Diagnosis and Management of Dementia: Review

Dementia risk prediction in individuals with mild cognitive impairment: a comparison of Cox regression and machine learning models

Background

Cox proportional hazards regression models and machine learning models are widely used for predicting the risk of dementia. Existing comparisons of these models have mostly been based on empirical datasets and have yielded mixed results. This study examines the accuracy of various machine learning and of the Cox regression models for predicting time-to-event outcomes using Monte Carlo simulation in people with mild cognitive impairment (MCI).

Methods

The predictive accuracy of nine time-to-event regression and machine learning models were investigated. These models include Cox regression, penalized Cox regression (with Ridge, LASSO, and elastic net penalties), survival trees, random survival forests, survival support vector machines, artificial neural networks, and extreme gradient boosting. Simulation data were generated using study design and data characteristics of a clinical registry and a large community-based registry of patients with MCI. The predictive performance of these models was evaluated based on three-fold cross-validation via Harrell’s concordance index (c-index), integrated calibration index (ICI), and integrated brier score (IBS).

Results

Cox regression and machine learning model had comparable predictive accuracy across three different performance metrics and data-analytic conditions. The estimated c-index values for Cox regression, random survival forests, and extreme gradient boosting were 0.70, 0.69 and 0.70, respectively, when the data were generated from a Cox regression model in a large sample-size conditions. In contrast, the estimated c-index values for these models were 0.64, 0.64, and 0.65 when the data were generated from a random survival forest in a large sample size conditions. Both Cox regression and random survival forest had the lowest ICI values (0.12 for a large sample size and 0.18 for a small sample size) among all the investigated models regardless of sample size and data generating model.

Conclusion

Cox regression models have comparable, and sometimes better predictive performance, than more complex machine learning models. We recommend that the choice among these models should be guided by important considerations for research hypotheses, model interpretability, and type of data.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01754-y.

Time to dementia diagnosis by race: A retrospective cohort study

BACKGROUND

Non-Hispanic Black individuals may be less likely to receive a diagnosis of dementia compared to non-Hispanic White individuals. These findings raise important questions regarding which factors may explain this observed association and any differences in the time to which disparities emerge following dementia onset.

METHODS

We conducted a retrospective cohort study using survey data from the 1995 to 2016 Health and Retirement Study linked with Medicare fee-for-service claims. Using the Hurd algorithm (a regression-based approach), we identified dementia onset among older adult respondents (age ≥65 years) from the Telephone Interview for Cognitive Status and proxy respondents. We determined date from dementia onset to diagnosis using Medicare data up to 3 years following onset using a list of established diagnosis codes. Cox Proportional Hazards modeling was used to examine the association between an individual's reported race and likelihood of diagnosis after accounting for sociodemographic characteristics, income, education, functional status, and healthcare use.

RESULTS

We identified 3435 older adults who experienced a new onset of dementia. Among them, 30.1% received a diagnosis within 36 months of onset. In unadjusted analyses, the difference in cumulative proportion diagnosed by race continued to increase across time following onset, p-value <0.001. 23.8% of non-Hispanic Black versus 31.4% of non-Hispanic White participants were diagnosed within 36 months of dementia onset, Hazard Ratio = 0.73 (95% CI: 0.61, 0.88). The association persisted after adjustment for functional status and healthcare use; however, these factors had less of an impact on the strength of the association than income and level of education.

CONCLUSION

Lower diagnosis rates of dementia among non-Hispanic Black individuals persists after adjustment for sociodemographic characteristics, functional status, and healthcare use. Further understanding of barriers to diagnosis that may be related to social determinants of health is needed to improve dementia-related outcomes among non-Hispanic Black Americans.

Association between frailty and cognitive function in older Chinese people: A moderated mediation of social relationships and depressive symptoms

BACKGROUND

To date, few studies have focused on examining either the direct or indirect effect of physical frailty on cognitive impairment. This study aimed to investigate the moderating effects of social relationships, including their individual components in the role of depressive symptoms as a mediator between frailty and cognitive impairment.

METHODS

This study included a total of 7525 Chinese older adults from the 2017-2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Mediation analyses and moderated mediation effect analysis fully adjusted for all potential confounding factors were conducted.

RESULTS

Significant correlations were found between frailty, depression, social relationships, and cognitive function. Depression partially mediated the association of frailty with cognitive function [B = -0.198; 95 % confidence interval (CI): (-0.258, -0.143)]. Social relationships moderated the effect of frailty on cognitive function through both path b (depression-cognitive function) [B = 0.137; 95 % CI: (0.045, 0.230)], and path c' (frailty-cognitive function) [B = 0.870; 95 % CI: (0.562, 1.178)]. In addition, social activities and social networks moderated both the direct and indirect effect of the moderated mediation model. Social support only moderated the direct effect.

LIMITATIONS

The cross-sectional design of this study precludes any conclusion from the results as to the causality of cognitive impairment.

CONCLUSIONS

Social relationships moderated both the direct and indirect effects of depressive symptoms on the association between frailty and cognitive impairment. The findings suggest that interventions, such as paying attention to the mental health of old people and improving the quality of social relationships, may help break the link between frailty and cognitive impairment.

A deep learning model for detection of Alzheimer's disease based on retinal photographs: a retrospective, multicentre case-control study

BACKGROUND

There is no simple model to screen for Alzheimer's disease, partly because the diagnosis of Alzheimer's disease itself is complex-typically involving expensive and sometimes invasive tests not commonly available outside highly specialised clinical settings. We aimed to develop a deep learning algorithm that could use retinal photographs alone, which is the most common method of non-invasive imaging the retina to detect Alzheimer's disease-dementia.

METHODS

In this retrospective, multicentre case-control study, we trained, validated, and tested a deep learning algorithm to detect Alzheimer's disease-dementia from retinal photographs using retrospectively collected data from 11 studies that recruited patients with Alzheimer's disease-dementia and people without disease from different countries. Our main aim was to develop a bilateral model to detect Alzheimer's disease-dementia from retinal photographs alone. We designed and internally validated the bilateral deep learning model using retinal photographs from six studies. We used the EfficientNet-b2 network as the backbone of the model to extract features from the images. Integrated features from four retinal photographs (optic nerve head-centred and macula-centred fields from both eyes) for each individual were used to develop supervised deep learning models and equip the network with unsupervised domain adaptation technique, to address dataset discrepancy between the different studies. We tested the trained model using five other studies, three of which used PET as a biomarker of significant amyloid β burden (testing the deep learning model between amyloid β positive vs amyloid β negative).

FINDINGS

12 949 retinal photographs from 648 patients with Alzheimer's disease and 3240 people without the disease were used to train, validate, and test the deep learning model. In the internal validation dataset, the deep learning model had 83·6% (SD 2·5) accuracy, 93·2% (SD 2·2) sensitivity, 82·0% (SD 3·1) specificity, and an area under the receiver operating characteristic curve (AUROC) of 0·93 (0·01) for detecting Alzheimer's disease-dementia. In the testing datasets, the bilateral deep learning model had accuracies ranging from 79·6% (SD 15·5) to 92·1% (11·4) and AUROCs ranging from 0·73 (SD 0·24) to 0·91 (0·10). In the datasets with data on PET, the model was able to differentiate between participants who were amyloid β positive and those who were amyloid β negative: accuracies ranged from 80·6 (SD 13·4%) to 89·3 (13·7%) and AUROC ranged from 0·68 (SD 0·24) to 0·86 (0·16). In subgroup analyses, the discriminative performance of the model was improved in patients with eye disease (accuracy 89·6% [SD 12·5%]) versus those without eye disease (71·7% [11·6%]) and patients with diabetes (81·9% [SD 20·3%]) versus those without the disease (72·4% [11·7%]).

INTERPRETATION

A retinal photograph-based deep learning algorithm can detect Alzheimer's disease with good accuracy, showing its potential for screening Alzheimer's disease in a community setting.

FUNDING

BrightFocus Foundation.

