaborou-se um questionário online, composto de 29 questões, divididas em quatro partes, com perguntas sobre infraestrutura existente, práticas clínicas relacionadas à DFT e sugestões para desenvolver a pesquisa nacional na área. O convite para participação foi enviado por e-mail a todos neurologistas afiliados à Academia Brasileira de Neurologia (n = 3658), e aos médicos que participaram da XII Reunião de Pesquisadores de Doença de Alzheimer, em 2019 (n = 187). O convite também foi divulgado através de mídias sociais. RESULTADOS: 256 médicos brasileiros responderam o questionário. Os três principais diagnósticos diferenciais de DFT foram doença de Alzheimer (n = 211), transtorno bipolar (n = 117) e demência com corpos de Lewy (n = 92). A maior parte dos respondedores (125/256) apontou a dificuldade em realizar testagem genética como o maior limite no diagnóstico de DFT. 93% e 63% dos respondedores indicaram que a avaliação de cognição social e o uso de biomarcadores liquóricos de doença de Alzheimer são úteis no diagnóstico de DFT, respectivamente. CONCLUSõES: Estes resultados devem ser considerados na educação e treinamento médicos, e no desenvolvimento da pesquisa brasileira em DFT.

Current clinical and research practices on frontotemporal dementia in Brazil: a national survey / Práticas clínicas e cenário de pesquisa em demência frontotemporal no Brasil: uma enquete nacional

Abstract Background Frontotemporal dementia (FTD) is a frequent cause of young-onset dementia and represents a major challenge for the diagnosis and clinical management. It is essential to evaluate the difficulties faced by physicians on the diagnostic workup and on patient care. Objective The aim of this study was to investigate the current practices and the local limits on the diagnosis and management of FTD in Brazil. Methods We elaborated an online survey, composed of 29 questions and divided in four parts, comprising questions about existing health facilities, clinical practices related to FTD, and suggestions to increment the national research on FTD. The invitation to participate was sent by email to all neurologists affiliated to the Brazilian Academy of Neurology (n = 3658), and to all physicians who attended the XII Meeting of Researchers on Alzheimer's disease, in 2019 (n = 187). The invitation was also diffused through social media. Results 256 Brazilian physicians answered the questionnaire. The three most relevant disorders for the differential diagnosis of FTD were Alzheimer's disease (AD) (n = 211), bipolar disorder (n = 117) and dementia with Lewy bodies (n = 92). Most respondents (125/256) reported the difficulty in performing genetic testing as the main limit in the diagnostic of FTD. 93% and 63% of participants considered that the assessment of social cognition and AD CSF biomarkers are useful for the diagnosis of FTD, respectively. Conclusions The present study may provide valuable insights for the medical education and clinical training of physicians, and to foster future research on FTD in Brazil.

Resumo Antecedentes A demência frontotemporal (DFT) é causa frequente de demência pré-senil e representa um desafio em termos de diagnóstico e de manejo clínico. É essencial avaliar as dificuldades existentes na propedêutica e nos cuidados médicos. Objetivo Investigar as práticas médicas e as dificuldades para diagnóstico e manejo da DFT no Brasil. Métodos Elaborou-se um questionário online, composto de 29 questões, divididas em quatro partes, com perguntas sobre infraestrutura existente, práticas clínicas relacionadas à DFT e sugestões para desenvolver a pesquisa nacional na área. O convite para participação foi enviado por e-mail a todos neurologistas afiliados à Academia Brasileira de Neurologia (n = 3658), e aos médicos que participaram da XII Reunião de Pesquisadores de Doença de Alzheimer, em 2019 (n = 187). O convite também foi divulgado através de mídias sociais. Resultados 256 médicos brasileiros responderam o questionário. Os três principais diagnósticos diferenciais de DFT foram doença de Alzheimer (n = 211), transtorno bipolar (n = 117) e demência com corpos de Lewy (n = 92). A maior parte dos respondedores (125/256) apontou a dificuldade em realizar testagem genética como o maior limite no diagnóstico de DFT. 93% e 63% dos respondedores indicaram que a avaliação de cognição social e o uso de biomarcadores liquóricos de doença de Alzheimer são úteis no diagnóstico de DFT, respectivamente. Conclusões Estes resultados devem ser considerados na educação e treinamento médicos, e no desenvolvimento da pesquisa brasileira em DFT.

