On the impact of age, gender and educational level on cognitive function in Alzheimer’s disease: A quantitative approach

Attention to the domains of Revised Hasegawa Dementia Scale and Mini-Mental State Examination in patients with Alzheimer's disease dementia

BACKGROUND

In Japan, Alzheimer's disease dementia (AD) is the most common cognitive disease, and the most widely used dementia screening tests are the Revised Hasegawa Dementia Scale (HDS-R) and Mini-Mental State Examination (MMSE). This study sought to elucidate the relationships of the individual domains of these tests with age and duration of school education in a large group of patients with AD.

METHODS

Participants were 505 new outpatients diagnosed with AD who completed the HDS-R and MMSE at the first visit. We investigated the relationships of total and individual domains of these tests with age and duration of school education using the least squares method. Next, we plotted regression lines of the individual domain scores against the total test scores.

RESULTS

Younger age and longer duration of school education were significantly associated with higher total HDS-R and MMSE scores in AD. Domain-specific results indicated that younger age was significantly associated with a higher immediate memory score on both the HDS-R and MMSE and with a higher orientation (time), repetition score on the MMSE. Longer duration of school education was significantly associated with a higher working memory score on the HDS-R and with higher serial 7, repetition and writing scores on the MMSE. In addition, shorter duration of school education was significantly associated with higher naming score on the MMSE. The regression lines of orientation of time, remote memory, visual memory, and verbal frequency hit the bottom on the HDS-R (4/30, 8/30, 4/30, and 6/30, respectively) and of orientation of time, serial 7, remote memory, and writing also hit the bottom on the MMSE (8/30, 9/30, 11/30, and 8/30, respectively).

CONCLUSIONS

We should pay attention to age, duration of school education, and the individual domains when using the HDS-R or MMSE to assess patients with AD.

Beyond CSF and Neuroimaging Assessment: Evaluating Plasma miR-145-5p as a Potential Biomarker for Mild Cognitive Impairment and Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia. New strategies for the early detection of MCI and sporadic AD are crucial for developing effective treatment options. Current techniques used for diagnosis of AD are invasive and/or expensive, so they are not suitable for population screening. Cerebrospinal fluid (CSF) biomarkers such as amyloid β1-42 (Aβ1-42), total tau (T-tau), and phosphorylated tau181 (P-tau181) levels are core biomarkers for early diagnosis of AD. Several studies have proposed the use of blood-circulating microRNAs (miRNAs) as potential novel early biomarkers for AD. We therefore applied a novel approach to identify blood-circulating miRNAs associated with CSF biomarkers and explored the potential of these miRNAs as biomarkers of AD. In total, 112 subjects consisting of 28 dementia due to AD cases, 63 MCI due to AD cases, and 21 cognitively healthy controls were included. We identified seven Aβ1-42-associated plasma miRNAs, six P-tau181-associated plasma miRNAs, and nine Aβ1-42-associated serum miRNAs. These miRNAs were involved in AD-relevant biological processes, such as PI3K/AKT signaling. Based on this signaling pathway, we constructed an miRNA-gene target network, wherein miR-145-5p has been identified as a hub. Furthermore, we showed that miR-145-5p performs best in the prediction of both AD and MCI. Moreover, miR-145-5p also improved the prediction performance of the mini-mental state examination (MMSE) score. The performance of this miRNA was validated using different datasets including an RT-qPCR dataset from plasma samples of 23 MCI cases and 30 age-matched controls. These findings indicate that blood-circulating miRNAs that are associated with CSF biomarkers levels and specifically plasma miR-145-5p alone or combined with the MMSE score can potentially be used as noninvasive biomarkers for AD or MCI screening in the general population, although studies in other AD cohorts are necessary for further validation.

Factors associated with social participation in Brazilian older adults with Alzheimer's disease: A correlational, cross-sectional study

The occurrence of Alzheimer's disease (AD) can exert a negative impact in social participation in affected older adults. The purpose of this study was to investigate whether social participation in older adults with AD is associated with disease stage and cognitive function as well as the quality of life and depressive symptoms in their caregivers. A correlational, cross-sectional study was conducted in 40 older adults with AD (28 women and 12 men) and 40 caregivers (30 women and 10 men). Social participation was assessed using the 'social participation' domain of the Activities of Daily Living Questionnaire. Disease stage was determined using the Clinical Dementia Rating scale and cognitive function was assessed using Addenbrooke's Cognitive Examination. Quality of life and depressive symptoms in the caregivers were evaluated using the Quality of Life Assessment Scale on Alzheimer's Disease and Beck Depression Inventory respectively. The older adults with AD had a mean percentage of 59.4% on the social participation domain and a mean score of 49.0 for cognitive function. The caregivers had mean scores of 39.1 for quality of life and 9.9 for depressive symptoms. The stepwise backward multiple linear regression model indicated that the predictors analysed together explained 48% of the variability in social participation among older adults with AD. Therefore, lower social participation among older adults with AD is associated with more advanced stages of the disease and cognitive decline in these individuals as well as a lower perception of quality of life and greater levels of depressive symptoms in their caregivers.