Reduction in manual asymmetry and decline in fine manual dexterity in right-handed older adults with mild cognitive impairment

Research in Parkinson's or Alzheimer's disease suggests that hand function is affected by neurodegenerative diseases. However, little is known about the relationship between hand function and mild cognitive impairment (MCI). Therefore, we conducted a kinematic analysis of unimanual hand movements in MCI patients to answer whether manual asymmetries and manual dexterity are affected or preserved in this condition. Forty-one MCI patients and fifty healthy controls were tested with the Purdue Pegboard test. All participants were right-handed. Kinematic analyses (by hand) were calculated for path length, angle, and linear and angular velocities during reaching, grasping, transport and inserting. Group differences were tested by with factorial MANOVAs and laterality indexes (LI) were assessed. Groups were compared on "Right-Left" hand correlations to identify kinematics that best single-out patients. Kinematics from grasping and inserting were significantly more deteriorated in the MCI group, while outcomes for reaching and transport denoted superior performance. LIs data showed symmetry of movements in the MCI group, during reaching and transport. Comparisons of "Right-Left" hand correlations revealed that kinematics in reaching and transport were more symmetrical in patients. This study showed a deterioration of fine manual dexterity, an enhancement in gross dexterity of upper-limbs, and symmetrical movements in MCI patients.

Global cognitive effects of second-generation antidepressants in patients with Alzheimer's disease: A systematic review and meta-analysis of randomized controlled trials

The second-generation antidepressants (SGAs) are used widely in patients with Alzheimer's disease (AD) for the treatment of mood disorder, sleep disturbance and psychiatric symptoms. Several evidences from AD mice confirmed that antidepressants could delaying cognitive decline. However, the conclusions varied in randomized controlled trials (RCTs) based on patients. This meta-analysis summarizes the cognitive impact of SGAs on AD patients with different neuropsychiatric symptoms (NPS). Results show there is no effect on cognition and depression between SGAs treatment and controls, and this remains in subgroups analyses of duration of medication (<12 weeks or ≥12 weeks), drug classes (SSRIs or non-SSRIs), combination with anti-dementia medication, various NPS, and degree of AD. The available evidence provides no support for the efficacy of SGAs for cognition and depression of AD patients. The implications of the findings and their mechanism relevance are also discussed in this paper.

Preliminary report of Iranian Registry of Alzheimer's disease in Tehran province: A cross-sectional study in Iran

Background and Aims

Alzheimer's disease (AD) is the main cause of dementia and over the 55 million people live with dementia worldwide. We aimed to establish the first database called the Iranian Alzheimer's Disease Registry to create a powerful source for future research in the country. In this report, the design and early results of the Iranian Alzheimer's Disease Registry will be described.

Methods

We performed this multicenter investigation and patients' data including age, sex, educational level, disease status, Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS) from 2018 to 2021 were collected, registered, and analyzed by GraphPad Prism software.

Results

Totally 200 AD patients were registered in our database. 107 (54%) were women and age of 147 (74%) were over 65. The mean age for men and women was 76.20 ± 8.29 and 76.40 ± 8.83 years, respectively. 132 (66%) were married and 64 (32%) were illiterate. Also, 94 (47%) were in the moderate stage of disease, and 150 (75%) lived at home together with their families. The most frequent neurological comorbidity was psychosis (n = 72, 36%), while hypertension was the most common non-neurological comorbidity (n = 104, 52%). The GDS score of women in the mild stage (5.23 ± 2.9 vs. 6.9 ± 2.6, p = 0.005) and moderate stage (5.36 ± 2.4 vs. 8.21 ± 2.06, p = <0.001) of the disease was significantly greater than men. In univariate analysis, MMSC score was remarkably associated with stroke (β = -2.25, p = 0.03), psychosis (β = -2.18, p = 0.009), diabetes (β = 3.6, p = <0.001), and hypercholesteremia (β = 1.67, p = 0.05). Also, the MMSE score showed a notable relationship with stroke (β = -2.13, p = 0.05) and diabetes (β = 3.26, p = <0.001) in multivariate analysis.

Conclusion

Iranian Alzheimer's Disease Registry can provide epidemiological and clinical data to use for purposes such as enhancing the current AD management in clinical centers, filling the gaps in preventative care, and establishing effective monitoring and cure for the disease.

Patchouli alcohol ameliorates the learning and memory impairments in an animal model of Alzheimer's disease via modulating SIRT1

BACKGROUND

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases. Patchouli alcohol (PA), a major active ingredient isolated from Pogostemonis Herba, exhibits extensive bioactivity in the central nervous system (CNS) and exerts neuroprotective effects.

PURPOSE

This study aimed to investigate the anti-AD effects of PA in an animal model of AD and to elucidate the underlying molecular mechanisms.

METHODS

The gas chromatography (GC) was used to determine the ability of PA to pass the blood-brain barrier (BBB) in rats after oral administration. The sporadic AD rat model was established by intracerebroventricularly (ICV) injection with streptozotocin (STZ). PA (25 and 50 mg/kg) was given to rat orally once daily for 42 consecutive days. Morris water maze (MWM) test was performed to determine the learning and memory functions of the STZ-induced AD rats. EX527, a silent information regulator 1 (SIRT1) selective inhibitor, was used to investigate the involvement of SIRT1 in the anti-AD effects of PA in rats.

RESULTS

PA could penetrate the BBB. MWM test results showed that PA could significantly ameliorate the learning and memory deficits induced by STZ in rats. Meanwhile, PA enhanced the expression of SIRT1, and markedly alleviated the tau pathology by inhibiting the hyperacetylation (at the site of Lys174) and hyperphosphorylation (at the sites of Thr181, Thr205, Ser396 and Ser404) of tau protein. PA also efficiently suppressed the activation of microglia and astrocytes, and the beta-amyloid (Aβ) expression and the deacetylation of nuclear factor-kappa B (NF-κB) at Lys 310 (K310) in the STZ-treated AD rats. EX527, a SIRT1 selective inhibitor, could partially abolish the cognitive deficits improving effect of PA and inhibit the down-regulation of acetylated tau and acetylated NF-κB p65, suggesting that PA exhibited neuroprotective effects against AD via upregulating SIRT1.

CONCLUSION

This study reported for the first time that PA could penetrate the BBB to exert its protective effects on the brain after a single-dose oral administration. The current experimental findings also amply demonstrated that PA could improve the cognitive and memory impairments in the STZ-induced AD rat model. The underlying mechanisms involve the alleviations of neuroinflammation, tau pathology and Aβ deposition via modulating of SIRT1 and NF-κB pathways. All these findings strongly suggest that PA is a promising naturally occurring compound worthy of further development into an anti-AD pharmaceutical.

Exploring carer resilience in the context of dementia: a meta-synthesis

AIMS

The aim of this literature review is to integrate the results of qualitative research on the resilience experiences of family carers of people with dementia (PWD).

DESIGN

A qualitative meta-synthesis study was conducted.

METHODS

The meta-ethnography method of Noblit and Hare (1988) was used. We searched five electronic bibliographic databases (PubMed, EMBASE, CINAHL, PsycINFO and Web of Science) using the keywords "caregivers", "family caregivers", "spouse caregivers", "qualitative research", "resilience, psychological" and "dementia." The inclusion criteria of the literature search found studies that explored the resilience experience of family carers of PWD, were qualitative, were published in English, and had participants 18 years of age or older.

RESULTS

Eleven studies, 1 from Australia, 4 from USA and 6 from UK, were included in the analysis. Through the process, three themes emerged: 'Seeing the life of a carer as one's duty', 'Setting boundaries in life', 'Moving forward toward a developing life.' These themes illustrated how family carers of PWD overcome the adversities they encounter.

CONCLUSION

This meta-synthesis showed how family carers of PWD adapt to and overcome the difficult situations they are confronted with as carers. This review suggests an important direction for enhancing the resilience of family carers of PWD.

Utility of Chinese Versions of Addenbrooke’s Cognitive Examination: A Narrative Review

Addenbrooke’s cognitive examination (ACE) is a cognitive screening tool that has developed through three stages: ACE, ACE-Revised (ACE-R), and ACE-Ⅲ. In addition, mini-Addenbrooke’s Cognitive Examination (M-ACE) and ACE mobile are the additional versions that is derived from ACE-III. ACE and its related versions show better performance than Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) in detecting mild cognitive impairment in different neurological disorders. It has been translated into numerous languages, including Chinese. Through reviewing the history, validity, and comparison with other cognitive tests of Chinese versions of ACE, it aims to facilitate the clinical and scientific use, further development, improvement, and validation of Chinese versions of ACE in various neurological disorders and ultimately promote early identification and management of cognitive impairment in China.