Whole-brain DTI parameters associated with tau protein and hippocampal volume in Alzheimer's disease.

The causes of the neurodegenerative processes in Alzheimer's disease (AD) are not completely known. Recent studies have shown that white matter (WM) damage could be more severe and widespread than whole-brain cortical atrophy and that such damage may appear even before the damage to the gray matter (GM). In AD, Amyloid-beta (Aß42 ) and tau proteins could directly affect WM, spreading across brain networks. Since hippocampal atrophy is common in the early phase of disease, it is reasonable to expect that hippocampal volume (HV) might be also related to WM integrity. Our study aimed to evaluate the integrity of the whole-brain WM, through diffusion tensor imaging (DTI) parameters, in mild AD and amnestic mild cognitive impairment (aMCI) due to AD (with Aß42 alteration in cerebrospinal fluid [CSF]) in relation to controls; and possible correlations between those measures and the CSF levels of Aß42 , phosphorylated tau protein (p-Tau) and total tau (t-Tau). We found a widespread WM alteration in the groups, and we also observed correlations between p-Tau and t-Tau with tracts directly linked to mesial temporal lobe (MTL) structures (fornix and hippocampal cingulum). However, linear regressions showed that the HV better explained the variation found in the DTI measures (with weak to moderate effect sizes, explaining from 9% to 31%) than did CSF proteins. In conclusion, we found widespread alterations in WM integrity, particularly in regions commonly affected by the disease in our group of early-stage disease and patients with Alzheimer's disease. Nonetheless, in the statistical models, the HV better predicted the integrity of the MTL tracts than the biomarkers in CSF.

Cholinesterase Inhibitors Response Might Be Related to Right Hippocampal Functional Connectivity in Mild Alzheimer's Disease.

Background: The response to cholinesterase inhibitors (ChEIs) treatment is variable in patients with Alzheimer's disease (AD). Patients and physicians would benefit if these drugs could be targeted at those most likely to respond in a clinical setting. Therefore, this study aimed to evaluate the ability of cerebrospinal fluid (CSF) AD biomarkers, hippocampal volumes, and Default Mode Network functional connectivity to predict clinical response to ChEIs treatment in mild AD. Methods: We followed up on 39 mild AD patients using ChEIs at therapeutic doses. All subjects underwent clinical evaluation, neuropsychological assessment, magnetic resonance imaging examination, and CSF biomarkers quantification at the first assessment. The Mini-Mental Status Examination (MMSE) was used to measure the global cognitive status before and after the follow-up. "Responders" were considered as those who have remained stable or improved the MMSE score between evaluations and "Nonresponders" as those who have worsened the MMSE score. We performed univariate and multivariate logistic regressions to predict the clinical response from each biomarker. Results: About 35.89% of patients were classified as "Responders" to ChEIs treatment after the follow-up. The multivariate model with measures of Right Hippocampus (RHIPPO), adjusted for gender and interval between assessments, was significant (odds ratio: 1.09 [95% confidence interval, 1.00-1.19], p = 0.0392). This model achieved an accuracy of 77.60%. Conclusion: Our findings suggest that the functional connectivity of RHIPPO might be an early imaging biomarker to predict clinical response to ChEIs drugs in mild AD. Impact statement The functional connectivity of the right hippocampus showed a direct relationship with the clinical response to cholinesterase inhibitors (ChEIs) treatment in patients with mild Alzheimer's disease. Transposing our findings to clinical settings could allow physicians to prescribe ChEIs for patients for whom treatment would be most beneficial.

Treatment of dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology.

