Music Therapy as a Complementary Treatment in Patients with Dementia Associated to Alzheimer's Disease: A Systematic Review

Background

Alzheimer's disease (AD) is a complex condition that affects various aspects of a patient's life. Music therapy may be considered a beneficial supplementary tool to traditional therapies, that not fully address the range of AD manifestations.

Objective

The purpose of this systematic review is to investigate whether music therapy can have a positive impact on AD patients and on which symptoms.

Methods

The main research databases employed have been PubMed and Cochrane, using the keywords "dementia", "music therapy", "Alzheimer", "fMRI", "music", and "EEG".

Results

After removing duplicates and irrelevant studies, 23 were screened using set criteria, resulting in the final inclusion of 15 studies. The total number of participants included in these studies has been of 1,196 patients. For the fMRI analysis the search resulted in 28 studies on PubMed, two of which were included in the research; the total number of participants was of 124 individuals. The studies conducted with EEG were found using PubMed. The initial search resulted in 15 studies, but after a more accurate evaluation only 2 have been included in the analysis.

Conclusions

Even though the data currently available is not sufficient to draw conclusions supported by robust statistical power, the impact of music therapy on AD neuropsychiatric symptoms deserves great interest. Further research should be ushered, possibly multicentric studies, led with neuroimaging and other recent techniques, which can eventually open views on the music role in improving the cognitive status in AD.

Factor structure and clinical applicability of new semantic tasks in Alzheimer's disease and aphasia

Semantic tasks are frequently used when examining language functions in patients with acquired disorders such as Alzheimer's disease (AD) and aphasia. Little is known about the possible covariation between different types of tasks or their factor structure in healthy adults. Additionally, few studies have examined semantic task performances in different patient groups. The aims of this data-driven study were to examine the factor structure in a wide range of semantic tasks in healthy older adults, the possible differences in factor variables between healthy controls, patients with AD and patients with stroke aphasia, as well as the clinical applicability of tasks in differentiating the two patient groups from controls. Participants included 59 healthy older adults, 13 patients with AD and 14 patients with aphasia. The results indicated a four-factor solution for the semantic task variables: (1) the Semantic association factor, (2) the Time factor, (3) the Verbal factor and (4) the Synonym factor. The Verbal factor was the only distinguishing factor between the two patient groups. Three factors reliably discriminated between the controls and the AD patients, and the Verbal factor reliably discriminated between the controls and the aphasia patients. In addition, a few single task variables showed outstanding discrimination for both patient groups. This study supports the notions of semantic tasks tapping into more than one cognitive subcomponent and a more general semantic impairment in AD than in aphasia. In clinical assessment, choosing appropriate semantic tasks is crucial in order to reliably detect the characteristics of the impairment.

The Role of the Anterior Thalamic Nuclei in the Genesis of Memory Disorders in Alzheimer's Disease: An Exploratory Study

BACKGROUND

Increasing evidence is demonstrating that degeneration of specific thalamic nuclei, in addition to the hippocampus, may occur in Alzheimer's disease (AD) from the prodromal stage (mild cognitive impairment - MCI) and contribute to memory impairment.

OBJECTIVE

Here, we evaluated the presence of macro and micro structural alterations at the level of the anterior thalamic nuclei (ATN) and medio-dorsal thalamic nuclei (MDTN) in AD and amnestic MCI (aMCI) and the possible relationship between such changes and the severity of memory impairment.

METHODS

For this purpose, a sample of 50 patients with aMCI, 50 with AD, and 50 age- and education-matched healthy controls (HC) were submitted to a 3-T MRI protocol with whole-brain T1-weighted and diffusion tensor imaging and a comprehensive neuropsychological assessment.

RESULTS

At macro-structural level, both the ATN and MDTN were found significantly smaller in patients with aMCI and AD when compared to HC subjects. At micro-structural level, instead, diffusion alterations that significantly differentiated aMCI and AD patients from HC subjects were found only in the ATN, but not in the MDTN. Moreover, diffusion values of the ATN were significantly associated with poor episodic memory in the overall patients' group.

CONCLUSIONS

These findings represent the first in vivo evidence of a relevant involvement of ATN in the AD-related neurodegeneration and memory profile and strengthen the importance to look beyond the hippocampus when considering neurological conditions characterized by memory decline.

Diffusion and structural MRI as potential biomarkers in people with Parkinson's disease and cognitive impairment

OBJECTIVE

To explore the neuroimage change in Parkinson's disease (PD) patients with cognitive impairments, this study investigated the correlation between plasma biomarkers and morphological brain changes in patients with normal cognition and mild cognitive impairment. The objective was to identify the potential target deposition regions of the plasma biomarkers and to search for the relevant early neuroimaging biomarkers on the basis of different cognitive domains.

METHODS

Structural brain MRI and diffusion weighted images were analyzed from 49 eligible PD participants (male/female: 27/22; mean age: 73.4 ± 8.5 years) from a retrospective analysis. Plasma levels of α-synuclein, amyloid beta peptide, and total tau were collected. A comprehensive neuropsychological assessment of the general and specific cognitive domains was performed. Difference between PD patients with normal cognition and impairment was examined. Regression analysis was performed to evaluate the correlation between image-derived index and plasma biomarkers or neuropsychological assessments.

RESULTS

Significant correlation was found between plasma Aβ-42 level and fractional anisotropy of the middle occipital, angular, and middle temporal gyri of the left brain, as well as plasma T-tau level and the surface area of the isthmus or the average thickness of the posterior part of right cingulate gyrus. Visuospatial and executive function is positively correlated with axial diffusivity in bilateral cingulate gyri.

CONCLUSION

In nondemented PD patients, the target regions for plasma deposition might be located in the cingulate, middle occipital, angular, and middle temporal gyri. Changes from multiple brain regions can be correlated to the performance of different cognitive domains.

CLINICAL RELEVANCE STATEMENT

Cognitive impairment in Parkinson's disease is primarily linked to biomarkers associated with Alzheimer's disease rather than those related to Parkinson's disease and resembles the frontal variant of Alzheimer's disease, which may guide management strategies for cognitive impairment in Parkinson's disease.

KEY POINTS

• Fractional anisotropy, surface area, and thickness in the cingulate, middle occipital, angular, and middle temporal gyri can be significantly correlated with plasma Aβ-42 and T-tau level. • Axial diffusivity in the cingulate gyri was correlated with visuospatial and executive function. • The pattern of cognitive impairment in Parkinson's disease can be similar to the frontal variant than typical Alzheimer's disease.

Frailty is associated with the clinical expression of neuropsychological deficits in older adults

BACKGROUND AND PURPOSE

The aim was to determine whether frailty is associated with the relationship between neuropsychological markers and global cognition in older adults.

METHODS

Cross-sectional analyzes were conducted of baseline data from three large cohort studies: National Alzheimer's Coordinating Center (NACC), Rush Memory and Aging Project (MAP) and Alzheimer's Disease Neuroimaging Initiative (ADNI). Studies recruited North American participants along the spectrum of cognitive functioning (44% no cognitive impairment at baseline). A frailty index was computed in each dataset. Frailty indices, neuropsychological tests (including measures of processing speed, episodic, semantic and working memory) and Mini-Mental State Examination (MMSE) scores were the variables of interest, with age, sex, education and apolipoprotein E ε4 evaluated as confounders.

RESULTS

Across all studies, 23,819 participants aged 55-104 (57% female) were included in analyzes. Frailty index scores were significantly and inversely associated with MMSE scores and significantly moderated relationships between neuropsychological test scores and MMSE scores. In participants with higher frailty index scores, lower neuropsychological test scores were more strongly associated with lower MMSE scores (standardized interaction coefficients ranged from -0.19 to -1.17 in NACC, -0.03 to -2.27 in MAP and -0.04 to -0.38 in ADNI, depending on the neuropsychological test). These associations were consistent across the different databases and were mostly independent of the composition of frailty indices (i.e., after excluding possible symptoms of dementia).

CONCLUSIONS

Amongst older Americans, frailty is associated with the cognitive expression of neuropsychological deficits. Implementation of frailty assessment in routine neurological and neuropsychological practice should be considered to optimize care outcomes for older adults.

Evaluating the effect of kidney function on brain volumes and dementia risk in the UK Biobank

OBJECTIVE

To investigate the association between kidney function with the risk of dementia and brain volumes.

METHODS

A total of 452,996 UK Biobank participants with calculated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) were included. We utilized Cox proportional hazards regression models and restricted cubic spline analyses to examine the relationships between kidney function and the risk of all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VD). Additionally, we explored the correlations between kidney function and brain magnetic resonance indicators among 40,380 participants.

RESULTS

During a median follow-up of 12 years, 5,258 incident ACD cases were identified. The deterioration of kidney function was associated with an increased risk of ACD. When compared to eGFR ≥ 90 ml/min/1.73 m², the highest risk increase was evident for eGFRcre < 30 ml/min/1.73 m² (adjusted HR = 2.372, 95% CI: 1.444-3.897, P < 0.001), with eGFRcys showing greater significance (adjusted HR = 3.045, 95% CI: 2.212-4.191, P < 0.001), especially in relation to AD. Compared to the ACR level in the range of 3-30 mg/mmol, the category of > 30 mg/mmol was associated with an increased risk of ACD (adjusted HR = 1.720, 95% CI: 1.350-2.190, P < 0.001). Moreover, the decline in kidney function was associated with the total brain volume atrophy and reduction in certain subcortical areas.

CONCLUSIONS

Our study indicates that diminished kidney function, as evidenced by a drop in eGFR and aggravated proteinuria, elevates dementia risk. Associated brain structural changes further underpin this connection from a neuro-pathophysiological perspective.