Impaired Dopamine Release and Latent Learning in Alzheimer's Disease Model Zebrafish

Alzheimer's disease (AD) is a progressive, fatal, neurodegenerative disorder for which only treatments of limited efficacy are available. Despite early mentions of dementia in the ancient literature and the first patient diagnosed in 1906, the underlying causes of AD are not well understood. This study examined the possible role of dopamine, a neurotransmitter that is involved in cognitive and motor function, in AD. We treated adult zebrafish (Danio rerio) with okadaic acid (OKA) to model AD and assessed the resulting behavioral and neurochemical changes. We then employed a latent learning paradigm to assess cognitive and motor function followed by neurochemical analysis with fast-scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes to measure the electrically stimulated dopamine release. The behavioral assay showed that OKA treatment caused fish to have lower motivation to reach the goal chamber, resulting in impeded learning and decreased locomotor activity compared to controls. Our voltammetric measurements revealed that the peak dopamine overflow in OKA-treated fish was about one-third of that measured in controls. These findings highlight the profound neurochemical changes that may occur in AD. Furthermore, they demonstrate that applying the latent learning paradigm and FSCV to zebrafish is a promising tool for future neurochemical studies and may be useful for screening drugs for the treatment of AD.

Immuno-digital invasive cleavage assay for analyzing Alzheimer's amyloid ß-bound extracellular vesicles

BACKGROUND

The protracted preclinical stage of Alzheimer's disease (AD) provides the opportunity for early intervention to prevent the disease; however, the lack of minimally invasive and easily detectable biomarkers and their measurement technologies remain unresolved. Extracellular vesicles (EVs) are nanosized membrane vesicles released from a variety of cells and play important roles in cell-cell communication. Neuron-derived and ganglioside-enriched EVs capture amyloid-ß protein, a major AD agent, and transport it into glial cells for degradation; this suggests that EVs influence Aß accumulation in the brain. EV heterogeneity, however, requires the use of a highly sensitive technique for measuring specific EVs in biofluid. In this study, immuno-digital invasive cleavage assay (idICA) was developed for quantitating target-intact EVs.

METHODS

EVs were captured onto ganglioside GM1-specific cholera toxin B subunit (CTB)-conjugated magnetic beads and detected with a DNA oligonucleotide-labeled Aß antibody. Fluorescence signals for individual EVs were then counted using an invasive cleavage assay (ICA). This idICA examines the Aß-bound and GM1-containing EVs isolated from the culture supernatant of human APP-overexpressing N2a (APP-N2a) cells and APP transgenic mice sera.

RESULTS

The idICA quantitatively detected Aß-bound and GM1-containing EVs isolated from culture supernatants of APP-N2a cells and sera of AD model mice. The idICA levels of Aß-associated EVs in blood gradually increased from 3- to 12-month-old mice, corresponding to the progression of Aß accumulations in the brain of AD model mice.

CONCLUSIONS

The present findings suggest that peripheral EVs harboring Aß and GM1 reflect Aß burden in mice. The idICA is a valuable tool for easy quantitative detection of EVs as an accessible biomarker for preclinical AD diagnosis.

Opportunities and challenges in delivering biologics for Alzheimer's disease by low-intensity ultrasound

Low-intensity ultrasound combined with intravenously injected microbubbles (US^+MB) is a novel treatment modality for brain disorders, including Alzheimer's disease (AD), safely and transiently allowing therapeutic agents to overcome the blood-brain barrier (BBB) that constitutes a major barrier for therapeutic agents. Here, we first provide an update on immunotherapies in AD and how US^+MB has been applied to AD mouse models and in clinical trials, considering the ultrasound and microbubble parameter space. In the second half of the review, we compare different in vitro BBB models and discuss strategies for combining US^+MB with BBB modulators (targeting molecules such as claudin-5), and highlight the insight provided by super-resolution microscopy. Finally, we conclude with a short discussion on how in vitro findings can inform the design of animal studies, and how the insight gained may aid treatment optimization in the clinical ultrasound space.

Cognitive impairment, age, quality of life, and treatment strategy for atrial fibrillation in older adults: The SAGE-AF study

BACKGROUND

Atrial fibrillation (AF) treatment includes anticoagulation for high stroke risk individuals and either rate or rhythm control strategies. We aimed to investigate the impact of age, geriatric factors, and medical comorbidities on choice of rhythm versus rate control strategy in older adults.

METHODS

Patients with AF aged ≥65 years with CHA2 DS2 VASc score ≥2 and eligible for anticoagulation were recruited for the Systematic Assessment of Geriatric Elements-AF (SAGE-AF) prospective cohort study. An interview that included measures of HRQoL, cognitive function, vision, hearing, and frailty was performed. The association between these elements and AF treatment strategy was examined by multivariable logistic regression models.

RESULTS

One thousand two hundred forty-four participants (mean age 76 years; 49% female; 85% non-Hispanic white) were enrolled. Rate and rhythm control were used in 534 and 710 participants, respectively. Compared to participants <75 years, those ≥75 were more likely to be treated with a rate control strategy (age 75-84 adjusted odds ratio [aOR] 1.37 [95% CI 0.99, 1.88]; age 85+ aOR = 2.05, 95% CI 1.30, 3.21). Those treated with a rate control strategy were more likely to have cognitive impairment (aOR = 1.50, 95% CI 1.13, 1.99), and peripheral vascular disease (PVD) (aOR = 1.82, 95% CI 1.22, 2.72) but less likely to have visual impairment (aOR 0.73 [0.55, 0.98]), congestive heart failure (CHF; aOR 0.68 [0.49, 0.94]) or receive anticoagulation (aOR 0.53, 95% CI 0.36, 0.78).

CONCLUSION

Older age, cognitive impairment, and PVD were associated with use of rate control strategy. Visual impairment, CHF, and anticoagulation use were associated with a rhythm control strategy. There was no difference in HRQoL between the rate and rhythm control groups. This study suggests that certain geriatric elements may be associated with AF treatment strategies. Further study is needed to evaluate how these decisions affect outcomes.

Dementia Prevention in Clinical Practice

Over 55 million people globally are living with dementia and, by 2050, this number is projected to increase to 131 million. This poses immeasurable challenges for patients and their families and a significant threat to domestic and global economies. Given this public health crisis and disappointing results from disease-modifying trials, there has been a recent shift in focus toward primary and secondary prevention strategies. Approximately 40% of Alzheimer's disease (AD) cases, which is the most common form of dementia, may be prevented or at least delayed. Success of risk reduction studies through addressing modifiable risk factors, in addition to the failure of most drug trials, lends support for personalized multidomain interventions rather than a "one-size-fits-all" approach. Evolving evidence supports early intervention in at-risk patients using individualized interventions directed at modifiable risk factors. Comprehensive risk stratification can be informed by emerging principals of precision medicine, and include expanded clinical and family history, anthropometric measurements, blood biomarkers, neurocognitive evaluation, and genetic information. Risk stratification is key in differentiating subtypes of dementia and identifies targetable areas for intervention. This article reviews a clinical approach toward dementia risk stratification and evidence-based prevention strategies, with a primary focus on AD.

miR-124: A Promising Therapeutic Target for Central Nervous System Injuries and Diseases

Central nervous system injuries and diseases, such as ischemic stroke, spinal cord injury, neurodegenerative diseases, glioblastoma, multiple sclerosis, and the resulting neuroinflammation often lead to death or long-term disability. MicroRNAs are small, non-coding, single-stranded RNAs that regulate posttranscriptional gene expression in both physiological and pathological cellular processes, including central nervous system injuries and disorders. Studies on miR-124, one of the most abundant microRNAs in the central nervous system, have shown that its dysregulation is related to the occurrence and development of pathology within the central nervous system. Herein, we review the molecular regulatory functions, underlying mechanisms, and effective delivery methods of miR-124 in the central nervous system, where it is involved in pathological conditions. The review also provides novel insights into the therapeutic target potential of miR-124 in the treatment of human central nervous system injuries or diseases.

