Mild cognitive impairment. Part 1: clinical characteristics and predictors of dementia

Incidence and risk factors of post-stroke cognitive impairment in convalescent elderly patients with first-episode acute ischemic stroke

A total of 350 first-time AIS elderly patients (aged ≥60 years) were collected and analyzed. Multivariate Logistic regression analysis showed that the lesion site, frontal temporal, cerebral white matter degeneration, age ≥ 75 years, BMI ≥ 28, onset in autumn/winter, hospitalization expenses > 20,000 yuan/month, high DBPV, high NIHSS score, and high HAMD score were risk factors for PSCI. Higher education level was a protective factor. In conclusion, the incidence of PSCI in elderly AIS patients was relatively high and related to the several factors, which indicated that more attention should be paid for such patients to prevent PSCI.

Apathy as a Predictor of Conversion from Mild Cognitive Impairment to Alzheimer's Disease: A Texas Alzheimer's Research and Care Consortium (TARCC) Cohort-Based Analysis

BACKGROUND

Apathy is among the neuropsychiatric symptoms frequently observed in people with cognitive impairment. It has been postulated to be a potential predictor of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

OBJECTIVE

To detect conversion rates from MCI to AD, and to determine the effect of apathy on the progression to AD in patients with MCI enrolled in the Texas Alzheimer's Research and Care Consortium (TARCC) cohort.

METHODS

Apathy was determined by a positive response to the respective item in the Neuropsychiatric Inventory -Questionnaire (NPI-Q) completed by family members or caregivers. The final dataset included 2,897 observations from 1,092 individuals with MCI at the baseline. Kaplan-Meier survival curves were estimated to provide indices of the probability of conversion to AD over time across all individuals as well as between those with and without apathy. Cox proportional hazards regression measured the hazard associated with apathy and several other predictors of interest.

RESULTS

Over a period of 8.21 years, 17.3% of individuals had conversion from MCI to AD (n = 190 of 1,092 total individuals) across observations. The median time-to-conversion across all participants was 6.41 years. Comparing individuals with apathy (n = 158) versus without apathy (n = 934), 36.1% and 14.2% had conversion to AD, respectively. The median time-to-conversion was 3.79 years for individuals with apathy and 6.83 years for individuals without apathy. Cox proportional hazards regression found significant effects of several predictors, including apathy, on time-to-conversion. Age and cognitive performance were found to moderate the relationship between apathy and time-to-conversion.

CONCLUSIONS

Apathy is associated with progression from MCI to AD, suggesting that it might improve risk prediction and aid targeted intervention delivery.

Multitask Versus Multicomponent Training on Cognitive and Motor Functions in Persons With Mild Cognitive Impairment: A Randomized Trial

This study aims to compare the effects of multitask (MTT; multiple tasks performed simultaneously) and multicomponent training (MCT; various types of exercise performed sequentially) on processing speed, cognitive functions, gait speed, and balance functions in persons with mild cognitive impairment. Forty-two persons with mild cognitive impairment were randomly allocated to MTT (n = 21) or MCT (n = 21). Outcome measures included processing speed, cognitive functions (attention and executive functions), single-task gait speed, dual-task gait speed (DTGS-Arithmetic and DTGS-Verbal), and balance functions. Processing speed (except inhibition), cognitive functions, gait speed, and balance functions improved in the MTT and MCT groups following training, with no significant differences between the groups in processing speed or cognitive functions. The MCT group improved more on single-task gait speed (F = 15.097; p = .000; r = .270) and DTGS (DTGS-Arithmetic; F = 10.594; p = .002; r = .214), while the MTT group improved more on balance functions (F = 4.366; p = .043; r = .101). MTT and MCT strategies can be used to improve cognitive and physical outcomes in persons with mild cognitive impairment.

VAMP2 Expression and Genotype Are Possible Discriminators in Different Forms of Dementia

Vascular alterations often overlap with neurodegeneration, resulting in mixed forms of dementia (MD) that are hard to differentiate from Alzheimer’s Disease (AD). The 26 bp intergenic polymorphism of VAMP2, a key component of SNARE complex, as well as its mRNA and protein levels are associated with neurological diseases. We evaluated ApoE4 and VAMP2 26 bp Ins/Del genotype distribution in 177 AD, 132 MD, 115 Mild Cognitive Impairment (MCI) and 250 individuals without cognitive decline (CT), as well as VAMP2 gene expression in a subset of 73 AD, 122 MD, 103 MCI and 140 CT. Forty-two MCI evolved to AD (22 MCI-AD) or MD (20 MCI-MD) over time. VAMP2 mRNA was higher in MD compared to AD (p = 0.0013) and CT (p = 0.0017), and in MCI-MD compared to MCI-AD (p < 0.001) after correcting for age, gender, MMSE and ApoE4 +/− covariates (p_c = 0.004). A higher VAMP2 expression was observed in subjects carrying the minor allele Del compared to those carrying the Ins/Ins genotype (p = 0.012). Finally, Del/Del genotype was more frequently carried by MD/MCI-MD compared to CT (p_c = 0.036). These results suggest that VAMP2 mRNA expression can discriminate mixed form of dementia from AD, possibly being a biomarker of AD evolution in MCI patients.

Neuropsychiatric Symptoms in Patients with Neurocognitive Disorder and Their Performance Between Mild and Major Stages

BACKGROUND

The neuropsychiatric symptoms (NPS) in patients with neurocognitive disorders (NCD) increases the risk of exhibiting significant cognitive and functional decline. However, to the best of our knowledge, few studies have evaluated to what extent the presence of chronic and early NPS impacts cognition and functionality in patients with minor or major stages of NCD.