Association between clusters of antibodies against periodontal microorganisms and Alzheimer disease mortality: Evidence from a nationally representative survey in the USA

BACKGROUND

Alzheimer disease (AD) has been linked with periodontal microorganisms such as Porphyromonas gingivalis in observational and mechanistic studies. IgG antibodies against periodontal microorganisms which are markers of past and current periodontal infection have been correlated with cognitive impairment. We examined associations between empirically derived groups of 19 IgG antibodies against periodontal microorganisms and AD mortality.

METHODS

Individuals participating in the Third National Health and Nutrition Examination Survey (NHANES III) with complete data on IgG titers were followed up between 1988 and December 31, 2019. The outcome was AD mortality, and the main exposures were IgG antibodies against periodontal microorganisms classified into four mutually exclusive groups using cluster analysis. Survey-weighted Cox proportional hazard models were used to evaluate adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for the relationship between clusters and AD mortality.

RESULTS

With up to 21 years of follow-up, 160 AD-related deaths were documented. In the multivariable-adjusted model, AD mortality overall was not associated with the Red-Green (aHR 1.18; 95% CI, 0.46-3.07), Yellow-Orange (aHR 1.36; 95% CI, 0.58-3.19), Orange-Blue (aHR 0.63; 95%, CI, 0.33-1.21), and the Orange-Red (aHR 0.79; 95% CI, 0.37-1.70) when the upper tertiles were compared to the bottom tertiles. However, the subgroup of middle-aged individuals in the highest tertile of the Red-Green cluster, but not older individuals, had a 13% higher risk of AD mortality (aHR 1.13; 95% CI, 1.02-1.26) compared with those in the bottom tertile.

CONCLUSION

Clusters of IgG antibodies against periodontal microorganisms did not predict AD mortality in this study.

Association Between Catheter Ablation and Dementia Among Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

Atrial fibrillation (AF) is associated with an increased risk of Dementia. However, the association between catheter ablation (CA) in patients with atrial fibrillation and the risk of dementia is not well established, with conflicting results to date. We aimed to evaluate the association between CA patients and the risk of Dementia. We performed a systematic literature search using the PubMed, Embase, Scopus, and Cochrane libraries for relevant articles from inception until 10th May 2023. Hazard ratios (HR) were pooled using a random-effect model, and a P-value of < 0.05 was considered statistically significant. A total of 5 studies with 125,649 patients (30,192 in the CA group and 95,457 in the non-CA group) were included. The mean age of patients among CA and non-CA groups was comparable (58.7 vs 58.18). The most common comorbidity among CA and non-CA groups was hypertension (18.49% vs 81.51%), respectively. Pooled analysis of primary outcome showed that CA was associated with a significant reduction in the risk of Dementia (HR, 0.63 [95% CI: 0.52-0.77], P < 0.001). Similarly, pooled analysis of secondary outcomes showed that the patients with CA had a lower risk of Alzheimer's disease (HR, 0.78 [95% CI: 0.66-0.92], P < 0.001) compared with the non-CA group. However, there was no statistically significant difference in the risk of vascular dementia (HR, 0.63 [95% CI: 0.38-1.06], P = 0.08) between both groups of patients. Our study suggested that catheter ablation reduced the risk of dementia and Alzheimer's disease compared to the nonablation group of patients.

Application of Suggestive Biomarkers in Dementia With Lewy Bodies With Masking of Typical Clinical Symptoms by Alzheimer Disease-type Pathology

Dementia with Lewy bodies (DLB) is strongly associated with Alzheimer disease (AD)-type pathology and tends to mask the core clinical features of DLB. Therefore, there may be cases of undiagnosed DLB without suggestive biomarkers of DLB. We describe the case of a 63-year-old woman who was initially diagnosed as having AD and later diagnosed with DLB based on suggestive biomarkers of DLB. In this case, transient sleep talking with physical movements for several days led to the assessment of suggestive biomarkers for DLB in the absence of the core clinical features of DLB. For clinicians, diagnosing DLB in patients with AD-type pathology is challenging. However, the application of biomarkers suggestive of DLB to all patients with dementia is not realistic. To overcome the difficulties of clinical diagnosis of DLB, further research is needed regarding strategies for the application of suggestive biomarkers for DLB to appropriately diagnose DLB.

Cytomegalovirus Infection and Alzheimer's Disease: A Meta-Analysis

BACKGROUND

Evidence on the association of cytomegalovirus (CMV) infection with Alzheimer's disease (AD) is scarce and the results are inconsistent.

OBJECTIVE

To investigate the association of CMV infection with the risk of AD.

METHODS

Observational studies on the relationship between CMV infection and AD were identified from PubMed, Embase, Web of Science, and the Cochrane Library until September 30, 2022. The quality of included studies was assessed using the Newcastle-Ottawa Scale. Random-effect meta-analysis was performed using a generic inverse-variance method, followed by sensitivity analyses and subgroup analyses based on study designs, regions, adjustments, and population types.

RESULTS

Our search yielded 870 articles, of which 200 were duplicates and 663 did not meet the inclusion criteria, and finally yielded seven studies with 6,772 participants. No strong evidence was observed in the summary analysis for the association of CMV infection and risk of AD (odds ratio [OR] = 1.33; 95% confidence interval [CI]: 0.88, 2.03, I2 =69.9%). However, subgroup analysis showed that an increased risk of AD was detected in East Asians (OR = 2.39; 95% CI: 1.63, 3.50, I2 = 0.00%), cohort studies (OR = 1.99; 95% CI: 1.35, 2.94, I2 = 28.20%), and studies with confounder adjustment (OR = 2.05; 95% CI: 1.52, 2.77, I2 = 0.00%).

CONCLUSIONS

This meta-analysis provides evidence to support the heterogeneity of the associations between CMV infection and AD. Future studies with larger sample sizes and multi-ethnic populations are necessary.

Associations of inner retinal layers with risk of incident dementia: An individual participant data analysis of four prospective cohort studies

INTRODUCTION

Our main objective was to investigate whether retinal neurodegeneration, estimated from lower thickness of inner retinal layers, was associated with incident all-cause dementia and Alzheimer's disease (AD).

METHODS

We performed an individual participant data meta-analysis using unpublished data from four prospective cohort studies with a total of 69,955 participants (n = 1087 cases of incident all-cause dementia; n = 520 cases incident AD; follow-up time median [interquartile range] 11.3 [8.8-11.5] years).

RESULTS

General baseline characteristics of the study population were mean (standard deviation) age, 58.1 (8.8) years; 47% women. After adjustment, lower baseline macular retinal nerve fiber layer thickness was significantly associated with a 10% and 11% higher incidence of all-cause dementia and AD, respectively. Lower baseline macular ganglion cell-inner plexiform layer thickness was not significantly associated with these outcomes.

DISCUSSION

These findings suggest that retinal neurodegeneration precedes the onset of clinical dementia. Retinal imaging tools may be informative biomarkers for the study of the early pathophysiology of dementia.

AT(N) biomarker profiles and Alzheimer's disease symptomology in Down syndrome

INTRODUCTION

Down syndrome (DS) is a genetic cause of early-onset Alzheimer's disease (AD). The National Institute on Aging-Alzheimer's Association AT(N) Research Framework is a staging model for AD biomarkers but has not been assessed in DS.

METHOD

Data are from the Alzheimer's Biomarker Consortium-Down Syndrome. Positron emission tomography (PET) amyloid beta (Aβ; 15 mCi of [11 C]Pittsburgh compound B) and tau (10 mCi of [18 F]AV-1451) were used to classify amyloid (A) -/+ and tau (T) +/-. Hippocampal volume classified neurodegeneration (N) -/+. The modified Cued Recall Test assessed episodic memory.

RESULTS

Analyses included 162 adults with DS (aged M = 38.84 years, standard deviation = 8.41). Overall, 69.8% of participants were classified as A-/T-/(N)-, 11.1% were A+/T-/(N)-, 5.6% were A+/T+/(N)-, and 9.3% were A+/T+/(N)+. Participants deemed cognitively stable were most likely to be A-T-(N)- and A+T-(N)-. Tau PET (T+) most closely aligning with memory impairment and AD clinical status.

DISCUSSION

Findings add to understanding of AT(N) biomarker profiles in DS.

HIGHLIGHTS

Overall, 69.8% of adults with Down syndrome (DS) aged 25 to 61 years were classified as amyloid (A)-/tau (T)-/neurodegeneration (N)-, 11.1% were A+/T-/(N)-, 5.6% were A+/T+/(N)-, and 9.3% were A+/T+/(N)+. The AT(N) profiles were associated with clinical Alzheimer's disease (AD) status and with memory performance, with the presence of T+ aligned with AD clinical symptomology. Findings inform models for predicting the transition to the prodromal stage of AD in DS.

Association of Vitamin D Levels with Risk of Cognitive Impairment and Dementia: A Systematic Review and Meta-Analysis of Prospective Studies

Background

Emerging evidence suggests the potential relationship between vitamin D deficiency and risk of cognitive impairment or dementia. To what extent the excess risk of dementia conferred by vitamin D deficiency is less clear.

Objective

We summarized the current evidence from several aspects and further quantified these associations.

Methods

We collected relevant prospective cohort studies by searching PubMed, Embase and Cochrane up to July 2023. The pooled relative risks (RR) were evaluated by random-effects models. Dose-response analyses were conducted by the method of two-stage generalized least squares regression.

