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BACKGROUND: The UN Convention on the Rights of Persons with Disabilities, and the reformed guardianship law in Germany, require that persons with a disability, including people with dementia in Alzheimer's disease (PwAD), are supported in making self-determined decisions. This support is achieved through communication. While content-related communication is a deficit of PwAD, relational aspects of communication are a resource. Research in supported decision-making (SDM) has investigated the effectiveness of different content-related support strategies for PwAD but has only succeeded in improving understanding, which, although one criterion of capacity to consent, is not sufficient to ensure overall capacity to consent. The aim of the 'spatial intervention study' of the DECIDE project is to examine an innovative resource-oriented SDM approach that focuses on relational aspects. We hypothesise that talking to PwAD in their familiar home setting (as opposed to a clinical setting) will reduce the complexity of the decision-making process and enhance overall capacity to consent. METHODS: People with a suspected or confirmed diagnosis of dementia in Alzheimer's disease will be recruited from two memory clinics (N = 80). We will use a randomised crossover design to investigate the intervention effect of the decision-making place on capacity to consent. Besides reasoning capacity, which is part of overall capacity to consent and will be the primary outcome, various secondary outcomes (e.g., other aspects of capacity to consent, subjective task complexity, decisional conflict) and suspected moderating or mediating variables (e.g., meaning of home, demographic characteristics) will be assessed. DISCUSSION: The results of the study will be used to develop a new SDM strategy that is based on relational resources for PwAD. If a change in location achieves the anticipated improvement in capacity to consent, future research should focus on implementing this SDM strategy in a cost-effective manner in clinical practice. TRIAL REGISTRATION: DRKS00030799 .
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Doença de Alzheimer , Humanos , Alemanha , Tomada de DecisõesRESUMO
BACKGROUND: Everybody has the right to decide whether to receive specific medical treatment or not and to provide their free, prior and informed consent to do so. As dementia progresses, people with Alzheimer's dementia (PwAD) can lose their capacity to provide informed consent to complex medical treatment. When the capacity to consent is lost, the autonomy of the affected person can only be guaranteed when an interpretable and valid advance directive exists. Advance directives are not yet common in Germany, and their validity is often questionable. Once the dementia diagnosis has been made, it is assumed to be too late to write an advance directive. One approach used to support the completion of advance directives is 'Respecting Choices'®-an internationally recognised, evidence-based model of Advance Care Planning (ACP), which, until now, has not been evaluated for the target group of PwAD. This study's aims include (a) to investigate the proportion of valid advance directives in a memory clinic population of persons with suspected AD, (b) to determine the predictors of valid advance directives, and (c) to examine whether the offer of ACP can increase the proportion of valid advance directives in PwAD. METHOD: We intend to recruit at least N = 250 participants from two memory clinics in 50 consecutive weeks. Of these, the first 25 weeks constitute the baseline phase (no offer of ACP), the following 25 weeks constitute the intervention phase (offer of ACP). The existence and validity of an advance directive will be assessed twice (before and after the memory clinic appointment). Moreover, potential predictors of valid advance directives are assessed. DISCUSSION: The results of this study will enhance the development of consent procedures for advance directives of PwAD based on the ACP/Respecting Choices (R) approach. Therefore, this project contributes towards increasing the autonomy and inclusion of PwAD and the widespread acceptance of valid advance directives in PwAD. Trial Registration DRKS, DRKS00026691, registered 15th of October 2021, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00026691.
