The critical period hypothesis of estrogen effects on cognition: Insights from basic research

Background

In addition to its primary role in reproduction estrogen impacts brain areas important for cognition, including the hippocampus and prefrontal cortex. It has been hypothesized that decline in estrogen levels in women following menopause is associated with, or can exacerbate, age-related cognitive decline. However, clinical evidence to support a role for estrogen in preventing cognitive decline in women as they age is equivocal. The critical period hypothesis of estrogen effects on cognition, which proposes that estrogen administration has to be initiated within a critical time period following the loss of ovarian function in order for it to exert positive effects on the central nervous system, is offered as one explanation for inconsistencies across studies.

Scope of review

This review details results from basic research using rodent models investigating the effects of estrogen on cognition in the aging female. Emphasis is placed on work investigating effects of timing of initiation of estrogen administration on its subsequent efficacy.

Major conclusions

Results of basic research provide support for the critical period hypothesis. Furthermore, results of work in rodent models suggest mechanisms by which the response to estrogen is altered if treatment is initiated following long-term ovarian hormone deprivation.

General significance

Understanding if and under what conditions hormone administration following the loss of ovarian function positively affects the brain and behavior could have important implications with regard to female cognitive aging. Results of basic research can contribute to this understanding and provide insight into the complex mechanisms by which estrogen affects cognition.     

Postmenopausal hormone therapy and cognition

This article is part of a Special Issue "Estradiol and cognition".Prior to the publication of findings from the Women's Health Initiative (WHI) in 2002, estrogen-containing hormone therapy (HT) was used to prevent age-related disease, especially cardiovascular disease, and to treat menopausal symptoms such as hot flushes and sleep disruptions. Some observational studies of HT in midlife and aging women suggested that HT might also benefit cognitive function, but randomized clinical trials have produced mixed findings in terms of health and cognitive outcomes. This review focuses on hormone effects on cognition and risk for dementia in naturally menopausal women as well as surgically induced menopause, and highlights findings from the large-scale WHI Memory Study (WHIMS) which, contrary to expectation, showed increased dementia risk and poorer cognitive outcomes in older postmenopausal women randomized to HT versus placebo. We consider the ‘critical window hypothesis’, which suggests that a window of opportunity may exist shortly after menopause during which estrogen treatments are most effective. In addition, we highlight emerging evidence that potential adverse effects of HT on cognition are most pronounced in women who have other health risks, such as lower global cognition or diabetes. Lastly, we point towards implications for future research and clinical treatments.     

Efectos de un programa de intervención neuropsicológica basado en mindfulness sobre la enfermedad de Alzheimer: ensayo clínico aleatorizado a doble ciego

Introduction

The purpose of this research was to assess effects of a mindfulness based neuropsychological intervention on the clinical course of Alzheimer's disease.

Material and method

A two year randomized and double blind clinical trial was conducted on 127 probable Alzheimer's disease patients, according to NINCDS-ADRDA scale. Patients were grouped into three experimental groups (cognitive stimulation, progressive muscular relaxation, and mindfulness) plus a control group. All participants were receiving donepezil. Cognitive skills were assessed with CAMCOG and MMSE, functional area with RDRS-2, and NPI was used for psychopathology screening. Three treatment sessions per week were carried out for two years, and follow up measurements were taken every six months.

Results

The global cognitive function, functionality and behavioral disorders measurements indicated that patients from the experimental group based on mindfulness were stable during the two years, while patients from the control group, as well as the other experimental groups, showed a mild but significant worsening of their mental capacities.

Conclusion

The mindfulness based neuropsychological program showed better cognitive and functional stability, as well as significant improvement in the psychopathological condition of mild to moderate Alzheimer’ patients. These results support the idea that a mindfulness based intervention can produce a clinically relevant improvement in the treatment of dementia. More research is needed to confirm these data.     

Are optimal levels of testosterone associated with better cognitive function in healthy older women and men?

Background

Sex steroids can positively affect the brain and from this it would follow that high levels of sex steroids could be associated with better cognitive function in older men and women.

Methods

This Healthy Ageing Study sample comprised of 521 older participants (51% women) without dementia at baseline, with an age range from 64 to 94 years. Testosterone and sex hormone binding globulin were measured using the automated Immulite 2000 and analyzed in association with baseline memory, global cognitive function and decline (assessed using the Mini-Mental Status Examination or MMSE) and controlling for potential confounds such as age, education, vascular disease, smoking, diabetes, thyroid function, and body mass index.

