scholarly journals 521 - The link between olfactory dysfunction and dementia: the road so far.

2021 ◽  
Vol 33 (S1) ◽  
pp. 69-70
Author(s):  
Marcela Leão Petersen ◽  
Monia Bresolin ◽  
Ariane Madruga Monteiro
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Neurodegenerative Diseases ◽  
Neurodegenerative Disorder ◽  
Functional Neuroimaging ◽  
Olfactory Dysfunction ◽  
Cochrane Library ◽  
Meta Analyses ◽  
Smell Tests

Dementia is characterized by the presence of progressive cognitive impairment losses in the individual’s social and occupational activities. Its etiological diagnosis has therapeutic and prognostic implications. Although its definitive diagnosis depends on neuropathological analysis, detailed anamnesis, physical and neuropsychological tests; biochemical and neuroimaging exams may enable a greater accuracy. Technological innovations using structural and functional neuroimaging methods, as well as biology and molecular genetics techniques, have presented perspectives for the early diagnosis of dementias, particularly Alzheimer’s disease (AD). However, such techniques burden the diagnostic investigation, making its practice unfeasible most the times. The probable link between neurodegenerative diseases and impaired olfactory dysfunction has long been studied. It is suggested that smell tests can be used in dementia’s early detection and differential diagnosis, reducing costs and facilitating the establishment of appropriate treatment. In order to verify the validity of this information, a medical literature search was carried out in may 2021 using PubMed and Cochrane Library, including the terms “olfaction” and “olfactory dysfunction” combined individually with “neurodegenerative disorder”, “dementia” and “Alzheimer’s disease”. Only systematic reviews and meta-analyses written in English from 1991 to 2021 were included. Results show that olfactory impairment in neurodegenerative diseases worsens progressively as patients progress from mild cognitive impairment to AD. It suggests that odor tests could potentially identify AD in the preclinical stages. Although, rigorously designed longitudinal cohort studies are necessary to clarify the value of olfactory identification testing in predicting the onset of AD and its value as an early marker of cognitive decline. In addition, AD patients are more impaired on odor identification and recognition tasks and Parkinson’s Disease (PD) patients on odor detection thresholds tasks, what suggests that PD patients are more impaired on low-level perceptual olfactory tasks whereas AD patients are more strongly impaired on higher-order olfactory tasks involving specific cognitive processes. The results suggest smell tests are a cheaper, simpler to apply and a promising weapon for detecting individuals at risk of dementia.

scholarly journals YKL-40 as a Potential Biomarker for the Differential Diagnosis of Alzheimer’s Disease

Medicina ◽  
2021 ◽  
Vol 58 (1) ◽  
pp. 60
Author(s):  
Ioannis Mavroudis ◽  
Rumana Chowdhury ◽  
Foivos Petridis ◽  
Eleni Karantali ◽  
Symela Chatzikonstantinou ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Differential Diagnosis ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Neurodegenerative Disorder ◽  
Neuronal Loss ◽  
Cochrane Library ◽  
Potential Biomarker ◽  
The Cochrane Library

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder, associated with extensive neuronal loss, dendritic and synaptic changes resulting in significant cognitive impairment. An increased number of studies have given rise to the neuroinflammatory hypothesis in AD. It is widely accepted that AD brains show chronic inflammation, probably triggered by the presence of insoluble amyloid beta deposits and neurofibrillary tangles (NFT) and is also related to the activation of neuronal death cascade. In the present study we aimed to investigate the role of YKL-40 levels in the cerebrospinal fluid (CSF) in the diagnosis of AD, and to discuss whether there are further potential roles of this protein in the management and treatment of AD. We conducted an online search on PubMed, Web of Science, and the Cochrane library databases from 1990 to 2021. The quantitative analysis showed that the levels of YKL-40 were significantly higher in Alzheimer’s disease compared to controls, to mild cognitive impairment (MCI) AD (MCI-AD) and to stable MCI. They were also increased in MCI-AD compared to stable MCI. The present study shows that the CSF levels of YKL-40 could be potentially used as a biomarker for the prognosis of mild cognitive impairment and the likelihood of progression to AD, as well as for the differential diagnosis between AD and MCI.

scholarly journals Neurotrophic Treatment Initiated During Early Postnatal Development Prevents the Alzheimer-Like Behavior and Synaptic Dysfunction

2021 ◽  
pp. 1-16
Author(s):  
Wei Wei ◽  
Yinghua Liu ◽  
Chunling Dai ◽  
Narjes Baazaoui ◽  
Yunn-Chyn Tung ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Early Development ◽  
Neurodegenerative Disorder ◽  
Synaptic Dysfunction ◽  
Early Postnatal Development ◽  
Wild Type Female

Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by impairments in synaptic plasticity and cognitive performance. Cognitive dysfunction and loss of neuronal plasticity are known to begin decades before the clinical diagnosis of the disease. The important influence of congenital genetic mutations on the early development of AD provides a novel opportunity to initiate treatment during early development to prevent the Alzheimer-like behavior and synaptic dysfunction. Objective: To explore strategies for early intervention to prevent Alzheimer’s disease. Methods: In the present study, we investigated the effect of treatment during early development with a ciliary neurotrophic factor (CNTF) derived peptidergic compound, P021 (Ac-DGGLAG-NH2) on cognitive function and synaptic plasticity in 3xTg-AD transgenic mouse model of AD. 3xTg-AD and genetic background-matched wild type female mice were treated from birth to postnatal day 120 with P021 in diet or as a control with vehicle diet, and cognitive function and molecular markers of neuroplasticity were evaluated. Results: P021 treatment during early development prevented cognitive impairment and increased expressions of pCREB and BDNF that activated downstream various signaling cascades such as PLC/PKC, MEK/ERK and PI3K/Akt, and ameliorated synaptic protein deficit in 4-month-old 3xTg-AD mice. Conclusion: These findings indicate that treatment with the neurotrophic peptide mimetic such as P021 during early development can be an effective therapeutic strategy to rescue synaptic deficit and cognitive impairment in familial AD and related tauopathies.

scholarly journals Subjective cognitive decline: The first clinical manifestation of Alzheimer's disease?

2016 ◽  
Vol 10 (3) ◽  
pp. 170-177 ◽  
Author(s):  
Adalberto Studart Neto ◽  
Ricardo Nitrini
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Decline ◽  
Clinical Manifestation ◽  
Neurodegenerative Disorder ◽  
Subjective Cognitive Decline ◽  
Subjective Memory ◽  
Increased Risk

ABSTRACT Background: Mild cognitive impairment is considered as the first clinical manifestation of Alzheimer's disease (AD), when the individual exhibits below performance on standardized neuropsychological tests. However, some subjects before having a lower performance on cognitive assessments already have a subjective memory complaint. Objective: A review about subjective cognitive decline, the association with AD biomarkers and risk of conversion to dementia. Methods: We performed a comprehensive non-systematic review on PubMed. The keywords used in the search were terms related to subjective cognitive decline. Results: Subjective cognitive decline is characterized by self-experience of deterioration in cognitive performance not detected objectively through formal neuropsychological testing. However, various terms and definitions have been used in the literature and the lack of a widely accepted concept hampers comparison of studies. Epidemiological data have shown that individuals with subjective cognitive decline are at increased risk of progression to AD dementia. In addition, there is evidence that this group has a higher prevalence of positive biomarkers for amyloidosis and neurodegeneration. However, Alzheimer's disease is not the only cause of subjective cognitive decline and various other conditions can be associated with subjective memory complaints, such as psychiatric disorders or normal aging. The features suggestive of a neurodegenerative disorder are: onset of decline within the last five years, age at onset above 60 years, associated concerns about decline and confirmation by an informant. Conclusion: These findings support the idea that subjective cognitive complaints may be an early clinical marker that precedes mild cognitive impairment due to Alzheimer's disease.

scholarly journals A comparison of resting state EEG and structural MRI for classifying Alzheimer’s disease and mild cognitive impairment

2019 ◽  
Author(s):  
FR Farina ◽  
DD Emek-Savaş ◽  
L Rueda-Delgado ◽  
R Boyle ◽  
H Kiiski ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Resting State ◽  
Healthy Aging ◽  
Neurodegenerative Disorder ◽  
Low Cost ◽  
Structural Mri ◽  
Lower Accuracy

AbstractAlzheimer’s disease (AD) is a neurodegenerative disorder characterised by severe cognitive decline and loss of autonomy. AD is the leading cause of dementia. AD is preceded by mild cognitive impairment (MCI). By 2050, 68% of new dementia cases will occur in low- and middle-income countries. In the absence of objective biomarkers, psychological assessments are typically used to diagnose MCI and AD. However, these require specialist training and rely on subjective judgements. The need for low-cost, accessible and objective tools to aid AD and MCI diagnosis is therefore crucial. Electroencephalography (EEG) has potential as one such tool: it is relatively inexpensive (cf. magnetic resonance imaging; MRI) and is portable. In this study, we collected resting state EEG, structural MRI and rich neuropsychological data from older adults (55+ years) with AD, with MCI and from healthy controls (n~60 per group). Our goal was to evaluate the utility of EEG, relative to MRI, for the classification of MCI and AD. We also assessed the performance of combined EEG and behavioural (Mini-Mental State Examination; MMSE) and structural MRI classification models. Resting state EEG classified AD and HC participants with moderate accuracy (AROC=0.76), with lower accuracy when distinguishing MCI from HC participants (AROC=0.67). The addition of EEG data to MMSE scores had no additional value compared to MMSE alone. Structural MRI out-performed EEG (AD vs HC, AD vs MCI: AROCs=1.00; HC vs MCI: AROC=0.73). Resting state EEG does not appear to be a suitable tool for classifying AD. However, EEG classification accuracy was comparable to structural MRI when distinguishing MCI from healthy aging, although neither were sufficiently accurate to have clinical utility. This is the first direct comparison of EEG and MRI as classification tools in AD and MCI participants.