OBJECTIVE

We aimed to assess the interplay between early and chronic NPS and cognitive and functional presentation of patients with mild and major forms of NCD.

METHODS

We used two NPS tools tracking early and late NPS and assessed to what extent they determine cognitive and functional outcomes in patients with mild and major forms of NCD.

RESULTS

We found an inverse relationship between the presence of NPS, as measured by the Neuropsychiatric Inventory and Mild Behavioral Impairment Checklist (MBI-C), and cognitive and functional variables in major forms of NCD. In contrast, the minor stage of NCD was associated with increased MBI-C scores.

CONCLUSION

Our results revealed that NPS are associated with cognitive and functional outcomes in mild and chronic forms of NCD. Crucially our results suggest that NPS could be considered as a pathological marker of the clinical course of dementia. Additionally, our study calls to study early and late forms of NPS as both impact cognition and functionality of NCD.

Validation of the Mini-Addenbrooke's Cognitive Examination in Mild Cognitive Impairment in Arabic Speakers

INTRODUCTION

Mild cognitive impairment (MCI) represents a target for early detection and intervention in dementia, yet there is a shortage of validated screening tools in Arabic to diagnose MCI. The mini-Addenbrooke's Cognitive Examination (m-ACE) is a brief cognitive battery that is scored out of 30 and can be administered in under 5 min providing a quick screening tool for assessment of cognition.

OBJECTIVE

We aimed to validate the m-ACE in Arabic speakers in Egypt with MCI to provide cut-off scores.

METHODS

We included 24 patients with MCI and 52 controls and administered the Arabic version of the m-ACE.

RESULTS

There was a statistically significant difference (p < 0.0001) on the total m-ACE score between MCI patients (mean 18.54, SD 3.05) and controls (mean 24.54, SD 2.68). There was also a statistically significant difference between MCI patients and controls on the total score and the fluency, visuospatial, and memory recall sub-scores of the m-ACE (p < 0.05). Performance on the m-ACE significantly correlated with both the Mini-Mental State Examination (MMSE) and the Addenbrooke's Cognitive Examination-III (ACE-III). Using a receiver operator characteristic curve, the optimal cut-off score for MCI on the m-ACE total score was 21 out of 30 (87.5% sensitivity, 84.6% specificity, and 85.5% accuracy).

CONCLUSIONS

We validated the Arabic m-ACE in Egyptian patients with MCI and provided objective validation of it as a screening tool for MCI, with good sensitivity, specificity, and accuracy that is comparable to other translated versions of the m-ACE in MCI.

Machine learning for the life-time risk prediction of Alzheimer's disease: a systematic review

Alzheimer’s disease is a neurodegenerative disorder and the most common form of dementia. Early diagnosis may assist interventions to delay onset and reduce the progression rate of the disease. We systematically reviewed the use of machine learning algorithms for predicting Alzheimer’s disease using single nucleotide polymorphisms and instances where these were combined with other types of data. We evaluated the ability of machine learning models to distinguish between controls and cases, while also assessing their implementation and potential biases. Articles published between December 2009 and June 2020 were collected using Scopus, PubMed and Google Scholar. These were systematically screened for inclusion leading to a final set of 12 publications. Eighty-five per cent of the included studies used the Alzheimer's Disease Neuroimaging Initiative dataset. In studies which reported area under the curve, discrimination varied (0.49–0.97). However, more than half of the included manuscripts used other forms of measurement, such as accuracy, sensitivity and specificity. Model calibration statistics were also found to be reported inconsistently across all studies. The most frequent limitation in the assessed studies was sample size, with the total number of participants often numbering less than a thousand, whilst the number of predictors usually ran into the many thousands. In addition, key steps in model implementation and validation were often not performed or unreported, making it difficult to assess the capability of machine learning models.

Validation of the Addenbrooke's Cognitive Examination-III in Mild Cognitive Impairment in Arabic Speakers in Egypt

BACKGROUND AND AIMS

Mild cognitive impairment (MCI) represents an important point on the pathway to developing dementia and a target for early detection and intervention. There is a shortage of validated cognitive screening tools in Arabic to diagnose MCI. The aim of this study was to validate Addenbrooke's Cognitive Examination-III (ACE-III) (Egyptian-Arabic version) in a sample of patients with MCI, to provide cut-off scores in Egyptian-Arabic speakers.

METHODS

A total of 24 patients with MCI and 54 controls were included in the study and were administered the Egyptian-Arabic version of the ACE-III.

RESULTS

There was a statistically significant difference (p < 0.001) in the total ACE-III score between MCI patients (mean 75.83, standard deviation (SD) 8.1) and controls (mean 86.26, SD 6.74). There was also a statistically significant difference between MCI patients and controls in the memory, fluency, and visuospatial sub-scores of the ACE-III (p < 0.05) but not in attention and language sub-scores. Using a receiver operator characteristic curve, the optimal cut-off score for diagnosing MCI on the ACE-III total score was 81, with 75% sensitivity, 82% specificity, and 80% accuracy.

CONCLUSIONS

The results of this study provide objective validation of the Egyptian-Arabic version of the ACE-III as a screening tool for MCI, with good sensitivity, specificity, and accuracy that are comparable to other translated versions of the ACE-III in MCI.

