What is 'early onset dementia'?

Blood pressure and Alzheimer's disease: A review of meta-analysis

Background

Alzheimer's disease (AD) is a neurological disorder of unknown cause, resulting in the death of brain cells. Identifying some of the modifiable risk factors for AD could be crucial for primary prevention and could lead to a reduction in the incidence of AD.

Objective

This study aimed to perform a meta-meta-analysis of studies in order to assess the effect of blood pressure (BP) on the diagnosis of AD.

Method

The search was restricted to meta-analyses assessing high systolic BP (SBP) and diastolic BP (DBP) and AD. We applied the PRISMA guidelines.

Results

A total of 214 studies were identified from major databases. Finally, five meta-analyses (52 studies) were analyzed in this review. Results confirm that high SBP is associated with AD. The exploration of parameters (sex, age, study design, region, and BP measurements) shows that only region significantly moderates the relationship between BP and AD. Asian people are those whose SBP levels >140 mmHg are associated with AD. BP is associated with AD in both people aged ≤65 years and those aged ≥65 years and in cross-sectional and longitudinal studies. In the case of DBP, only women are at a higher risk of AD, particularly when its levels are >90.

Conclusion

SBP is associated with both cerebrovascular disease and AD. Therefore, future studies should use other uncontrolled factors, such as cardiovascular diseases, diabetes, and stroke, to explain the relationship between SBP and AD.

Experiences of influencing one's own life when living with working-age dementia

Having opportunities to make decisions and choices regarding one's life is crucial when living with dementia. This inter-disciplinary study draws on the concept of relational autonomy to explore how working-age people living dementia seek to influence their lives, and what makes it easier or more difficult for them in their everyday life. The data consist of three focus group discussions conducted with 12 retired adults who developed dementia while still employed. The results illuminate various resources that enable a person to (a) handle their difficulties at work and related consequences with dignity, (b) manage everyday tasks and live a fulfilling life, and (c) fight the stigma associated with (working-age) dementia. Challenges related to these aspects reported by the participants reveal gaps and obstacles that impede the full realisation of the rights of people living with early onset dementia. This research highlights the need for workplace education for different stakeholders, equal and ongoing access to guidance and counselling for younger people who live with dementia, and an effort by society as a whole to eradicate stigma.

An Integrative Literature Review on the Nomenclature and Definition of Dementia at a Young Age

Background:

There has been growing interest in young people living with dementia. Future research requires consensus on the terminology and operational definition of this group.

Objective:

The purpose of this integrative review was to explore and include all operational definitions used to define dementia at a young age.

Methods:

On August 14, 2020, the PubMed, Embase, Cinahl, and PsycInfo databases were searched for empirical and theoretical literature using Google. Various terms to describe and define ‘dementia’ and ‘at a young age’ were used to collect literature concerning terminology; age-related aspects, including cut-off ages and criteria; and etiologies of dementia at a young age.

Results:

The search yielded 6,891 empirical and 4,660 theoretical publications, resulting in the inclusion of 89 publications, including 36 publications containing an explicit discussion and 53 publications as confirmation. ‘Young-onset dementia’ was the most commonly used term of seven identified terms, in the last two decades. The age of 65 years at symptom onset was used most frequently when considering a total of six upper age limits and four criteria to define a cut-off age. Eight lower age limits and an option for subdivision based on age were included. We identified 251 different etiologies and 27 categories of etiologies.

Conclusion:

Despite relative consensus on the term young-onset dementia and an age at symptom onset being used as a cut-off criterion, much is still unclear concerning possible etiologies of dementia at a young age. In the current study, controversies were detected for discussion in an international consensus study.

Huperzine A ameliorates obesity-related cognitive performance impairments involving neuronal insulin signaling pathway in mice