Effects of Exercise in the Treatment of Alzheimer’s Disease: An Umbrella Review of Systematic Reviews and Meta-Analyses

2021 ◽  
pp. 1-17
Author(s):  
Alexandro Andrade ◽  
Thais Cristina Siqueira ◽  
Anderson D’Oliveira ◽  
Fábio Hech Dominski
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Systematic Reviews ◽  
Web Of Science ◽  
Cochrane Library ◽  
Umbrella Review ◽  
Disease Symptoms ◽  
Moderate Quality ◽  
Low Incidence ◽  
Meta Analyses

The authors aimed to provide an overview of the evidence on the effects of exercise in people with Alzheimer’s disease through a comprehensive review of the existing systematic reviews and meta-analyses. A literature search was performed in CINAHL, Cochrane Library, EMBASE, PubMed, SPORTDiscus, Scopus, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The AMSTAR-2-Tool was used for the quality assessment. Twenty-three reviews fulfilled the criteria. Most of the reviews investigated the effects of aerobic exercise on Alzheimer’s disease symptoms. The largest effects of exercise were seen in terms of improved cognition by multiple exercises. The majority of the reviews were rated as being of moderate quality and none were classified as having high quality. Exercise is an effective way to treat Alzheimer’s disease symptoms and has a low incidence of related adverse events. As most reviews were evaluated as low-moderate quality, caution is needed in the interpretation of the results.

scholarly journals Overview of Meta-Analyses of Five Non-pharmacological Interventions for Alzheimer's Disease

2020 ◽  
Vol 12 ◽  
Author(s):  
Liao-Yao Wang ◽  
Jian Pei ◽  
Yi-Jun Zhan ◽  
Yi-Wen Cai
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Acupuncture Therapy ◽  
Exercise Intervention ◽  
Cognitive Intervention ◽  
Grade System ◽  
Cochrane Library ◽  
Pharmacological Interventions ◽  
Meta Analyses

Background: Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive memory deficits, cognitive decline, and spatial disorientation. Non-pharmacological interventions to treat AD have been reported in many meta-analyses (MAs), but robust conclusions have not been made because of variations in the scope, quality, and findings of these reviews.Objective: This work aimed to review existing MAs to provide an overview of existing evidence on the effects of five non-pharmacological interventions in AD patients on three outcomes: Mini-Mental State Examination (MMSE), activities of daily living (ADL), and Alzheimer's Disease Assessment Scale-cognitive section (ADAS-cog).Methods: The databases PubMed, Cochrane Library, Embase, and Web of Science were searched to collect MAs of non-pharmacological interventions for AD. Two reviewers independently conducted literature screening, data extraction, and quality assessment. We assessed the quality of MAs with the Measurement Tool to Assess Systematic Reviews (AMSTAR) 2 and assessed the evidence quality for significant outcomes using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.Results: We found 10 eligible MAs, which included between three (133 patients) and 15 randomized trials (1,217 patients), and five non-pharmacological interventions, namely, acupuncture therapy (40%), exercise intervention (30%), music therapy (10%), cognitive intervention (10%), and repetitive transcranial magnetic stimulation (rTMS) (10%). All the included MAs were critically low to low quality by AMSTAR 2. Acupuncture therapy and exercise intervention showed the preliminary potential to improve ADL and MMSE. rTMS and acupuncture therapy show benefits in decreasing ADAS-cog, and there were some evidence of improved MMSE with cognitive intervention. All these outcomes scored very low quality to moderate quality of evidence on the GRADE system.Conclusions: Non-pharmacological therapy shows promise for the treatment of AD, but there is still a lack of high-quality evidence. In the future, the quality of the original research needs to be improved, and strictly designed MAs should be carried out following methodological requirements.

scholarly journals Occupational Exposures and Neurodegenerative Diseases—A Systematic Literature Review and Meta-Analyses

2019 ◽  
Vol 16 (3) ◽  
pp. 337 ◽  
Author(s):  
Lars-Gunnar Gunnarsson ◽  
Lennart Bodin
Keyword(s):  
Alzheimer’S Disease ◽  
Parkinson’S Disease ◽  
Alzheimer's Disease ◽  
Parkinson's Disease ◽  
Occupational Exposure ◽  
Neurodegenerative Diseases ◽  
Meta Analysis ◽  
Occupational Exposures ◽  
Increased Risk ◽  
Meta Analyses

