Psychophysiological correlates of cognitive deficits in family caregivers of patients with Alzheimer Disease

A Systematic Review of Intervention Trials Utilizing Biomarkers Among Informal Caregivers of People with Alzheimer's Disease & Related Dementias

Informal caregivers of people with Alzheimer's Disease and Related Dementias (ADRD) experience unique stressors, reduced quality of life, and report poorer health, compared to non-caregivers. Throughout the last thirty years, researchers have developed and tested various psychosocial interventions and their ability to improve caregiver health. Due to an exclusive focus on self-report methods, however, no existing systematic literature reviews specifically examine intervention studies employing biomarkers; this systematic review aims to address this gap in the literature. In each database (PubMed and Web of Science, respectively), a title search was conducted with the following keywords: "alzheimer*" OR "dementia" AND "caregiv*" AND "intervention", followed by a second search using identical keywords except "intervention" was replaced with "program." Study or intervention protocol articles, exclusively qualitative studies, cultural applicability papers, dissemination studies, descriptive articles or program reports, acceptability/feasibility studies, studies utilizing formal caregiving samples, commentaries, review papers, and meta-analyses, erratums/corrections, measure development articles, factor analyses, and case reports were excluded from the final pool of studies. In this systematic review, the findings of 14 studies are summarized, and are organized based on specific types of biomarkers: neuroendocrine, immune, and autonomic physiological. Overall, the review yielded mixed results, which may, in part, be due to differences in the types of interventions tested, as well as differing biomarker measurement, methodology, and analysis. More biobehavioral intervention trials are needed among ADRD caregivers. Including biological parameters as pre- and post-measures can shed insight into the extent to which interventions may help caregivers heal from the stress of caregiving.

Protective roles of meditation practice and self-esteem on cognitive functions over time: findings from the Midlife in the United States study

BACKGROUND

Cognitive function is an important component of healthy ageing. However, it is unclear whether relaxation/meditation practices provide cognitive benefits, particularly in midlife and early late life. Meditative practices are associated with higher self-esteem, and self-esteem serves as a general protective factor for many health outcomes. The current study examines associations between meditation practice, self-esteem, and change over 10 years in midlife cognitive performance.

METHODS

Data were from waves 2 (2003-2004) and 3 (2013-2014) of the Midlife in the United States (MIDUS) study. We used structural equation modelling to examine whether persistent meditation practice at both waves or episodic practice at one wave is associated with better cognitive function over 10 years, compared to no meditation practice, while controlling for prior cognitive function and covariates (baseline socio-demographics, health, and functional status). Additionally, we assessed if self-esteem mediates the above associations.

RESULTS

We included 2168 individuals (Mage  = 65 ± 11). After controlling for covariates, the findings revealed that persistent meditation practice in both waves was associated with significantly less decline in episodic memory; however, no such effects were found for executive function. Further, although participants' higher self-esteem was significantly associated with less decline in executive function and episodic memory, it did not mediate the associations between meditation practice and cognitive functions.

CONCLUSIONS

While both persistent meditation practice and self-esteem have associations with cognitive outcomes for middle-aged and older adults in MIDUS, self-esteem as a mediator was not supported. Thus, future investigations should examine mechanisms that underlie these protective factors on cognitive performances across adulthood.

The Healthy Caregiver? A Positive Impact of Informal Caregiving Status on Cognitive Functions Over Time From the Midlife in the United States Study

OBJECTIVES

The current study examined whether informal caregivers performed worse, better, or similar to non-caregivers on cognitive tests of executive functioning and episodic memory over 10 years. Methods: Data were from waves 2 (2003-04) and 3 (2013-14) of the Midlife in the United States (MIDUS) study (N = 2086). Multiple linear regression models examined whether caregiving at both waves 2 and 3 predicted better cognitive functioning at wave 3, than caregiving at only one time point or no caregiving (reference) while controlling for baseline covariates (i.e., sociodemographic, health, and functional status).

RESULTS

After controlling for covariates, caregiving at both waves was independently associated with better performance in episodic memory (b = .24, SE = .10, p = .013) but not executive function (b = -.06, SE = .05, p = .246). Discussion:The findings partially supported both healthy caregiver and stress process models, indicating caregiving may be associated with better episodic memory but not executive functioning over time among the middle-aged and older adults.

A Literature Review on the Burden of Alzheimer's Disease on Care Partners

BACKGROUND

Many individuals with Alzheimer's disease (AD) are dependent on nonprofessional care partners. Providing informal care can result in emotional, physical, and financial burdens; however, there is a need for a better understanding of the impact of AD on care partners to support the clinical and economic assessment of potential new treatments.