Results

Of 9,267 identified literatures, 23 were eligible for inclusion in the meta-analyses, among which 9 and 4 literatures were included in the dose-response analyses for the risk of dementia and Alzheimer's disease (AD). Vitamin D deficiency exhibited a 1.42 times risk for dementia (95% confidence interval (CI) = 1.21-1.65) and a 1.57-fold excess risk for AD (95% CI = 1.15-2.14). And vitamin D deficiency was associated with 34% elevated risk with cognitive impairment (95% CI = 1.19-1.52). Additionally, vitamin D was non-linearly related to the risk of dementia (pnonlinearity = 0.0000) and AD (pnonlinearity = 0.0042). The approximate 77.5-100 nmol/L 25-hydroxyvitamin D [25(OH)D] was optimal for reducing dementia risk. And the AD risk seemed to be decreased when the 25(OH)D level >40.1 nmol/L.

Conclusions

Vitamin D deficiency was a risk factor for dementia, AD, and cognitive impairment. The nonlinear relationships may further provide the optimum dose of 25(OH)D for dementia prevention.

Association Between Self- and Proxy-Reported Depression and Quality of Life in Mild-Moderate Alzheimer's Disease

OBJECTIVE

Prior studies have reported an association between depression and quality of life (QOL) in Alzheimer's disease (AD), but the effect of self- versus proxy rating of mood and QOL has not been described.

DESIGN

In this secondary analysis of data from a cohort study, the authors used a linear mixed-effects model to determine if the association between depression and QOL is affected by whether both measures are assessed by the same member of the patient-caregiver dyad.

SETTING

Participants and caregiver informants were recruited from 10 California Alzheimer Disease Centers.

PARTICIPANTS

A total of 137 participants with mild-to-moderate Alzheimer's disease and their caregivers.

MEASUREMENTS

Self- and proxy-rated scores on both the Geriatric Depression Scale (GDS) and the Quality of Life in Alzheimer's Disease scale (QoL-AD). Multivariable linear mixed-effects models were used to estimate the association between depression and QOL.

RESULTS

Results of the multivariable linear mixed-effects models showed a significant association between self-rated QoL-AD and self-rated (B = -0.49, p <0.0001) but not proxy-rated GDS (B = -0.07, p = 0.19) after adjusting for confounders. Likewise, there was a significant association between proxy-rated QoL-AD and proxy-rated GDS (B = -0.48, p <0.0001) but not self-rated GDS (B = 0.05, p = 0.36).

CONCLUSION

Depression was associated with QOL in AD over short-term longitudinal follow-up, but the association was not statistically significant if both instruments are not administered to the same member of the patient-caregiver dyad. The choice of self- versus proxy-reported QOL should be intentionally considered in future studies as it may influence reported outcomes.

Psychosis in Neurodegenerative Dementias: A Systematic Comparative Review

Background

Psychosis, characterized by delusions and/or hallucinations, is frequently observed during the progression of Alzheimer's disease (AD) and other neurodegenerative dementias (ND) (i.e., dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD)) and cause diagnostic and management difficulties.

Objective

This review aims at presenting a concise and up-to-date overview of psychotic symptoms that occur in patients with ND with a comparative approach.

Methods

A systematic review was conducted following the PRISMA guidelines. 98 original studies investigating psychosis phenotypes in neurodegenerative dementias were identified (40 cohort studies, 57 case reports).

Results

Psychosis is a frequently observed phenomenon during the course of ND, with reported prevalence ranging from 22.5% to 54.1% in AD, 55.9% to 73.9% in DLB, and 18% to 42% in FTD. Throughout all stages of these diseases, noticeable patterns emerge depending on their underlying causes. Misidentification delusions (16.6-78.3%) and visual hallucinations (50-69.6%) are frequently observed in DLB, while paranoid ideas and somatic preoccupations seem to be particularly common in AD and FTD, (respectively 9.1-60.3% and 3.10-41.5%). Limited data were found regarding psychosis in the early stages of these disorders.

Conclusions

Literature data suggest that different ND are associated with noticeable variations in psychotic phenotypes, reflecting disease-specific tendencies. Further studies focusing on the early stages of these disorders are necessary to enhance our understanding of early psychotic manifestations associated with ND and help in differential diagnosis issues.

Associations Between Plasma Orexin-A Level and Constipation in Cognitive Impairment

BACKGROUND

Constipation is a common symptom in dementia, and the cause is controversial. Rare clinical studies focused on plasma orexin-A levels and constipation in dementia.

OBJECTIVE

To evaluate the associations between orexin-A and constipation in patients with cognitive impairment.

METHODS

A total of 21 patients with mild cognitive impairment (MCI), 142 with Alzheimer's disease (AD), and 57 with Lewy body dementia (LBD) were conducted. Besides informant-based history, neurological examinations or neuropsychological assessments, plasma levels of orexin-A, and constipation were assessed. The associations between orexin-A and constipation were evaluated by logistic regression models.

RESULTS

There were 47/220 (21.36%) cognitive impairment patients having constipation, and the proportion of constipation in LBD (61.40%) was significantly higher than AD (5.63%) and MCI (19.05%). No significant age or sex differences in the prevalence of constipation were found in the MCI, AD, and LBD groups. We found the cognitive impairment patients with constipation had lower levels of plasma orexin-A [1.00 (0.86, 1.28) versus 1.29 (1.01, 1.50) ng/ml, p < 0.001] than those without. And the plasma levels of orexin-A were significantly associated with the occurrence of constipation after adjusting for all variables in all patients with cognitive impairment (OR = 0.151, 95% CI: 0.042-0.537, p = 0.003). And the same finding was more prominent in the LBD group (p = 0.048).

CONCLUSIONS

The decrease of plasma level of orexin-A is closely associated with the occurrence of constipation. Orexin-A has an intestinal protective effect and is involved in the gastrointestinal symptoms of patients with cognitive impairment.

Impact of Concurrent Visual and Hearing Impairment on Incident Alzheimer's Disease: The LIFE Study

Background

The prevalence of Alzheimer's disease (AD) is increasing in Japan due to population aging. The association between sensory impairment and incident AD remains unclear.

Objective

This study aimed to investigate the impact of sensory impairment on incident AD.

Methods

We analyzed residents of five municipalities participating in the Longevity Improvement & Fair Evidence (LIFE) Study. The participants comprised individuals who had newly applied for long-term care needs certification between 2017 and 2022 and had no cognitive impairment upon application or AD diagnosis within the preceding six months. Participants were classified according to sensory impairment status: visual impairment (VI), hearing impairment (HI), neither sensory impairment (NSI), and dual sensory impairment (DSI). The month succeeding the certification application was set as the index month, and the interval from that month until AD onset was assessed. Multivariable Cox proportional hazards analysis was performed to calculate the risk of AD onset according to sensory impairment status while adjusting for sex, age, dependence level, self-reliance level, and comorbidities.

Results

Among 14,186 participants, we identified 1,194 (8.4%) who developed AD over a median follow-up period of 22.6 months. VI and HI only were not associated with incident AD. However, DSI conferred a significantly higher risk (HR: 1.6, CI: 1.1-2.2, p = 0.008) of AD onset than NSI.

Conclusions

Individuals with concurrent DSI have a higher risk of developing AD than those with single or NSI. Preventing and treating sensory impairment may not only improve functional outcomes, but could also help to reduce the future risk of AD.

Prognostic Information on Progression to Dementia: Quantification of the Impact on Quality of Life

Background

The increasing interest in early identification of people at risk of developing dementia, has led to the development of numerous models aimed at estimating the likelihood of progression from mild cognitive impairment (MCI) to dementia. It is important to study both the need for and possible outcomes related with such prediction models, including the impact of risk predictions on perceived quality of life (QoL).

Objective

This study aimed to quantify the impact that receiving a risk prediction on progression from MCI to dementia has on QoL.

Methods

A Discrete Choice Experiment (DCE) and Time Trade Off (TTO) study were performed. Participants completed choice tasks related to dementia prognosis while imagining having MCI. We collected DCE data by an online survey, and TTO data via videoconferencing interviews. DCE data were analyzed using a mixed multinomial logit model and were anchored to a health state utility scale using mean observed TTO valuations.

Results

296 people participated in the DCE and 42 in the TTO. Moderate and high predicted dementia risks were associated with decrements in utility (-0.05 and -0.18 respectively), compared to no prognostic information. Low predicted risk was associated with an increase in utility (0.06), as well as the availability of medication or lifestyle interventions (0.05 and 0.13 respectively).

Conclusions

This study shows a significant impact of dementia risk predictions on QoL and highlights the importance of caution when sharing information about expected MCI disease courses.

Development of a Lived Experience Panel to inform the design of embedded pragmatic trials of dementia care interventions

BACKGROUND

The National Institute on Aging (NIA) Imbedded Pragmatic Alzheimer's Disease and Alzheimer's Related Dementia Clinical Trials (IMPACT) Collaboratory convened a Lived Experience Panel (LEP) to inform the development of research priorities and provide input on conducting embedded pragmatic clinical trials (ePCTs) of dementia care interventions. Given the importance of people with lived experience to dementia research, and the unique considerations of engaging people with dementia, we report on our process for the recruitment, selection, and initial convening of the IMPACT LEP.

METHODS

The IMPACT Engaging Partners Team, in partnership with the Alzheimer's Association, sought nominations of individuals with mild cognitive impairment or early-stage dementia, care partners of other people living with dementia (PLWD), and proxy representatives for individuals with mid-to-late stage dementia. The 11-member LEP was composed of individuals with diverse personal experiences in part due to their age, race, ethnicity, gender, sexual orientation, geography, disability, or type of dementia. In its first year, the LEP met with IMPACT's Patient and Caregiver Relevant Outcomes Core and Ethics and Regulation Core.