Alzheimer's Disease and Functional Foods: An Insight on Neuroprotective Effect of its Combination

Alzheimer's disease (AD) is a progressive neurodegenerative disease which impairs memory and cognitive function. Currently, AD has no cure and treatments are focused on relieving its symptoms. Several functional plants and foods, such as pomegranate, date fruits, honey, black seeds and figs, possess nutritious properties which alleviate AD. In vitro and in vivo studies reported that these functional foods exert neuroprotective effects through their antioxidant and anti-inflammatory properties. This review are going to discusses the bioactive components and neuroprotective activities of the functional foods such as pomegranate, dates, honey, black seeds and figs and the potential of functional foods combinations to alleviate AD. Functional food combinations have potential to be consumed for health benefit for the prevention and treatment of AD. This review summarises the functional foods which can be useful for the prevention, treatment and management of AD via oxidative and inflammatory mechanisms. Besides, it provides a new insight on the potential of functional food combinations for the prevention and treatment of AD.

Vehicular traffic density and cognitive performance in the ELSA-Brasil study

BACKGROUND

Despite the knowledge about the deleterious effects of air pollutants and their influence on mortality and morbidity due to respiratory and cardiovascular diseases, little is known about the relationship between atmospheric pollutants and neurological diseases. Recently, studies from high-income countries have suggested an association between exposures to air pollutants with cognitive impairment. Thus, we investigated the association of air pollution with cognitive performance in the participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS

Cognitive function was evaluated using the word list, the verbal fluency, and the trail making tests (TMT). Pollutant exposure was evaluated indirectly using the distance-weighted traffic density (DWTD) of participants' residence and workplace. We investigated the cross-sectional association between DWTD and cognitive test scores using adjusted linear regression models for sociodemographic and clinical variables.

RESULTS

3050 were included (mean age = 52.1 ± 9.2 years old, 56.5% women, and 63.6% white). In the simple linear regression models, participants in the higher tertile of combined DWTD (residence and workplace) presented better cognitive performance in all tests when compared to participants in the lower tertile. The DWTD was not associated with cognitive performance in adjusted linear models especially when adjusted for socioeconomic variables (age, sex, education, and race). We found similar results when we investigated the association of cognitive performance with DTWD near participants' workplace and residence separately.

CONCLUSION

Air pollutants were not associated with worse cognitive performance in a large sample of middle-aged and older adults.

Evaluation of GammaH2AX in Buccal Cells as a Molecular Biomarker of DNA Damage in Alzheimer's Disease in the AIBL Study of Ageing

In response to double-stranded breaks (DSBs) in chromosomal DNA, H2AX (a member of histone H2A family) becomes phosphorylated to form γH2AX. Although increased levels of γH2AX have been reported in the neuronal nuclei of Alzheimer's disease (AD) patients, the understanding of γH2AX responses in buccal nuclei of individuals with mild cognitive impairment (MCI) and AD remain unexplored. In the current study, endogenous γH2AX was measured in buccal cell nuclei from MCI (n = 18) or AD (n = 16) patients and in healthy controls (n = 17) using laser scanning cytometry (LSC). The γH2AX level was significantly elevated in nuclei of the AD group compared to the MCI and control group, and there was a concomitant increase in P-trend for γH2AX from the control group through MCI to the AD group. Receiver-operating characteristic curves were carried out for different γH2AX parameters; γH2AX in nuclei resulted in the greatest area under the curve value of 0.7794 (p = 0.0062) with 75% sensitivity and 70% specificity for the identification of AD patients from control. In addition, nuclear circularity (a measure of irregular nuclear shape) was significantly higher in the buccal cell nuclei from the AD group compared with the MCI and control groups. Additionally, there was a positive correlation between the nuclear circularity and γH2AX signals. The results indicated that increased DNA damage is associated with AD.

Early diagnosis and treatment of Alzheimer's disease: new definitions and challenges

The prevalence of Alzheimer's disease (AD), a progressive neurodegenerative disorder, is expected to more than double by 2050. Studies on the pathophysiology of AD have been changing our understanding of this disorder and setting a new scenario for drug development and other therapies. Concepts like the "amyloid cascade" and the "continuum of AD," discussed in this article, are now well established. From updated classifications and recommendations to advances in biomarkers of AD, we aim to critically assess the literature on AD, addressing new definitions and challenges that emerged from recent studies on the subject. Updates on the status of major clinical trials are also given, and future perspectives are discussed.

Autobiographical narratives in the elderly with neurocognitive disorder: an integrative literature review

ABSTRACT Objective: to carry out an integrative review of the literature on autobiographical narratives as a discursive activity in the older adult with neurocognitive disorder. Methods: a descriptive study that covered the Scopus, SciELO, PubMed, and Science Direct databases, from 2009 to 2019, using the keywords autobiographical, narrative, dementia, reminiscence, the elderly, and the Boolean operator. A narrative synthesis was adopted considering the characteristics of the clinical, and methodological heterogeneity of the studies. Results: the results included 3 articles published between 2012 and 2018, in the English language, from the United Kingdom, Brazil, and Argentina, which highlighted the autobiographical narratives. Although in a strict sense they did not present the narrative as a specific objective of the autobiographical study, they did provide interesting and related data which justified their inclusion. Conclusion: it is observed that the literature researched presents a limited number of articles, adressing the autobiographical narrative as a discursive activity in the elderly with neurocognitive disorder.