Type 2 diabetes (T2D) and Alzheimer's disease (AD) share several common pathophysiological features. Huperzine A (Hup A), a Lycopodium alkaloid extracted from the Chinese herb moss Huperzia serrata, is a specific and reversible inhibitor of acetylcholinesterase, which is clinically used for the treatment of AD. In this study, we investigated whether Hup A improved the metabolic and cognitive functions in the high fat-induced (HFD) obese mice and genetic ob/ob mice. HFD and ob/ob mice were treated with Hup A (0.1, 0.3 mg · kg-1 · d-1, ig) for 3 months. Body weight was monitored and glucose tolerance tests were performed. Novel object recognition test and Morris water maze assay were conducted to evaluate the cognitive functions. We found that the Hup A treatment had no significant effect on peripheral metabolism of obese mice, whereas Hup A (0.1, mg · kg-1 · d-1) improved both the abilities of object recognition and spatial memory in HFD-fed mice, but not in ob/ob mice. Furthermore, Hup A treatment significantly upregulated the insulin and phosphorylated Akt levels in the cortex of HFD-fed mice, but not ob/ob mice. In addition, Hup A (0.3, mg · kg-1 · d-1) significantly decreased cortical β-secretase (BACE1) expression. In conclusion, these results demonstrate that treatment with Hup A (0.1, mg · kg-1 · d-1) can effectively improve the cognitive functions, at least in diet-induced obese mice.

Gene Expression Studies on Human Trisomy 21 iPSCs and Neurons: Towards Mechanisms Underlying Down's Syndrome and Early Alzheimer's Disease-Like Pathologies

The cause of Alzheimer disease (AD) is not well understood and there is no cure. Our ability to understand the early events in the course of AD is severely limited by the difficulty of identifying individuals who are in the early, preclinical stage of this disease. Most individuals with Down's syndrome (DS, trisomy 21) will predictably develop AD and that they will do so at a young age makes them an ideal population in which to study the early stages of AD. Several recent studies have exploited induced pluripotent stem cells (iPSCs) generated from individuals with familial AD, spontaneous AD and DS to attempt to identify early events and discover novel biomarkers of disease progression in AD. Here, we summarize the progress and limitations of these iPSC studies with a focus on iPSC-derived neurons. Further, we outline the methodology and results for comparing gene expression between AD and DS iPSC-derived neurons. We highlight differences and commonalities in these data that may implicate underlying genes and pathways that are causative for AD.

Glucose-6-phosphate dehydrogenase deficiency and Alzheimer's disease: Partners in crime? The hypothesis

Alzheimer's disease is a multifaceted brain disorder which involves various coupled irreversible, progressive biochemical reactions that significantly reduce quality of life as well as the actual life expectancy. Aging, genetic predispositions, head trauma, diabetes, cardiovascular disease, deficiencies in insulin signaling, dysfunction of mitochondria-associated membranes, cerebrovascular changes, high cholesterol level, increased oxidative stress and free radical formation, DNA damage, disturbed energy metabolism, and synaptic dysfunction, high blood pressure, obesity, dietary habits, exercise, social engagement, and mental stress are noted among the risk factors of this disease. In this hypothesis review I would like to draw the attention on glucose-6-phosphate dehydrogenase deficiency and its relationship with Alzheimer's disease. This enzymopathy is the most common human congenital defect of metabolism and defined by decrease in NADPH+H(+) and reduced form of glutathione concentration and that might in turn, amplify oxidative stress due to essentiality of the enzyme. This most common enzymopathy may manifest itself in severe forms, however most of the individuals with this deficiency are not essentially symptomatic. To understand the sporadic Alzheimer's disease, the writer of this paper thinks that, looking into a crystal ball might not yield much of a benefit but glucose-6-phosphate dehydrogenase deficiency could effortlessly give some clues.

Prevalence and correlates of psychotropic drug use in community-dwelling people with young-onset dementia: the NeedYD-study

BACKGROUND

Young-onset dementia (YOD) is defined as dementia that develops before the age of 65 years. The prevalence and type of neuropsychiatric symptoms (NPS) in YOD differ from patients with late onset dementia. NPS in dementia patients are often treated with psychotropic drugs. The aim of this study was to investigate psychotropic drug use (PDU) in Dutch community-dwelling YOD patients and the association between age, gender, dementia etiology and severity, symptoms of depression, disease awareness, unmet needs, and type of NPS.

METHODS

Psychotropic drug use in 196 YOD patients was registered. Drugs were categorized according to the Anatomical Therapeutical Chemical classification. The association between age, gender, dementia type, dementia stage, type of NPS, depressive symptoms, disease awareness, and amount of unmet needs on total PDU was analyzed using binomial logistic regression analysis.

