Prevalence and Severity of Neuropsychiatric Symptoms in Early- Versus Late-Onset Alzheimer's Disease

Demographics, Symptoms, Psychotropic Use, and Caregiver Distress in Patients With Early vs Late Onset Dementia

BACKGROUND

Understanding experiences and challenges faced by persons living with Early-Onset Dementia (EOD) compared to individuals diagnosed with Late-Onset Dementia (LOD) is important for the development of targeted interventions.

OBJECTIVE

Describe differences in sociodemographic, neuropsychiatric behavioral symptoms, caregiver characteristics, and psychotropic use.

DESIGN, SETTING, PARTICIPANTS

Cross-sectional, retrospective study including 908 UCLA Alzheimer's Dementia Care Program participants (177 with EOD and 731 with LOD).

MEASUREMENTS

Onset of dementia was determined using age at program enrollment, with EOD defined as age <65 years and LOD defined as age >80 years. Sociodemographic and clinical characteristics were measured once at enrollment. Behavioral symptoms were measured using the Neuropsychiatric Inventory Questionnaire (NPI-Q) severity score and caregiver distress was measured using the NPI-Q distress score. Medications included antipsychotic, antidepressant, benzodiazepines and other hypnotics, antiepileptics, and dementia medications.

RESULTS

EOD compared to LOD participants were more likely men, college graduates, married, live alone, and have fewer comorbidities. EOD caregivers were more often spouses (56% vs 26%, p <0.01), whereas LOD caregivers were more often children (57% vs 10%, p <0.01). EOD was associated with lower odds of being above the median (worse) NPI-Q severity (adjusted odds ratio [aOR], 0.58; 95% CI 0.35-0.96) and NPI-Q distress scores (aOR, 0.53; 95% CI 0.31-0.88). Psychotropic use did not differ between groups though symptoms were greater for LOD compared to EOD.

CONCLUSION

Persons with EOD compared to LOD had sociodemographic differences, less health conditions, and fewer neuropsychiatric symptoms. Future policies could prioritize counseling for EOD patients and families, along with programs to support spousal caregivers of persons with EOD.

Neuropsychological Profiles, Etiologies, and Medical Comorbidities in Early-Onset Dementia and Cognitive Impairment: A Memory Outpatient Clinic Cohort Study

Background

Although early-onset dementia (EOD) is associated with diagnostic challenges that differ from those of related to late-onset dementia, only limited studies have addressed the neuropsychological and health characteristics or specified the diagnoses underlying early-onset cognitive impairment in a real-world clinical setting.

Objective

To investigate the neuropsychological profiles, etiologies, and comorbidities of an unselected cohort of memory clinic patients (≤65 years at symptom onset).

Methods

The patients' (n = 210) diagnoses were determined based on comprehensive diagnostic workup. Medical comorbidities and neuropsychological profiles were compared between clinically relevant patient groups, namely early-onset dementia (n = 55), mild cognitive impairment due to vascular or suspected neurodegenerative (MCI-n, n = 35) or non-neurodegenerative (MCI-o, n = 106) etiologies, and subjective cognitive decline (n = 14).

Results

The most prevalent diagnoses were Alzheimer's disease (AD, 14%) and depression (11%). Multiple prior medical conditions were common (67%); however, EOD patients had fewer other diagnoses (p = 0.008) than MCI-o patients. Compared to other groups, EOD patients had more severe deficits (p < 0.001) on immediate and delayed memory, processing speed, symptom awareness, and global cognition. AD patients had weaker memory retention ability but less behavioral symptoms than frontotemporal dementia (FTD) patients (p≤0.05). Depression was associated with better immediate memory, symptom awareness, and global cognition than AD and FTD (p < 0.05).

Conclusions

EOD is associated with more severe and widespread neuropsychological deficits but fewer prior medical diagnoses than nondegenerative etiologies of cognitive impairment. AD and depression are common etiologies and the neuropsychological profiles are partly overlapping; however, memory, symptom awareness and global cognitive impairment measures may help in the differential diagnosis.

The Effect of Apathy and Depressive Syndromes on Functional Outcomes in Alzheimer's Disease

Background

Alzheimer's disease (AD) is the most common cause of dementia. Its initially characterized by progressive short-term memory loss followed by cross-domain cognitive decline in later stages resulting in significant functional deficits and loss of activities of daily living (ADLs) independence. Apathy and depression are frequent neuropsychiatric sequelae in AD, but their contribution to functional deficits is poorly understood.