Objectives: To carry out an integrated and stratified meta-analysis on occupational exposure to electromagnetic fields (EMFs), metals and pesticides and its effects on amyotrophic lateral sclerosis (ALS) and Parkinson’s and Alzheimer’s disease, and investigate the possibility of publication bias. Methods: In the current study, we updated our recently published meta-analyses on occupational exposures in relation to ALS, Alzheimer’s and Parkinson’s disease. Based on 66 original publications of good scientific epidemiological standard, according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines, we analysed subgroups by carrying out stratified meta-analyses on publication year, statistical precision of the relative risk (RR) estimates, inspection of the funnel plots and test of bias. Results: Based on 19 studies the weighted RR for occupational exposure to EMFs was 1.26 (95% confidence interval (CI) 1.07–1.50) for ALS, 1.33 (95% CI 1.07–1.64) for Alzheimer’s disease and 1.02 (95% CI 0.83–1.26) for Parkinson’s disease. Thirty-one studies concerned occupational exposure to pesticides and the weighted RR was 1.35 (95% CI 1.02–1.79) for ALS, 1.50 (95% CI 0.98–2.29) for Alzheimer’s disease and 1.66 (95% CI 1.42–1.94) for Parkinson’s disease. Finally, 14 studies concerned occupational exposure to metals and only exposure to lead (five studies) involved an elevated risk for ALS or Parkinson’s disease and the weighted RR was 1.57 (95% CI 1.11–2.20). The weighted RR for all the non-lead exposures was 0.97 (95% CI 0.88–1.06). Conclusions: Exposure to pesticides increased the risk of getting the mentioned neurodegenerative diseases by at least 50%. Exposure to lead was only studied for ALS and Parkinson’s disease and involved 50% increased risk. Occupational exposure to EMFs seemed to involve some 10% increase in risk for ALS and Alzheimer’s disease only.

scholarly journals Progressive Supranuclear Palsy: A Review of Co-existing Neurodegeneration

2008 ◽  
Vol 35 (5) ◽  
pp. 602-608 ◽  
Author(s):  
J Keith-Rokosh ◽  
L C Ang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Neurodegenerative Diseases ◽  
Progressive Supranuclear Palsy ◽  
Lewy Bodies ◽  
Corticobasal Degeneration ◽  
Pathological Changes ◽  
Subcortical Regions ◽  
Argyrophilic Grains

Objectives:The neuropathological findings of 32 progressive supranuclear palsy (PSP) cases over a period of 17 years were reviewed.Results:Of the 26 cases with adequate clinical data, 20 patients either presented with cognitive dysfunction or developed a cognitive impairment subsequently during the course of the disease. Co-existing changes of argyrophilic grains and corticobasal degeneration (CBD) were found in 28% and 32% of the cases respectively. Alzheimer-related pathology was found in 69% of cases but only 18.75% of cases fulfilled the consortium to establish a registry for Alzheimer's disease (CERAD) criteria for either definite or probable Alzheimer's disease. Lewy bodies were noted in four cases (12.5%), all in the subcortical regions. Only seven cases of PSP showed no pathological evidence of other co-existing neurodegenerative diseases. The severity of the cerebrovascular pathology in this cohort was insufficient to explain any clinical symptomatology.Conclusions:As in previous studies, this study has demonstrated the frequent co-existence of pathological changes usually noted in other neurodegenerative diseases in PSP. Whether these coexisting pathological changes contribute to the cognitive impairment in PSP remains uncertain.

scholarly journals Alzheimer's disease and sleep disturbances: a review

2019 ◽  
Vol 77 (11) ◽  
pp. 815-824 ◽  
Author(s):  
Conrado Regis Borges ◽  
Dalva Poyares ◽  
Ronaldo Piovezan ◽  
Ricardo Nitrini ◽  
Sonia Brucki
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Sleep Disturbances ◽  
Neurodegenerative Process ◽  
Preclinical Ad ◽  
Scientific Attention ◽  
Meta Analyses ◽  
The Impact

ABSTRACT The association between Alzheimer's disease (AD) and sleep disturbances has received increasing scientific attention in the last decades. However, little is known about the impact of sleep and its disturbances on the development of preclinical AD stages, such as mild cognitive impairment. This review describes the evolution of knowledge about the potential bidirectional relationships between AD and sleep disturbances exploring recent large prospective studies and meta-analyses and studies of the possible mechanisms through which sleep and the neurodegenerative process could be associated. The review also makes a comprehensive exploration of the sleep characteristics of older people, ranging from cognitively normal individuals, through patients with mild cognitive impairment, up to the those with dementia with AD.

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