RESULTS

Fifty-two percent of the patients were prescribed at least one psychotropic drug; 36.2% of patients used one drug, and 12.2% used two different drugs. Antidepressants (36.2%) and antipsychotic drugs (17.3%) were the most frequently prescribed psychotropic drugs. Anti-dementia drugs were prescribed in 51.5% of the patients. Increasing age and moderate to severe depressive symptoms were positively associated with the total use of psychotropic drugs.

CONCLUSIONS

Community-dwelling YOD patients have a high prevalence of PDU. More research is needed to study the association between unmet needs, NPS, and PDU, and psychosocial interventions have to be developed to limit the use of psychotropic drugs in YOD.

Characteristics of institutionalized young onset dementia patients--the BEYOnD study

BACKGROUND

People with Young Onset Dementia (YOD) have specific needs for care. These people eventually require institutional care, usually delivered by institutions designed for the elderly. The Dutch network of care organizations delivering specialized YOD care offers a unique opportunity to obtain more knowledge of this special population.

METHODS

Our cross-sectional study collected data from 230 people with YOD in eight care homes providing YOD specialized care. Data collected: demographic data, disease duration, dementia subtype, comorbidity, dementia severity (Global Deterioration Scale - GDS), neuropsychiatric symptoms (NPS; Neuropsychiatric Inventory - NPI, Cohen Mansfield Agitation Inventory - CMAI), disease awareness (Guidelines for the Rating of Awareness Deficits - GRAD), need for assistance (hierarchic Activities of Daily Living (ADL) scale - Resident Assessment Instrument - Minimum Data Set (RAI-MDS)).

RESULTS

The mean age of the residents with YOD in care homes was 60 years and 53% of them were men. There is a large variety of etiologic diagnoses underlying the dementia. Dementia severity was very mild to mild in 18%, moderate in 25%, and severe or very severe in 58% of the participants. The prevalence of NPS was high with 90% exhibiting one or more clinically relevant NPS. Comorbidity was present in more than three quarters of the participants, most frequently psychiatric disorders.

CONCLUSIONS

The institutionalized YOD population is heterogeneous. NPS occur in almost all institutionalized people with YOD, and frequency and severity of NPS are higher than in late onset dementia (LOD) and community-dwelling YOD patients. Care should be delivered in settings accommodating a mixed male and female population, with appropriate, meaningful activities for all individuals. Further research is needed on NPS in YOD, to enhance quality of life and work in specialized YOD-care.

Symptom onset in autosomal dominant Alzheimer disease: a systematic review and meta-analysis

OBJECTIVE

To identify factors influencing age at symptom onset and disease course in autosomal dominant Alzheimer disease (ADAD), and develop evidence-based criteria for predicting symptom onset in ADAD.

METHODS

We have collected individual-level data on ages at symptom onset and death from 387 ADAD pedigrees, compiled from 137 peer-reviewed publications, the Dominantly Inherited Alzheimer Network (DIAN) database, and 2 large kindreds of Colombian (PSEN1 E280A) and Volga German (PSEN2 N141I) ancestry. Our combined dataset includes 3,275 individuals, of whom 1,307 were affected by ADAD with known age at symptom onset. We assessed the relative contributions of several factors in influencing age at onset, including parental age at onset, age at onset by mutation type and family, and APOE genotype and sex. We additionally performed survival analysis using data on symptom onset collected from 183 ADAD mutation carriers followed longitudinally in the DIAN Study.

RESULTS

We report summary statistics on age at onset and disease course for 174 ADAD mutations, and discover strong and highly significant (p < 10(-16), r2 > 0.38) correlations between individual age at symptom onset and predicted values based on parental age at onset and mean ages at onset by mutation type and family, which persist after controlling for APOE genotype and sex.

CONCLUSIONS

Significant proportions of the observed variance in age at symptom onset in ADAD can be explained by family history and mutation type, providing empirical support for use of these data to estimate onset in clinical research.

Parkinsonism and distinct dementia patterns in a family with the MAPT R406W mutation

BACKGROUND

The Arg406Trp (R406W) missense mutation in the microtubule-associated protein-tau gene (MAPT) is a known cause of early-onset dementia. Various dementia phenotypes have been described, including frontotemporal dementia (FTD), FTD with parkinsonism, and early-onset Alzheimer disease (EOAD)-like presentations.

METHODS

Using whole-exome capture with subsequent sequencing, we identified the R406W mutation in a family with multiple individuals with clinically diagnosed EOAD, in a pattern suggesting autosomal dominant inheritance. We reevaluated all available family members clinically.