Objective

We aimed to quantitatively investigate if apathy and depressive symptoms predict ADLs in AD. We also wanted to fractionate apathy dimensions by factor-analyzing the apathy evaluation scale (AES) and then investigate the dimensions' relation to ADLs.

Methods

We recruited a sample of 115 patients with probable or possible AD and assessed them for depression, apathy, and ADLs alongside other measures. We hypothesized that apathy and depressive symptoms would predict ADLs and that AES items will load into cognitive, behavioral, and affective factors that would differentially relate to ADLs.

Results

Our results indicated that apathy symptoms predict ADLs deficits. The AES items resolved into a three-factor solution but the manner of clustering diverged from that proposed by AES authors. When these factors were regressed simultaneously, only behavioral apathy predicted global ADLs. Distinguishing basic from instrumental ADLs showed that behavioral and cognitive apathy symptoms associate with ADLs deficits while affective symptoms do not.

Conclusions

Our results highlight the influence of apathy on ADLs in AD. This has important implications for patient care considering the high prevalence of apathy in AD and other dementing illnesses.

Post-Diagnostic Support for Behaviour Changes in Young-Onset Dementia in Australia

Behaviour changes (BCs) are common in young-onset dementia (YOD). Access to knowledgeable and age-appropriate support services is needed to assist with the appropriate management of BCs. We sought to investigate the types of YOD-related BCs that most commonly require support, the formal services being accessed for support, and the experiences of those seeking support in Australia. We employed a cross-sectional online questionnaire for individuals living with YOD as well as individuals providing informal or formal care for someone with YOD. Thirty-six questionnaire responses were recorded. Of the total sample, 83% reported YOD-related BCs requiring support, the most common being appetite/eating changes, followed by agitation/aggression and apathy/indifference. Seventy-six percent of these individuals had attempted to seek support from a formal service, with Dementia Australia, Dementia Support Australia, and general practitioners most commonly approached. Responses suggested that the support access pathway is suboptimal, with a lack of clarity about what services to approach for support and long wait times. Furthermore, 28% of participants had not gained access to support utilizing non-pharmacological strategies. Individuals who need support for YOD-related BCs demonstrated a high rate of help-seeking from formal support services; however, the support access pathway is slow, is difficult to navigate, and does not result in the best-practice management of BCs. Formal services resourced to provide efficient support with the implementation of behavioural strategies are needed, along with clear, accessible guidelines on the pathway to access them.

DNA methylation: The epigenetic mechanism of Alzheimer's disease

Nowadays, with the development of the social health care system, there is an increasing trend towards an aging society. The incidence of Alzheimer's disease (AD) is also on the rise. AD is a kind of neurodegenerative disease that can be found in any age group. For years, scientists have been committing to discovering the cause of AD. DNA methylation is one of the most common epigenetic mechanisms in mammals and plays a vital role in the pathogenesis of several diseases, including tumors. Studying chemical changes in the epigenome, or DNA methylation can help us understand the effects of our environment and life on diseases, such as smoking, depression, and menopause, which may affect people's chances of developing Alzheimer's or other diseases. Recent studies have identified some crucial genes like ANK1, RHBDF2, ABCA7, and BIN1, linking DNA methylation to AD. This review focuses on elucidating the relationship between DNA methylation and the pathogenesis of AD and provides an outlook on possible targeted therapeutic modalities.

Clinical characteristics of early-onset versus late-onset Alzheimer's disease: a systematic review and meta-analysis

OBJECTIVES

A number of studies have compared Alzheimer's disease (AD), the commonest form of dementia, based on their age of onset, i.e. before the age of 65 years (early-onset AD, EO-AD) to those developing after 65 years of age (late-onset AD, LO-AD), but the differences are not clear. We performed a systematic review and meta-analysis to compare clinical characteristics between EO-AD and LO-AD.

DESIGN, MEASUREMENTS, AND PARTICIPANTS

Medline, Embase, PsycINFO, and CINAHL databases were systematically searched for studies comparing time to diagnosis, cognitive scores, annual cognitive decline, activities of daily living (ADLs), neuropsychiatric symptoms (NPS), quality of life (QoL), and survival time for EO-AD and LO-AD patients.

RESULTS

Forty-two studies were included (EO-AD participants n = 5,544; LO-AD participants n = 16,042). An inverse variance method with random effects models was used to calculate overall effect estimates for each outcome. People with EO-AD had significantly poorer baseline cognitive performance and faster cognitive decline but longer survival times than people with LO-AD. There was no evidence that EO-AD patients differ from people with LO-AD in terms of symptom onset to diagnosis time, ADLs, and NPS. There were insufficient data to estimate overall effects of differences in QoL in EO-AD compared to LO-AD.