There is currently no cure for neurodegenerative or vascular dementias, but some pharmacological and non-pharmacological interventions may contribute to alleviate symptoms, slow disease progression and improve quality of life. Current treatment approaches are based on etiology, symptom profile and stage of dementia. This manuscript presents recommendations on pharmacological and non-pharmacological treatments of dementia due to Alzheimer's disease, vascular cognitive impairment, frontotemporal dementia, Parkinson's disease dementia, and dementia with Lewy bodies.

Atualmente não há tratamento curativo para as demências neurodegenerativas ou para a demência vascular, mas algumas intervenções farmacológicas e não farmacológicas podem contribuir para aliviar os sintomas, retardar a progressão da doença e melhorar a qualidade de vida. As abordagens terapêuticas atuais são baseadas na etiologia, no perfil dos sintomas e no estágio da demência. Neste artigo apresentamos recomendações sobre os tratamentos farmacológicos e não farmacológicos da demência devida à doença de Alzheimer, comprometimento cognitivo vascular, demência frontotemporal, demência da doença de Parkinson e demência com corpos de Lewy.

Diagnosis of Alzheimer's disease: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology.

This paper presents the consensus of the Scientific Department of Cognitive Neurology and Aging from the Brazilian Academy of Neurology on the diagnostic criteria for Alzheimer's disease (AD) in Brazil. The authors conducted a literature review regarding clinical and research criteria for AD diagnosis and proposed protocols for use at primary, secondary, and tertiary care levels. Within this clinical scenario, the diagnostic criteria for typical and atypical AD are presented as well as clinical, cognitive, and functional assessment tools and complementary propaedeutics with laboratory and neuroimaging tests. The use of biomarkers is also discussed for both clinical diagnosis (in specific conditions) and research.

Este artigo apresenta o consenso realizado pelo Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia sobre os critérios diagnósticos da Doença de Alzheimer (DA) no Brasil. Foi realizada uma revisão da literatura e dos critérios clínicos e de pesquisa para DA, sendo propostos protocolos para o diagnóstico de DA em níveis de atenção primária, secundária e terciária. Dentro deste cenário clínico, são apresentados os critérios diagnósticos para DA típica e atípica, além de instrumentos de avaliação clínica, cognitiva e funcional; bem como propedêutica complementar com exames laboratoriais e de neuroimagem. A utilização de biomarcadores é também apresentada, tanto para o diagnóstico clínico em situações específicas quanto para pesquisa.

Diagnosis of frontotemporal dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology.

"Frontotemporal dementia" (FTD) is a clinical syndrome characterized by the focal involvement of the frontal and/or temporal lobes. FTD has three clinical phenotypes: the behavioral variant and two linguistic subtypes, namely, non-fluent/agrammatic primary progressive aphasia (PPA-NF/A) and semantic PPA (PPA-S). FTD is the second most common cause of dementia in individuals under the age of 65 years. This article presents recommendations for the diagnosis of FTD in the Brazilian scenario, considering the three levels of complexity of the health system: primary health care, secondary and tertiary levels. Diagnostic guidelines are proposed, including cognitive testing, behavioral and language assessments, laboratory tests, and neuroimaging.

A "demência frontotemporal" (DFT) é uma síndrome clínica, cujo denominador comum é o acometimento focal dos lobos frontais e/ou temporais. A DFT tem três fenótipos clínicos distintos: a variante comportamental e dois subtipos linguísticos, a saber, a afasia progressiva primária não-fluente/agramática (APP-NF/A) e a afasia progressiva primária semântica (APP-S). A DFT é a segunda causa mais comum de demência em indivíduos com idade inferior a 65 anos, após a doença de Alzheimer. O presente artigo apresenta recomendações para diagnóstico da DFT no cenário brasileiro, considerando os três níveis de complexidade do sistema de saúde: atenção primária à saúde e níveis secundários. São propostos protocolos de investigação diagnóstica abrangendo testagem cognitiva, avaliação comportamental, avaliação fonoaudiológica, exames laboratoriais e de neuroimagem.