RESULTS

Each of the affected individuals had a course meeting clinical criteria for EOAD. Two distinct disease trajectories were apparent: one rapidly progressive, and the other long and gradual. Four of five affected individuals also manifested parkinsonian symptoms. FTD features were not prominent and, when present, appeared only late in the course of dementia.

CONCLUSIONS

The MAPT R406W mutation is associated with EOAD-like symptoms and parkinsonism without FTD, as well as distinct cognitive courses.

Caregivers' perspectives on the pre-diagnostic period in early onset dementia: a long and winding road

BACKGROUND

Recognizing and diagnosing early onset dementia (EOD) can be complex and often takes longer than for late onset dementia. The objectives of this study are to investigate the barriers to diagnosis and to develop a typology of the diagnosis pathway for EOD caregivers.

METHODS

Semi-structured interviews with 92 EOD caregivers were analyzed using constant comparative analysis and grounded theory. A conceptual model was formed based on 21 interviews and tested in 29 additional transcripts. The identified categories were quantified in the whole sample.

RESULTS

Seven themes emerged: (1) changes in the family member, (2) disrupted family life, (3) misattribution, (4) denial and refusal to seek advice, (5) lack of confirmation from social context, (6) non-responsiveness of a general practitioner (GP), and (7) misdiagnosis. Cognitive and behavioral changes in the person with EOD were common and difficult to understand for caregivers. Marital difficulties, problems with children and work/financial issues were important topics. Confirmation of family members and being aware of problems at work were important for caregivers to notice deficits and/or seek help. Other main issues were a patient's refusal to seek help resulting from denial and inadequate help resulting from misdiagnosis.

CONCLUSION

EOD caregivers experience a long and difficult period before diagnosis. We hypothesize that denial, refusal to seek help, misattribution of symptoms, lack of confirmation from the social context, professionals' inadequate help and faulty diagnoses prolong the time before diagnosis. These findings underline the need for faster and more adequate help from health-care professionals and provide issues to focus on when supporting caregivers of people with EOD.

Association between NMDA receptor subunit 2b gene polymorphism and Alzheimer's disease in Chinese Han population in Shanghai

OBJECTIVE

N-methyl-D-aspartate (NMDA) receptor has been indicated to be involved in the pathogenesis of Alzheimer's disease (AD). The NMDA receptor subunit 2b (NR2B) has attracted more attention due to its characteristic distribution and selective reduction in AD brain. The present study aimed to explore the association between NMDA gene polymorphism and AD.

METHODS

A total of 63 AD patients and 68 normal controls in Shanghai city were employed in this study. Genotype of C2664T variant (rs1806201) in the exon13 of GRIN2B gene was determined by gene sequencing.

RESULTS

Among AD patients, 15 (23.6%) subjects were identified as C/C genotype, and 35 (55.6%) were identified as C/T genotype. The left 13 (20.6%) subjects were identified as T/T genotype. In normal controls, 15 (22.1%) subjects were identified as C/C genotype, 39 (57.4%) as C/T genotype and 14 (20.6%) as T/T genotype. The distribution frequency of neither GRIN2B C2664T genotype (P=0.895) nor allele (P=0.790) was significantly different between AD patients and normal controls, even when the subjects were stratified by gender and age of disease onset in AD patients.

CONCLUSION

The results suggest that there is no relation between GRIN2B C2664T polymorphism and AD in Chinese Han population of Shanghai City.

Two cases of frontotemporal dementia with predominant temporal lobe atrophy

Frontotemporal dementia (FTD) is a subtype of frontotemporal lobar degeneration, which also includes semantic dementia (SD) and progressive non-fluent aphasia. Frontotemporal dementia is characterized by changes in personality and behavioral abnormalities, generally associated with predominant frontal lobe atrophy. Conversely, SD is typically characterized by Gogi (word meaning) aphasia based on semantic memory impairment and is associated with predominant temporal lobe atrophy. However, in the present cases, we diagnosed FTD on the basis of clinical symptoms, such as disinhibition, indifference, and stereotypy, without semantic memory impairment, even though neuroimaging showed predominant temporal lobe atrophy. We suggest that clinical symptoms are the most important cues for an accurate clinical diagnosis and there is no exclusive relationship between the syndrome and atrophy of the temporal lobes.