CONCLUSIONS

Our findings suggest that EO-AD differs from LO-AD in baseline cognition, cognitive decline, and survival time but otherwise has similar clinical characteristics to LO-AD. Larger studies using standardized questionnaires focusing on the clinical presentations are needed to better understand the impact of age of onset in AD.

Indolylazine Derivative Induces Chaperone Expression in Aged Neural Cells and Prevents the Progression of Alzheimer's Disease

The risk of progression of most sporadic neurodegenerative diseases, including Alzheimer's disease, increases with age. Traditionally, this is associated with a decrease in the efficiency of cell protection systems, in particular, molecular chaperones. Thus, the development of small molecules able to induce the synthesis of chaperones is a promising therapeutic approach to prevent neural diseases associated with ageing. Here, we describe a new compound IA-50, belonging to the class of indolylazines and featured by a low size of topological polar surface area, the property related to substances with potentially high membrane-penetrating activity. We also estimated the absorption, distribution, metabolism and excretion characteristics of IA-50 and found the substance to fit the effective drug criteria. The new compound was found to induce the synthesis and accumulation of Hsp70 in normal and aged neurons and in the hippocampi of young and old mice. The transgenic model of Alzheimer's disease, based on 5xFAD mice, confirmed that the injection of IA-50 prevented the formation of β-amyloid aggregates, loss of hippocampal neurons and the development of memory impairment. These data indicate that this novel substance may induce the expression of chaperones in neural cells and brain tissues, suggesting its possible application in the therapy of ageing-associated disorders.

Clinico-demographics of people with younger-onset dementia and neuropsychiatric symptoms referred to an Australian dementia support service: A comparison study with older-onset dementia

OBJECTIVE

Younger-onset dementia accounts for about 5-10% of all dementias in Australia. Little data is available on neuropsychiatric symptoms in people with younger-onset dementia compared to those with older-onset dementia. This study aims to compare the types of neuropsychiatric symptoms and their clinico-demographic characteristics of people with younger-onset dementia and older-onset dementia who are referred to a specific dementia support service.

METHODS

A 2-year retrospective observational cross-sectional analysis was undertaken on referrals with neuropsychiatric symptoms from Dementia Support Australia programmes. Neuropsychiatric symptoms were measured using the Neuropsychiatric Inventory total severity scores and distress scores. Contributing factors to neuropsychiatric symptoms for dementia groups were examined. Logistic regression was used to examine the relationship between individual neuropsychiatric symptoms and having older-onset dementia vs younger-onset dementia.

RESULTS

Of the 15,952 referrals, about 5% (n = 729, mean age: 60.7 years, standard deviation = 5.4) were individuals with younger-onset dementia. Referrals with older-onset dementia were more likely to be female (56%), whereas referrals with younger-onset dementia were more likely to be male (54%). There was a four times greater rate of frontotemporal dementia for those with younger-onset dementia (16.0%, n = 117) compared to those with older-onset dementia (2.8%, n = 427), χ² (1) = 366.2, p < 0.001. Referrals with younger-onset dementia were more likely to be referred from community settings and those with older-onset dementia were more likely to be from residential aged care. Overall, there was no difference in the severity and distress of neuropsychiatric symptoms between the two groups. Contributing factors to neuropsychiatric symptoms were different between the groups, with pain being more frequently endorsed for individuals with older-onset dementia whereas communication difficulties were more commonly identified for those with younger-onset dementia.

CONCLUSION

Clinico-demographics of referrals with younger-onset dementia differ from those with older-onset dementia. There were some differences in the characteristics of neuropsychiatric symptoms between younger-onset dementia and older-onset dementia. Our findings have implications for service provision and support for people with dementia at different ages.

Modified cued recall test in the French population with Down syndrome: A retrospective medical records analysis

BACKGROUND

Adults with Down syndrome (DS) are at increased risk of developing Alzheimer's disease (AD) due to genetic predisposition. Identification of patients with AD is difficult since intellectual disabilities (ID) may confound diagnosis. The objective of this study was to evaluate the ability of the French version of the modified cued recall test (mCRT) to distinguish between subjects with and without AD in the adult DS population.