Diagnosis of vascular cognitive impairment: recommendations of the scientific department of cognitive neurology and aging of the Brazilian Academy of Neurology.

Since the publication of the latest recommendations for the diagnosis and treatment of Vascular Dementia by the Brazilian Academy of Neurology in 2011, significant advances on the terminology and diagnostic criteria have been made. This manuscript is the result of a consensus among experts appointed by the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology (2020-2022). We aimed to update practical recommendations for the identification, classification, and diagnosis of Vascular Cognitive Impairment (VCI). Searches were performed in the MEDLINE, Scopus, Scielo, and LILACS databases. This guideline provides a comprehensive review and then synthesizes the main practical guidelines for the diagnosis of VCI not only for neurologists but also for other professionals involved in the assessment and care of patients with VCI, considering the different levels of health care (primary, secondary and tertiary) in Brazil.

Desde a publicação das últimas recomendações para o diagnóstico e tratamento da Demência Vascular pela Academia Brasileira de Neurologia em 2011, avanços significativos ocorreram na terminologia e critérios diagnósticos. O presente manuscrito é resultado do consenso entre especialistas indicados pelo Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia (2020-2022). O objetivo foi atualizar as recomendações práticas para a identificação, classificação e diagnóstico do Comprometimento Cognitivo Vascular (CCV). As buscas foram realizadas nas plataformas MEDLINE, Scopus, Scielo e LILACS. As recomendações buscam fornecer uma ampla revisão sobre o tema, então sintetizar as evidências para o diagnóstico do CCV não apenas para neurologistas, mas também para outros profissionais de saúde envolvidos na avaliação e nos cuidados ao paciente com CCV, considerando as diferentes realidades dos níveis de atenção à saúde (primário, secundário e terciário) no Brasil.

Tratamento da demência: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia / Treatment of dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

RESUMO Atualmente não há tratamento curativo para as demências neurodegenerativas ou para a demência vascular, mas algumas intervenções farmacológicas e não farmacológicas podem contribuir para aliviar os sintomas, retardar a progressão da doença e melhorar a qualidade de vida. As abordagens terapêuticas atuais são baseadas na etiologia, no perfil dos sintomas e no estágio da demência. Neste artigo apresentamos recomendações sobre os tratamentos farmacológicos e não farmacológicos da demência devida à doença de Alzheimer, comprometimento cognitivo vascular, demência frontotemporal, demência da doença de Parkinson e demência com corpos de Lewy.

ABSTRACT There is currently no cure for neurodegenerative or vascular dementias, but some pharmacological and non-pharmacological interventions may contribute to alleviate symptoms, slow disease progression and improve quality of life. Current treatment approaches are based on etiology, symptom profile and stage of dementia. This manuscript presents recommendations on pharmacological and non-pharmacological treatments of dementia due to Alzheimer's disease, vascular cognitive impairment, frontotemporal dementia, Parkinson's disease dementia, and dementia with Lewy bodies.

Diagnóstico da doença de Alzheimer: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia / Diagnosis of Alzheimer's disease: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

RESUMO Este artigo apresenta o consenso realizado pelo Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia sobre os critérios diagnósticos da Doença de Alzheimer (DA) no Brasil. Foi realizada uma revisão da literatura e dos critérios clínicos e de pesquisa para DA, sendo propostos protocolos para o diagnóstico de DA em níveis de atenção primária, secundária e terciária. Dentro deste cenário clínico, são apresentados os critérios diagnósticos para DA típica e atípica, além de instrumentos de avaliação clínica, cognitiva e funcional; bem como propedêutica complementar com exames laboratoriais e de neuroimagem. A utilização de biomarcadores é também apresentada, tanto para o diagnóstico clínico em situações específicas quanto para pesquisa.