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Planejamento Antecipado de Cuidados , Doença de Alzheimer , Humanos , Estudos Prospectivos , Diretivas Antecipadas , RespeitoRESUMO
Background: Alzheimer's disease (AD) pathology is present many years before the onset of clinical symptoms. AD dementia cannot be treated. Timely and early detection of people at risk of developing AD is key for primary and secondary prevention. Moreover, understanding the underlying pathology that is present in the earliest stages of AD, and the genetic predisposition to that might contribute to the development of targeted disease-modifying treatments. Objectives: In this study, we aimed to explore whether genetic disposition to AD in asymptomatic individuals is associated with altered intrinsic functional connectivity as well as cognitive performance on neuropsychological tests. Methods: We examined 136 cognitively healthy adults (old group: mean age = 69.32, SD = 4.23; young group: mean age = 31.34, SD = 13.12). All participants had undergone resting-state functional magnetic resonance imagining (fMRI), DNA genotyping to ascertain polygenic risk scores (PRS), and neuropsychological testing for global cognition, working memory, verbal fluency, and executive functions. Results: Two-step hierarchical regression analysis revealed that higher PRS was significantly associated with lower scores in working memory tasks [Letter Number Span: ΔR 2 = 0.077 (p < 0.05); Spatial Span: ΔR 2 = 0.072 (p < 0.05)] in older adults (>60 years). PRS did not show significant modulations of the intrinsic functional connectivity of the posterior cingulate cortex (PCC) with other regions of interest in the brain that are affected in AD. Conclusion: Allele polymorphisms may modify the effect of other AD risk factors. This potential modulation warrants further investigations, particularly in cognitively healthy adults.
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The right to make autonomous decisions is enshrined in law. However, the question how persons with cognitive deficits can be enabled to make autonomous decisions has not been satisfactorily addressed. In particular, the concept of supported decision-making and its implementation into practice has been poorly explored for persons with dementia (PwD).This article describes the empirical development and implementation of support tools to enhance informed consent processes (so called enhanced consent procedures/ECP) for PwD on whether to undergo lumbar puncture. In the end of the process of pilot testing and further development of the tools, the following tools were defined: (1) Standardized Interview Structure, (2) Elaborated Plain Language, (3) Ambience and Room Design, (4) Keyword Lists, (5) Priority Cards, (6) Visualization, and (7) Simplified Written Informed Consent (Patient Information), as well as the general attitude (8) Person-Centered Attitude of the facilitator. As the development, implementation and evaluation of ECP tools is one objective of the transnational ENSURE project, we also include an overview of future empirical procedures. So far, our findings can serve as a selection of possibilities to support PwD in decision-making and help practitioners achieve an appropriate balance between the autonomy and protection of PwD in complex decision-making situation. Future studies should address the question if the proposed set of tools is effective to enhance informed consent processes in PwD.
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Aromatic nitration has tremendous importance in organic chemistry as nitroaromatic compounds serve as versatile building blocks. This study represents the electrochemical aromatic nitration with NBu4 NO2 , which serves a dual role as supporting electrolyte and as a safe, readily available, and easy-to-handle nitro source. Stoichiometric amounts of 1,1,1-3,3,3-hexafluoroisopropan-2-ol (HFIP) in MeCN significantly increase the yield by solvent control. The reaction mechanism is based on electrochemical oxidation of nitrite to NO2 , which initiates the nitration reaction in a divided electrolysis cell with inexpensive graphite electrodes. Overall, the reaction is demonstrated for 20 examples with yields of up to 88 %. Scalability is demonstrated by a 13-fold scale-up.
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BACKGROUND: Dietary lipids (omega-3 polyunsaturated fatty acids (n-3) PUFAs) and saturated fatty acids (SFA) seem to play an important role in brain health. (n-3) PUFAs have been shown to improve cerebral perfusion and to promote synaptogenesis. In this study, we investigated the relationship between dietary fat composition, cognitive performance and brain morphology in cognitively healthy individuals. METHODS: A total of 101 cognitively healthy participants (age: 42.3 ± 21.3 years, 62 females) were included in this study. Verbal memory was assessed using the California Verbal Learning Test (CVLT). Intake of (n-3) PUFA and SFA was calculated from food-frequency questionnaire-derived data (EPIC-FFQ). Magnetic resonance imaging (MRI) data were obtained (Siemens Trio 3T scanner) and grey matter volumes (GMV) were assessed by voxel-based morphometry (VBM/SPM8). We examined the association of SFA/(n-3) PUFA ratio and memory performance as well as GMV using regression models adjusted for age, sex, education, body mass index, apolipoprotein E (APOE) status and alcohol consumption. For VBM data, a multiple regression analysis was performed using the same covariates as mentioned before with intracranial volume as an additional covariate. RESULTS: A high SFA/(n-3) PUFA ratio was significantly (p < 0.05) correlated with poorer verbal memory performance and with lower GMV in areas of the left prefrontal cortex that support memory processes. CONCLUSIONS: These findings suggest that a diet rich in PUFAs is likely to exert favourable effects on brain morphology in brain areas important for memory and executive functions. This could constitute a possible mechanism for maintaining cognitive health in older age.