A Perspective: Challenges in Dementia Research

Although dementia is a common and devastating disease that has been studied intensely for more than 100 years, no effective disease modifying treatment has been found. At this impasse, new approaches are important. The purpose of this paper is to provide, in the context of current research, one clinician's perspective regarding important challenges in the field in the form of specific challenges. These challenges not only illustrate the scope of the problems inherent in finding treatments for dementia, but can also be specific targets to foster discussion, criticism and new research. One common theme is the need to transform research activities from small projects in individual laboratories/clinics to larger multinational projects, in which each clinician and researcher works as an integral part. This transformation will require collaboration between researchers, large corporations, regulatory/governmental authorities and the general population, as well as significant financial investments. However, the costs of transforming the approach are small in comparison with the cost of dementia.

Association between antibiotics and dementia risk: A retrospective cohort study

Background: The possible relation between antibiotic exposure and the alteration of gut microbiota, which may affect dementia risk, has been revealed. However, the association between antibiotics and dementia incidence has rarely been studied. We aimed to determine the association between antibiotic exposure and the risk of dementia.

Methods: This population-based retrospective cohort study used data from the National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) in South Korea. Exposure was the cumulative days of antibiotic prescription from 2002 to 2005. Newly diagnosed overall dementia, Alzheimer’s disease (AD), and vascular dementia (VD) were identified based on diagnostic codes and prescriptions for dementia-related drugs. The follow-up investigation was carried out from 1 January 2006 to 31 December 2013. The Cox proportional hazards regression was used to assess the association between cumulative antibiotic prescription days and dementia incidence.

Results: A total of 313,161 participants were analyzed in this study. Compared to antibiotic non-users, the participants who used antibiotics for 91 or more days had an increased risk of overall dementia [adjusted hazard ratio (aHR), 1.44; 95% confidence interval (CI), 1.19–1.74], AD (aHR, 1.46; 95% CI, 1.17–1.81), and VD (aHR, 1.38; 95% CI, 0.83–2.30). Those who used five or more antibiotic classes had higher risks of overall dementia (aHR, 1.28; 95% CI, 1.00–1.66) and AD (aHR, 1.34; 95% CI, 1.00–1.78) than antibiotic non-users.

Conclusion: Antibiotic exposure may increase the risk of dementia in a cumulative duration-dependent manner among adult participants. Future studies are needed to assess the causality between the long-term prescription of antibiotics and dementia risk.

From Small Peptides to Large Proteins against Alzheimer’sDisease

Alzheimer’s disease (AD) is the most common neurodegenerative disorder in the elderly. The two cardinal neuropathological hallmarks of AD are the senile plaques, which are extracellular deposits mainly constituted by beta-amyloids, and neurofibrillary tangles formed by abnormally phosphorylated Tau (p-Tau) located in the cytoplasm of neurons. Although the research has made relevant progress in the management of the disease, the treatment is still lacking. Only symptomatic medications exist for the disease, and, in the meantime, laboratories worldwide are investigating disease-modifying treatments for AD. In the present review, results centered on the use of peptides of different sizes involved in AD are presented.

Digital Technologies to Prevent Social Isolation and Loneliness in Dementia: A Systematic Review

Background: Dementia poses significant and sustained challenges to global society. Diagnosis can lead to increased feelings of loneliness and social isolation. People with dementia living alone are particularly at risk. Considering the growing number of technologies proposed to aid people with dementia address social isolation and loneliness, we reviewed the existing literature. Objective: To collate and summarize current evidence for digital technologies to prevent social isolation and loneliness for people with dementia. Methods: Following the PRISMA guidelines, we systematically searched five databases to identify studies of digital technologies designed to support or prevent social isolation or loneliness for people with dementia. Pre-specified outcomes included social isolation, loneliness, and quality of life. We used deductive thematic analysis to synthesize the major themes emerging from the studies. Results: Ten studies met our inclusion criteria where all studies reported improvements in quality of life and seven reported benefits regarding social inclusion or a reduction in loneliness. Technologies were varied across purpose, delivery format, theoretical models, and levels of personalization. Two studies clearly described the involvement of people with dementia in the study design and five technologies were available outside the research context. Conclusion: There is limited— but increasing— evidence that technologies hold potential to improve quality of life and reduce isolation/loneliness for people with dementia. Results presented are largely based in small-scale research studies. Involvement of people with dementia was limited and few research concepts are reaching implementation. Closer collaboration with people with dementia to provide affordable, inclusive, and person-centered solutions is urgently required.

Ginsenoside and Its Therapeutic Potential for Cognitive Impairment

Cognitive impairment (CI) is one of the major clinical features of many neurodegenerative diseases. It can be aging-related or even appear in non-central nerve system (CNS) diseases. CI has a wide spectrum that ranges from the cognitive complaint with normal screening tests to mild CI and, at its end, dementia. Ginsenosides, agents extracted from a key Chinese herbal medicine (ginseng), show great promise as a new therapeutic option for treating CI. This review covered both clinical trials and preclinical studies to summarize the possible mechanisms of how ginsenosides affect CI in different diseases. It shows that ginsenosides can modulate signaling pathways associated with oxidative stress, apoptosis, inflammation, synaptic plasticity, and neurogenesis. The involved signaling pathways mainly include the PI3K/Akt, CREB/BDNF, Keap1/Nrf2 signaling, and NF-κB/NLRP3 inflammasome pathways. We hope to provide a theoretical basis for the treatment of CI for related diseases by ginsenosides.

Recent Progress on NIR Fluorescent Probes for Enzymes

The majority of diseases' biomarkers are enzymes, and the regulation of enzymes is fundamental but crucial. Biological system disorders and diseases can result from abnormal enzymatic activity. Given the biological significance of enzymes, researchers have devised a plethora of tools to map the activity of particular enzymes in order to gain insight regarding their function and distribution. Near-infrared (NIR) fluorescence imaging studies on enzymes may help to better understand their roles in living systems due to their natural imaging advantages. We review the NIR fluorescent probe design strategies that have been attempted by researchers to develop NIR fluorescent sensors of enzymes, and these works have provided deep and intuitive insights into the study of enzymes in biological systems. The recent enzyme-activated NIR fluorescent probes and their applications in imaging are summarized, and the prospects and challenges of developing enzyme-activated NIR fluorescent probes are discussed.

Potentially Inappropriate Medication Use in Patients with Dementia

The objective of this study was to characterize the epidemiology of using potentially inappropriate medications associated with dementia exacerbation (DPIMs) in elderly outpatients with dementia. Electronic medical records were retrospectively reviewed for geriatric patients with dementia who were prescribed at least one medication in 2016 at a tertiary, university-affiliated hospital. The 2015 Beers criteria were used to define DPIMs. Logistic regression was performed to identify factors associated with prescribing DPIMs in patients with dementia. Among 2100 patients included in our study, 987 (47.0%) patients were prescribed at least one DPIM. Benzodiazepines were the most frequently prescribed DPIM followed by anticholinergics, histamine H2-receptor blockers, and zolpidem. The risk of prescribing DPIMs was significantly increased in female patients (odds ratio (OR) 1.355) with polypharmacy (OR 5.146) and multiple comorbidities (OR 1.129) (p < 0.05 for all). Coexistence of Parkinson's disease (OR 1.799), mood disorder (OR 1.373), or schizophrenia (OR 4.116) in patients with dementia further increased the likelihood of receiving DPIMs. In conclusion, DPIMs were commonly used in elderly patients with dementia in Korea with benzodiazepines most frequently prescribed followed by anticholinergics. Female patients using polypharmacy with multiple comorbidities should be closely monitored to minimize unnecessary DPIM use and, ultimately, DPIM-related harms.

A review of stem cell therapy: An emerging treatment for dementia in Alzheimer's and Parkinson's disease

AIM

This article aims to study the benefits and disadvantages of stem cell therapy, especially for patients who have dementia.

METHODS

The databases PubMed, Google Scholar, and the National Library of Medicine were searched for literature. All papers on Alzheimer's disease, Lewy body dementia, Parkinson's disease, stem cell therapy, and its effect on dementia treatment were considered.