Results

In healthy older men and women, optimal levels of testosterone were associated with better MMSE scores at baseline. Follow-up analyses indicated that in men, low testosterone levels (OR = .94, 95% CI = .88 to 1.00) were a risk factor for a sharp cognitive decline after 2 years, perhaps indicative of dementia. Associations were independent of covariates and baseline MMSE. Conversely, women at risk for a sharp drop in cognitive function showed some evidence for higher calculated free testosterone levels at baseline.

Conclusions

Results replicate earlier cross-sectional findings that high levels of sex steroids are not associated with better cognitive function in older people. In men, age accelerated endocrinological change could be associated with dementia pathology.

General significance

These data do not support increasing testosterone levels to prevent cognitive decline in men and women over 65 years of age.     

Construction and validation of a scale to assess attitudes toward patients with Alzheimer's disease and related disorders

Introduction

Patients suffering from dementia are often subjected to discriminatory attitudes, but there are few instruments able to measure these.

Objective

the construction and validation of a scale to detect negative attitudes toward patients with dementia and determine its psychometric properties, reliability criteria, and convergent and divergent validity.

Participants and methods

Fifty subjects were recruited for item selection. The scale was validated using 296 subjects of both genders, and included psychology, medical and nursing students.

Material and methods

A Likert-type attitudes scale of 30 items with 7 answers options was developed. After the pilot analysis of the scale and total item-item correlation a definitive tool of 20 items was developed, with a Cronbach‘s alpha index of 0.89. After the main component analysis, a 3 factors solution was preferred (rejection, effect and experience), which alone could explain the 65.7% of the total variance. Confirmatory factorial analysis with structural equations showed good fitting indexes (CFI=0.92; GFI=0.94; AGFI=0.90; PGFI=0.91; RMSEA=0.05). Convergent validation showed a positive correlation with scales measuring attitudes toward dementia, handicapped people, aging, and a questionnaire on negative stereotypes toward aging.

Results

Higher education and previous contact with the elderly were associated with more positive attitudes (F=29.16 and z=12.45, respectively).

Conclusions

The attitudes toward dementia scale is a valid and reliable instrument to detect these in the general population.     

Rising Midlife Obesity Will Worsen Future Prevalence of Dementia

Background

Midlife body weight status has been found to affect late life dementia outcomes. A cohort projections model was developed to assess the impact of midlife body mass index (BMI) profile on dementia in older Australians.

Methods

A baseline projection using age-sex specific dementia prevalence rates was constructed and the results of scenarios that took account of midlife BMI were compared with those from population ageing only.

Results

This modelling predicts that if the rising trend in midlife obesity and declining trend in midlife normal weight in Australia are to be taken into account in projecting future numbers of Australians with dementia then the number of people aged 65 or more years with dementia, by 2050, would be 14% higher than that expected from demographic ageing only. If midlife obesity prevalence was decreased to 20% and normal weight increased to 40% over the period of 2015–2025, then dementia cases among persons aged 65–69 years would be lower by about 10% in 2050 compared with the “doing nothing to stop current trends in obesity” projection.

Conclusion

The rising tide of obesity in Australian adults will increase the dementia epidemic expected in future years.     

Adaptación y validación de la versión española de la escala de evaluación de dolor en personas con demencia avanzada: PAINAD-Sp

Introduction

Pain in elderly people is considered a major concern in nursing home facilities affecting between 49% and 83% of the residents. Progression of Alzheimer's Disease causes more communication difficulties in patients with advanced dementia and therefore more problems to understand even the most simple pain evaluation scales. Identification and implementation of appropriate pain management strategies depends on an adequate pain assessment.

Material and methods

The main objective of the study was to validate the Spanish version of the PAINAD Scale (PAINAD-Sp) and to assess its applicability in Spanish Geriatric Nursing Homes. The 20 patients diagnosed with severe dementia from a Geriatric Centre in Spain were observed by five observers with different professional profiles for 5 minutes to each participant, and PAINAD-Sp Scale was administered simultaneously to a Visual Analogical Scale-VAS. Three different observational conditions were established: resting condition, during presumably pleasant activity and during presumable painful activity.

Results

Cronbach's alpha ranged between 0.467 and 0.827 (average 0.692), and rose if Breathing item was deleted. Inter-rater reliability ranged between 0.587 and 0.956. Correlation between PAINAD-Sp Scale total measures and VAS was statistically significant (P<.05) in all measures and ranged from 0.517 to 0.868.