RESULTS

LEP members provided valuable insights and nuanced discussion of issues relevant to ePCTs in dementia care from a broad range of personal experience. Panelists identified key research priorities and provided insight on outcomes often studied by researchers. The LEP also informed investigators' approaches to waivers and modifications of written informed consent and evaluation of minimal risk. Summary reports of the LEP meetings with each Core are available on the IMPACT website. At the end of the first year, changes were made to the composition of the LEP, and opportunities were identified for expanding panelist engagement with IMPACT investigators, as were priorities and scope for future input.

CONCLUSIONS

The IMPACT LEP provides a model for engaging PLWD and care partners in the research process as collaborators.

Associations of Frailty with Neuropsychiatric Symptoms of Alzheimer's Disease: A Longitudinal Study

Background

Frailty is a vulnerability state increasing the risk of many adverse health outcomes, but little is known about the effects of frailty on neuropsychiatric health.

Objective

To explore the associations between frailty and the risk of neuropsychiatric symptoms (NPSs) in Alzheimer's disease (AD), especially in its different clinical stages.

Methods

We included 2,155 individuals assessed using modified frailty index-11 (mFI-11), Neuropsychiatric Inventory (NPI) and Neuropsychiatric Inventory Questionnaire (NPI-Q) in the Alzheimer's Disease Neuroimaging Initiative (ADNI). The relationships between frailty and NPSs were explored with logistic regression models and Cox proportional hazard regression models. Causal mediation analyses were conducted to explore the mediation factors between frailty and NPSs.

Results

Among mild cognitive impairment (MCI) participants, frailty was cross-sectionally associated with an increased risk of apathy, and longitudinally associated with increased risk of depression and apathy. Among AD participants, frailty was cross-sectionally associated with increased risk of depression and anxiety, and longitudinally associated with an increased risk of apathy. Among participants with cognitive progression, frailty was associated with increased risk of depression and apathy. In MCI participants, the influence of frailty on NPSs was partially mediated by hippocampus volume, whole brain volume, and monocytes, with mediating proportions ranging from 8.40% to 9.29%.

Conclusions

Frailty was associated with NPSs such as depression, anxiety, and apathy among MCI, AD, and cognitive progression participants. Atrophy of the hippocampus and whole brain, as well as peripheral immunity may be involved in the potential mechanisms underlying the above associations.

Sex differences in the association between tau PET and cognitive performance in a non-Hispanic White cohort with preclinical AD

INTRODUCTION

We investigated how the associations between tau and cognitive measures differ by sex in the preclinical Alzheimer's disease (AD) stage.

METHODS

A total of 343 cognitively unimpaired, amyloid-positive individuals (205 women, 138 men) who self-identified as non-Hispanic White from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study were included. We assessed sex-stratified associations between 18 F-flortaucipir positron emission tomography (PET) standardized uptake value ratio (SUVR) in the meta-temporal region and Preclinical Alzheimer's Cognitive Composite (PACC) and Computerized Cognitive Composite (C3) components.

RESULTS

We observed that higher tau level was significantly associated with worse cognitive performance only in women: PACC and its components except for Mini-Mental State Examination (MMSE) and C3 components: First Letter Name Recall (FNLT) and One-Card Learning Reaction Time (OCL RT). These associations except for FNLT were apolipoprotein E (APOE) ε4 independent.

DISCUSSION

Women show stronger associations between tau PET and cognitive outcomes in preclinical AD. These findings have important implications for sex-specific tau-targeted preventive AD clinical trials.

HIGHLIGHTS

The tau positron emission tomography (PET) signal in the meta-temporal region was associated with poor cognitive performance in preclinical Alzheimer's disease (AD). After sex stratification, the associations between regional tau PET and cognitive outcomes were observed only in women. The associations between tau PET and some cognitive outcomes were independent of apolipoprotein E (APOE) ε4.

Vulnerability of Spatial Pattern Separation in 5xFAD Alzheimer's Disease Mouse Model

Background

Alzheimer's disease (AD) is the most common cause of dementia and remains incurable. This age-related neurodegenerative disease is characterized by an early decline in episodic and spatial memory associated with progressive disruption of the hippocampal functioning. Recent clinical evidence suggests that impairment of the spatial pattern separation (SPS) function, which enables the encoding and storage of episodic spatial information, may be an indicator of the early stages of AD.

Objective

The aim of our study was to characterize SPS performance at a prodromal stage in 5xFAD transgenic mouse model of AD.

Methods

Behavioral performance of male wild-type (WT) and 5xFAD mice (n = 14 per group) was assessed from the age of 4 months in two validated paradigms of SPS function either based on spontaneous exploration of objects or on the use of a touchscreen system.

Results

Compared with age-matched WT littermates, a mild deficit in SPS function was observed in the object recognition task in 5xFAD mice, whereas both groups showed similar performance in the touchscreen-based task. These results were observed in the absence of changes in locomotor activity or anxiety-like behavior that could have interfered with the tasks assessing SPS function.

Conclusions

Our results indicate an early vulnerability of the SPS function in 5xFAD mice in the paradigm based on spontaneous exploration of objects. Our work opens up the possibility of examining the early neurobiological processes involved in the decline of episodic memory and may help to propose new therapeutic strategies in the context of AD.

Amyloid Pathology Modulates the Associations of Neuropsychiatric Symptoms with Cognitive Impairments and Neurodegeneration in Non-Demented Elderly

BACKGROUND

The associations between neuropsychiatric symptoms (NPSs) and Alzheimer's disease (AD) have been well-studied, yet gaps remain.

OBJECTIVE

We aimed to examine the associations of four subsyndromes (hyperactivity, psychosis, affective symptoms, and apathy) of NPSs with cognition, neurodegeneration, and AD pathologies.

METHODS

Totally 1,040 non-demented elderly (48.07% males) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were included. We assessed the relationships between NPSs and AD neuropathologies, cognition, neurodegeneration, and clinical correlates in cross-sectional and longitudinal via multiple linear regression, linear mixed effects, and Cox proportional hazard models. Causal mediation analyses were conducted to explore the mediation effects of AD pathologies on cognition and neurodegeneration.

RESULTS

We found that individuals with hyperactivity, psychosis, affective symptoms, or apathy displayed a poorer cognitive status, a lower CSF amyloid-β (Aβ) level and a higher risk of clinical conversion (p < 0.05). Hyperactivity and affective symptoms were associated with increasing cerebral Aβ deposition (p < 0.05). Except psychosis, the other three subsyndromes accompanied with faster atrophy of hippocampal volume (p < 0.05). Specific NPSs were predominantly associated with different cognitive domains decline through an 8-year follow-up (p < 0.05). Moreover, the relationships between NPSs and cognitive decline, neurodegeneration might be associated with Aβ, the mediation percentage varied from 6.05% to 17.51% (p < 0.05).

CONCLUSIONS

NPSs could be strongly associated with AD. The influences of NPSs on cognitive impairments, neurodegeneration might be partially associated with Aβ.

Altered Motor Activity Patterns within 10-Minute Timescale Predict Incident Clinical Alzheimer's Disease

Background

Fractal motor activity regulation (FMAR), characterized by self-similar temporal patterns in motor activity across timescales, is robust in healthy young humans but degrades with aging and in Alzheimer's disease (AD).

Objective

To determine the timescales where alterations of FMAR can best predict the clinical onset of AD.

Methods

FMAR was assessed from actigraphy at baseline in 1,077 participants who had annual follow-up clinical assessments for up to 15 years. Survival analysis combined with deep learning (DeepSurv) was used to examine how baseline FMAR at different timescales from 3 minutes up to 6 hours contributed differently to the risk for incident clinical AD.

Results

Clinical AD occurred in 270 participants during the follow-up. DeepSurv identified three potential regions of timescales in which FMAR alterations were significantly linked to the risk for clinical AD: <10, 20-40, and 100-200 minutes. Confirmed by the Cox and random survival forest models, the effect of FMAR alterations in the timescale of <10 minutes was the strongest, after adjusting for covariates.

Conclusions

Subtle changes in motor activity fluctuations predicted the clinical onset of AD, with the strongest association observed in activity fluctuations at timescales <10 minutes. These findings suggest that short actigraphy recordings may be used to assess the risk of AD.

A real-world assessment of healthcare costs associated with agitation in Alzheimer's dementia

AIMS

To describe and compare clinical characteristics, healthcare costs, and institutionalization/mortality outcomes among patients with and without agitation associated with Alzheimer's dementia (AAD).

METHODS

Data from the Reliant Medical Group database (01/01/2016-03/31/2020) were used, including claims, electronic medical records, and clinical information/physician notes abstracted from medical charts. Patients aged ≥55 years with Alzheimer's dementia (AD) were observed during a randomly selected 12-month study period after AD diagnosis. Using information recorded in medical charts, patients were classified into cohorts based on experiencing (agitation cohort) and not experiencing (no agitation cohort) agitated behaviours during the study period. Entropy balancing was used to create reweighted cohorts with similar characteristics. Study outcomes (patient demographic and clinical characteristics, treatments received, healthcare costs, institutionalization and death events) were compared between cohorts; agitation characteristics were described for the agitation cohort only.

RESULTS

Among 711 patients included in the study, 240 were classified in the agitation cohort and 471 in the no agitation cohort. After reweighting, several comorbidities were more frequently observed in the agitation versus no agitation cohort, including infection, depression, and altered mental status. Use of antidepressants, anticonvulsants, antipsychotics, and antianxiety medications was more common in the agitation versus no agitation cohort. Common agitated behaviours included hitting (20.8%), pacing/aimless wandering (17.5%), and cursing/verbal aggression (15.0%). Total all-cause healthcare costs were $4287 per-patient-per-year higher in the agitation cohort versus no agitation cohort (p = 0.04), driven by higher inpatient costs. Death was more common and time to death and institutionalization were shorter in the agitation versus no agitation cohort.