RESULTS

Stem cell treatment has demonstrated promising outcomes in animal studies by positively modifying the degenerative alterations in dementia. However, it is not without drawbacks, such as ethical concerns while using embryonic stem cells and the danger of developing cancer if the cells undergo uncontrolled differentiation.

CONCLUSION

Although stem cell therapy has its risks, it has the potential to be a viable therapeutic option for patients with dementia if developed appropriately. Hence, more research and clinical trials are needed to establish its efficacy in this context.

A consolidated review on stem cell therapy for treatment and management of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common forms of dementia and affects around 50 million people around the globe. AD is diagnosed mainly through imaging techniques and to date only five drugs are approved for management of AD but no promising treatment is available for AD. So in this review, we are focusing on stem cell therapy for AD. This review will cover all stem cells like mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, and neural stem cells. Clinical trials of AD have also been discussed. Finally, limitations of stem cells are discussed with ongoing clinical trials, and in the future stem cell therapy can be used for treatment of AD.

Exploring nurse and nursing student experience of using an artist-produced photobook to learn about dementia

Background

Improving understanding about dementia in nursing is a priority area for educators and policymakers. This is due to poor professional understanding about dementia and suboptimal healthcare practice. While many educational interventions exist, there has been a paucity of research which has considered the use of artist-produced photobooks to improve knowledge and understanding about dementia. The aim of this study is to understand the impact of an artist-produced photobook on nurses’ attitudes and beliefs about dementia.

Results

Following a thematic analysis of four focus group interviews with 22 nurses and nursing students from Northern Ireland, three themes emerged. Theme one was about how the artist-produced photobook helped participants to humanise the person living with dementia. Theme two related to how the artist-produced photobook supported participants to actively construct their own meanings about dementia based on their previous professional and personal experiences. Theme three explored how an artist-produced photobook could be successfully used to complement existing dementia education in the future.

Conclusions

Using an artist-produced photobook was an innovative way to learn about dementia for nurses and nursing students. The photobook functioned as a tool underpinned by arts-based pedagogy (ABP), supporting nurses to understand the person behind the dementia disease. As such, an artist-produced photobook has the potential to be a useful complementary resource for supporting professional education about dementia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12912-022-00991-2.

Clinical investigations of compounds targeting metabotropic glutamate receptors

Pharmacological modulation of glutamate has long been considered to be of immense therapeutic utility. The metabotropic glutamate receptors (mGluRs) are potential targets for safely altering glutamate-driven excitation. Data support the potential therapeutic use of mGluR modulators in the treatment of anxiety, depression, schizophrenia, and other psychiatric disorders, pain, epilepsy, as well as neurodegenerative and neurodevelopmental disorders. For each of the three mGluR groups, compounds have been constructed that produce either potentiation or functional blockade. PET ligands for mGlu5Rs have been studied in a range of patient populations and several mGlu5R antagonists have been tested for potential efficacy in patients including mavoglurant, diploglurant, basimglurant, GET 73, and ADX10059. Efficacy with mGlu5R antagonists has been reported in trials with patients with gastroesophageal reflux disease; data from patients with Parkinson's disease or Fragile X syndrome have not been as robust as hoped. Fenobam was approved for use as an anxiolytic prior to its recognition as an mGlu5R antagonist. mGlu2/3R agonists (pomaglumated methionil) and mGlu2R agonists (JNJ-40411813, AZD 8529, and LY2979165) have been studied in patients with schizophrenia with promising but mixed results. Antagonists of mGlu2/3Rs (decoglurant and TS-161) have been studied in depression where TS-161 has advanced into a planned Phase 2 study in treatment-resistant depression. The Group III mGluRs are the least developed of the mGluR receptor targets. The mGlu4R potentiator, foliglurax, did not meet its primary endpoint in patients with Parkinson's disease. Ongoing efforts to develop mGluR-targeted compounds continue to promise these glutamate modulators as medicines for psychiatric and neurological disorders.

Expert appraisal and prioritization of barriers to mHealth use for older adults living with Alzheimer's disease and related Dementias: A Delphi study

INTRODUCTION

Older adults living with Alzheimer's disease and related dementias (ADRD) can benefit from mHealth innovations in (daily) care. However, successful implementation and adoption of such innovations can be hindered by a lack of inclusive design. Inclusive design can be challenging, due to the variety of ADRD- and aging-related symptoms that can pose barriers to using mHealth. Previously, a literature-based model with 53 barriers to mHealth use for this population has been developed ("MHealth for OLder adults living with DEMentia - USability" or MOLDEM-US). In this study, we aim to prioritize these through a Delphi study with ADRD experts (case managers, informal caregivers, hospital healthcare professionals, district nurses, and researchers).

METHODS

In the first round, participant characteristics and potentially new insights into barriers to mHealth use for older adults living with ADRD were gathered. The consensus questionnaire was submitted in the second round, containing barriers to mHealth use for this population (from MOLDEM-US) with questions inquiring its impact and frequency. In the third round, participants rejudged those barriers for which no consensus (<51 %) or minor consensus (51 % - 60 %) was reached.

RESULTS

Thirty-seven participants completed the three rounds of the study. Consensus was reached for eleven barriers after the second round, all having major impact and frequency: integration of functions during daily activities, perceived complexity, efficiency in seeing benefits, trust in own ability, restlessness and agitation, computer literacy, self confidence in using wearables, learnability, working memory, and visual acuity.

CONCLUSION

After round three, consensus was achieved for all 53 barriers. Twenty-six barriers are considered to majorly affect mHealth use, most of which relate to cognition and frame of mind. This study contributes to the development of mHealth design guidelines that take into account the progressive and diverse ADRD- and aging-related symptoms negatively affecting mHealth implementation and adoption.

Exploration of combined physical activity and music for patients with Alzheimer’s disease: A systematic review

Objective

Alzheimer’s disease (AD) can be treated in different ways, one of which is combined physical activity and music intervention, which is a non-pharmacological one. This study provided a thorough systematic review on the application of combined physical activity and music intervention in patients with AD.

Method

Online sources, such as PubMed, Web of Science, SAGE Premier, EBSCO, and Cochrane, published from January 2002 to March 2022 were searched for articles. Reviewer screened articles on inclusion criteria and identified relevant studies. 200 studies were selected as potentially relevant; of these, eight met all the inclusion criteria.

Results

The systemic review looked at eight studies, two of which had high methodological quality and six were of moderate quality. Various types of research were included: randomized controlled tails, single-subject study, crossover study, and case report. Music intervention was conducted during an exercise program in six studies. A cognitive stimulation was applied with music therapy and physical activities among two studies. The physical activities or movements included balance training, stretching, strengthening, and different sports activities. Outcome assessment, including the Barthel index in two studies and the functional independence measure, was conducted to evaluate the daily functional score. Mental health was evaluated by Mini-Mental State Examination in three studies.

Conclusion

Combined physical activity and music intervention are beneficial and improve the cognition, function and well-being of patients with AD. Supporting combined physical and music intervention will play a key role in helping clinical guidelines for both physical therapists and music therapists.

How do cardiovascular risk factors correlate with post-stroke cognitive function: Directly or indirectly through stroke severity?

Objectives

Cognitive impairment may affect one-third of stroke survivors. Cardiovascular risk factors and stroke severity were known to be associated with cognitive function after stroke. However, it is unclear whether cardiovascular risk factors directly affect cognition after stroke, indirectly affect cognition by changing stroke severity, or both. Moreover, the effect of a combination of hypertension and diabetes mellitus was conflicting. We aimed to investigate the multiple direct and indirect associations and inspire potential intervention strategies.

Materials and methods

From February 2020 to January 2021, 350 individuals received cognitive tests within 7 days after incident stroke. Cognitive tests were performed using the Chinese version of the Mini-Mental State Examination (MMSE). A moderated mediation model was constructed to test the indirect associations between cardiovascular and demographic risk factors and cognition mediated through stroke severity, the direct associations between risk factors and cognition, and the moderating effects of hypertension and diabetes.