ABSTRACT This paper presents the consensus of the Scientific Department of Cognitive Neurology and Aging from the Brazilian Academy of Neurology on the diagnostic criteria for Alzheimer's disease (AD) in Brazil. The authors conducted a literature review regarding clinical and research criteria for AD diagnosis and proposed protocols for use at primary, secondary, and tertiary care levels. Within this clinical scenario, the diagnostic criteria for typical and atypical AD are presented as well as clinical, cognitive, and functional assessment tools and complementary propaedeutics with laboratory and neuroimaging tests. The use of biomarkers is also discussed for both clinical diagnosis (in specific conditions) and research.

Diagnóstico da demência frontotemporal: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia / Diagnosis of frontotemporal dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

RESUMO A "demência frontotemporal" (DFT) é uma síndrome clínica, cujo denominador comum é o acometimento focal dos lobos frontais e/ou temporais. A DFT tem três fenótipos clínicos distintos: a variante comportamental e dois subtipos linguísticos, a saber, a afasia progressiva primária não-fluente/agramática (APP-NF/A) e a afasia progressiva primária semântica (APP-S). A DFT é a segunda causa mais comum de demência em indivíduos com idade inferior a 65 anos, após a doença de Alzheimer. O presente artigo apresenta recomendações para diagnóstico da DFT no cenário brasileiro, considerando os três níveis de complexidade do sistema de saúde: atenção primária à saúde e níveis secundários. São propostos protocolos de investigação diagnóstica abrangendo testagem cognitiva, avaliação comportamental, avaliação fonoaudiológica, exames laboratoriais e de neuroimagem.

ABSTRACT "Frontotemporal dementia" (FTD) is a clinical syndrome characterized by the focal involvement of the frontal and/or temporal lobes. FTD has three clinical phenotypes: the behavioral variant and two linguistic subtypes, namely, non-fluent/agrammatic primary progressive aphasia (PPA-NF/A) and semantic PPA (PPA-S). FTD is the second most common cause of dementia in individuals under the age of 65 years. This article presents recommendations for the diagnosis of FTD in the Brazilian scenario, considering the three levels of complexity of the health system: primary health care, secondary and tertiary levels. Diagnostic guidelines are proposed, including cognitive testing, behavioral and language assessments, laboratory tests, and neuroimaging.

Diagnóstico do comprometimento cognitivo vascular: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia / Diagnosis of vascular cognitive impairment: recommendations of the scientific department of cognitive neurology and aging of the Brazilian Academy of Neurology

RESUMO Desde a publicação das últimas recomendações para o diagnóstico e tratamento da Demência Vascular pela Academia Brasileira de Neurologia em 2011, avanços significativos ocorreram na terminologia e critérios diagnósticos. O presente manuscrito é resultado do consenso entre especialistas indicados pelo Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia (2020-2022). O objetivo foi atualizar as recomendações práticas para a identificação, classificação e diagnóstico do Comprometimento Cognitivo Vascular (CCV). As buscas foram realizadas nas plataformas MEDLINE, Scopus, Scielo e LILACS. As recomendações buscam fornecer uma ampla revisão sobre o tema, então sintetizar as evidências para o diagnóstico do CCV não apenas para neurologistas, mas também para outros profissionais de saúde envolvidos na avaliação e nos cuidados ao paciente com CCV, considerando as diferentes realidades dos níveis de atenção à saúde (primário, secundário e terciário) no Brasil.

ABSTRACT Since the publication of the latest recommendations for the diagnosis and treatment of Vascular Dementia by the Brazilian Academy of Neurology in 2011, significant advances on the terminology and diagnostic criteria have been made. This manuscript is the result of a consensus among experts appointed by the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology (2020-2022). We aimed to update practical recommendations for the identification, classification, and diagnosis of Vascular Cognitive Impairment (VCI). Searches were performed in the MEDLINE, Scopus, Scielo, and LILACS databases. This guideline provides a comprehensive review and then synthesizes the main practical guidelines for the diagnosis of VCI not only for neurologists but also for other professionals involved in the assessment and care of patients with VCI, considering the different levels of health care (primary, secondary and tertiary) in Brazil.