LIMITATIONS

Results may not be generalizable to the US population with AD.

CONCLUSIONS

Among patients with AD, agitation was associated with shorter time to death/institutionalization and increased comorbidities, medication use, and healthcare costs, highlighting the additional clinical and economic burden that agitation poses to patients and the healthcare system.

DNA from multiple viral species is associated with Alzheimer's disease risk

INTRODUCTION

Multiple infectious agents, including viruses, bacteria, fungi, and protozoa, have been linked to Alzheimer's disease (AD) risk by independent lines of evidence. We explored this association by comparing the frequencies of viral species identified in a large sample of AD cases and controls.

METHODS

DNA sequence reads that did not align to the human genome in sequences were mapped to viral reference sequences, quantified, and then were tested for association with AD in whole exome sequences (WES) and whole genome sequences (WGS) datasets.

RESULTS

Several viruses were significant predictors of AD according to the machine learning classifiers. Subsequent regression analyses showed that herpes simplex type 1 (HSV-1) (odds ratio [OR] = 3.71, p = 8.03 × 10-4) and human papillomavirus 71 (HPV-71; OR = 3.56, p = 0.02), were significantly associated with AD after Bonferroni correction. The phylogenetic-related cluster of Herpesviridae was significantly associated with AD in several strata of the data (p < 0.01).

DISCUSSION

Our results support the hypothesis that viral infection, especially HSV-1, is associated with AD risk.

Cognitive symptoms progress with limbic-predominant age-related TDP-43 encephalopathy stage and co-occurrence with Alzheimer disease

Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is a neuropathologic entity characterized by transactive response DNA-binding protein of 43-kDa (TDP-43)-immunoreactive inclusions that originate in the amygdala and then progress to the hippocampi and middle frontal gyrus. LATE-NC may mimic Alzheimer disease clinically and often co-occurs with Alzheimer disease neuropathologic change (ADNC). This report focuses on the cognitive effects of isolated and concomitant LATE-NC and ADNC. Cognitive/neuropsychological, neuropathologic, genetic, and demographic variables were analyzed in 28 control, 31 isolated LATE-NC, 244 isolated ADNC, and 172 concurrent LATE-NC/ADNC subjects from the National Alzheimer's Coordinating Center. Cases with LATE-NC and ADNC were significantly older than controls; cases with ADNC had a significantly higher proportion of cases with at least one APOE ε4 allele. Both LATE-NC and ADNC exhibited deleterious effects on overall cognition proportional to their neuropathological stages; concurrent LATE-NC/ADNC exhibited the worst overall cognitive effect. Multivariate logistic regression analysis determined an independent risk of cognitive impairment for progressive LATE-NC stages (OR 1.66; p = 0.0256) and ADNC levels (OR 3.41; p < 0.0001). These data add to the existing knowledge on the clinical consequences of LATE-NC pathology and the growing literature on the effects of multiple concurrent neurodegenerative pathologies.

Amyloid precursor protein facilitates SARS-CoV-2 virus entry into cells and enhances amyloid-β-associated pathology in APP/PS1 mouse model of Alzheimer's disease

Although there are indications of a trend towards less severe acute respiratory symptoms and a decline in overall lethality from the novel Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), more and more attention has been paid to the long COVID, including the increased risk of Alzheimer's disease (AD) in COVID-19 patients. In this study, we aim to investigate the involvement of N-terminal amyloid precursor protein (APP) in SARS-CoV-2-induced amyloid-β (Aβ) pathology. Utilizing both in vitro and in vivo methodologies, we first investigated the interaction between the spike protein of SARS-CoV-2 and N-terminal APP via LSPR and CoIP assays. The in vitro impacts of APP overexpression on virus infection were further evaluated in HEK293T/ACE2 cells, SH-SY5Y cells, and Vero cells. We also analyzed the pseudovirus infection in vivo in a mouse model overexpressing human wild-type APP. Finally, we evaluated the impact of APP on pseudovirus infection within human brain organoids and assessed the chronic effects of pseudovirus infection on Aβ levels. We reported here for the first time that APP, the precursor of the Aβ of AD, interacts with the Spike protein of SARS-CoV-2. Moreover, both in vivo and in vitro data further indicated that APP promotes the cellular entry of the virus, and exacerbates Aβ-associated pathology in the APP/PS1 mouse model of AD, which can be ameliorated by N-terminal APP blockage. Our findings provide experimental evidence to interpret APP-related mechanisms underlying AD-like neuropathology in COVID-19 patients and may pave the way to help inform risk management and therapeutic strategies against diseases accordingly.

White matter integrity is associated with cognition and amyloid burden in older adult Koreans along the Alzheimer's disease continuum

BACKGROUND

White matter (WM) microstructural changes in the hippocampal cingulum bundle (CBH) in Alzheimer's disease (AD) have been described in cohorts of largely European ancestry but are lacking in other populations.

METHODS

We assessed the relationship between CBH WM integrity and cognition or amyloid burden in 505 Korean older adults aged ≥ 55 years, including 276 cognitively normal older adults (CN), 142 with mild cognitive impairment (MCI), and 87 AD patients, recruited as part of the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's disease (KBASE) at Seoul National University.

RESULTS

Compared to CN, AD and MCI subjects showed significantly higher RD, MD, and AxD values (all p-values < 0.001) and significantly lower FA values (left p ≤ 0.002, right p ≤ 0.015) after Bonferroni adjustment for multiple comparisons. Most tests of cognition and mood (p < 0.001) as well as higher medial temporal amyloid burden (p < 0.001) were associated with poorer WM integrity in the CBH after Bonferroni adjustment.

CONCLUSION

These findings are consistent with patterns of WM microstructural damage previously reported in non-Hispanic White (NHW) MCI/AD cohorts, reinforcing existing evidence from predominantly NHW cohort studies.

T1 and FLAIR signal intensities are related to tau pathology in dominantly inherited Alzheimer disease

Carriers of mutations responsible for dominantly inherited Alzheimer disease provide a unique opportunity to study potential imaging biomarkers. Biomarkers based on routinely acquired clinical MR images, could supplement the extant invasive or logistically challenging) biomarker studies. We used 1104 longitudinal MR, 324 amyloid beta, and 87 tau positron emission tomography imaging sessions from 525 participants enrolled in the Dominantly Inherited Alzheimer Network Observational Study to extract novel imaging metrics representing the mean (μ) and standard deviation (σ) of standardized image intensities of T1-weighted and Fluid attenuated inversion recovery (FLAIR) MR scans. There was an exponential decrease in FLAIR-μ in mutation carriers and an increase in FLAIR and T1 signal heterogeneity (T1-σ and FLAIR-σ) as participants approached the symptom onset in both supramarginal, the right postcentral and right superior temporal gyri as well as both caudate nuclei, putamina, thalami, and amygdalae. After controlling for the effect of regional atrophy, FLAIR-μ decreased and T1-σ and FLAIR-σ increased with increasing amyloid beta and tau deposition in numerous cortical regions. In symptomatic mutation carriers and independent of the effect of regional atrophy, tau pathology demonstrated a stronger relationship with image intensity metrics, compared with amyloid pathology. We propose novel MR imaging intensity-based metrics using standard clinical T1 and FLAIR images which strongly associates with the progression of pathology in dominantly inherited Alzheimer disease. We suggest that tau pathology may be a key driver of the observed changes in this cohort of patients.

Dementia subtypes, cognitive decline and survival among older adults attending a memory clinic in Cape Town, South Africa: a retrospective study

BACKGROUND

There are no published longitudinal studies from Africa of people with dementia seen in memory clinics. The aim of this study was to determine the proportions of the different dementia subtypes, rates of cognitive decline, and predictors of survival in patients diagnosed with dementia and seen in a memory clinic.

METHODS

Data were collected retrospectively from clinic records of patients aged ≥ 60 seen in the memory clinic at Groote Schuur Hospital, Cape Town, South Africa over a 10-year period. Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria were used to identify patients with Major Neurocognitive Disorders (dementia). Additional diagnostic criteria were used to determine the specific subtypes of dementia. Linear regression analysis was used to determine crude rates of cognitive decline, expressed as mini-mental state examination (MMSE) points lost per year. Changes in MMSE scores were derived using mixed effects modelling to curvilinear models of cognitive change, with time as the dependent variable. Multivariable cox survival analysis was used to determine factors at baseline that predicted mortality.

RESULTS

Of the 165 patients who met inclusion criteria, 117(70.9%) had Major Neurocognitive Disorder due to Alzheimer's disease (AD), 24(14.6%) Vascular Neurocognitive Disorder (VND), 6(3.6%) Dementia with Lewy Bodies (DLB), 5(3%) Parkinson disease-associated dementia (PDD), 3(1.8%) fronto-temporal dementia, 4(2.4%) mixed dementia and 6(3.6%) other types of dementia. The average annual decline in MMSE points was 2.2(DLB/PDD), 2.1(AD) and 1.3(VND). Cognitive scores at baseline were significantly lower in patients with 8 compared to 13 years of education and in those with VND compared with AD. Factors associated with shorter survival included age at onset greater than 65 (HR = 1.82, 95% C.I. 1.11, 2.99, p = 0.017), lower baseline MMSE (HR = 1.05, 95% C.I. 1.01, 1.10, p = 0.029), Charlson's comorbidity scores of 3 to 4 (HR = 1.88, 95% C.I. 1.14, 3.10, p = 0.014), scores of 5 or more (HR = 1.97, 95% C.I. 1.16, 3.34, p = 0.012) and DLB/PDD (HR = 3.07, 95% C.I. 1.50, 6.29, p = 0.002). Being female (HR = 0.59, 95% C.I.0.36, 0.95, p = 0.029) was associated with longer survival.