Dietary intakes and biomarker patterns of folate, vitamin B6, and vitamin B12 can be associated with cognitive impairment by hypermethylation of redox-related genes NUDT15 and TXNRD1

BACKGROUND

B vitamins in the one-carbon metabolism pathway (folate, vitamin B₆, and vitamin B₁₂) have been implicated in DNA methylation, and their deficiency may contribute to cognitive decline through increased homocysteine (Hcy) levels and subsequent oxidative damage. The aim of this study was to investigate whether B vitamin deficiency and increased Hcy could interact with DNA methylation of oxidative-related genes and exacerbate cognitive impairment.

METHODS

Participants were selected from a large cohort study entitled the Effects and Mechanism Investigation of Cholesterol and Oxysterol on Alzheimer's disease (EMCOA) study. We included 2533 participants who completed a selection of comprehensive cognitive tests and a semiquantitative food frequency questionnaire (FFQ) and were followed for an average of 2.3 years. The longitudinal effects of B vitamin intake on cognitive decline were examined using linear mixed-effect models. Seven mild cognitive impairment (MCI) patients, in the predementia stage of Alzheimer's disease (AD), and fivev healthy controls were selected for the discovery of genome-wide differentially methylated CpG sites. Candidate oxidative stress-related genes significantly correlated with serum levels of B vitamins were selected for validation in 102 MCI patients and 68 controls. The correlations between DNA methylation levels and serum concentrations of B vitamins and oxidative biomarkers were analyzed with Spearman's correlation. The interactive effects of DNA methylation and B vitamins on cognitive performance were further evaluated by multiple linear regression.

RESULTS

In the prospective analysis, inadequate dietary intake of vitamin B₁₂ was significantly associated with accelerated cognitive decline, whereas adequate folate, vitamin B₆, and vitamin B₁₂ intakes were significantly associated with better cognitive reserve. In the case-control analysis, the DNA methylation levels of NUDT15 and TXNRD1 were examined, and significantly hypermethylated sites were identified in MCI patients. Significant correlations of hypermethylated sites with serum levels of folate, homocysteine (Hcy), and oxidative biomarkers were observed, and interactive effects of B vitamins and hypermethylated sites were significantly associated with cognitive performance.

CONCLUSION

Adequate dietary folate at baseline predicted a better cognitive reserve, while decreased serum levels of B vitamins may contribute to cognitive impairment by affecting methylation levels of specific redox-related genes.

TRIAL REGISTRATION

EMCOA, ChiCTR-OOC-17011882, Registered 5th, July 2017-Retrospectively registered, http://www.medresman.org/uc/project/projectedit.aspx?proj=2610.

TRPC6 mRNA levels in peripheral leucocytes of patients with Alzheimer's disease and mild cognitive impairment: A case-control study

BACKGROUND

Transient receptor potential canonical (TRPC) 6 inhibits Aβ in Alzheimer's disease (AD) mouse brain and improves the behavioral performance.

AIMS

To evaluate the association of TRPC6 expression in peripheral leucocytes from AD and mild cognitive impairment (MCI) patients and to explore its potential value in early diagnosis of AD.

METHODS

TRPC6 mRNA levels in peripheral leucocytes were detected by quantitative real-time PCR. The Spearman correlation test was used to ascertain the associations between TRPC6 and the scores of MMSE, ADL, CSDD, CDR. The Receiver Operating Characteristic (ROC) curve was drawn to evaluate the diagnostic potential of TRPC6 for AD and MCI.

RESULTS

There were 108 CE, 136 MCI, 164 Con and 60 PD in the study. The expression of TRPC6 mRNA level in peripheral leucocytes was significantly lower: 1) in patients with AD and MCI compared to Con; 2) in AD compared to MCI; 3) in hospitalized AD compared to AD from communities. There was a significantly positive correlation between TRPC6 mRNA and MMSE score (p = .001, R = 0.327). Significantly inverse correlations were found between TRPC6 and CDR score (p < 0.001, R = -0.303) as well as between TRPC6 and ADL score (p = .001, R = -0.342) for all AD. The area under curve of ROC was 0.881 for the classification of AD, and 0.706 for the classification of MCI, respectively.

CONCLUSION

TRPC6 expression is inversely correlated with cognitive performance of AD. TRPC6 in peripheral leucocytes may be a potential biomarker for the diagnosis of AD.

Serum miRNAs Expression and SNAP-25 Genotype in Alzheimer's Disease

MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression by binding their 3' untranslated region (3'UTR) region; these molecules play a fundamental role in several pathologies, including Alzheimer's disease (AD). Synaptosomal-associated protein of 25 kDa (SNAP-25) is a vesicular protein of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) involved in neural plasticity and in the exocytosis of neurotransmitters, processes that are altered in AD. Recent results showed that a reduction of SNAP-25 is associated with dementia, and that the rs363050 SNAP-25 polymorphism correlates with cognitive decline and brain atrophy, as well as with the outcome of multistructured rehabilitation in AD patients. We verified the presence of possible correlations between the serum concentration of miRNAs that bind the SNAP-25 3'UTR region and AD. Six different microRNAs (miR-181a-5p, miR-361-3p, miR-23a-3p, miR-15b-3p, 130a-3p and miR-27b-3p) that bind the SNAP-25 3'UTR region were measured by qPCR in serum of AD patients (n = 22), mild cognitive impairment (MCI) subjects (n = 22) and age- and sex-matched controls (n = 22); analysis of results was done stratified for the rs363050 SNAP-25 genotype. Results showed that miR-27b-3p, miR-23a-3p and miR181a-5p serum concentration was significantly reduced in rs363050 SNAP-25 GG homozygous AD patients. Notably, concentration of these miRNAs was comparable in rs363050 AA homozygous AD patients, MCI and healthy controls (HCs). Data herein suggest that miRNAs that bind the SNAP-25 3'UTR region interact with SNAP-25 polymorphisms to influence the neural plasticity typical of AD brains, possibly as a consequence of modulatory activity on SNAP-25 mRNA and/or protein.