METHODS

This was a retrospective, single-centre, medical records study including data between March 2014 and July 2020. Adults aged ≥30 years with DS who had at least one mCRT record available were eligible. Age, sex and ID level were extracted, and subjects were attributed to three groups: patients with AD, patients with co-occurring conditions that may impact cognitive function and subjects without AD. mCRT scores, adjusted by sex, age and ID level, were compared between groups. The optimal cut-off value to distinguish between patients with and without AD was determined using the receiver operating characteristic curve. The impact of age and ID level on mCRT scores was assessed.

RESULTS

Overall, 194 patients with DS were included: 12 patients with AD, 94 patients with co-occurring conditions and 88 healthy subjects. Total recall scores were significantly lower (P < 0.0001) in patients with AD compared with healthy subjects. The optimal cut-off value to discriminate between patients with AD and healthy subjects was 22, which compares well with the cut-off value of 23 originally reported for the English version of the mCRT. Patients aged 30-44 years had higher mCRT total recall scores compared with patients aged ≥45 years (P = 0.0221). Similarly, patients with mild ID had higher mCRT scores compared with patients with severe ID (P < 0.0001).

INTERPRETATION

The mCRT is a sensitive tool that may help in the clinical diagnosis of AD in subjects with DS. Early recognition of AD is paramount to deliver appropriate interventions to this vulnerable population.

Anxiety and depression in Alzheimer's disease: a systematic review of pathogenetic mechanisms and relation to cognitive decline

Objectives

To explore the pathogenetic hypothesis provided to explain the comorbidity of anxious and depressive symptomatology and AD and to assess the association between anxious and depressive symptoms and the AD-related cognitive impairment.

Methods

In October 2020 and March 2021, PsycINFO, Embase, Ovid, and CINAHL were searched for peer-reviewed original articles investigating anxiety and/or depression in AD.

Results

A total of 14,760 studies were identified and 34 papers on AD patients were included in the review. Suggested biological causes of depression and anxiety in AD include higher strychnine-sensitive glycine receptor (GlyRS) functioning and selective reduction of N-methyl-d-aspartate (NMDA) receptor NR2A density, cortical and limbic atrophy, lower resting cortical metabolism, lower CSF Aβ42 and higher t-tau and p-tau levels, and neuritic plaques. At the same time, dysthymia arises in the early stages of AD as an emotional reaction to the progressive cognitive decline and can cause it; anxiety can appear as an initial compensating behaviour; and depression might be related to AD awareness and loss of functional abilities. Affective symptoms and the expression of the depressive symptoms tend to reduce as AD progresses.

Conclusion

The neurodegeneration of areas and circuits dealing with emotions can elicit anxiety and depression in AD. In the early stages of the disease, anxiety and depression could arise as a psychological reaction to AD and due to coping difficulties. In late AD stages, the cognitive impairment reduces the emotional responses and their expression. Anxiety and depression are more intense in early-onset AD, due to the major impact of AD on the individual.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-022-06068-x.

Behavioural and psychological symptoms of early-onset and late-onset Alzheimer's disease among Chinese adults: analysis of modifiable factors

BACKGROUND

To conduct a comprehensive comparison of behavioural and psychological symptoms of dementia (BPSD) in Chinese people with early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD) and analyse the factors of differences.

METHODS

A cross-sectional survey of 93 EOAD and100 LOAD and their caregivers in China from November 2018 to May 2019.

RESULTS

The total Neuropsychiatric Inventory score was significantly higher in LOAD. A higher level of agitation in EOAD was related to a lower quality of life of caregivers and the emotional expression of ignoring people with dementia. Higher euphoria scores in LOAD were associated with reduced negative coping by caregivers and reduced stability and predictability at home.

CONCLUSION

The early identification and management of specific BPSD of EOAD and LOAD by family members and health professionals may improve the quality of care and life for people with dementia and that of caregivers.

Music and Psychology & Social Connections Program: Protocol for a Novel Intervention for Dyads Affected by Younger-Onset Dementia

Psychosocial interventions targeting the specific needs of people affected by younger-onset dementia are lacking. Younger-onset dementia refers to dementia where symptom onset occurs at less than 65 years old. Because of its occurrence in middle age, the impact on spouses is particularly marked and dyadic-based interventions are recommended. Music And Psychology & Social Connections (MAPS) is a novel online intervention, informed by the theory of adaptive coping by Bannon et al. (2021) for dyads affected by younger-onset dementia. MAPS combines therapeutic songwriting, cognitive behaviour therapy, and a private social networking group that focuses on the dyads. This will be a randomised controlled trial with a waitlist control. The primary aims are to assess whether MAPS improves depressive, anxiety, and stress symptoms in caregivers, with secondary aims to assess whether MAPS improves depressive symptoms in people with younger-onset dementia. The trial also aims to assess dyadic social connectedness; caregiver coping skills; and neuropsychiatric symptoms in people with younger-onset dementia. We will recruit 60 dyads to participate in a group-based weekly online program for 8 weeks facilitated by a credentialed music therapist and psychologist. Sessions 1 and 8 will include both caregivers and people with younger-onset dementia and Sessions 2–7 will involve separate group sessions for caregivers and those with dementia. There will be focus groups for qualitative feedback. Due to its online administration, MAPS has the potential to reach many dyads affected by younger-onset dementia.