Executive Functions in Alzheimer’s Disease: A Systematic Review

Background: In Alzheimer’s disease, in addition to memory, attention has been given to cognitive testing due to its interface and connection with memory. Objective: The aim of this study is to take a global view of executive functions and place the concept within the theoretical framework of Alzheimer’s disease dementia, verifying their role in the cognitive functioning of the human mind, as well as how they are compromised in this pathology. Methods: An initial search was carried out in databases such as PubMed, ScienceDirect, and Web of Science. The guiding question presented at the end of the introduction was elaborated from the PICO/PIO/PEO strategy. The selected articles, therefore, answered the guiding question, were made available in full, and published in the period from 2000 to 2020. Studies without specific methodology and which correlated with other diseases or other types of dementia were excluded. To meet the objective, an integrative literature review was adopted. Results: The results indicate that, although the tests to verify the performance of cognitive functions have their limitations, they bring some evidence that they have been compromised, especially when analyzed periodically during the development of dementia. Conclusion: It is concluded that there is an interference of executive functions in function of Alzheimer’s and that memory and attention are the most evident in this type of dementia.

Past, present and future of therapeutic strategies against amyloid-β peptides in Alzheimer's disease: a systematic review

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in ageing, affecting around 46 million people worldwide but few treatments are currently available. The etiology of AD is still puzzling, and new drugs development and clinical trials have high failure rates. Urgent outline of an integral (multi-target) and effective treatment of AD is needed. Accumulation of amyloid-β (Aβ) peptides is considered one of the fundamental neuropathological pillars of the disease, and its dyshomeostasis has shown a crucial role in AD onset. Therefore, many amyloid-targeted therapies have been investigated. Here, we will systematically review recent (from 2014) investigational, follow-up and review studies focused on anti-amyloid strategies to summarize and analyze their current clinical potential. Combination of anti-Aβ therapies with new developing early detection biomarkers and other therapeutic agents acting on early functional AD changes will be highlighted in this review. Near-term approval seems likely for several drugs acting against Aβ, with recent FDA approval of a monoclonal anti-Aβ oligomers antibody -aducanumab- raising hopes and controversies. We conclude that, development of oligomer-epitope specific Aβ treatment and implementation of multiple improved biomarkers and risk prediction methods allowing early detection, together with therapies acting on other factors such as hyperexcitability in early AD, could be the key to slowing this global pandemic.

Effect of age stratification on the association between carotid intima-media thickness and cognitive impairment in Chinese hypertensive patients: new insight from the secondary analysis of the China Stroke Primary Prevention Trial (CSPPT)

The current study aimed to explore the association between carotid intima-media thickness (CIMT) and cognitive function assessed by the Mini-Mental State Examination (MMSE) and to examine possible effect modifiers in hypertensive patients. A total of 14,322 hypertensive participants (mean age 64.2 ± 7.4 years; 40.9% male) from the China Stroke Primary Prevention Trial (CSPPT) were included in the final analysis. CIMT was measured by ultrasound, and data were collected at the last follow-up visit; MMSE was used to evaluate cognitive function. Nonparametric smoothing plots, multivariate linear regression analysis, subgroup analyses and interaction testing were performed to examine the relationship between the CIMI and cognitive function and effect modification. The mean CIMT was 0.74 ± 0.11 mm, and the mean MMSE score was 23.5 ± 4.8. There was a significant interaction (P interaction < 0.05) in both male and female populations stratified by age (<60 vs. ≥60 years), and higher CIMT was significantly associated with decreased MMSE scores only in participants aged ≥60 years (male: β = -2.29, 95% CI -3.23 to -1.36; female: β = -1.96, 95% CI -2.97 to -0.95). Males with abnormal HDL-C showed a stronger negative association (β = -3.16, 95% CI -4.85 to -1.47) than those with normal HDL-C (normal vs. abnormal, P for interaction = 0.004). We observed that increased CIMT was significantly associated with cognitive impairment in the hypertensive population, especially among individuals with an age greater than 60 years and HDL-C deficiency. Overall, upon diagnosis of hypertension, treatment should start at the earliest opportunity to prevent end-organ damage and cognitive decline.

Autoregressive cross-lagged modelling of the relationship between social activity, depressive symptoms, and cognitive function in Korean elderly

BACKGROUND

This study aimed to verify the reciprocal relationship between social activity, depressive symptoms, and cognitive function in Korean elderly, utilizing data from the Korean Longitudinal Study of Aging (conducted by the Korea Employment Information Service biennially from 2006 to 2018).

METHODS

The data of 5549 people aged 60 and over (mean age 70.27 years, standard deviation = 7.26) were used in the final analysis. Autoregressive cross-lagged analysis was used to examine bidirectional relationships between the variables over time. Frequency of participation in social activities, the Center for Epidemiologic Studies Depression Scale, and the Korean version of the Mini-Mental State Examination were used to measure social activity, depressive symptoms, and cognitive function.

RESULTS

Results of the analysis were as follows. First, social activity was found to have a negative effect on depressive symptoms over time, but depressive symptoms did not affect social activity. Second, a bidirectional relationship between depressive symptoms and cognitive function was identified. In other words, more depressive symptoms were related to lower cognitive function, and cognitive function had a negative impact on depressive symptoms over time. Third, social activity was found to positively affect cognitive function, but cognitive function did not affect social activity over time.

CONCLUSIONS

The results of this study indicate that social activity is closely related to depressive symptoms and cognitive function in the elderly, and suggests that social activity can be a key preventive factor for depression and cognitive impairment in this population.