Conclusions

Findings in the study showed that the scale is useful to measure pain in non communicative patients suffering from dementia. The scale maintains good levels of reliability for different healthcare professionals even when they have little training.     

Medaka fish exhibits longevity gender gap,a natural drop in estrogen and telomere shortening during aging: a unique model for studying sex-dependent longevity

Introduction

Females having a longer telomere and lifespan than males have been documented in many animals. Such linkage however has never been reported in fish. Progressive shortening of telomere length is an important aging mechanism. Mounting in vitro evidence has shown that telomere shortening beyond a critical length triggered replicative senescence or cell death. Estrogen has been postulated as a key factor contributing to maintenance of telomere and sex-dependent longevity in animals. This postulation remains unproven due to the lack of a suitable animal system for testing. Here, we introduce a teleost model, the Japanese medaka Oryzias latipes, which shows promise for research into the molecular mechanism(s) controlling sex difference in aging.

Results

Using the medaka, we demonstrate for the first time in teleost that (i) sex differences (female?>?male) in telomere length and longevity also exist in fish, and (ii) a natural, ‘menopause’-like decline of plasma estrogen was evident in females during aging. Estrogen levels significantly correlated with telomerase activity as well as telomere length in female organs (not in males), suggesting estrogen could modulate telomere length via telomerase activation in a sex -specific manner. A hypothetical in vivo ‘critical’ terminal restriction fragment (TRF, representing telomere) length of approximately 4 kb was deduced in medaka liver for prediction of organismal mortality, which is highly comparable with that for human cells. An age conversion model was also established to enable age translation between medaka (in months) and human (in years). These novel tools are useful for future research on comparative biology of aging using medaka.

Conclusion

The striking similarity in estrogen profile between aging female O. latipes and women enables studying the influence of “postmenopausal” decline of estrogen on telomere and longevity without the need of invasive ovariectomy. Medaka fish is advantageous for studying the direct effect of increased estrogen on telomere length and longevity without the breast cancer complications reported in rodents. The findings strongly support the notion that O. latipes is a unique non-mammalian model for validation of estrogenic influence on telomere and longevity in vertebrates. This laboratory model fish is of potential significance for deciphering the ostensibly conserved mechanism(s) of sex-associated longevity in vertebrates.

     

Age-dependent guanine oxidation in DNA of different brain regions of Wistar rats and prematurely aging OXYS rats

Background

Oxidative damage to the cell, including the formation of 8-oxoG, has been regarded as a significant factor in carcinogenesis and aging. An inbred prematurely aging rat strain (OXYS) is characterized by high sensitivity to oxidative stress, lipid peroxidation, protein oxidation, DNA rearrangements, and pathological conditions paralleling several human degenerative diseases including learning and memory deterioration.

Methods

We have used monoclonal antibodies against a common pre-mutagenic base lesion 8-oxoguanine (8-oxoG) and 8-oxoguanine DNA glycosylase (OGG1) in combination with indirect immunofluorescence microscopy and image analysis to follow the relative amounts and distribution of 8-oxoG and OGG1 in various cells of different brain regions from OXYS and control Wistar rats.

Results

It was shown that 8-oxoG increased with age in mature neurons, nestin- and glial fibrillary acidic protein (GFAP)-positive cells of hippocampus and frontal cortex in both strains of rats, with OXYS rats always displaying statistically significantly higher levels of oxidative DNA damage than Wistar rats. The relative content of 8-oxoG and OGG1 in nestin- and GFAP-positive cells was higher than in mature neurons in both Wistar and OXYS rats. However, there was no significant interstrain difference in the content of OGG1 for all types of cells and brain regions analyzed, and no difference in the relative content of 8-oxoG between different brain regions.

Conclusions

Oxidation of guanine may play an important role in the development of age-associated decrease in memory and learning capability of OXYS rats.

General significance

The findings are important for validation of the OXYS rat strain as a model of mammalian aging.     

Desarrollo de un instrumento de registro de implicación/engagement en la actividad para la observación sistemática de personas mayores con deterioro cognitivo

Introduction

As the level of cognitive impairment in people with dementia increases, it seems that the interventions aimed at this group do not obtain the expected results. Thus, it is clear that there is a need to develop specific assessment tools. One of the important aspects in people with dementia is the engagement, involvement in task and activities. Engagement is considered a quality of life and quality of care indicator. The aim of the study is to develop an Engagement recording tool for mapping people with dementia, and to obtain reliability measures.