Gut microbiome in neuropsychiatric disorders.

BACKGROUND: Neuropsychiatric disorders are a significant cause of death and disability worldwide. The mechanisms underlying these disorders include a constellation of structural, infectious, immunological, metabolic, and genetic etiologies. Advances in next-generation sequencing techniques have demonstrated that the composition of the enteric microbiome is dynamic and plays a pivotal role in host homeostasis and several diseases. The enteric microbiome acts as a key mediator in neuronal signaling via metabolic, neuroimmune, and neuroendocrine pathways. OBJECTIVE: In this review, we aim to present and discuss the most current knowledge regarding the putative influence of the gut microbiome in neuropsychiatric disorders. METHODS: We examined some of the preclinical and clinical evidence and therapeutic strategies associated with the manipulation of the gut microbiome. RESULTS: targeted taxa were described and grouped from major studies to each disease. CONCLUSIONS: Understanding the complexity of these ecological interactions and their association with susceptibility and progression of acute and chronic disorders could lead to novel diagnostic biomarkers based on molecular targets. Moreover, research on the microbiome can also improve some emerging treatment choices, such as fecal transplantation, personalized probiotics, and dietary interventions, which could be used to reduce the impact of specific neuropsychiatric disorders. We expect that this knowledge will help physicians caring for patients with neuropsychiatric disorders.

Gut microbiome in neuropsychiatric disorders / O microbioma intestinal nas doenças neuropsiquiátricas

ABSTRACT Background: Neuropsychiatric disorders are a significant cause of death and disability worldwide. The mechanisms underlying these disorders include a constellation of structural, infectious, immunological, metabolic, and genetic etiologies. Advances in next-generation sequencing techniques have demonstrated that the composition of the enteric microbiome is dynamic and plays a pivotal role in host homeostasis and several diseases. The enteric microbiome acts as a key mediator in neuronal signaling via metabolic, neuroimmune, and neuroendocrine pathways. Objective: In this review, we aim to present and discuss the most current knowledge regarding the putative influence of the gut microbiome in neuropsychiatric disorders. Methods: We examined some of the preclinical and clinical evidence and therapeutic strategies associated with the manipulation of the gut microbiome. Results: targeted taxa were described and grouped from major studies to each disease. Conclusions: Understanding the complexity of these ecological interactions and their association with susceptibility and progression of acute and chronic disorders could lead to novel diagnostic biomarkers based on molecular targets. Moreover, research on the microbiome can also improve some emerging treatment choices, such as fecal transplantation, personalized probiotics, and dietary interventions, which could be used to reduce the impact of specific neuropsychiatric disorders. We expect that this knowledge will help physicians caring for patients with neuropsychiatric disorders.

RESUMO Antecedentes: Os transtornos neuropsiquiátricos são uma importante causa de morte e invalidez no mundo. Os mecanismos subjacentes a esses transtornos incluem uma constelação de etiologias estruturais, infecciosas, imunológicas, metabólicas e genéticas. Avanços nas técnicas de sequenciamento do DNA têm demonstrado que a composição do microbioma entérico é dinâmica e desempenha um papel fundamental não apenas na homeostase do hospedeiro, mas também em várias doenças. O microbioma entérico atua como mediador na sinalização das vias metabólica, neuroimune e neuroendócrina. Objetivo: Apresentar os estudos mais recentes sobre a possível influência do microbioma intestinal nas diversas doenças neuropsiquiátricas e discutir tanto os resultados quanto a eficácia dos tratamentos que envolvem a manipulação do microbioma intestinal. Métodos: foram examinadas algumas das evidências pré-clínicas e clínicas e estratégias terapêuticas associadas à manipulação do microbioma intestinal. Resultados: os táxons-alvo foram descritos e agrupados a partir dos principais estudos para cada doença. Conclusões: Entender a fundo a complexidade das interações ecológicas no intestino e sua associação com a suscetibilidade a certas doenças agudas e crônicas pode levar ao desenvolvimento de novos biomarcadores diagnósticos com base em alvos moleculares. Além disso, o estudo do microbioma intestinal pode auxiliar na otimização de tratamentos não farmacológicos emergentes, tais como o transplante de microbiota fecal, o uso de probióticos e intervenções nutricionais personalizadas. Dessa forma, terapias alternativas poderiam ser usadas para reduzir o impacto dos transtornos neuropsiquiátricos na saúde pública. Esperamos que esse conhecimento seja útil para médicos que cuidam de pacientes com diversos transtornos neuropsiquiátricos.