CONCLUSIONS

Knowledge of dementia subtypes, the rate and factors affecting cognitive decline and survival outcomes will help inform decisions about patient selection for potential future therapies and for planning dementia services in resource-poor settings.

Hypertension linked to Alzheimer's disease via stroke: Mendelian randomization

This study aimed to investigate the relationship between hypertension and Alzheimer's disease (AD) and demonstrate the key role of stroke in this relationship using mediating Mendelian randomization. AD, a neurodegenerative disease characterized by memory loss, cognitive impairment, and behavioral abnormalities, severely affects the quality of life of patients. Hypertension is an important risk factor for AD. However, the precise mechanism underlying this relationship is unclear. To investigate the relationship between hypertension and AD, we used a mediated Mendelian randomization method and screened for mediating variables between hypertension and AD by setting instrumental variables. The results of the mediated analysis showed that stroke, as a mediating variable, plays an important role in the causal relationship between hypertension and AD. Specifically, the mediated indirect effect value for stroke obtained using multivariate mediated MR analysis was 54.9%. This implies that approximately 55% of the risk of AD owing to hypertension can be attributed to stroke. The results suggest that the increased risk of AD owing to hypertension is mediated through stroke. The finding not only sheds light on the relationship between hypertension and AD but also indicates novel methods for the prevention and treatment of AD. By identifying the critical role of stroke in the link between hypertension and AD, this study provides insights into potential interventions that could mitigate the impact of hypertension on AD. This could help develop personalized treatments and help improve the quality of life of patients with AD who suffer from hypertension.

Correlation between white matter hyperintensity and delusional symptoms in Alzheimer's disease

BACKGROUND

Patients with Alzheimer's disease (AD) often exhibit neuropsychiatric symptoms (NPS), particularly delusions. Previous studies have shown an association between white matter hyperintensities (WMH) and specific NPS. This study aims to explore the relationship between WMH volume and delusions in AD patients by comparing the WMH volumes of delusional and non-delusional subgroups.

METHODS

80 AD patients were divided into a delusion group (n = 36) and a non-delusion group (n = 44) based on the Neuropsychiatric Inventory (NPI). The brain cortical volume and WMH volume were quantitatively calculated for all 80 patients, including total WMH volume, periventricular WMH (PVWMH) volume, deep WMH volume, as well as bilateral frontal lobe, temporal lobe, parietal lobe, and occipital lobe WMH volumes. Firstly, we compared the differences in WMH volumes between the delusion group and non-delusion group. Then, within the delusion group, we further categorized patients based on severity scores of their delusional symptoms into mild (1 point), moderate (2 points), or severe groups (3 points). We compared the WMH volumes among these three groups to investigate the role of WMH volume in delusional symptoms.

RESULTS

There was a significant difference in left occipital lobe WMH volume between the delusion group and non-delusion group(P < 0.05). Within the delusion group itself, there were significant differences in overall WMH volume as well as PVWMH volume among patients with mild or severe levels of delusions(P < 0.05).

CONCLUSION

Left occipital lobe WMH volume may be associated with the occurrence of delusional AD patients, and the total volume of whole-brain WMH and PVWMH volume may affect the degree of severity of delusional symptoms.

Use of benzodiazepine and related drugs in migrants and Finnish-born persons: a nationwide register-based study

AIMS

Benzodiazepines and related drugs (BZDR) are often used longer than generally recommended. The aim is to study patterns of use among migrant and Finnish-born users of BZDR, and to identify factors that are associated with long-term use and BZDR polytherapy.

METHODS

This register-based study includes a nationwide sample of migrants (n=8729) and their Finnish-born controls (n=11 388) who had purchased BZDR in 2011-2014, but not in 2009-2010. Information on drug purchases was obtained from the National Prescription Register and the duration of drug use was estimated using PRE2DUP method. The main outcomes were long-term use of BZDR, polytherapy and time until discontinuation of BZDR use. Sociodemographic variables and information on preceding psychiatric diagnoses were included as covariates. Logistic and Cox regression analyses were the statistical methods used.

RESULTS

Only migrants from Sub-Saharan Africa were more likely to discontinue the medication once initiated than Finnish-born users. Migrants were significantly less likely to be long-term users (adjusted odds ratio 0.79, 95% CI 0.70-0.89) or polytherapy users (aOR 0.90, 95% CI 0.84-0.97) of BZDR compared with Finnish-born participants.

CONCLUSIONS

Migrants had less long-term and concomitant use of several BZDR than Finnish-born participants. The pattern of use is more optimal among migrants, but it may also reflect poorer access to mental health treatment.

Polygenic risk scores for Alzheimer's disease in relation to cognitive change: A representative sample from the general population followed over 16 years

BACKGROUND

Polygenic risk scores for Alzheimer's disease (AD-PRSs) have been associated with cognition. However, few studies have examined the effect of AD-PRS beyond the APOE gene, and the influence of genetic variants related to level of cognitive ability (COG-PRS) on cognitive performance over time in the general older population.

METHOD

A population-based sample of 965 individuals born in 1930, with genetic and standardized cognitive data on six psychometric tests (Thurstone's picture memory, immediate recall of 10 words, Block design, word fluency, figure identification, delayed recall of 12 items), were examined at age 70, 75, 79, and 85 years. Non-APOE AD-PRSs and COG-PRSs (P < 5e-8, P < 1e-5, P < 1e-3, P < 1e-1) were generated from recent genome-wide association studies. Linear mixed effect models with random intercepts and slope were used to analyze the effect of APOE ε4 allele, AD-PRSs, and COG-PRSs, on cognitive performance and rate of change. Analyses were repeated in samples excluding dementia.

RESULTS

APOE ε4 and AD-PRS predicted change in cognitive performance (APOE ε4*age: β = -0.03, P < 0.0001 and AD-PRS *age: β = -0.01, P = 0.02). The results remained similar in the sample excluding those with dementia. COG-PRS predicted level of cognitive performance, while APOE ε4 and AD-PRS did not. COG-PRSs did not predict change in cognitive performance.

CONCLUSION

We found that genetic predisposition of AD predicted cognitive decline among 70-year-olds followed over 16 years, regardless of dementia status, while polygenic risk for general cognitive performance did not.

Gait and/or balance disturbances associated with Alzheimer's dementia among older adults with amnestic mild cognitive impairment: A longitudinal observational study

AIMS

To explore whether gait and/or balance disturbances are associated with the onset of Alzheimer's dementia (AD) among older adults with amnestic mild cognitive impairment (MCI).

DESIGN

This study employed a longitudinal retrospective cohort design.

METHODS

We obtained data from the National Alzheimer's Coordinating Center's Uniform Data Set collected from 35 National Institute on Aging Alzheimer's Disease Research Centers between September 2005 and December 2021. The mean age of participants (n = 2692) was 74.5 years with women making up 47.2% of the sample. Risk of incident AD according to baseline gait and/or balance disturbances as measured using the Postural Instability and Gait Disturbance Score, a subscale of the Unified Parkinson's Disease Rating Scale Motor Score, was examined by the Cox proportional hazards regression models adjusting for baseline demographics, medical conditions and study sites. The mean follow-up duration was 4.0 years.

RESULTS

Among all the participants, the presence or the severity of gait and/or balance disturbances was associated with an increased risk of AD. The presence or the severity of gait and/or balance disturbances was associated with a higher risk of Alzheimer's dementia among the subgroups of female and male participants.

CONCLUSION

Gait and/or balance disturbances may increase the risk of developing AD, regardless of sex.

IMPACT

Gait and/or balance disturbances among community-dwelling older adults with amnestic MCI may need to be frequently assessed by nurses to identify potential risk factors for cognitive decline.

NO PATIENT OR PUBLIC CONTRIBUTION

Given the secondary analysis, patients, service users, caregivers or members of the public were not directly involved in this study.

Structural and Metabolic Retinal Changes Associated With Mild Cognitive Impairment in Type 2 Diabetes

Type 2 diabetes is associated with cognitive impairment and a twofold increased risk of dementia compared with age-matched individuals without diabetes. Given that the eye and the brain share similar embryologic origin and anatomical features, the retina offers a unique window to the brain. In this study, we wanted to determine whether there was a difference in retinal imaging-based neuronal and vascular markers in individuals with type 2 diabetes with or without mild cognitive impairment (MCI). We included 134 persons with type 2 diabetes. Based on neuropsychological tests, the prevalence of MCI was 28%. We performed seven-field color fundus photos, optical coherence tomography (OCT), OCT-angiography (OCT-A), and retinal oximetry to analyze retinal markers. In a multivariable cluster analysis, persons with MCI had a significantly thinner macular retinal nerve fiber layer and macular ganglion cell layer, and less venular oxygen saturation in the nasal quadrant compared with those without MCI. There were no differences in retinal vessel density, fractal dimension, width, tortuosity, or OCT-A markers. People with type 2 diabetes and MCI demonstrate alterations in retinal structure and metabolism, suggesting noninvasive retinal markers may be useful to detect people with type 2 diabetes at risk for cognitive dysfunction.

ARTICLE HIGHLIGHTS

Type 2 diabetes is associated with mild cognitive impairment (MCI). Therefore, retinal and cerebral neurodegeneration may run in parallel. To assess whether there was a difference in retinal structure, vessel, and metabolic parameters in individuals with MCI. We found those with MCI had a thinner macular retinal nerve fiber layer, macular ganglion cell layer, and less venular oxygen saturation. We suggest noninvasive retinal markers may be useful to detect those at risk of cognitive dysfunction.