Method

The present paper aims to present the current development of engagement behaviours. The pilot study had a sample of 19 people distributed into two groups, which were observed in order to obtain inter-rater reliability measurements using the percentage of inter-rater agreement.

Results

An observational mapping instrument was developed that achieved a high inter-rater reliability.

Conclusion

The Engagement recording tool makes it possible to gather promising results on the effects of the interventions for people with severe dementia. On the other hand, these results point to the possibilities of more specific tools to assess the different interventions which aim is to improve quality of life and quality of care in people with dementia.     

A Clinical Index to Predict Progression from Mild Cognitive Impairment to Dementia Due to Alzheimer's Disease

Background

Mild cognitive impairment is often a precursor to dementia due to Alzheimer''s disease, but many patients with mild cognitive impairment never develop dementia. New diagnostic criteria may lead to more patients receiving a diagnosis of mild cognitive impairment.

Objective

To develop a prediction index for the 3-year risk of progression from mild cognitive impairment to dementia relying only on information that can be readily obtained in most clinical settings.

Design and Participants

382 participants diagnosed with amnestic mild cognitive impairment enrolled in the Alzheimer''s Disease Neuroimaging Initiative (ADNI), a multi-site, longitudinal, observational study.

Main Predictors Measures

Demographics, comorbid conditions, caregiver report of participant symptoms and function, and participant performance on individual items from basic neuropsychological scales.

Main Outcome Measure

Progression to probable Alzheimer''s disease.

Key Results

Subjects had a mean (SD) age of 75 (7) years and 43% progressed to probable Alzheimer''s disease within 3 years. Important independent predictors of progression included being female, resisting help, becoming upset when separated from caregiver, difficulty shopping alone, forgetting appointments, number of words recalled from a 10-word list, orientation and difficulty drawing a clock. The final point score could range from 0 to 16 (mean [SD]: 4.2 [2.9]). The optimism-corrected Harrell''s c-statistic was 0.71(95% CI: 0.68–0.75). Fourteen percent of subjects with low risk scores (0–2 points, n = 124) converted to probable Alzheimer''s disease over 3 years, compared to 51% of those with moderate risk scores (3–8 points, n = 223) and 91% of those with high risk scores (9–16 points, n = 35).

Conclusions

An index using factors that can be obtained in most clinical settings can predict progression from amnestic mild cognitive impairment to probable Alzheimer''s disease and may help clinicians differentiate between mild cognitive impairment patients at low vs. high risk of progression.     

Role of estrogen receptors in pro-oxidative and anti-oxidative actions of estrogens: A perspective

Background

Estrogens are steroid hormones responsible for the primary and secondary sexual characteristics in females. While pre-menopausal women use estrogens as the main constituents of contraceptive pills, post-menopausal women use the same for Hormone Replacement Therapy. Estrogens produce reactive oxygen species by increasing mitochondrial activity and redox cycling of estrogen metabolites. The phenolic hydroxyl group present at the C3 position of the A ring of estrogens can get oxidized either by accepting an electron or by losing a proton. Thus, estrogens might act as pro-oxidant in some settings, resulting in complicated non-communicable diseases, namely, cancer and cardiovascular disorders. However, in some other settings the phenolic hydroxyl group of estrogens may be responsible for the anti-oxidative beneficial functions and thus protect against cardiovascular and neurodegenerative diseases.

Scope of review

To date, no single review article has mentioned the implication of estrogen receptors in both the pro-oxidative and anti-oxidative actions of estrogens.

Major conclusion

The controversial role of estrogens as pro-oxidant or anti-oxidant is largely dependent on cell types, ratio of different types of estrogen receptors present in a particular cell and context specificity of the estrogen hormone responses. Both pro-oxidant and anti-oxidant effects of estrogens might involve different estrogen receptors that can have either genomic or non-genomic action to manifest further hormonal response.

General significance

This review highlights the role of estrogen receptors in the pro-oxidative and anti-oxidative actions of estrogens with special emphasis on neuronal cells.     

Influence of individual and combined healthy behaviours on successful aging

Background:

Increases in life expectancy make it important to remain healthy for as long as possible. Our objective was to examine the extent to which healthy behaviours in midlife, separately and in combination, predict successful aging.