Results

Age (estimate, -0.112), atrial fibrillation (estimate, -4.092), and stroke severity (estimate, -1.994) were directly associated with lower cognitive function after stroke. Vascular disease (estimate, 1.951) and male sex (estimate, 2.502) were directly associated with better cognition after stroke. Higher education level was associated with better cognition directly (estimate, 1.341) and indirectly (estimate, 0.227) through stroke severity. The combination of hypertension decreased the magnitude of the negative association between atrial fibrillation and cognition (estimate, from -4.092 to -3.580).

Conclusion

This is the first Chinese study exploring the moderated and mediating associations between cardiovascular risk factors, stroke severity, and cognitive function after stroke. Age, female sex, and atrial fibrillation were directly associated with lower cognition after stroke. The combination of hypertension might have a positive effect on cognition.

3-[(1H-Benzo[d][1,2,3]triazol-1-yl)oxy]propyl 9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-3aH-cyclopenta[a]chrysene-3a-carboxylate

We herein report on the synthesis of a pentacyclic triterpene functionalized through derivation of betulinic acid with hydroxybenzotriazole. The compound was fully characterized by proton (1H-NMR), carbon-13 (13C-NMR), heteronuclear single quantum coherence (HSQC) and distortionless enhancement by polarization transfer (DEPT-135 and DEPT-90) nuclear magnetic resonance. Ultraviolet (UV), and Fourier-transform infrared (FTIR) spectroscopies as well as and high-resolution mass spectrometry (HRMS) were also adopted. Computational studies were conducted to foresee the interactions between compound 3 and phosphodiesterase 9, a relevant target in the field of neurodegenerative diseases. Additionally, preliminary calculation of physico-chemical descriptors was performed to evaluate the drug-likeness of compound 3.

Multimodal Neurocognitive Markers of Naturalistic Discourse Typify Diverse Neurodegenerative Diseases

Neurodegeneration has multiscalar impacts, including behavioral, neuroanatomical, and neurofunctional disruptions. Can disease-differential alterations be captured across such dimensions using naturalistic stimuli? To address this question, we assessed comprehension of four naturalistic stories, highlighting action, nonaction, social, and nonsocial events, in Parkinson's disease (PD) and behavioral variant frontotemporal dementia (bvFTD) relative to Alzheimer's disease patients and healthy controls. Text-specific correlates were evaluated via voxel-based morphometry, spatial (fMRI), and temporal (hd-EEG) functional connectivity. PD patients presented action-text deficits related to the volume of action-observation regions, connectivity across motor-related and multimodal-semantic hubs, and frontal hd-EEG hypoconnectivity. BvFTD patients exhibited social-text deficits, associated with atrophy and spatial connectivity patterns along social-network hubs, alongside right frontotemporal hd-EEG hypoconnectivity. Alzheimer's disease patients showed impairments in all stories, widespread atrophy and spatial connectivity patterns, and heightened occipitotemporal hd-EEG connectivity. Our framework revealed disease-specific signatures across behavioral, neuroanatomical, and neurofunctional dimensions, highlighting the sensitivity and specificity of a single naturalistic task. This investigation opens a translational agenda combining ecological approaches and multimodal cognitive neuroscience for the study of neurodegeneration.

Enriched environment priors to TET1 hippocampal administration for regulating psychiatric behaviors via glial reactivity in chronic cerebral hypoperfusion models

BACKGROUND

Chronic cerebral hypoperfusion (CCH) has been gradually regarded as a common etiologic mechanism for cognitive and psychiatric disturbances. Ten-eleven translocation methylcytosine dioxygenase 1 (TET1) played an important role in adult hippocampal neurogenesis (AHN), neuronal circuits formation, cognition and psychiatric disorders. Enriched environment (EE) showed a beneficial effect on cognition and depression via effectively regulating AHN and glial reactivity. This study aimed to assess which strategy was feasible to improve cognition and psychiatric disturbances by comparing the TET1 hippocampal microinjection and EE in CCH models and to investigate the possible mechanisms.

METHOD

CCH rats were established via permanent bilateral common carotid artery occlusion (2-VO). Rats were stereotaxically injected with the human catalytic domain of TET1 (hTET1) to overexpress the hTET1 in the hippocampus 10 days before 2-VO. 3 days after 2-VO, rats were subjected to standard environment or EE with free access to food and water. Behavioral tests were used to appraise depression and cognition before sacrifice. Epigenetic molecules, adult neurogenesis, synaptic proteins expression, and glial activation were analyzed using immunofluorescent staining, qRT-PCR and western blot.

RESULTS

In the present study, we found both EE and genetical treatment with overexpressing hTET1 were sufficient for stimulating AHN. However, promoting ANH could not deal with the cognitive dysfunction and depressive-like behaviors in CCH rats. Notably, a healthy local brain environment with elevated BDNF and astrocytes was conducive to improving cognitive dysfunction. Meanwhile, astrocytes were involved in the cognitive regulating process of neurons, presynaptic function and microglia. In general, we held that depressive disturbances were determined by BDNF levels, neuronal and presynaptic function, as well as glial activation containing astrocytes and microglia. To further support this point, we investigated severe depressive symptoms that were strongly correlated with the activation of astroglia and microglia. Importantly, causal mediation analysis showed significant mediation by the presence of reactive glial cells in the relation between neural plasticity and depressive symptoms. Finally, we showed EE performed better than hTET1 treatment for cognitive deficits and depression. EE with less glial reactivity was much more resistant to depression, while hTET1 with more glial activation was more vulnerable to depressive disorders.

CONCLUSIONS

EE was likely to be superior to TET1 hippocampal administration for cognition and psychiatric behaviors in CCH rats. Furthermore, a healthy local brain environment with elevated BDNF and astrocytes was conducive to improving cognitive dysfunction. More glial activation, and more vulnerable to depressive disorders. These results were important for our understanding of disease mechanisms and provided valuable tools for the overall management of CCH patients.

Abnormal Functional Connectivity of Thalamic Subdivisions in Alzheimer's Disease: A Functional Magnetic Resonance Imaging Study

Alzheimer's disease (AD) is characterized by global cognitive impairment in multiple cognitive domains. Thalamic dysfunction during AD progression has been reported. However, there are limited studies regarding dysfunction in the functional connectivity (FC) of thalamic subdivisions and the relationship between such dysfunction and clinical assessments. This study examined dysfunction in the FC of thalamic subdivisions and determined the relationship between such dysfunction and clinical assessments. Forty-eight patients with AD and 47 matched healthy controls were recruited and assessed with scales for multiple cognitive domains. Group-wise comparisons of FC with thalamic subdivisions as seed points were conducted to identify abnormal cerebral regions. Moreover, correlation analysis was conducted to evaluate the relationship between abnormal FC and cognitive performance. Decreased FC of the intralaminar and medial nuclei with the left precuneus was observed in patients but not in heathy controls. The abnormal FC of the medial nuclei with the left precuneus was correlated with the Mini Mental State Examination score in the patient group. Using the FC values showing between-group differences, the linear support vector machine classifier achieved quite good in accuracy, sensitivity, specificity and area under the curve. Dysfunction in the FC of the intralaminar and medial thalamus with the precuneus may comprise a potential neural substrate for cognitive impairment during AD progression, which in turn may provide new treatment targets.

ERp57 chaperon protein protects neuronal cells from Aβ-induced toxicity

Alzheimer's disease (AD) is a neurodegenerative disorder whose main pathological hallmark is the accumulation of Amyloid-β peptide (Aβ) in the form of senile plaques. Aβ can cause neurodegeneration and disrupt cognitive functions by several mechanisms, including oxidative stress. ERp57 is a protein disulfide isomerase involved in the cellular stress response and known to be present in the cerebrospinal fluid of normal individuals as a complex with Aβ peptides, suggesting that it may be a carrier protein which prevents aggregation of Aβ. Although several studies show ERp57 involvement in neurodegenerative diseases, no clear mechanism of action has been identified thus far. In this work, we gain insights into the interaction of Aβ with ERp57, with a special focus on the contribution of ERp57 to the defense system of the cell. Here, we show that recombinant ERp57 directly interacts with the Aβ25-35 fragment in vitro with high affinity via two in silico-predicted main sites of interaction. Furthermore, we used human neuroblastoma cells to show that short-term Aβ25-35 treatment induces ERp57 decrease in intracellular protein levels, different intracellular localization, and ERp57 secretion in the cultured medium. Finally, we demonstrate that recombinant ERp57 counteracts the toxic effects of Aβ25-35 and restores cellular viability, by preventing Aβ25-35 aggregation. Overall, the present study shows that extracellular ERp57 can exert a protective effect from Aβ toxicity and highlights it as a possible therapeutic tool in the treatment of AD.