Capgras Syndrome as the Core Manifestation of Early-Onset Alzheimer’s Disease

Capgras syndrome (CS) was usually considered a symptom of a functional disorder in the young, most commonly schizophrenia, or an organic disorder in the elderly. The occurrence of CS among early-onset Alzheimer’s disease (EOAD) is extremely rare. We describe a case in which the unrecognition of CS as part of EOAD resulted in a wrong psychiatric diagnosis and inappropriate treatment. This paper aims to acknowledge CS as an early or core manifestation and highlight EOAD as a differential diagnosis of mental disorders in young people, even without a remarkable family history.

Association of Neurofibrillary Tangle Distribution With Age at Onset-Related Clinical Heterogeneity in Alzheimer Disease: An Autopsy Study

BACKGROUND AND OBJECTIVE

Patients with earlier age at onset of sporadic Alzheimer disease (AD) are more likely than those with later onset to present with atypical clinical and cognitive features. We sought to determine whether this age-related clinical and cognitive heterogeneity is mediated by different topographic distributions of tau-aggregate neurofibrillary tangles (NFTs) or by variable amounts of concomitant non-AD neuropathology.

METHODS

The relative distribution of NFT density in hippocampus and midfrontal neocortex was calculated, and α-synuclein, TAR DNA binding protein 43 (TDP-43), and microvascular copathologies were staged, in patients with severe AD and age at onset of 51-60 (n = 40), 61-70 (n = 41), and >70 (n = 40) years. Regression, mediation, and mixed effects models examined relationships of pathologic findings with clinical features and longitudinal cognitive decline.

RESULTS

Patients with later age at onset of AD were less likely to present with nonmemory complaints (odds ratio [OR] 0.46 per decade, 95% confidence interval [CI] 0.22-0.88), psychiatric symptoms (β = -0.66, 95% CI -1.15 to -0.17), and functional impairment (β = -1.25, 95% CI -2.34 to -0.16). TDP-43 (OR 2.00, 95% CI 1.23-3.35) and microvascular copathology (OR 2.02, 95% CI 1.24-3.40) were more common in later onset AD, and α-synuclein copathology was not related to age at onset. NFT density in midfrontal cortex (β = -0.51, 95% CI -0.72 to -0.31) and midfrontal/hippocampal NFT ratio (β = -0.18, 95% CI -0.26 to -0.10) were lower in those with later age at onset. Executive function (β = 0.48, 95% CI 0.09-0.90) and visuospatial cognitive deficits (β = 0.97, 95% CI 0.46-1.46) were less impaired in patients with later age at onset. Mediation analyses showed that the effect of age at onset on severity of executive function deficits was mediated by midfrontal/hippocampal NFT ratio (β = 0.21, 95% CI 0.08-0.38) and not by concomitant non-AD pathologies. Midfrontal/hippocampal NFT ratio also mediated an association between earlier age at onset and faster decline on tests of global cognition, executive function, and visuospatial abilities.

DISCUSSION

Worse executive dysfunction and faster cognitive decline in people with sporadic AD with earlier rather than later age at onset is mediated by greater relative midfrontal neocortical to hippocampal NFT burden and not by concomitant non-AD neuropathology.

The severity of neuropsychiatric symptoms is higher in early-onset than late-onset Alzheimer's disease

BACKGROUND AND PURPOSE

The faster rates of cognitive decline and predominance of atypical forms in early-onset Alzheimer's disease (EOAD) suggest that neuropsychiatric symptoms could be different in EOAD compared to late-onset AD (LOAD); however, prior studies based on non-biomarker-diagnosed cohorts show discordant results. Our goal was to determine the profile of neuropsychiatric symptoms in EOAD and LOAD, in a cohort with biomarker/postmortem-confirmed diagnoses. Additionally, the contribution of co-pathologies was explored.