Methods:

We used a prospective cohort design involving 5100 men and women aged 42–63 years. Participants were free of cancer, coronary artery disease and stroke when their health behaviours were assessed in 1991–1994 as part of the Whitehall II study. We defined healthy behaviours as never smoking, moderate alcohol consumption, physical activity (≥ 2.5 h/wk moderate physical activity or ≥ 1 h/wk vigorous physical activity), and eating fruits and vegetables daily. We defined successful aging, measured over a median 16.3-year follow-up, as good cognitive, physical, respiratory and cardiovascular functioning, in addition to the absence of disability, mental health problems and chronic disease (coronary artery disease, stroke, cancer and diabetes).

Results:

At the end of follow-up, 549 participants had died and 953 qualified as aging successfully. Compared with participants who engaged in no healthy behaviours, participants engaging in all 4 healthy behaviours had 3.3 times greater odds of successful aging (95% confidence interval [CI] 2.1–5.1). The association with successful aging was linear, with the odds ratio (OR) per increment of healthy behaviour being 1.3 (95% CI 1.2–1.4; population-attributable risk for 1–4 v. 0 healthy behaviours 47%). When missing data were considered in the analysis, the results were similar to those of our main analysis.

Interpretation:

Although individual healthy behaviours are moderately associated with successful aging, their combined impact is substantial. We did not investigate the mechanisms underlying these associations, but we saw clear evidence of the importance of healthy behaviours for successful aging.Increases in life expectancy make remaining free of disease and in good functional health for as long as possible an important objective for the present and future generations.¹ Most research in this domain has focused on risk factors for single health outcomes, such as mortality, chronic diseases or functioning. However, good health at older ages is a multidimensional concept, having been defined variously with reference to absence of disease and good functional status.^2–5 There is considerable research on disability outcomes at older ages,^2,6–8 but less attention has been paid to successful aging combining favourable functioning outcomes with good mental health and the absence of chronic diseases and disability.^9–13Smoking, alcohol consumption, poor diet and physical inactivity are among the top 10 leading risk factors for death and disability in intermediate- and high-income countries.¹⁴ There is increasing interest in the combined effect of these behaviours on health. Studies show that people who engage in multiple unhealthy behaviours have a higher risk of death,^15–23 chronic disease^24–30 and poor cognitive function than people who do not engage in as many unhealthy behaviours.³¹ However, whether healthy behaviours determine good functional status at older ages, combined with the absence of chronic diseases, remains unknown.Our objective was to examine the extent to which individual and combined healthy behaviours in midlife predict successful aging about 16 years later, at 60 years of age or older. We used a comprehensive definition of successful aging that included having good mental health, having good cognitive, physical and cardiorespiratory function, and being free of disability and chronic disease (coronary artery disease, stroke, diabetes and cancer).     

Biosilica aging: From enzyme-driven gelation via syneresis to chemical/biochemical hardening

Background

The distinguished property of the siliceous sponge spicules is their enzyme (silicatein)-catalyzed biosilica formation. The enzymatically formed, non-structured biosilica product undergoes a molding, syneresis, and hardening process to form the species-specifically shaped, hard structured skeletal spicules. Besides of silicatein, a silicatein-associated protein, silintaphin-2, is assumed to be involved in the process of biosilica formation in vivo.

Methods

Biosilica has been synthesized enzymatically and determined quantitatively. In addition, the subsequent hardening/aging steps have been followed by spectroscopic and electron microscopic analyses.

Results

The young spicules, newly formed in sponge cell aggregates, comprise high concentrations of sodium (~ 1 w/w %) and potassium (0.3%). During aging the two alkali metals are removed from the spicules by 80%. In parallel, water is withdrawn from the biosilica deposits. A protein, the silicatein-α interactor silintaphin-2, comprises clusters rich in the anionic amino acids aspartic acid [D] and glutamic acid [E]. The very acidic peptide was found to significantly enhance silica polymerization. This peptide also caused a strong aggregation of silicatein/biosilica particles.

Conclusions

The observations are explained by sodium ion removal from the initially formed biosilica deposits to the acidic amino acids in silintaphin-2. The crucial amino acids facilitating/forcing the silicatein-mediated biosilica reaction are D and E.

General significance

The data presented here provide a reaction mechanism that at neutral pH the extent of biosilica formation can be strongly intensified by the removal of cations. The results contribute to an understanding of the structuring process taking place during the formation of the solid spicule rods.     