Efficacy of non-pharmacological interventions to reduce pain in people with dementia: A systematic review and meta-analysis

AIMS AND OBJECTIVES

To identify the efficacy of non-pharmacological interventions designed to reduce pain in people with dementia.

BACKGROUND

Pain is prevalent among patients with dementia but frequently remains untreated. Although non-pharmacological interventions have been used to reduce pain in people with dementia, the efficacy of these interventions for pain management in people with dementia has not been thoroughly synthesised.

DESIGN

Systematic review and meta-analysis.

METHODS

The study was conducted in accordance with PRISMA guidelines and Cochrane criteria for systematic reviews. A comprehensive search was performed using the Academic Search Complete, CINAHL, Cochrane Library, EMBASE, MEDLINE, PubMed, OVID and Web of Science databases, from databases inception to 13 March 2022. The modified Cochrane risk-of-bias tool (ROB-2) was used to evaluate the methodological quality of each included study. Standardised mean differences (SMDs) with 95% confidence intervals (CIs) were synthesised using a random-effects model to assess the efficacy of non-pharmacological interventions for reducing pain in people with dementia (using Stata 16.0).

RESULTS

The final analysis assessed 12 studies, including 989 persons with dementia. Non-pharmacological interventions were found to reduce pain in 4-8 weeks after the interventions (SMD: -0.32; 95% CI: -0.62 to -0.02). However, the effects of intervention frequency and patient age remain unknown.

CONCLUSIONS

Non-pharmacological interventions are effective for reducing pain in people with dementia. Further investigations remain necessary to explore the effectiveness of specific non-pharmacological therapies for pain reduction in people with dementia (e.g. aromatherapy, play activity, singing or robotic care).

RELEVANCE TO CLINICAL PRACTICE

The findings of this study can guide healthcare practitioners when considering the use of non-pharmacological pain management methods for people with dementia and may improve the implementation of these methods in clinical practice.

PATIENT OR PUBLIC CONTRIBUTIONS

The study suggests non-pharmacological interventions to reduce pain and underlines the relevance of health provider's viewpoints. The types, duration and length of follow-up of non-pharmacological interventions can be offered based on patient's conditions and the standard of clinical practice.

The Role of Blood-Brain Barrier Dysfunction in Mild Cognitive Impairment: a Scientometric and Visualization Analysis from 2000 to 2021

Mild cognitive impairment (MCI) is a pathological stage between normal cognitive aging and dementia. The blood-brain barrier (BBB) breakdown is emerging as an early biomarker of MCI. This study aimed to visually analyze the literatures related to MCI caused by BBB dysfunction in recent 20 years, systematically identify collaboration networks, track research trends, highlight current hot spots, and predict future frontiers in this field. The related literatures published from 2000 to 2021 were obtained from the Web of Science with the search term "mild cognitive impairment and (blood-brain barrier or neurovascular unit or neurovascular coupling)". VOSviewer software was used to present knowledge map, CiteSpace software was used to extract literature information and make tables, including the top most influential countries, authors, institutions, periodicals, keywords, and references. A total of 333 literatures were used for visual analysis. After 2013, the literatures in the field of BBB dysfunction-induced MCI showed an increased trend in terms of year of publication and quantity of material, with more than 40 publications published each year. USA, England, China, and Sweden cooperated closely. In terms of institutions, Harvard Med Sch ranked first in the number of papers published, followed by Mstricht Univ and Univ Washington. In terms of journals, three of the top five co-cited journals belonged to USA, the other two journals were Neurobiol Aging and J Alzheimers DIS, which were from England and Netherlands respectively. A total of 1752 authors were identified, with Abhay P Sagare the most published and Zlokovic BV the most cited. Keyword emergence detection analysis showed that inflammation, oxidative stress, and memory were new research hot spot in this field. Overall, the research on BBB dysfunction-induced MCI is booming. In the future, cooperation and communication between different countries and institutions should be strengthened.

An Intelligent Learning System for Unbiased Prediction of Dementia Based on Autoencoder and Adaboost Ensemble Learning

Dementia is a neurological condition that primarily affects older adults and there is still no cure or therapy available to cure it. The symptoms of dementia can appear as early as 10 years before the beginning of actual diagnosed dementia. Hence, machine learning (ML) researchers have presented several methods for early detection of dementia based on symptoms. However, these techniques suffer from two major flaws. The first issue is the bias of ML models caused by imbalanced classes in the dataset. Past research did not address this issue well and did not take preventative precautions. Different ML models were developed to illustrate this bias. To alleviate the problem of bias, we deployed a synthetic minority oversampling technique (SMOTE) to balance the training process of the proposed ML model. The second issue is the poor classification accuracy of ML models, which leads to a limited clinical significance. To improve dementia prediction accuracy, we proposed an intelligent learning system that is a hybrid of an autoencoder and adaptive boost model. The autoencoder is used to extract relevant features from the feature space and the Adaboost model is deployed for the classification of dementia by using an extracted subset of features. The hyperparameters of the Adaboost model are fine-tuned using a grid search algorithm. Experimental findings reveal that the suggested learning system outperforms eleven similar systems which were proposed in the literature. Furthermore, it was also observed that the proposed learning system improves the strength of the conventional Adaboost model by 9.8% and reduces its time complexity. Lastly, the proposed learning system achieved classification accuracy of 90.23%, sensitivity of 98.00% and specificity of 96.65%.

Highly sensitive Curcumin-conjugated nanotheranostic platform for detecting amyloid-beta plaques by magnetic resonance imaging and reversing cognitive deficits of Alzheimer's disease via NLRP3-inhibition

BACKGROUND

Alzheimer's disease (AD) is the most common neurodegenerative disorder without effective therapy and lack diagnosis strategy for preclinical AD patients. There is an urgent need for development of both early diagnosis and therapeutic intervention of AD.

RESULTS

Herein, we developed a nanotheranostics platform consisting of Curcumin (Cur), an anti-inflammatory molecule, and superparamagnetic iron oxide (SPIO) nanoparticles encapsulated by diblock 1,2-dio-leoyl-sn-glycero-3-phosphoethanolamine-n-[poly(ethylene glycol)] (DSPE-PEG) that are modified with CRT and QSH peptides on its surface. Furthermore, we demonstrated that this multifunctional nanomaterial efficiently reduced β-amyloid plaque burden specifically in APP/PS1 transgenic mice, with the process noninvasively detected by magnetic resonance imaging (MRI) and the two-dimensional MRI images were computed into three-dimension (3D) plot. Our data demonstrated highly sensitive in vivo detection of β-amyloid plaques which more closely revealed real deposition of Aβ than previously reported and we quantified the volumes of plaques for the first time based on 3D plot. In addition, memory deficits of the mice were significantly rescued, probably related to inhibition of NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasomes.

CONCLUSIONS

Gathered data demonstrated that this theranostic platform may have both early diagnostic and therapeutic potential in AD.