Cognitive Assessment Test: Validation of a Short Cognitive Test for the Detection of Mild Cognitive Disorder

Introduction

Cognitive disorders are a clinical and research challenge; in particular, the mild cognitive disorder (MiCD) requires diagnostic suspicion and tools with adequate performance for its detection. The objective of this study was the validation of a short cognitive test (CATest) for the detection of MiCD in population of 50 years or more.

Methods

A diagnostic accuracy study was assembled and performed in a prospective cohort. A consecutive sample of 200 Colombian subjects who represented the whole spectrum of the condition of interest allowed us to reach the objective. Validity was determined by concurrent criteria. The cut points were determined by the ROC curves considering the best overall performance and accuracy of the test.

Results

CATest was validated to detection of MiCD at a cut-off point of 18. As a result, scores lower than 18 classified the participants as MiCD. At this cut-off point, CATest showed sensitivity of 84.3% (CI 76 to 90.16), specificity of 71.4% (CI 95% 61.8 to 79.43), positive predictive value of 75% ( 95% CI 66.79 to 82.42), and area under curve AUC 0.8518 (standard error SE 0.0265).

Discussion

CATest has an adequate performance as a short cognitive test for the detection of MiCD. Its performance is superior to MiniMental and similar to Montreal Cognitive test (MoCA) according to the data reported in the literature. The advantages over other tests are the evaluation of all cognitive domains, time of application, and easy interpretation of results. CATest is a free use alternative for MiCD detection.

Ground Kayak Paddling Exercise Improves Postural Balance, Muscle Performance, and Cognitive Function in Older Adults with Mild Cognitive Impairment: A Randomized Controlled Trial

Background

Kayaking is an interesting and posturally challenging activity; however, kayaking may be limited by safety issues in older adults. The aim of this study was to determine whether ground kayak paddling (GKP) exercise can improve postural balance, muscle performance, and cognitive function in older adults with mild cognitive impairment.

Material/Methods

Sixty participants were randomly allocated to a GKP group (n=30; mean age, 74 years) or a control group (n=30; mean age, 74 years). GKP exercise consisted 5 types of exercise protocols, including paddling and multi-directional reaching with repetitive trunk and upper-extremities movements, which was performed for 60 min twice a week for 6 weeks. The outcome measures included the Timed Up and Go Test, the Functional Reach Test, the Berg Balance Scale, the Arm Curl Test, handgrip strength, and the Montreal Cognitive Assessment.

Results

In this study, adherence to the regimen was 96% in the GKP group. Postural balance, muscle performance, and cognitive function were significantly improved after intervention (p<0.05), and all the values in the GKP group, except for the Berg Balance Scale scores, were significantly decreased or increased compared to the control group. Differences between the 2 groups were Timed Up and Go Test −0.74 s; Functional Reach Test +7.20 cm; Arm Curl Test +5.56 repetitions; right handgrip strength +3.57 kg; left handgrip strength +3.08 kg; and Montreal Cognitive Assessment, +3.46 score (p<0.05).

Conclusions

GKP exercise improves the physical and psychological ability of older adults with mild cognitive impairment.

A simple and clinically relevant combination of neuroimaging and functional indexes for the identification of those at highest risk of Alzheimer's disease

The current challenge in clinical practice is to identify those with mild cognitive impairment (MCI), who are at greater risk of Alzheimer's disease (AD) conversion in the near future. The aim of this study was to assess a clinically practical new hippocampal index-hippocampal volume normalized by cerebellar volume (hippocampus to cerebellum volume ratio) used alone or in combination with scores on the Mini-Mental State Examination, as a predictor of conversion from MCI to AD. The predictive value of the HCCR was also contrasted to that of the hippocampal volume to intracranial volume ratio. The findings revealed that the performance of the combination of measures was significantly better than that of each measure used individually. The combination of Mini-Mental State Examination and hippocampal volume, normalized by the cerebellum or by intracranial volume, accurately discriminated individuals with MCI who progress to AD within 5 years from other MCI types (stable, reverters) and those with intact cognition (area under receiver operating curve of 0.88 and 0.89, respectively). Normalization by cerebellar volume was as accurate as normalization by intracranial volume with the advantage of being more practical, particularly for serial assessments.

A systematic review of the diagnostic accuracy of automated tests for cognitive impairment

OBJECTIVE

The aim of this review is to determine whether automated computerised tests accurately identify patients with progressive cognitive impairment and, if so, to investigate their role in monitoring disease progression and/or response to treatment.

METHODS

Six electronic databases (Medline, Embase, Cochrane, Institute for Scientific Information, PsycINFO, and ProQuest) were searched from January 2005 to August 2015 to identify papers for inclusion. Studies assessing the diagnostic accuracy of automated computerised tests for mild cognitive impairment (MCI) and early dementia against a reference standard were included. Where possible, sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios were calculated. The Quality Assessment of Diagnostic Accuracy Studies tool was used to assess risk of bias.

RESULTS

Sixteen studies assessing 11 diagnostic tools for MCI and early dementia were included. No studies were eligible for inclusion in the review of tools for monitoring progressive disease and response to treatment. The overall quality of the studies was good. However, the wide range of tests assessed and the non-standardised reporting of diagnostic accuracy outcomes meant that statistical analysis was not possible.