Role of visceral adipose tissue in aging

Background

Visceral fat (VF) accretion is a hallmark of aging in humans. Epidemiologic studies have implicated abdominal obesity as a major risk factor for insulin resistance, type 2 diabetes, cardiovascular disease, metabolic syndrome and death.

Methods

Studies utilizing novel rodent models of visceral obesity and surgical strategies in humans have been undertaken to determine if subcutaneous (SC) abdominal or VF are causally linked to age-related diseases.

Results

Specific depletion or expansion of the VF depot using genetic or surgical tools in rodents has been shown to have direct effects on disease risk. In contrast, surgically removing large quantities of SC fat does not consistently improve metabolic parameters in humans or rodents, while benefits were observed with SC fat expansion in mice, suggesting that SC fat accrual is not an important contributor to metabolic decline. There is also compelling evidence in humans that abdominal obesity is a stronger risk factor for mortality risk than general obesity. Likewise, we have shown that surgical removal of VF improves mean and maximum lifespan in rats, providing the first causal evidence that VF depletion may be an important underlying cause of improved lifespan with caloric restriction.

General significance

This review provides both corollary and causal evidence for the importance of accounting for body fat distribution, and specifically VF, when assessing disease and mortality risk. Given the hazards of VF accumulation on health, treatment strategies aimed at selectively depleting VF should be considered as a viable tool to effectively reduce disease risk in humans.     

Inhibiting toxic aggregation of amyloidogenic proteins: A therapeutic strategy for protein misfolding diseases

Background

The deposition of self-assembled amyloidogenic proteins is associated with multiple diseases, including Alzheimer's disease, Parkinson's disease and type 2 diabetes mellitus. The toxic misfolding and self-assembling of amyloidogenic proteins are believed to underlie protein misfolding diseases. Novel drug candidates targeting self-assembled amyloidogenic proteins represent a potential therapeutic approach for protein misfolding diseases.

Scope of review

In this perspective review, we provide an overview of the recent progress in identifying inhibitors that block the aggregation of amyloidogenic proteins and the clinical applications thereof.

Major conclusions

Compounds such as polyphenols, certain short peptides, and monomer- or oligomer-specific antibodies, can interfere with the self-assembly of amyloidogenic proteins, prevent the formation of oligomers, amyloid fibrils and the consequent cytotoxicity.

General significance

Some inhibitors have been tested in clinical trials for treating protein misfolding diseases. Inhibitors that target the aggregation of amyloidogenic proteins bring new hope to therapy for protein misfolding diseases.     

Tracing the pathway of compositional changes in bone mineral with age: Preliminary study of bioapatite aging in hypermineralized dolphin's bulla

Background

Studies of mineral compositional effects during bone aging are complicated by the presence of collagen.

Methods

Hypermineralized bullae of Atlantic bottlenose dolphins of < 3 months, 2.5 years, and 20 years underwent micrometer-scale point analysis by Raman spectroscopy and electron microprobe in addition to bulk analysis for carbon.

Results

Bulla central areas have a mineral content of ~ 96 wt.% and 9–10 wt.% carbonate in their bioapatite, which is ~ 2 wt.% more than edge areas. Ca/P atomic ratios (~ 1.8) and concentrations of Mg, S, and other minor/trace elements are almost constant in central areas over time. Maturity brings greater over-all homogeneity in mineral content, stoichiometry, and morphology throughout the central and edge areas of the bullae. During aging, edge areas become less porous, whereas the concentration of organics in the edge is reduced. Enhancement of coupled substitutions of CO₃^2 − for PO₄^3 − and Na for Ca during aging increases carbonate content up to ~ 10 wt.% in the adult bulla.

Conclusions

1) Changes in physical properties during aging did not occur simultaneously with changes in chemical properties of the bone mineral. 2) Compositional changes in bone mineral were minor during the neonatal to sub-adult stage, but significant during later maturity. 3) Na and CO₃ concentrations co-vary in a 1:1 molar proportion during aging. 4) The mineral's crystallinity did not decrease as CO₃ concentration increased during aging.

General significance

Hypermineralized dolphin's bulla, due to extreme depletion in collagen, is an ideal material for investigating mineralogical changes in bioapatite during bone aging.     

Resiliencia en cuidadores de personas con demencia: estudio preliminar

Introduction

Caring for a relative with dementia often has negative effects on the caregive?s physical and psychological health. However, many caregivers successfully cope with the stress factors arising from care, and even have uplifts during their experience, showing high resilience levels. This study presents a preliminary analysis of resilience in caregivers of patients with dementia, exploring its relationship with different variables.