OBJECTIVE

We conducted a literature review to evaluate the burden experienced by care partners of individuals with AD.

METHODS

Electronic screening and supplementary searches identified studies published from 2011 to 2022 describing the association between AD and the quality of life (QoL) and physical health of care partners, and the economic or financial burden of AD.

RESULTS

Following electronic screening, 62, 25, and 39 studies were included on care partner burden, cost, and healthcare resource use in AD, respectively. Supplementary searches identified an additional 32 studies, resulting in 149 unique studies. These studies showed that care partners of individuals with AD report moderate to severe burden. Higher burden and lower QoL were observed in those caring for individuals with more severe AD. Care partners of individuals with AD experience higher burden, lower QoL, and higher levels of stress, depression, and anxiety than those without caring responsibilities. Informal care costs increased with AD severity and accounted for the greatest proportion of overall societal cost.

CONCLUSIONS

Care partners of individuals with AD experience emotional and economic burden, which increases with AD severity. These impacts should be quantified comprehensively in future studies and captured in economic evaluations of AD interventions.

Family Caregivers of People with Dementia Associate with Poor Health-Related Quality of Life: A Nationwide Population-Based Study

Despite the growing awareness of poor health-related quality of life (HRQoL) in family caregivers of people with dementia (PWD), their relationship has rarely been explored with population-based samples. The current cross-sectional study aimed to determine the detrimental impact of informal dementia caregiving on HRQoL by using nationally representative population-based samples from the Korean Community Health Survey. Demographics, socioeconomic, and physical and mental health-related characteristics as well as HRQoL measured by the Korean version of the European Quality of Life Questionnaire Five Dimension (EQ-5D) were compared between 9563 family caregivers of PWD and 186,165 noncaregivers. Caregivers had lower index scores and higher frequency of some/extreme problems in all five dimensions of the EQ-5D compared with noncaregivers. Logistic regression adjusting for potential confounding factors found that caregivers had a higher frequency of poor HRQoL (lowest quartile of EQ-5D index) than noncaregivers (adjusted odds ratio [95% confidence interval] = 1.46 [1.39-1.53]). Compared to noncaregivers, caregivers had a higher frequency of some/extreme problems in each dimension of the EQ-5D: mobility (1.30 [1.21-1.40]), self-care (1.62 [1.46-1.80]), usual activity (1.39 [1.29-1.51]), pain/discomfort (1.37 [1.31-1.45]), and anxiety/depression (1.51 [1.42-1.61]). A one-to-one propensity score matching analysis confirmed that poor HRQoL was more frequently found in caregivers compared to noncaregivers (1.38 [1.29-1.48]). Our results indicated that family caregivers of PWD are significantly associated with overall poor HRQoL, underscoring the detrimental impact of informal dementia caregiving on HRQoL. Given the high frequency of poor HRQoL in dementia caregivers and the important recognition of its serious consequences on physical and mental health, clinicians should take into consideration efficient interventions to improve health and HRQoL for family caregivers of PWD.

Family Caregivers of People with Dementia Have Poor Sleep Quality: A Nationwide Population-Based Study

Previous studies have documented cognitive impairments, psychological stress, and depressive symptoms in family caregivers of people with dementia (PWD), which could be attributed to their sleep disturbances. Notwithstanding the increasing recognition of poor sleep quality and sleep disturbances in family caregivers of PWD, their association has not been tested yet using population-representative samples. We conducted a retrospective, cross-sectional study using population-based data from the 2018 Korean Community Health Survey. Sociodemographic, mental health-related, and physical health-related variables as well as sleep quality evaluated by the Pittsburgh Sleep Quality Index (PSQI) were compared between 2537 cohabitating caregivers of PWD, 8864 noncohabitating caregivers of PWD, and 190,278 non-caregivers. Two sets of multivariable logistic regressions were conducted to examine the associations between dementia caregiving and poor sleep quality in cohabitating and noncohabitating caregivers versus noncaregivers. Both cohabitating and noncohabitating caregivers had higher global PSQI scores and higher prevalence of poor sleep quality (PSQI score > 5) than did noncaregivers. Multivariable logistic regressions adjusted for potential confounders revealed that cohabitating caregivers (odds ratio (OR) 1.26, 95% confidence interval (CI) 1.15-1.38) and noncohabitating caregivers (OR 1.15, CI 1.10-1.21) were significantly associated with poor sleep quality. Our results showed that both cohabitating and noncohabitating caregivers of PWD experienced overall poorer sleep quality compared to noncaregivers, indicating the deleterious effect of dementia caregiving on sleep quality, regardless of living arrangements. Given the high prevalence of poor sleep quality in family caregivers of PWD and the increasing awareness of the serious health consequences of poor-quality sleep, physicians should consider active sleep interventions to promote health and wellbeing not only for the dementia patients but also for family caregivers.