Differences in structural and functional default mode network connectivity in amyloid positive mild cognitive impairment: a longitudinal study.

PURPOSE: Default mode network (DMN) has emerged as a potential biomarker of Alzheimer's disease (AD); however, it is not clear whether it can differentiate amnestic mild cognitive impairment with altered amyloid (aMCI-Aß +) who will evolve to AD. We evaluated if structural and functional connectivity (FC), hippocampal volumes (HV), and cerebrospinal fluid biomarkers (CSF-Aß42, p-Tau, and t-Tau) can differentiate aMCI-Aß + converters from non-converters. METHODS: Forty-eight individuals (18 normal controls and 30 aMCI subjects in the AD continuum - with altered Aß42 in the CSF) were followed up for an average of 13 months. We used MultiAtlas, UF2C, and Freesurfer software to evaluate diffusion tensor imaging, FC, and HV, respectively, INNOTEST® kits to measure CSF proteins, and neuropsychological tests. Besides, we performed different MANOVAs with further univariate analyses to differentiate groups. RESULTS: During follow-up, 8/30 aMCI-Aß + converted (26.6%) to AD dementia. There were no differences in multivariate analysis between groups in CSF biomarkers (p = 0.092) or at DMN functional connectivity (p = 0.814). aMCI-Aß + converters had smaller right HV than controls (p = 0.013), and greater right cingulum parahippocampal bundle radial diffusivity than controls (p < 0.001) and non-converters (p = 0.036). CONCLUSION: In this exploratory study, structural, but not functional, DMN connectivity alterations may differentiate aMCI-Aß + subjects who converted to AD dementia.

Neuropsychiatric Symptoms in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease: A 12-Month Follow-Up Study.

Introduction: Neuropsychiatric symptoms in patients with frontotemporal dementia (FTD) are highly prevalent and may complicate clinical managements. Objective: To test whether the Neuropsychiatry Inventory (NPI) could detect change in neuropsychiatric symptoms and caregiver's distress in patients diagnosed with behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD) from baseline to a 12-month follow-up and to investigate possible predictors of change in NPI scores. Methods: The sample consisted of 31 patients diagnosed with bvFTD and 28 patients with AD and their caregivers. The Mini-Mental State Examination (MMSE), Addenbrooke's Cognitive Examination Revised (ACE-R), the INECO Frontal Screening (IFS), the Frontal Assessment Battery (FAB), the Executive Interview (EXIT-25) and the NPI were applied. Descriptive statistics, Mann-Whitney U test, Wilcoxon test, Chi square (χ2) test and Linear Regression Analysis were used. Results: NPI total and caregiver distress scores were statistically higher among bvFTD patients at both assessment points. MMSE, ACE-R scores significantly declined and NPI Total and Distress scores significantly increased in both groups. In the bvFTD group, age was the only independent predictor variable for the NPI total score at follow up. In the AD group, ACE-R and EXIT-25, conjunctively, were associated with the NPI total score at follow up. Conclusions: In 12 months, cognition declined and neuropsychiatric symptoms increased in bvFTD and AD groups. In the AD group only, cognitive impairment was a significant predictor of change in neuropsychiatric symptoms.