CONCLUSION

Some tests have shown promising results for identifying MCI and early dementia. However, concerns over small sample sizes, lack of replicability of studies, and lack of evidence available make it difficult to make recommendations on the clinical use of the computerised tests for diagnosing, monitoring progression, and treatment response for MCI and early dementia. Research is required to establish stable cut-off points for automated computerised tests used to diagnose patients with MCI or early dementia.

Automated tests for diagnosing and monitoring cognitive impairment: a diagnostic accuracy review

BACKGROUND

Cognitive impairment is a growing public health concern, and is one of the most distinctive characteristics of all dementias. The timely recognition of dementia syndromes can be beneficial, as some causes of dementia are treatable and are fully or partially reversible. Several automated cognitive assessment tools for assessing mild cognitive impairment (MCI) and early dementia are now available. Proponents of these tests cite as benefits the tests' repeatability and robustness and the saving of clinicians' time. However, the use of these tools to diagnose and/or monitor progressive cognitive impairment or response to treatment has not yet been evaluated.

OBJECTIVES

The aim of this review was to determine whether or not automated computerised tests could accurately identify patients with progressive cognitive impairment in MCI and dementia and, if so, to investigate their role in monitoring disease progression and/or response to treatment.

DATA SOURCES

Five electronic databases (MEDLINE, EMBASE, The Cochrane Library, ISI Web of Science and PsycINFO), plus ProQuest, were searched from 2005 to August 2015. The bibliographies of retrieved citations were also examined. Trial and research registers were searched for ongoing studies and reviews. A second search was run to identify individual test costs and acquisition costs for the various tools identified in the review.

REVIEW METHODS

Two reviewers independently screened all titles and abstracts to identify potentially relevant studies for inclusion in the review. Full-text copies were assessed independently by two reviewers. Data were extracted and assessed for risk of bias by one reviewer and independently checked for accuracy by a second. The results of the data extraction and quality assessment for each study are presented in structured tables and as a narrative summary.

RESULTS

The electronic searching of databases, including ProQuest, resulted in 13,542 unique citations. The titles and abstracts of these were screened and 399 articles were shortlisted for full-text assessment. Sixteen studies were included in the diagnostic accuracy review. No studies were eligible for inclusion in the review of tools for monitoring progressive disease. Eleven automated computerised tests were assessed in the 16 included studies. The overall quality of the studies was good; however, the wide range of tests assessed and the non-standardised reporting of diagnostic accuracy outcomes meant that meaningful synthesis or statistical analysis was not possible.

LIMITATIONS

The main limitation of this review is the substantial heterogeneity of the tests assessed in the included studies. As a result, no meta-analyses could be undertaken.

CONCLUSION

The quantity of information available is insufficient to be able to make recommendations on the clinical use of the computerised tests for diagnosing and monitoring MCI and early dementia progression. The value of these tests also depends on the costs of acquisition, training, administration and scoring.

FUTURE WORK

Research is required to establish stable cut-off points for automated computerised tests that are used to diagnose patients with MCI or early dementia. Additionally, the costs associated with acquiring and using these tests in clinical practice should be estimated.

STUDY REGISTRATION

The study is registered as PROSPERO CRD42015025410.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Olfactory evaluation in Mild Cognitive Impairment: correlation with neurocognitive performance and endothelial function

Mild Cognitive Impairment (MCI) is an intermediate condition between normal aging and dementia, associated with an increased risk of progression into the latter within months or years. Olfactory impairment, a well-known biomarker for neurodegeneration, might be present in the condition early, possibly representing a signal for future pathological onset. Our study aimed at evaluating olfactory function in MCI and healthy controls in relation to neurocognitive performance and endothelial function. A total of 85 individuals with MCI and 41 healthy controls, matched for age and gender, were recruited. Olfactory function was assessed by Sniffin' Sticks Extended Test (Burghart, Medizintechnik, GmbH, Wedel, Germany). A comprehensive neurocognitive assessment was performed. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery by ultrasound. MCI individuals showed an impaired olfactory function compared to controls. The overall olfactory score is able to predict MCI with a good sensitivity and specificity (70.3 and 77.4% respectively). In MCI, olfactory identification score is correlated with a number of neurocognitive abilities, including overall cognitive status, dementia rating, immediate and delayed memory, visuospatial ability and verbal fluency. FMD was reduced in MCI (2.90 ± 2.15 vs. 3.66 ± 1.96%, P = 0.016) and was positively associated with olfactory identification score (ρ_s =0.219, P = 0.025). The association remained significant after controlling for age, gender, and smoking. In conclusion, olfactory evaluation is able to discriminate between MCI and healthy individuals. Systemic vascular dysfunction might be involved, at least indirectly, in olfactory dysfunction in MCI.

Correlation of MRI Visual Scales with Neuropsychological Profile in Mild Cognitive Impairment of Parkinson's Disease

Few studies have evaluated magnetic resonance imaging (MRI) visual scales in Parkinson's disease-Mild Cognitive Impairment (PD-MCI). We selected 79 PD patients and 92 controls (CO) to perform neurologic and neuropsychological evaluation. Brain MRI was performed to evaluate the following scales: Global Cortical Atrophy (GCA), Fazekas, and medial temporal atrophy (MTA). The analysis revealed that both PD groups (amnestic and nonamnestic) showed worse performance on several tests when compared to CO. Memory, executive function, and attention impairment were more severe in amnestic PD-MCI group. Overall analysis of frequency of MRI visual scales by MCI subtype did not reveal any statistically significant result. Statistically significant inverse correlation was observed between GCA scale and Mini-Mental Status Examination (MMSE), Montreal Cognitive Assessment (MoCA), semantic verbal fluency, Stroop test, figure memory test, trail making test (TMT) B, and Rey Auditory Verbal Learning Test (RAVLT). The MTA scale correlated with Stroop test and Fazekas scale with figure memory test, digit span, and Stroop test according to the subgroup evaluated. Visual scales by MRI in MCI should be evaluated by cognitive domain and might be more useful in more severely impaired MCI or dementia patients.