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Encéfalo/anatomia & histologia , Cognição/fisiologia , Gorduras na Dieta/análise , Desempenho Psicomotor/fisiologia , Adulto , Índice de Massa Corporal , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Estudos Transversais , Gorduras na Dieta/farmacologia , Função Executiva , Ácidos Graxos/administração & dosagem , Ácidos Graxos Insaturados/administração & dosagem , Feminino , Substância Cinzenta/anatomia & histologia , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória/fisiologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tamanho do ÓrgãoRESUMO
Sulfonamides are among the most important chemical motifs in pharmaceuticals and agrochemicals. However, there is no methodology to directly introduce the sulfonamide group to a non-prefunctionalized aromatic compound. Herein, we present the first dehydrogenative electrochemical sulfonamide synthesis protocol by exploiting the inherent reactivity of (hetero)arenes in a highly convergent reaction with SO2 and amines via amidosulfinate intermediate. The amidosulfinate serves a dual role as reactant and supporting electrolyte. Direct anodic oxidation of the aromatic compound triggers the reaction, followed by nucleophilic attack of the amidosulfinate. Boron-doped diamond (BDD) electrodes and a HFIP-MeCN solvent mixture enable selective formation of the sulfonamides. In total, 36â examples are demonstrated with yields up to 85 %.
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Mild cognitive impairment (MCI) often precedes Alzheimer's Dementia (AD), and in a high proportion of individuals affected by MCI, there are already neuropathological processes ongoing that become more evident when patients progress to AD. Accordingly, there is a need for reliable biomarkers to distinguish between normal aging and incipient AD. Recent research suggests that, in addition to established biomarkers such as CSF Aß42, total tau and hyperphosphorylated tau, resting state connectivity established by functional magnetic resonance imaging might also be a feasible biomarker for prodromal stages of AD. In order to explore this possibility, we investigated resting state functional connectivity as well as cerebrospinal fluid (CSF) biomarker profiles in patients with MCI (n = 30; age 66.43 ± 7.06 years) and cognitively healthy controls (n = 38; age 66.89 ± 7.12 years). CSF Aß42, total tau and hyperphosphorylated tau concentrations were correlated with measures of cognitive performance (immediate and delayed recall, global cognition, processing speed). Moreover, MCI-related alterations in intrinsic functional connectivity within the default mode network were investigated using functional resting state MRI. As expected, MCI patients showed decreased CSF Aß42 and increased total tau concentrations. These alterations were associated with cognitive performance. However, there were no differences between MCI patients and cognitively healthy controls regarding intrinsic functional connectivity. In conclusion, our results indicate that CSF protein profiles seem to be more closely related to cognitive decline than alterations in resting state activity. Thus, resting state connectivity might not be a reliable biomarker for early stages of AD.
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Doença de Alzheimer/líquido cefalorraquidiano , Biomarcadores/líquido cefalorraquidiano , Encéfalo/fisiopatologia , Disfunção Cognitiva/líquido cefalorraquidiano , Rede Nervosa/fisiopatologia , Idoso , Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Disfunção Cognitiva/diagnóstico , Correlação de Dados , Progressão da Doença , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/líquido cefalorraquidiano , Valor Preditivo dos Testes , Valores de Referência , Fatores de Risco , Proteínas tau/líquido cefalorraquidianoRESUMO
The apolipoprotein E (ApoE) É4 allele is a well-established genetic risk factor for sporadic Alzheimer's disease. Some evidence suggests a negative role of the ApoE É4 allele for cognitive performance in late life, while beneficial effects on cognition have been shown in young age. We investigated age-related effects of the ApoE gene on brain function by assessing cognitive performance, as well as functional activation patterns during retrieval of Face-Name pairs in a group of young (nâ=â50; age 26.4±4.6 years, 25 É4 carriers) and old (nâ=â40; age 66.1±7.0 years, 20 É4 carriers) participants. A cross-sectional factorial design was used to examine the effects of age, ApoE genotype, and their interaction on both cognitive performance and the blood oxygenation level dependent (BOLD) brain response during retrieval of Face-Name pairs. While there were no genotype-related differences in cognitive performance, we found a significant interaction of age and ApoE genotype on task-related activation bilaterally in anterior cingulate gyrus and superior frontal gyrus, as well as left and right insula. Old age was associated with increased activity in É4 carriers. The increased BOLD response in old É4 carriers during retrieval could indicate a neurocognitive disadvantage associated with the É4 allele with increasing age. Furthermore, recruitment of neuronal resources resulted in enhanced memory performance in young É4 carriers, pointing to a better neurofunctional capacity associated with the ApoE4 genotype in young age.