METHODS

In all, 219 participants (135 EOAD, 84 LOAD) meeting National Institute on Aging and Alzheimer's Association criteria for AD (115 amyloid positron emission tomography/cerebrospinal fluid biomarkers, 104 postmortem diagnosis) at the University of California San Francisco were evaluated. The Neuropsychiatric Inventory-Questionnaire (NPI-Q) was assessed at baseline and during follow-up. The NPI-Q mean comparisons and regression models adjusted by cognitive (Mini-Mental State Examination) and functional status (Clinical Dementia Rating Sum of Boxes) were performed to determine the effect of EOAD/LOAD and amnestic/non-amnestic diagnosis on NPI-Q. Regression models assessing the effect of co-pathologies on NPI-Q were performed.

RESULTS

At baseline, the NPI-Q scores were higher in EOAD compared to LOAD (p < 0.05). Longitudinally, regression models showed a significant effect of diagnosis, where EOAD had higher NPI-Q total, anxiety, motor disturbances and night-time behavior scores (p < 0.05). No differences between amnestics/non-amnestics were found. Argyrophilic grain disease co-pathology predicted a higher severity of NPI-Q scores in LOAD.

CONCLUSIONS

Anxiety, night-time behaviors and motor disturbances are more severe in EOAD than LOAD across the disease course. The differential patterns of neuropsychiatric symptoms observed between EOAD/LOAD could suggest a pattern of selective vulnerability extending to the brain's subcortical structures. Further, co-pathologies such as argyrophilic grain disease in LOAD may also play a role in increasing neuropsychiatric symptoms.

A Comparison of Behavioral and Psychological Symptoms of Dementia (BPSD) and BPSD Sub-Syndromes in Early-Onset and Late-Onset Alzheimer's Disease

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) have a large impact on the quality of life of patients with Alzheimer's disease (AD). Few studies have compared BPSD between early-onset (EOAD) and late-onset (LOAD) patients, finding conflicting results.

OBJECTIVE

The aims of this study were to: 1) characterize the presence, overall prevalence, and time of occurrence of BPSD in EOAD versus LOAD; 2) estimate the prevalence over time and severity of each BPSD in EOAD versus LOAD in three stages: pre-T0 (before the onset of the disease), T0 (from onset to 5 years), and T1 (from 5 years onwards); 3) track the manifestation of BPSD sub-syndromes (i.e., hyperactivity, psychosis, affective, and apathy) in EOAD versus LOAD at T0 and T1.

METHODS

The sample includes 1,538 LOAD and 387 EOAD diagnosed from 1996 to 2018. Comprehensive assessment batteries, including the Neuropsychiatric Inventory (NPI), were administered at the first medical assessment and at different follow-up period.

RESULTS

The overall prevalence for the most of BPSD was significantly higher in EOAD compared to LOAD whereas most BPSD appeared significantly later in EOAD patients. Between the two groups, from pre-T0 to T1 we recorded a different pattern of BPSD prevalence over time as well as for BPSD sub-syndromes at T0 and T1. Results on severity of BPSD did not show significant differences.

CONCLUSION

EOAD and LOAD represent two different forms of a single entity not only from a neuropathological, cognitive, and functional level but also from a psychiatric point of view.

Exploring the Bidirectional Associations Between Short or Long Sleep Duration and Lower Cognitive Function: A 7-Year Cohort Study in China

Background: Sleep duration is linked to cognitive function, but whether short or prolonged sleep duration results from impaired cognition or vice versa has been controversial in previous studies. We aimed to investigate the bidirectional association between sleep duration and cognitive function in older Chinese participants.

Methods: Data were obtained from a nationally representative study conducted in China. A total of 7984 participants aged 45 years or older were assessed at baseline between June 2011 and March 2012 (Wave 1), 2013 (Wave 2), 2015 (Wave 3), and 2018 (Wave 4). Nocturnal sleep duration was evaluated using interviews. Cognitive function was examined via assessments of global cognition, including episodic memory, visuospatial construction, calculation, orientation and attention capacity. Latent growth models and cross-lagged models were used to assess the bidirectional association between sleep duration and cognitive function.

Results: Among the 7,984 participants who were followed in the four waves of the study, the baseline mean (SD) age was 64.7 (8.4) years, 3862 (48.4%) were male, and 6453 (80.7%) lived in rural areas. Latent growth models showed that both sleep duration and global cognition worsened over time. Cross-lagged models indicated that short or long sleep duration in the previous wave was associated with lower global cognition in the subsequent wave (standardized β = −0.066; 95% CI: −0.073, −0.059; P < 0.001; Wave 1 to 2) and that lower global cognition in the previous wave was associated with short or long sleep duration in the subsequent wave (standardized β = −0.106; 95% CI: −0.116, −0.096; P < 0.001; Wave 1 to 2).