Latest Trends in Outcome Measures in Dementia and Mild Cognitive Impairment Trials

Disease modification trials in dementia and mild cognitive impairment (MCI) have not met with success. One potential criticism of these trials is the lack of sensitive outcome measures. A large number of outcome measures have been employed in dementia and MCI trials. This review aims to describe and analyze the utility of cognitive/clinical outcome measures in Alzheimer's disease (AD) and MCI trials. Methods: A PubMed search was conducted using relevant MeSH terms and exploded keywords. The search was confined to English language publications of human studies from the last five years which describe the latest trends in the use of outcome measures. Results: Despite broad use, the outcome measures employed are heterogeneous, with little data on correlations between scales. Another problem is that most studies are over-reliant on clinician/researcher assessment and cognitive outcomes, and there is a definite lack of stakeholder input. Finetuning of the paradigm is also required for people with early-stage disease, mild to moderate disease, and advanced dementia, as the outcome measures in these subgroups have varying relevance. Disease modification/prevention is an appropriate goal in early disease, whereas palliation and freedom from discomfort are paramount in later stages. The outcome measures selected must be suitable for and sensitive to these particular care goals. Although there is a shift to enrich MCI cohorts using a biomarker-based approach, the clinical relevance of such outcome measures remains uncertain. Conclusions: Outcome measures in dementia/MCI trials remain inhomogeneous and diverse, despite extensive use. Outcome measures fall within several paradigms, including cognitive, functional, quality-of-life, biomarker-based, and patient-reported outcome measures. The success of future disease-modifying trials is reliant to a large extent on the selection of outcome measures which combine all outcomes of clinical relevance as well as clinical meaning. Outcome measures should be tied to the type and stage of dementia and to the specific interventions employed.

Does protracted radon exposure play a role in the development of dementia?

Radon is a ubiquitous radioactive gas that decays into a series of solid radioactive decay products. Radon, and its decay products, enter the human body primarily through inhalation and can be delivered to various tissues including the brain through systemic circulation. It can also reach the brain by neuronal pathways via the olfactory system. While ionizing radiation has been suggested as a risk factor of dementia for decades, studies exploring the possible role of radon exposure in the development of Alzheimer's Diseases (AD) and other dementias are sparse. We systematically reviewed the literature and found several lines of evidence suggesting that radon decay products (RDPs) disproportionally deposit in the brain of AD patients with selective accumulation within the protein fractions. Ecologic study findings also indicate a significant positive correlation between geographic-level radon distribution and AD mortality in the US. Additionally, pathologic studies of radon shed light on the potential pathways of radon decay product induced proinflammation and oxidative stress that may result in the development of dementia. In summary, there are plausible underlying biological mechanisms linking radon exposure to the risk of dementia. Since randomized clinical trials on radon exposure are not feasible, well-designed individual-level epidemiologic studies are urgently needed to elucidate the possible association between radon (i.e., RDPs) exposure and the onset of dementia.

Chronic Noise Exposure and Risk of Dementia: A Systematic Review and Dose-Response Meta-Analysis

Objective

Evidence is scarce about the effect of noise exposure on the risk of dementia. We conducted a systematic review and dose-response meta-analysis, aiming to explore the association between noise exposure and the risk of dementia.

Methods

We searched PubMed, EMBASE and the Cochrane Library to collect studies on chronic noise exposure and the risk of dementia from database inception to September 18, 2021 without language limitations. Two authors independently screened the literature, extracted data and assessed the risk of bias of the included studies. A dose-response meta-analysis and subgroup analysis were then conducted to detect the association between noise exposure and the risk of dementia by using Stata 14.0 software. This study is registered on PROSPERO (CRD42021249243).

Results

A total of 11 studies were eligible for qualitative synthesis, and nine were eligible for quantitative data synthesis. All of them showed moderate to high quality scores in the assessment of risk of bias. We found a positive linear association between the noise increment and dementia risk (R2 = 0.58). When noise exposure increased 57 dB, the RR of dementia was 1.47 (95% CI: 1.21–1.78). From the outcome subgroup of AD, AD and dementia, VaD and NAD, we also found a positive association (R2 = 0.68, 0.68, 0.58, respectively). When noise exposure increased by 25 dB, the RRs were 1.18 (95% CI: 1.14–1.23), 1.19 (95% CI: 1.14–1.23) and 1.17 (95% CI: 1.06–1.30), respectively. We found a nonlinear association between the noise increment and dementia risk when only cohort studies were included (R2 = 0.58). When noise exposure increased by 25 dB, the RR of dementia was 1.16 (95% CI: 1.12–1.20). From the subgroup of AD, AD and dementia, VaD and NAD of cohort studies, the regression curve showed a nonlinear positive association (R2 = 0.74, 0.71, 0.43, respectively). When noise exposure increased by 25 dB, the RRs were 1.17 (95% CI: 1.12–1.21), 1.17 (95% CI: 1.12–1.22) and 1.13 (95% CI: 0.99–1.28), respectively.

Conclusion

Based on the current evidence, exposure to noise may be a specific risk factor for dementia. To better prevent dementia, more rigorously designed studies are needed to explore the etiological mechanism of noise and dementia.

The Kappa Opioid Receptor: A Promising Therapeutic Target for Multiple Pathologies

Kappa-opioid receptors (KOR) are widely expressed throughout the central nervous system, where they modulate a range of physiological processes depending on their location, including stress, mood, reward, pain, inflammation, and remyelination. However, clinical use of KOR agonists is limited by adverse effects such as dysphoria, aversion, and sedation. Within the drug-development field KOR agonists have been extensively investigated for the treatment of many centrally mediated nociceptive disorders including pruritis and pain. KOR agonists are potential alternatives to mu-opioid receptor (MOR) agonists for the treatment of pain due to their anti-nociceptive effects, lack of abuse potential, and reduced respiratory depressive effects, however, dysphoric side-effects have limited their widespread clinical use. Other diseases for which KOR agonists hold promising therapeutic potential include pruritis, multiple sclerosis, Alzheimer's disease, inflammatory diseases, gastrointestinal diseases, cancer, and ischemia. This review highlights recent drug-development efforts targeting KOR, including the development of G-protein-biased ligands, mixed opioid agonists, and peripherally restricted ligands to reduce side-effects. We also highlight the current KOR agonists that are in preclinical development or undergoing clinical trials.

Therapeutic nanotechnologies for Alzheimer's disease: a critical analysis of recent trends and findings

Alzheimer's Disease (AD) is an irreversible neurodegenerative disease for which no disease modifying therapies are presently available. Besides the identification of pathological targets, AD presents numerous clinical and pharmacological challenges such as efficient active delivery to the central nervous system, cell targeting, and long-term dosing. Nanoparticles have been explored to overcome some of these challenges as drug delivery vehicles or drugs themselves. However, early promises have failed to materialize as no nanotechnology-based product has been able to reach the market and very few have moved past preclinical stages. In this review, we perform a critical analysis of the past decade's research on nanomedicine-based therapies for AD at the preclinical and clinical stages. The main obstacles to nanotechnology products and the most promising approaches were also identified, including renewed promise with gene editing, gene modulation, and vaccines.

Hospitality in dementia-friendly environments is significant to caregivers during hospitalisation of their loved ones. A qualitative study

AIM AND OBJECTIVES

To explore what is meaningful to caregivers in relation to a dementia-friendly environment during hospitalisation of their loved ones with dementia or cognitive impairment.

BACKGROUND

Implementation of dementia-friendly initiatives and person-centred care approach have shaped the political agenda within Danish society. Patients with dementia or cognitive impairment and their accompanying caregivers are challenged when admitted to hospital. During hospitalisation, caregivers find themselves in a vulnerable state of mind. Thus, the implementation of a dementia-friendly environment and adherence to person-centred care in hospital settings leaves room for improvement.

METHODS

This study was guided by a qualitative and explorative approach. Data were collected through 17 semi-structured interviews with caregivers at a subacute neurological ward. Thematic analysis was employed to interpret data. The study reports according to the COREQ checklist.

RESULTS

The following three themes were identified: 1) Being a watchful bystander. 2) Visiting an undefined and foreign environment. 3) Longing for kindness.

CONCLUSION

Hospitality expressed by staff towards caregivers is significant in allowing caregivers to experience hospital environments as "friendly." Dementia-friendly environments embrace existential aspects that go far beyond physical spaces; hence, experiences of kind acts shape caregivers' sense of safety and comfort during hospitalisation. Hospitality is an essential part of nursing in dementia care because caregivers are contextually vulnerable. Our study sheds new light on the provision of person-centred care to people with dementia and their families in healthcare.

RELEVANCE TO CLINICAL PRACTICE

Nurses need to be aware that caregivers experience vulnerability and to involve caregivers in the care provided for patients with dementia. We recommend that a permanent contact person be appointed to follow patients throughout their admission period. Furthermore, systematic interventions focusing on phenomena such as hospitality and kindness may serve to form a person-centred clinical culture; an issue that warrants further investigation.