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Envelhecimento/genética , Envelhecimento/fisiologia , Apolipoproteínas E/genética , Encéfalo/fisiopatologia , Cognição/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/psicologia , Aprendizagem por Associação/fisiologia , Mapeamento Encefálico , Circulação Cerebrovascular/fisiologia , Estudos de Coortes , Estudos Transversais , Técnicas de Genotipagem , Heterozigoto , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Testes Neuropsicológicos , Oxigênio/sangue , Reconhecimento Visual de Modelos/fisiologia , Adulto JovemRESUMO
We tested the effects of variation of stimulus onset asynchrony (SOA) on visual working memory (WM) performance across different load levels and the underlying brain activation patterns using functional magnetic resonance imaging (fMRI) in 48 healthy participants. Participants were instructed to memorise arrays of coloured squares and had to perform a match/non-match judgement on a probe stimulus after a jittered delay. We presented visual pattern masks at four SOAs after the offset of the memory array (100 ms, 200 ms, 400 ms, and 800 ms). Memory performance decreased with increased load and shortened SOA. Brain activation data showed significant effects of load (during encoding and retrieval), SOA (retrieval) and an interaction of load by SOA (encoding), mainly in frontal and parietal areas. There was also a direct relationship between successfully stored items and activation in the right inferior parietal lobule and the left middle frontal gyrus. The neurobehavioral results suggest that the frontal regions, together with the inferior parietal lobe, are associated with successful WM performance, especially under the most challenging conditions of high load and short SOAs.
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Encéfalo/fisiologia , Neuroimagem Funcional , Imageamento por Ressonância Magnética/métodos , Memória de Curto Prazo/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Mapeamento Encefálico , Estudos de Casos e Controles , Cognição/fisiologia , Feminino , Lobo Frontal/fisiopatologia , Humanos , Masculino , Memória , Lobo Parietal/fisiologia , Adulto JovemRESUMO
The apolipoprotein E ε4 (ApoE ε4) allele not only represents the strongest single genetic risk factor for sporadic Alzheimer's disease, but also imposes independent effects on brain function in healthy individuals where it has been shown to promote subtle memory deficits and altered intrinsic functional brain network connectivity. Based on previous work showing a potential relevance of the default mode network (DMN) functional connectivity for episodic memory function, we hypothesized that the ApoE ε4 genotype would affect memory performance via modulation of the DMN. We assessed 63 healthy individuals (50-80 years old), of which 20 carried the ε4 allele. All participants underwent resting-state functional magnetic resonance imaging (fMRI), high-resolution 3D anatomical MRI imaging and neuropsychological assessment. Functional connectivity analysis of resting-state activity was performed with a predefined seed region located in the left posterior cingulate cortex (PCC), a core region of the DMN. ApoE ε4 carriers performed significantly poorer than non-carriers in wordlist recognition and cued recall. Furthermore, ε4 carriers showed increased connectivity relative to ε4 non-carriers between the PCC seed region and left-hemispheric middle temporal gyrus (MTG). There was a positive correlation between recognition memory scores and resting-state connectivity in the left MTG in ε4 carriers. These results can be interpreted as compensatory mechanisms strengthening the cross-links between DMN core areas and cortical areas involved in memory processing.