Conclusion: There was a bidirectional association between sleep duration and cognitive function, with lower cognitive function having a stronger association with long or short sleep duration than the reverse relationship. Global cognition was likely the major driver in these reciprocal associations.

Influence of Pathogenic and Metabolic Genes on the Pharmacogenetics of Mood Disorders in Alzheimer's Disease

Background: Mood disorders represent a risk factor for dementia and are present in over 60% of cases with Alzheimer’s disease (AD). More than 80% variability in drug pharmacokinetics and pharmacodynamics is associated with pharmacogenetics. Methods: Anxiety and depression symptoms were assessed in 1006 patients with dementia (591 females, 415 males) and the influence of pathogenic (APOE) and metabolic (CYP2D6, CYP2C19, and CYP2C9) gene variants on the therapeutic outcome were analyzed after treatment with a multifactorial regime in a natural setting. Results and Conclusions: (i) Biochemical, hematological, and metabolic differences may contribute to changes in drug efficacy and safety; (ii) anxiety and depression are more frequent and severe in females than males; (iii) both females and males respond similarly to treatment, showing significant improvements in anxiety and depression; (iv) APOE-3 carriers are the best responders and APOE-4 carriers tend to be the worst responders to conventional treatments; and (v) among CYP2D6, CYP2C19, and CYP2C9 genophenotypes, normal metabolizers (NMs) and intermediate metabolizers (IMs) are significantly better responders than poor metabolizers (PMs) and ultra-rapid metabolizers (UMs) to therapeutic interventions that modify anxiety and depression phenotypes in dementia. APOE-4 carriers and CYP-related PMs and UMs deserve special attention for their vulnerability and poor response to current treatments.

Female dominance of both spatial cognitive dysfunction and neuropsychiatric symptoms in a mouse model of Alzheimer's disease

Alzheimer’s disease (AD) is a prevalent neurological disorder affecting memory function in elderly persons. Indeed, AD exhibits abnormality in cognitive behaviors and higher susceptibility to neuropsychiatric symptoms (NPS). Various factors including aging, sex difference and NPS severity, are implicated during in development of AD. In this study, we evaluated behavioral abnormalities of AD model, PDAPP transgenic mice at young age using the Morris Water Maze test, which was established to assess hippocampal-dependent learning and memory. We found that female AD model mice exhibited spatial learning dysfunction and highly susceptible to NPS such as anxiety and depression, whereas spatial reference memory function was comparable in female PDAPP Tg mice to female wild type (WT) mice. Spatial learning function was comparable in male AD model mice to male WT mice. Multiple regression analysis showed that spatial learning dysfunction was associated with NPS severity such as anxiety and depression. Furthermore, the analysis showed that spatial reference memory function was associated with status of depression, but not anxiety. Thus, these results suggest female dominance of spatial learning dysfunction in the AD model mice accompanying increased NPS severity. The understandings of AD model may be useful for the development of therapeutic agents and methods in human AD.

Comorbidity between Alzheimer's disease and major depression: a behavioural and transcriptomic characterization study in mice

BACKGROUND

Major depression (MD) is the most prevalent psychiatric disease in the population and is considered a prodromal stage of the Alzheimer's disease (AD). Despite both diseases having a robust genetic component, the common transcriptomic signature remains unknown.

METHODS

We investigated the cognitive and emotional behavioural responses in 3- and 6-month-old APP/PSEN1-Tg mice, before β-amyloid plaques were detected. We studied the genetic and pathway deregulation in the prefrontal cortex, striatum, hippocampus and amygdala of mice at both ages, using transcriptomic and functional data analysis.

RESULTS

We found that depressive-like and anxiety-like behaviours, as well as memory impairments, are already present at 3-month-old APP/PSEN1-Tg mutant mice together with the deregulation of several genes, such as Ciart, Grin3b, Nr1d1 and Mc4r, and other genes including components of the circadian rhythms, electron transport chain and neurotransmission in all brain areas. Extending these results to human data performing GSEA analysis using DisGeNET database, it provides translational support for common deregulated gene sets related to MD and AD.

CONCLUSIONS

The present study sheds light on the shared genetic bases between MD and AD, based on a comprehensive characterization from the behavioural to transcriptomic level. These findings suggest that late MD could be an early manifestation of AD.