Material and methods

Resilience was assessed (by CD-RISC) in 53 family caregivers of patients with dementia. Resilience was correlated to the following variables: caregiving context, stressors (e.g., cognitive impairment), appraisals (e.g., burden), moderators (e.g., personality traits and resources), and caregiving consequences (physical and psychological health).

Results

The participants showed moderate scores on resilience. Resilience was associated with poor emotional and physical status (significant inverse correlations with anxiety, depression, psycho-active drug use, health habits…). High resilience scores were significantly correlated to burden, neuroticism and extraversion, self-efficacy, self-esteem and less use of emotion focused coping strategies.

Conclusions

Higher resilience relates to a good emotional and physical status in caregivers. Moreover, resilience is more associated with caregiver variables (e.g., appraisal and coping with care, personality features), than to situational variables. The data highlight the strengthening of these types of appraisal and coping as a way to improve caregivers’ resilience and, consequently, their health.     

Multi factorial interactions in the pathogenesis pathway of Alzheimer’s disease: a new risk charts for prevention of dementia

Background

The population longitudinal study named “The Conselice Study” has been the focus of the present investigation. 65 years old or older participants of this population study on brain aging were followed up for 5 years: 937 subjects completed the follow-up. Relationships of 46 genetic, phenotypic, clinical and nutritional factors on incident cognitive decline and incident dementia cases were investigated.

Results

A new statistical approach, called the Auto Contractive Map (AutoCM) was applied to find relationship between variables and a possible hierarchy in the relevance of each variable with incident dementia. This method, based on an artificial adaptive system, was able to define the association strength of each variable with all the others. Moreover, few variables resulted to be aggregation points in the variable connectivity map related to cognitive decline and dementia. Gene variants and cognate phenotypic variables showed differential degrees of relevance to brain aging and dementia. A risk map for age associated cognitive decline and dementia has been constructed and will be presented and discussed.

Conclusion

This map of variables may be use to identify subjects with increased risk of developing cognitive decline end/or dementia and provide pivotal information for early intervention protocols for prevention of dementia.

     

Are the effects of a non-drug multimodal activation therapy of dementia sustainable? Follow-up study 10 months after completion of a randomised controlled trial

Background

Little is known about the long-term success of non-drug therapies for treating dementia, especially whether the effects are sustained after therapy ends. Here, we examined the effects of a one-year multimodal therapy 10 months after patients completed the therapy.

Methods

This randomised, controlled, single-blind, longitudinal trial involved 61 patients (catamnesis: n?=?52) with primary degenerative dementia in five nursing homes in Bavaria, Germany. The highly standardised intervention, MAKS, consisted of motor stimulation, practice of activities of daily living (ADLs), and cognitive stimulation. Each group of 10 patients was treated for 2 h, 6 days a week for 12 months. Control patients received standard nursing home care. At baseline, at the end of therapy (month 12), and 10 months thereafter (month 22), cognitive functioning was assessed using the cognitive subscale of the Alzheimer’s Disease Assessment Scale, and the ability to perform ADLs was assessed using the Erlangen Test of Activities of Daily Living.

Results

During the therapy phase, the MAKS patients maintained their cognitive function and ability to carry out ADLs. After the end of therapy, both the control and the MAKS groups deteriorated in both their cognitive function (control, p?=?0.02; MAKS, p?<?0.001) and their ability to carry out ADLs (control, p?<?0.001; MAKS, p?=?0.001). However, in a confound-adjusted multiple regression model, the ability of the MAKS group to perform ADLs remained significantly higher than that of the control group even 10 months after the end of therapy (H₀: β_MAKS?+?β_{MAKS month 22}?=?0; χ²?=?3.8568, p?=?0.0496). Cohen’s d for the difference between the two groups in ADLs and cognitive abilities 10 months after the end of therapy was 0.40 and 0.22, respectively.

Conclusions

A multimodal non-drug therapy of dementia resulted in stabilisation of the ability to perform ADLs, even beyond the end of therapy. To prevent functional decline for as long as possible, therapy should be performed continuously until the benefit for the patient ends. Follow-up studies on larger numbers of patients are needed to definitively confirm these results.

Trial registration

http://www.isrctn.com Identifier: ISRCTN87391496