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Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Apolipoproteína E4/genética , Giro do Cíngulo/fisiologia , Reconhecimento Psicológico/fisiologia , Lobo Temporal/fisiologia , Idoso , Encéfalo/fisiologia , Mapeamento Encefálico , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/fisiologia , Testes Neuropsicológicos , Descanso , Fatores de RiscoRESUMO
The apolipoprotein E ε4 allele is a well established genetic risk factor for sporadic Alzheimer's disease. It is associated with structural and functional brain changes in healthy young, middle-aged and elderly subjects. In the current study, we assessed the impact of the ApoE genotype on brain macro- and microstructure, cognitive functioning and brain activity in fifty healthy young subjects (25 ApoE ε4 (ε4+) carriers and 25 non-carriers (ε4-), mean age 26.4±4.6years). We used diffusion tensor imaging (DTI) and voxel based morphometry (VBM) to assess brain structure, an extensive neuropsychological battery to test cognitive functioning and event-related functional magnetic resonance imaging (fMRI) to capture brain activity during episodic memory encoding and retrieval. ApoE ε4 carriers differed from non-carriers in fMRI activations but not in cognitive performance nor in brain micro- and macrostructure. These results suggest functional alterations in the episodic memory network that are modulated by the ε4 allele and might precede clinical or structural neurodegeneration.
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Apolipoproteína E4/genética , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Memória Episódica , Adulto , Mapeamento Encefálico , Imagem de Tensor de Difusão , Feminino , Genótipo , Humanos , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Adulto JovemRESUMO
Mild cognitive impairment (MCI) is a syndrome which, depending on various neurobiological, psychological and social factors, carries a high risk of developing into dementia. As far as diagnostic uncertainty and the heterogeneous underlying pathophysiological mechanisms are concerned, only limited therapeutic options are currently available. Clinical trials involving a wide range of substances have failed to show efficacy on primary and secondary outcome parameters. Most results reflect not only a lack of effectiveness of drug therapy but also methodological constraints in true prodromal Alzheimer´s disease (AD) based on clinical criteria. Biomarkers may help to identify MCI as a prodromal phase of dementia, so it is important to use them to improve specificity of case selection in future studies. For MCI as a prodromal syndrome of AD, clinical trials with disease modifying drugs that target underlying pathological mechanisms such as amyloid-beta accumulation and neurofibrillary tangle formation may help develop effective treatment options in the future. Alternative pharmacological approaches are currently being evaluated in ongoing phase 1 and phase 2 studies. Nevertheless, a lack of approved pharmacotherapeutic options has led to specific interventions that focus on patient education and life-style related factors receiving increasing attention.
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BACKGROUND: Episodic memory deficits affect the majority of patients with bipolar disorder (BD). AIMS: The study investigates episodic memory performance through different approaches, including behavioural measures, physiological parameters, and the underlying functional activation patterns with functional neuroimaging (fMRI). METHODS: 26 Remitted BD patients and a matched group of healthy controls underwent a verbal episodic memory test together with monitored autonomic response, psychopathological ratings and functional magnetic resonance imaging (fMRI) during the verbal episodic memory test. RESULTS: Compared to healthy controls, BD patients performed significantly worse during the episodic memory task. The results further indicate that verbal episodic memory deficits in BD are associated with abnormal functional activity patterns in frontal, occipital and limbic regions, and an increase in stress parameters. LIMITATIONS: We aimed to minimise sample heterogeneity by setting clear criteria for remission, based on the scores of a depression (BDI II) and mania scale (BRMAS) and on the DSM IV criteria. However, our patients were not symptom-free and scored higher on BDI II scores than the control group. CONCLUSIONS: The results are of interest for the treatment of cognitive symptoms in BD patients, as persistent cognitive impairment may hamper full rehabilitation.
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Transtorno Bipolar/fisiopatologia , Transtornos Cognitivos/psicologia , Transtornos da Memória/psicologia , Memória Episódica , Adulto , Transtorno Bipolar/complicações , Transtorno Bipolar/psicologia , Transtornos Cognitivos/complicações , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Transtornos da Memória/complicações , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
Major depression disorder (MDD) is one of the most common causes of disability in people over 60years of age. Previous studies have linked affective and cognitive symptoms of MDD to white matter (WM) disruption in limbic-cortical circuits. However, the relationship between clinical cognitive deficits and loss of integrity in particular WM tracts is poorly understood. Fractional anisotropy (FA) as a measure of WM integrity was investigated in 17 elderly MDD subjects in comparison with 18 age-matched controls using tract-based spatial statistics (TBSS) and correlated with clinical and cognitive parameters. MDD patients revealed significantly reduced FA in the right posterior cingulate cluster (PCC) compared with controls. FA in the right PCC (but not in the left PCC) showed a significant positive correlation with performance in a verbal naming task, and showed a non-significant trend toward a correlation with verbal fluency and episodic memory performance. In control subjects, no correlations were found between cognitive tasks and FA values either in the right or left PCC. Results provide additional evidence supporting the neuronal disconnection hypothesis in MDD and suggest that cognitive deficits are related to the loss of integrity in WM tracts associated with the disorder.