Deepen into sleep and wake patterns across Alzheimer's disease phenotypes

Although, the clinical variants of Alzheimer's disease (AD) show distinct patterns of cognitive and behavioral decline, disease progression, and neuropathological features, it is unclear if this clinical heterogeneity extends to sleep-wake patterns. Sleep and wake disturbances are frequent in typical AD, often preceding memory loss and negatively impacting the quality of life of patients and caregivers alike. Still, sleep and wake disorders are often misdiagnosed and undertreated in typical AD. Better characterization of sleep-wake features in AD clinical variants is an unmet gap of high importance because these differing patterns may require tailored treatment strategies. Moreover, as wake-promoting neurons are located in subcortical nuclei and degenerate early in typical AD, contrasting the profiles of sleep-wake patterns in typical and atypical AD aids diagnosis and brings a unique opportunity to uncover the mechanisms underlying AD clinical variants at the subcortical level and mechanisms for selective neuronal vulnerability.

The Relationship Between Anxiety and Alzheimer's Disease

Although Alzheimer’s disease (AD) is primarily a neurocognitive disorder, it also results in prominent neuropsychiatric symptoms (NPS). Much literature has investigated the NPS of apathy and depression in association with AD, but relatively less is known regarding anxiety, the third most common NPS in this disorder. The prevalence of anxiety symptoms in AD is about 40%, and it can be a prelude of AD. Anxiety can be especially present among patients with mild cognitive impairment, mild dementia, or early-onset forms of the disease, and can promote progression or conversion to Alzheimer’s clinical syndrome. A number of studies have established that anxiety is associated with positive amyloid scans, mesial temporal changes with atrophy and hypometabolism in the entorhinal region, and neurofibrillary tangles present on pathological examination of this region. In addition to psychosocial factors, proposed neurobiological mechanisms for increased anxiety in AD include decreased sensorimotor gating, relatively increased activation of amygdalae or the Salience Network, and the presence of comorbid pathology, particularly Lewy bodies. Having management strategies for anxiety in patients with AD is important as anxiety can worsen cognitive deficits. Interventions involve psychological support, behavioral management, and the judicious use of the psychiatric armamentarium of medications.

Emerging risk of environmental factors: insight mechanisms of Alzheimer's diseases

Neurodegenerative disorders are typically sporadic in nature in addition to usually influenced through an extensive range of environmental factors, lifestyle, and genetic elements. Latest observations have hypothesized that exposure of environmental factors may increase the prospective risk of Alzheimer's diseases (AD). However, the role of environmental factors as a possible dangerous issue has extended importance concerned in AD pathology, although actual etiology of the disorder is still not yet clear. Thus, the aim of this review is to highlight the possible correlation between environmental factors and AD, based on the present literature view. Environmental risk factors might play an important role in decelerating or accelerating AD progression. Among well-known environmental risk factors, prolonged exposure to several heavy metals, for example, aluminum, arsenic, cadmium, lead, and mercury; particulate air, and some pesticides as well as metal-containing nanoparticles have been participated to cause AD. These heavy metals have the capacity to enhance amyloid β (Aβ) peptide along with tau phosphorylation, initiating amyloid/senile plaques, as well as neurofibrillary tangle formation; therefore, neuronal cell death has been observed. Furthermore, particulate air, pesticides, and heavy metal exposure have been recommended to lead AD susceptibility and phenotypic diversity though epigenetic mechanisms. Therefore, this review deliberates recent findings detailing the mechanisms for a better understanding the relationship between AD and environmental risk factors along with their mechanisms of action on the brain functions.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6–10 drugs/day with the consequent risk for drug–drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Is Sleep Disruption a Cause or Consequence of Alzheimer's Disease? Reviewing Its Possible Role as a Biomarker

In recent years, the idea that sleep is critical for cognitive processing has gained strength. Alzheimer's disease (AD) is the most common form of dementia worldwide and presents a high prevalence of sleep disturbances. However, it is difficult to establish causal relations, since a vicious circle emerges between different aspects of the disease. Nowadays, we know that sleep is crucial to consolidate memory and to remove the excess of beta-amyloid and hyperphosphorilated tau accumulated in AD patients' brains. In this review, we discuss how sleep disturbances often precede in years some pathological traits, as well as cognitive decline, in AD. We describe the relevance of sleep to memory consolidation, focusing on changes in sleep patterns in AD in contrast to normal aging. We also analyze whether sleep alterations could be useful biomarkers to predict the risk of developing AD and we compile some sleep-related proposed biomarkers. The relevance of the analysis of the sleep microstructure is highlighted to detect specific oscillatory patterns that could be useful as AD biomarkers.