Neuroanatomical and Neuropsychological Markers of Amnestic MCI: A Three-Year Longitudinal Study in Individuals Unaware of Cognitive Decline

Structural brain changes underlying mild cognitive impairment (MCI) have been well-researched, but most previous studies required subjective cognitive complaints (SCC) as a diagnostic criterion, diagnosed MCI based on a single screening test or lacked analyses in relation to neuropsychological impairment. This longitudinal voxel-based morphometry study aimed to overcome these limitations: The relationship between regional gray matter (GM) atrophy and behavioral performance was investigated over the course of 3 years in individuals unaware of cognitive decline, identified as amnestic MCI based on an extensive neuropsychological test battery. Region of interest analyses revealed GM atrophy in the left amygdala, hippocampus, and parahippocampus in MCI individuals compared to normally aging participants, which was specifically related to verbal memory impairment and evident already at the first measurement point. These findings demonstrate that GM atrophy is detectable in individuals with amnestic MCI despite unawareness of beginning cognitive decline. Thus, individuals with GM atrophy in regions associated with verbal memory impairment do not necessarily need to experience SCC before meeting neuropsychological criteria for MCI. These results have important implications for future research and diagnostic procedures of MCI.

Modulation of Immune Responses to Herpes Simplex Virus Type 1 by IFNL3 and IRF7 Polymorphisms: A Study in Alzheimer's Disease

Herpes simplex virus type 1 (HSV-1) has long been suspected to play a role in Alzheimer's disease (AD), the most common form of dementia. IFN-lambda (IFN-λ) is one of the key cytokine in innate antiviral defenses and, in particular, has an appreciable antiviral activity against HSV-1 infection. IFN-λ expression is regulated by the interaction between two different proteins: Mediator Complex 23 (MED23) and Interferon-Responsive Transcription Factor 7 (IRF7); single nucleotide polymorphisms (SNPs) in these genes as well as in IFNL3 were shown to be differently distributed in AD patients. In this study, allelic discrimination analysis for IFNL3 rs12979860, MED23 rs3756784, and IRF7 rs6598008, as well as IFN-λ serum concentration and anti-HSV-1 antibody (Ab) titers were performed in 79 AD patients, 57 mild cognitive impairment (MCI) individuals, and 81 healthy controls (HC) who were HSV-1-seropositive. Results showed that INF-λ serum concentration was increased in AD and MCI carrying the IFNL3 T allele compared to HC (AD versus HC: p = 0.014; MCI versus HC: p = 0.029), with the highest anti-HSV-1 Ab titers seen in AD patients carrying the IFNL3 CC genotype (p = 0.012 versus HC). Notably, anti-HSV-1 Ab titers were higher in AD and MCI individuals carrying the IRF7 AA genotype compared to HC (p = 0.018 for both). MED23 polymorphisms did not show any statistical association either with serum IFN-λ or with anti-HSV-1 Ab. Data herein suggest that the IFNL3 rs12979860 and IRF7 rs6598008 polymorphisms modulate immune responses against HSV-1 via their effect on the IFN-λ pathway. These results help to clarify the possible role of HSV-1 infection in AD pathogenesis.

Plasma Brain-Derived Neurotrophic Factor as a Biomarker for the Main Types of Mild Neurocognitive Disorders and Treatment Efficacy: A Preliminary Study

Decreased levels of brain-derived neurotrophic factor (BDNF) are assumed to play a crucial role in the pathophysiology of mild neurocognitive disorders (MNCDs). In this study, we compared plasma BDNF levels (at baseline and after two months of treatment with escitalopram) in patients with the main types of MNCDs and normal controls. 21 patients met the DSM-5 diagnostic criteria for possible MNCD due to Alzheimer's disease (MNCD-AD); 22 patients fulfilled the diagnostic criteria for subcortical vascular MNCD (ScVMNCD) according to Frisoni et al. (2002) and neuroimaging-supported probable diagnosis of vascular MNCD according to DSM-5; 16 subjects entered control group. At baseline, we detected lower BDNF levels in both MNCD groups, which was significant only in subjects with MNCD-AD. Moreover, plasma BDNF level of 21160 pg/mL showed high sensitivity (94%) to discriminate patients with MNCD-AD. Decreased plasma BDNF highly correlated with the severity of memory impairment and total MMSE score in MNCD-AD group. Escitalopram treatment in patients with MNCD-AD or ScVMNCD led to an increase of plasma BDNF concentrations and as a result to a decrease of cognitive, depressive, and anxiety symptom severity. In conclusion, plasma BDNF might be a reliable biomarker for the validation of MNCD-AD diagnosis and treatment efficacy.

Depressive symptoms increase the risk of progression to dementia in subjects with mild cognitive impairment: systematic review and meta-analysis

OBJECTIVE

There is a long-standing debate in the literature whether depressive symptoms increase the risk of dementia in older with mild cognitive impairment (MCI). We aim to conduct a meta-analysis of studies that evaluated the risk of dementia in subjects with MCI and depressive symptoms compared with subjects with MCI and no depressive symptoms.