Dysphagia and dementia: a 'double dilemma'

PURPOSE OF REVIEW

Dementia and its variants, including Alzheimer's disease, become more prevalent with age. Dysphagia, that is, difficulty swallowing, also occurs with aging, and is often associated with dementia. Currently, there is no cure for dementia, and dysphagia, unrecognized or untreated, can have life-altering, even fatal consequences. Prolonged ability to eat safely and effectively could contribute to improved quality of life in a fragile population. In this review, difficulties associated with the management of dysphagia in individuals with dementia, as well as promising possibilities for continued investigation, will be discussed.

RECENT FINDINGS

Recent reports point to unique problems related to understanding the comorbidities of dysphagia and dementia. These include delays in identifying dysphagia in affected individuals, as well as a lack of prevalence data for dysphagia in types and stages of dementia, or according to setting, for example, residential center, hospital. Emphasis on new tools, and new applications of existing tools, are needed.

SUMMARY

New evidence not only underscores complexities and shortcomings of our understanding of dysphagia in dementia but also points to existing applications with potential for improving the situation, and new investigational directions that may elaborate our further understanding of these comorbidities.

Exploring depression in Alzheimer's disease: an Italian Delphi Consensus on phenomenology, diagnosis, and management

BACKGROUND

In Alzheimer's disease (AD), the progressive cognitive impairment is often combined with a variety of neuropsychiatric symptoms, firstly depression. Nevertheless, its diagnosis and management is difficult, since specific diagnostic criteria and guidelines for treatment are still lacking. The aim of this Delphi study is to reach a shared point of view among different Italian specialists on depression in AD.

METHODS

An online Delphi survey with 30 questions regarding epidemiology, diagnosis, clinical features, and treatment of depression in AD was administered anonymously to a panel of 53 expert clinicians.

RESULTS

Consensus was achieved in most cases (86%). In the 80% of statements, a positive consensus was reached, while in 6% a negative consensus was achieved. No consensus was obtained in 14%. Among the most relevant findings, the link between depression and AD is believed to be strong and concerns etiopathogenesis and phenomenology. Further, depression in AD seems to have specific features compared to major depressive disorder (MDD). Regarding diagnosis, the DSM 5 diagnostic criteria for MDD seems to be not able to detect the specific aspects of depression in AD. Concerning treatment, antidepressant drugs are generally considered the main option for depression in dementia, according to previous guidelines. In order to limit side effects, multimodal and SSRI antidepressant are preferred by clinicians. In particular, the procognitive effect of vortioxetine seems to be appealing for the treatment of depression in AD.

CONCLUSIONS

This study highlights some crucial aspects of depression in AD, but more investigations and specific recommendations are needed.

Etiology of White Matter Hyperintensities in Autosomal Dominant and Sporadic Alzheimer Disease

Importance

Increased white matter hyperintensity (WMH) volume is a common magnetic resonance imaging (MRI) finding in both autosomal dominant Alzheimer disease (ADAD) and late-onset Alzheimer disease (LOAD), but it remains unclear whether increased WMH along the AD continuum is reflective of AD-intrinsic processes or secondary to elevated systemic vascular risk factors.

Objective

To estimate the associations of neurodegeneration and parenchymal and vessel amyloidosis with WMH accumulation and investigate whether systemic vascular risk is associated with WMH beyond these AD-intrinsic processes.

Design, Setting, and Participants

This cohort study used data from 3 longitudinal cohort studies conducted in tertiary and community-based medical centers-the Dominantly Inherited Alzheimer Network (DIAN; February 2010 to March 2020), the Alzheimer's Disease Neuroimaging Initiative (ADNI; July 2007 to September 2021), and the Harvard Aging Brain Study (HABS; September 2010 to December 2019).

Main Outcome and Measures

The main outcomes were the independent associations of neurodegeneration (decreases in gray matter volume), parenchymal amyloidosis (assessed by amyloid positron emission tomography), and vessel amyloidosis (evidenced by cerebral microbleeds [CMBs]) with cross-sectional and longitudinal WMH.

Results

Data from 3960 MRI sessions among 1141 participants were included: 252 pathogenic variant carriers from DIAN (mean [SD] age, 38.4 [11.2] years; 137 [54%] female), 571 older adults from ADNI (mean [SD] age, 72.8 [7.3] years; 274 [48%] female), and 318 older adults from HABS (mean [SD] age, 72.4 [7.6] years; 194 [61%] female). Longitudinal increases in WMH volume were greater in individuals with CMBs compared with those without (DIAN: t = 3.2 [P = .001]; ADNI: t = 2.7 [P = .008]), associated with longitudinal decreases in gray matter volume (DIAN: t = -3.1 [P = .002]; ADNI: t = -5.6 [P < .001]; HABS: t = -2.2 [P = .03]), greater in older individuals (DIAN: t = 6.8 [P < .001]; ADNI: t = 9.1 [P < .001]; HABS: t = 5.4 [P < .001]), and not associated with systemic vascular risk (DIAN: t = 0.7 [P = .40]; ADNI: t = 0.6 [P = .50]; HABS: t = 1.8 [P = .06]) in individuals with ADAD and LOAD after accounting for age, gray matter volume, CMB presence, and amyloid burden. In older adults without CMBs at baseline, greater WMH volume was associated with CMB development during longitudinal follow-up (Cox proportional hazards regression model hazard ratio, 2.63; 95% CI, 1.72-4.03; P < .001).

Conclusions and Relevance

The findings suggest that increased WMH volume in AD is associated with neurodegeneration and parenchymal and vessel amyloidosis but not with elevated systemic vascular risk. Additionally, increased WMH volume may represent an early sign of vessel amyloidosis preceding the emergence of CMBs.

White matter hyperintensities in cognitive impairment with Lewy body disease: a multicentre study

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) are associated with cognitive deficits and worse clinical outcomes in dementia, but rare studies have been carried out of cognitive impairment in Lewy body disease (CI-LB) patients. The objective was to investigate the associations between WMHs and clinical manifestations in patients with CI-LB.

METHODS

In this retrospective multicentre cohort study, 929 patients (486 with dementia with Lewy bodies [DLB], 262 with Parkinson's disease dementia [PDD], 74 with mild cognitive impairment [MCI] with Lewy bodies [MCI-LB] and 107 with Parkinson's disease with MCI [PD-MCI]) were analysed from 22 memory clinics between January 2018 and June 2022. Demographic and clinical data were collected by reviewing medical records. WMHs were semi-quantified according to the Fazekas method. Associations between WMHs and clinical manifestations were investigated by multivariate linear or logistic regression models.

RESULTS

Dementia with Lewy bodies patients had the highest Fazekas scores compared with PDD, MCI-LB and PD-MCI. Multivariable regressions showed the Fazekas score was positively associated with the scores of Unified Parkinson's Disease Rating Scale Part III (p = 0.001), Hoehn-Yahn stage (p = 0.004) and total Neuropsychiatric Inventory (p = 0.001) in MCI-LB and PD-MCI patients. In patients with DLB and PDD, Fazekas scores were associated with the absence of rapid eye movement sleep behaviour disorder (p = 0.041) and scores of Unified Parkinson's Disease Rating Scale Part III (p < 0.001), Hoehn-Yahn stage (p < 0.001) and the Montreal Cognitive Assessment (p = 0.014).

CONCLUSION

White matter hyperintensity burden of DLB was higher than for PDD, MCI-LB and PD-MCI. The greater WMH burden was significantly associated with poorer cognitive performance, worse motor function and more severe neuropsychiatric symptoms in CI-LB.

Disentangling in-vivo microstructural changes of white and gray matter in mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis

The microstructural characteristics of white and gray matter in mild cognitive impairment (MCI) and the early-stage of Alzheimer's disease (AD) remain unclear. This study aimed to systematically identify the microstructural damages of MCI/AD in studies using neurite orientation dispersion and density imaging (NODDI), and explore their correlations with cognitive performance. Multiple databases were searched for eligible studies. The 10 eligible NODDI studies were finally included. Patients with MCI/AD showed overall significant reductions in neurite density index (NDI) of specific white matter structures in bilateral hemispheres (left hemisphere: -0.40 [-0.53, -0.27], P < 0.001; right: -0.33 [-0.47, -0.19], P < 0.001), involving the bilateral superior longitudinal fasciculus (SLF), uncinate fasciculus (UF), the left posterior thalamic radiation (PTR), and the left cingulum. White matter regions exhibited significant increased orientation dispersion index (ODI) (left: 0.25 [0.02, 0.48], P < 0.05; right: 0.27 [0.07, 0.46], P < 0.05), including the left cingulum, the right UF, and the bilateral parahippocampal cingulum (PHC), and PTR. Additionally, the ODI of gray matter showed significant reduction in bilateral hippocampi (left: -0.97 [-1.42, -0.51], P < 0.001; right: -0.90 [-1.35, -0.45], P < 0.001). The cognitive performance in MCI/AD was significantly associated with NDI (r = 0.50, P < 0.001). Our findings highlight the microstructural changes in MCI/AD were characterized by decreased fiber orientation dispersion in the hippocampus, and decreased neurite density and increased fiber orientation dispersion in specific white matter tracts, including the cingulum, UF, and PTR. Moreover, the decreased NDI may indicate the declined cognitive level of MCI/AD patients.

Acoustic stimulation as a promising technique to enhance slow-wave sleep in Alzheimer's disease: results of a pilot study

STUDY OBJECTIVES

Sleep disturbances are common in people with Alzheimer's disease (AD), and a reduction in slow-wave activity is the most striking underlying change. Acoustic stimulation has emerged as a promising approach to enhance slow-wave activity in healthy adults and people with amnestic mild cognitive impairment. In this phase 1 study we investigated, for the first time, the feasibility of acoustic stimulation in AD and piloted the effect on slow-wave sleep (SWS).