Cognitive Reserve Relates to Functional Network Efficiency in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common form of dementia, with no means of cure or prevention. The presence of abnormal disease-related proteins in the population is, in turn, much more common than the incidence of dementia. In this context, the cognitive reserve (CR) hypothesis has been proposed to explain the discontinuity between pathophysiological and clinical expression of AD, suggesting that CR mitigates the effects of pathology on clinical expression and cognition. fMRI studies of the human connectome have recently reported that AD patients present diminished functional efficiency in resting-state networks, leading to a loss in information flow and cognitive processing. No study has investigated, however, whether CR modifies the effects of the pathology in functional network efficiency in AD patients. We analyzed the relationship between CR, pathophysiology and network efficiency, and whether CR modifies the relationship between them. Fourteen mild AD, 28 amnestic mild cognitive impairment (aMCI) due to AD, and 28 controls were enrolled. We used education to measure CR, cerebrospinal fluid (CSF) biomarkers to evaluate pathophysiology, and graph metrics to measure network efficiency. We found no relationship between CR and CSF biomarkers; CR was related to higher network efficiency in all groups; and abnormal levels of CSF protein biomarkers were related to more efficient networks in the AD group. Education modified the effects of tau-related pathology in the aMCI and mild AD groups. Although higher CR might not protect individuals from developing AD pathophysiology, AD patients with higher CR are better able to cope with the effects of pathology-presenting more efficient networks despite pathology burden. The present study highlights that interventions focusing on cognitive stimulation might be useful to slow age-related cognitive decline or dementia and lengthen healthy aging.

Intranetwork and internetwork connectivity in patients with Alzheimer disease and the association with cerebrospinal fluid biomarker levels.

BACKGROUND: In the last decade, many studies have reported abnormal connectivity within the default mode network (DMN) in patients with Alzheimer disease. Few studies, however, have investigated other networks and their association with pathophysiological proteins obtained from cerebrospinal fluid (CSF). METHODS: We performed 3 T imaging in patients with mild Alzheimer disease, patients with amnestic mild cognitive impairment (aMCI) and healthy controls, and we collected CSF samples from the patients with aMCI and mild Alzheimer disease. We analyzed 57 regions from 8 networks. Additionally, we performed correlation tests to investigate possible associations between the networks' functional connectivity and the protein levels obtained from the CSF of patients with aMCI and Alzheimer disease. RESULTS: Our sample included 41 patients with Alzheimer disease, 35 with aMCI and 48 controls. We found that the main connectivity abnormalities in those with Alzheimer disease occurred between the DMN and task-positive networks: these patients presented not only a decreased anticorrelation between some regions, but also an inversion of the correlation signal (positive correlation instead of anticorrelation). Those with aMCI did not present statistically different connectivity from patients with Alzheimer disease or controls. Abnormal levels of CSF proteins were associated with functional disconnectivity between several regions in both the aMCI and mild Alzheimer disease groups, extending well beyond the DMN or temporal areas. LIMITATIONS: The presented data are cross-sectional in nature, and our findings are dependent on the choice of seed regions used. CONCLUSION: We found that the main functional connectivity abnormalities occur between the DMN and task-positive networks and that the pathological levels of CSF biomarkers correlate with functional connectivity disruption in patients with Alzheimer disease.

Self, cortical midline structures and the resting state: Implications for Alzheimer's disease.

Different aspects of the self have been reported to be affected in many neurological or psychiatric diseases such as Alzheimer's disease (AD), including mainly higher-level cognitive self-unawareness. This higher sense of self-awareness is most likely related to and dependent on episodic memory, due to the proper integration of ourselves in time, with a permanent conservation of ourselves (i.e., sense of continuity across time). Reviewing studies in this field, our objective is thus to raise possible explanations, especially with the help of neuroimaging studies, for where such self-awareness deficits originate in AD patients. We describe not only episodic (and autobiographical memory) impairment in patients, but also the important role of cortical midline structures, the Default Mode Network, and the resting state (intrinsic brain activity) for the processing of self-related information.