METHODS

We calculated the relative risk of progression to dementia in subjects with MCI and depressive symptoms compared with subjects with MCI and no depressive symptoms using a generic inverse variance method with random effect models.

RESULTS

Eighteen studies were included in the meta-analysis, with a sample size of 10,861 MCI subjects. The pooled relative risk of progressing to dementia was 1.28 CI95% [1.09-1.52] (p = 0.003) in the group of MCI subjects with depressive symptoms compared with the MCI subjects with no depressive symptoms.

DISCUSSION

Our results provide additional evidence that depressive symptoms determine an additive risk effect to the progression to dementia in subjects with MCI. The comorbidity between depression and cognitive impairment can be an intervention target for prevention of dementia in MCI subjects. Copyright © 2015 John Wiley & Sons, Ltd.

Cerebral microbleeds in early Alzheimer's disease

We hypothesize that cerebral microbleeds (CMB) in patients with different neuropsychological profiles (amnestic or non-amnestic) and MRI features of vascular damage could provide important information on the underlying pathological process in early Alzheimer's disease. The study was performed at two trial sites. We studied 136 outpatients with cognitive decline. MRI was performed using a magnetic field of 1.5 and 3 T. Neuropsychological assessment included Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment scale (MoCA), Addenbrooke's Cognitive Examination (ACE-R), Cambridge Cognitive Examination battery (CAMCOG) (Part 3), Clock Drawing Test, fluency test and the visual memory test (SCT). CSF was examined for standard parameters such as tau, phosphorylated tau, amyloid-β 1-40 and 42 and Qalbumin, in accordance with established protocols and genotype. In 61 patients (45 %), at least 1 CMB was found. Most of the CMBs were described in the amnestic profile (67 %). In 86 % of the cases, multiple CMB were observed. The ratio of Aβ1-40/42 in non-amnestic patients with CMB was significantly lower (mean 0.6) than in patients without CMB (mean 1.2). A notable difference in the albumin ratio as an indicator of the BBB was observed between groups with and without CMB. In the CMP-positive group, the E2 genotype was observed more frequently, and the E4 genotype less frequently, than in the CMB-negative group. Based on the cerebrospinal fluid-serum albumin ratio, we were able to show that patients with CMB present several features of BBB dysfunction. According to logistic regression, the predictive factors for CMB in patients with cognitive decline were age, WMHs score and albumin ratio. We found a significant reduction in the Aβ-amyloid ratio in the non-amnestic profile group with CMB (particularly in the cortical region) in comparison to those without CMB. While this is an interesting finding, its significance needs to be assessed in a prospective follow-up.

Application and Revision of Montreal Cognitive Assessment in China's Military Retirees with Mild Cognitive Impairment

Objective

In an effort to accommodate MOCA to better fit for the Chinese context, this study was designed to employ the MOCA criteria to screen mild cognitive impairment (MCI) and analyze associated risk factors in military retirees.

Methods

Three hundred and four retired military cadres were recruited using a random cluster sampling technique with information collected including personal, prevalence, MOCA scale, and related neuropsychiatry scale. Thirty retirees were randomly chosen to be further analyzed one month later using the revised MOCA scale.

Results

①Our data indicated an incidence rate of 64.8% for mild cognitive impairment in retired military cadres. The incidence rate for MCI was significantly higher in those aged 80 or above compared with those 80 years of age or younger (P<0.05). The incidence rate of MCI was significantly higher in those with fewer than 6 years of education compared with those with over 7 years of education (P<0.05). The MCI incidence was higher for those with little exercise than those taking regular exercise (P<0.01). Moreover, the MCI incidence was higher in stroke patients than those who never had a stroke episode (P<0.05). ②There was a significant correlation between MOCA and MMSE scale scores (r = 0.81). MOCA scale scores were negatively correlated with ADL and CES-D scores (although not PSQI scores). ③ MOCA recension Cronbach’s alpha value was 0.862. The related coefficient of MOCA and MOCA recension was 0.878(P<0.01). When the Score of cut-off -point of the MOCA recension was 28, the area in ROC curve analyses was 0.859, as well as the largest area.

Conclusion

Retired cadres exhibited a greater incidence of MCI (than general population), which was closely associated with age, level of education and physical exercise and cerebral apoplexy. Revised MOCA scale displays a better validity and reaction degree of reliability and is more suitable for screening and diagnosis of MCI in the elderly in China.

Brain FDG PET and the diagnosis of dementia

OBJECTIVE

We review the role of brain FDG PET in the diagnosis of Alzheimer disease, frontotemporal dementia, dementia with Lewy bodies, and vascular dementia. Characteristic spatial patterns of brain metabolism on FDG PET can help differentiate various subtypes of dementia.

CONCLUSION

In patients with different subtypes of dementia, FDG PET/CT shows distinct spatial patterns of metabolism in the brain and can help clinicians to make a reasonably accurate and early diagnosis for appropriate management or prognosis.

Cognitive impairment in older adults and oral health considerations: treatment and management

Worldwide incidences of degenerative cognitive diseases are increasing as the population ages. This decline in mental function frequently causes behavioral changes that directly affect oral health. The loss of interest and ability to complete the simple tasks of brushing and flossing can cause a rapid development of hard and soft tissue diseases that result in decreased function and increased dental pain. The challenge for the dental community is to understand and to identify the early signs of cognitive dysfunction so as to develop a rational treatment strategy that allows patients to comfortably maintain their teeth for as long as possible.