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Encéfalo/patologia , Transtornos Cognitivos/patologia , Transtorno Depressivo Maior/patologia , Imagem de Difusão por Ressonância Magnética , Giro do Cíngulo/patologia , Interpretação de Imagem Assistida por Computador , Leucoencefalopatias/patologia , Fibras Nervosas/patologia , Rede Nervosa/patologia , Idoso , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Mapeamento Encefálico , Córtex Cerebral/patologia , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Transtorno Depressivo Maior/diagnóstico , Transtorno Depressivo Maior/psicologia , Progressão da Doença , Dominância Cerebral/fisiologia , Feminino , Humanos , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/psicologia , Sistema Límbico/patologia , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos/estatística & dados numéricos , Psicometria , Valores de ReferênciaRESUMO
OPINION STATEMENT: To date, there are no approved and established pharmacologic treatment options for tauopathies, a very heterogenous group of neuropsychiatric diseases often leading to dementia and clinically diagnosed as atypical Parkinson syndromes. Among these so-called Parkinson plus syndromes are progressive supranuclear palsy (PSP), also referred to as Steele-Richardson-Olszewski syndrome; frontotemporal dementia (FTD); and corticobasal degeneration (CBD). Available treatment strategies are based mainly on small clinical trials, miscellaneous case reports, or small case-controlled studies. The results of these studies and conclusions about the efficacy of the medication used are often contradictory. Approved therapeutic agents for Alzheimer´s dementia, such as acetylcholinesterase inhibitors and memantine, have been used off-label to treat cognitive and behavioral symptoms in tauopathies, but the outcome has not been consistent. Therapeutic agents for the symptomatic treatment of Parkinson's disease (levodopa or dopamine agonists) are used for motor symptoms in tauopathies. For behavioral or psychopathological symptoms, treatment with antidepressants-especially selective serotonin reuptake inhibitors-could be helpful. Antipsychotics are often not well tolerated because of their adverse effects, which are pronounced in tauopathies; these drugs should be given very carefully because of an increased risk of cerebrovascular events. In addition to pharmacologic options, physical, occupational, or speech therapy can be applied to improve functional abilities. Each pharmacologic or nonpharmacologic intervention should be fitted to the specific symptoms of the individual patient, and decisions about the type and duration of treatment should be based on its efficacy for the individual and the patient's tolerance. Currently, no effective treatment is available that targets the cause of these diseases. Current research focuses on targeting tau protein pathology, including pathologic aggregation or phosphorylation; these approaches seem to be very promising.
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Alzheimers disease (AD) represents the most prevalent neurodegenerative disorder that causes cognitive decline in old age. In its early stages, AD is associated with microstructural abnormalities in white matter (WM). In the current study, multiple indices of diffusion tensor imaging (DTI) and brain volumetric measurements were employed to comprehensively investigate the landscape of AD pathology. The sample comprised 58 individuals including cognitively normal subjects (controls), amnestic mild cognitive impairment (MCI) and AD patients. Relative to controls, both MCI and AD subjects showed widespread changes of anisotropic fraction (FA) in the corpus callosum, cingulate and uncinate fasciculus. Mean diffusivity and radial changes were also observed in AD patients in comparison with controls. After controlling for the gray matter atrophy the number of regions of significantly lower FA in AD patients relative to controls was decreased; nonetheless, unique areas of microstructural damage remained, e.g., the corpus callosum and uncinate fasciculus. Despite sample size limitations, the current results suggest that a combination of secondary and primary degeneration occurrs in MCI and AD, although the secondary degeneration appears to have a more critical role during the stages of disease involving dementia.