METHODS

Eleven adults with mild to moderate AD first wore the DREEM 2 headband for 2 nights to establish a baseline registration. Using machine learning, the DREEM 2 headband automatically scores sleep stages in real time. Subsequently, the participants wore the headband for 14 consecutive "stimulation nights" at home. During these nights, the device applied phase-locked acoustic stimulation of 40-dB pink noise delivered over 2 bone-conductance transducers targeted to the up-phase of the delta wave or SHAM, if it detected SWS in sufficiently high-quality data.

RESULTS

Results of the DREEM 2 headband algorithm show a significant average increase in SWS (minutes) [t(3.17) = 33.57, P = .019] between the beginning and end of the intervention, almost twice as much time was spent in SWS. Consensus scoring of electroencephalography data confirmed this trend of more time spent in SWS [t(2.4) = 26.07, P = .053].

CONCLUSIONS

Our phase 1 study provided the first evidence that targeted acoustic stimuli is feasible and could increase SWS in AD significantly. Future studies should further test and optimize the effect of stimulation on SWS in AD in a large randomized controlled trial.

CITATION

Van den Bulcke L, Peeters A-M, Heremans E, et al. Acoustic stimulation as a promising technique to enhance slow-wave sleep in Alzheimer's disease: results of a pilot study. J Clin Sleep Med. 2023;19(12):2107-2112.

Brexpiprazole for the Treatment of Agitation in Alzheimer Dementia: A Randomized Clinical Trial

Importance

Agitation is a prevalent, distressing, and burdensome manifestation of Alzheimer dementia in need of an efficacious, safe, and well-tolerated treatment.

Objective

To confirm the efficacy, safety, and tolerability of brexpiprazole in patients with agitation in Alzheimer dementia.

Design, Setting, and Participants

This randomized clinical trial was a 12-week, double-blind, placebo-controlled, fixed-dose, parallel-arm trial that ran from May 2018 to June 2022 at 123 clinical trial sites in Europe and the United States. Participants included patients with agitation in Alzheimer dementia in a care facility or community-based setting. Stable Alzheimer disease medications were permitted.

Interventions

In this 2-arm trial, patients were randomized to receive oral brexpiprazole or placebo (2:1 ratio) for 12 weeks. Within the brexpiprazole arm, patients were further randomized to receive fixed doses of 2 mg/d or 3 mg/d in a 1:2 ratio.

Main Outcomes and Measures

The primary end point was change in Cohen-Mansfield Agitation Inventory total score (which measures the frequency of 29 agitated behaviors) from baseline to week 12 for brexpiprazole, 2 or 3 mg, vs placebo. Safety was assessed by standard measures, including treatment-emergent adverse events.

Results

A total of 345 patients were randomized to receive brexpiprazole (n = 228) or placebo (n = 117); completion rates were 198 (86.8%) for brexpiprazole and 104 (88.9%) for placebo. Mean (SD) age was 74.0 (7.5) years, and 195 of 345 patients were female (56.5%). Patients receiving brexpiprazole, 2 or 3 mg (n = 225), demonstrated statistically significantly greater improvement than those taking placebo (n = 116) in Cohen-Mansfield Agitation Inventory total score from baseline to week 12 (brexpiprazole baseline, 80.6, mean change, -22.6; placebo baseline, 79.2, mean change, -17.3; least-squares mean difference, -5.32; 95% CI, -8.77 to -1.87; P = .003; Cohen d effect size, 0.35). No treatment-emergent adverse events had an incidence of 5% or more with brexpiprazole and greater incidence than placebo. The proportion of patients who discontinued because of adverse events was 12 of 226 (5.3%) for brexpiprazole and 5 of 116 (4.3%) for placebo.

Conclusions and Relevance

In this study, patients with Alzheimer dementia who took brexpiprazole, 2 or 3 mg, showed a statistically significant improvement vs placebo in agitation over 12 weeks. Brexpiprazole was generally well tolerated over 12 weeks in this vulnerable patient population.

Trial Registration

ClinicalTrials.gov Identifier: NCT03548584.

Multi-omics data reveals aberrant gut microbiota-host glycerophospholipid metabolism in association with neuroinflammation in APP/PS1 mice

Numerous studies have described the notable impact of gut microbiota on the brain in Alzheimer's disease (AD) via the gut - brain axis. However, the molecular mechanisms underlying the involvement of gut microbiota in the development of AD are limited. This study aimed to explore the potential mechanisms of gut microbiota in AD by integrating multi-omics data. In this study, APP/PS1 and WT mice at nine months of age were used as study mouse model. Cognitive function was assessed using the Morris water maze test. The levels of Aβ plaque and neuroinflammation in the brain were detected using immunofluorescence and PET/CT. In addition, we not only used 16S rRNA gene sequencing and metabolomics to explore the variation characteristics of gut microbiota and serum metabolism abundance, but also combined spatial metabolomics and transcriptomics to explore the change in the brain and identify their potential correlation. APP/PS1 mice showed significant cognitive impairment and amyloid-β deposits in the brain. The abundance of gut microbiota was significantly changed in APP/PS1 mice, including decreased Desulfoviobrio, Enterococcus, Turicibacter, and Ruminococcus and increased Pseudomonas. The integration of serum untargeted metabolomics and brain spatial metabolomics showed that glycerophospholipid metabolism was a common alteration pathway in APP/PS1 mice. Significant proliferation and activation of astrocyte and microglia were observed in APP/PS1 mice, accompanied by alterations in immune pathways. Integration analysis and fecal microbiota transplantation (FMT) intervention revealed potential association of gut microbiota, host glycerophospholipid metabolism, and neuroinflammation levels in APP/PS1 mice.

Weight loss and risk of dementia in individuals with versus without obesity

INTRODUCTION

Using nationwide cohort data, we aimed to elucidate whether baseline obesity altered the relationship between loss in body mass index (BMI) or waist circumference (WC) and risk of dementia.

METHODS

Among 9689 participants whose BMIs and WCs were repeatedly measured over 1 year, 1:1 propensity score matching was conducted between participants with and without obesity (n = 2976 per group, mean age 70.9). For each group, we explored the association between loss in BMI, or WC, and incidence of dementia during an approximately 4-year follow-up period.

RESULTS

BMI loss was associated with an increased risk of all-cause dementia and Alzheimer's disease in participants without obesity; however, this association was absent in participants with obesity. WC loss was associated with decreased Alzheimer's disease risk only in participants with obesity.

DISCUSSION

Only unfavorable loss (loss from non-obese state) in BMI, not WC, can be a metabolic biomarker of prodromal dementia.

Association Between Common Urologic Medications and Onset of Alzheimer's Disease and Related Dementias in Men With Prostate Cancer Managed by Different Primary Treatment Modalities

OBJECTIVE

To understand the relationship between common urologic medications phosphodiesterase-5 inhibitors (PDE5i) and anticholinergics (AC) and risk of dementia onset in men who underwent different primary treatments for prostate cancer.

MATERIALS AND METHODS

Patients (>50years) with prostate cancer (1998-2022) without Alzheimer's disease or related dementias were selected from Cancer of the Prostatic Strategic Urologic Research Endeavor Registry. Minimum medication use was 3months. Fine-Gray regression was performed to determine the association between medication exposure and dementia onset ≥12months after primary treatment in men matched on age, race, comorbid conditions, smoking, and type of clinical site, with competing risk of death.

RESULTS

Among 5937 men (53% PDE5i; 14% AC), PDE5i users were younger (63 vs 70, P < .01) with less CAD, CVA, DM (all P < .01); AC users were older (68 vs 66, P < .01) with higher incidence of comorbidities (P < .01). Median months of use was 24.3 (IQR 12.1, 48.7) for PDE5i and 12.2 (IQR 6.1, 24.3) for AC users. Cumulative incidence of Alzheimer's disease or related dementias was 6.5% at 15years. PDE5i (P = .07) and AC (P = .06) were not associated with dementia regardless of primary treatment modality.

CONCLUSION

In this retrospective cohort study, PDE5i and AC use do not appear independently associated with risk of dementia. Notably, our cohort was generally healthy and younger which may limit our ability to detect significance. We recommend prospective investigation into association between PDE5i and dementia and advise continued judicious stewardship of AC in older patient populations.

Linderae Radix Ameliorates Cognitive Dysfunction by Inhibiting Neuroinflammation and Synaptic Damage in Alzheimer's Disease Models

Neuroinflammation and synaptic damage are important etiologies associated with the progression of Alzheimer's disease (AD). Linderae Radix (LR) has antioxidant and anti-inflammatory properties. This study investigated whether LR attenuates microglia activation-mediated neuroinflammation and synaptic degeneration and improves AD pathological phenotypes induced by amyloid beta oligomers (AβO) or lipopolysaccharide (LPS) toxicity. For in vitro studies, we treated LR to AβO-stimulated HT22 cells or LR LPS-stimulated BV2 cells. For in vivo studies, we administered LR to mice and AβO was injected by stereotaxic to induce cognitive impairment, neuroinflammation, and synaptic loss. We found that LR increased the cell viability reduced by AβO. Moreover, LR inhibited pro-inflammatory mediators such as nitric oxide (NO), inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2), and downregulated p38 mitogen-activated protein kinase (MAPK) signaling in BV2 cells. Behavioral assessments demonstrated that LR administration significantly improved cognitive decline induced by AβO-injection. Furthermore, we found that microglia activation increased, and the expression of synaptic proteins decreased in the hippocampus of the AβO-injected group, which was alleviated in the LR-treated group. These findings suggest that LR may be a potential candidate for protection against neuroinflammation and synaptic loss, and may prevent or delay AD progression.