Stress and its contribution to the development of depression symptoms are reduced in caregivers of elderly with higher educational level

Caregivers of elderly people with neurodegenerative diseases are highly vulnerable to stressful situations and mood disorders due to their work conditions. Stress has been associated with an increased risk of developing depression, and studies have supported that caffeine consumption can act as an independent protective factor for disorder. This study investigated indexes of stress and depression symptoms in caregivers of the elderly with neurodegenerative diseases, their caffeine intake and the association between stress and depressive symptoms with the salivary biomarkers cortisol, nitric oxide and DNA damage. Participants (n = 81) were recruited from the community between July 2018 and April 2019. Stress was assessed using Lipp's Inventory of Stress Symptoms, and depressive symptoms were measured using the Hamilton Depressive Rating Scale. Participants provided a 72-hour recall of their diet to measure caffeine intake. Saliva samples were used to measure cortisol and nitric oxide. DNA damage was measured through micronuclei frequency after swabbing on the buccal mucosa. The majority of caregivers displayed stress and depressive symptoms. Stress was associated with educational level, tobacco use and total DNA damage. The indexes found in this population were not associated with caffeine intake or other salivary biomarkers, indicating that only some salivary molecules could be used as biomarkers for stress-related disorders. Caregivers of the elderly are exposed to stressful situations daily, however, we observed that educational level can reduce the psychological symptoms of stress and thus reduce the negative impact on quality of life.

Family and Community Support, Brain-Derived Neurotrophic Factor, and Cognitive Performance in Older Adults: Findings From the Health, Wellbeing and Aging Study Population-Based Cohort

Background: Social networks can modulate physiological responses, protects against the detrimental consequences of prolonged stress, and enhance health outcomes. Family ties represent an essential source of social networks among older adults. However, the impact of family support on cognitive performance and the biological factors influencing that relationship is still unclear. We aimed to determine the relationship between family support, cognitive performance and BDNF levels. Methods: Cross-sectional data from three-hundred, eight-six individuals aged on average 60 years enrolled in the Health, Wellbeing and Aging Study (SABE), a population-cohort study, were assessed for family support, community support and cognitive performance. Structural and functional family support was evaluated based on family size and interactions allied to scores in the Family APGAR questionnaire. Community assistance (received or provided) assessed the community support. Cognitive performance was determined using the Mini-Mental State Examination (MMSE), verbal fluency (animals per minute) and backward digital span. Blood samples were obtained to determine BDNF levels. Results: Multivariate analysis showed that functional family support, but not structural, was associated with higher MMSE, verbal fluency and digit span scores, even controlling for potential cofounders (p < 0.001). Providing support to the community, rather than receiving support from others, was associated with better cognitive performance (p < 0.001). BDNF concentration was not associated with community support, family function, or cognitive performance. Conclusion: These findings suggest that emotional components of functional family and community support (e.g., loving and empathic relationship) may be more significant to cognitive health than size and frequency of social interactions.

Integrative psycho-biophysiological markers in predicting psychological resilience

The hypothalamic-pituitary-adrenal (HPA) and parasympathetic nervous systems have been reported to play important roles in emotion regulation and stress coping. Yet, their direct relationship with psychological resilience remains unclear. These biophysiological features should be considered together with the traditional psychometric properties in studying resilience more comprehensively. The current study aimed to examine the role of these systems during a laboratory stress task and to determine the prediction power of resilience by combining psychological and biophysiological features. One hundred and seven (52 females) university students without psychiatric disorders underwent the Trier Social Stress Task (TSST). Psychometric properties of resilience were measured at rest; vagal heart rate variability (HRV), salivary cortisol, and dehydroepiandrosterone (DHEA) levels were captured at baseline, during, and after TSST. Multivariate linear regression as well as support vector regression machine-learning analyses were performed to investigate significant predictors and the prediction power of resilience. Results showed that positive and negative affects, HRV during the anticipatory phase of stress, and the ratio of cortisol/DHEA at the first recovery time point were significant predictors of resilience. The addition of biophysiological features increased the prediction power of resilience by 1.2-fold compared to psychological features alone. Results from machine learning analyses further demonstrated that the increased prediction power of resilience by adding the ratio of cortisol/DHEA was significant in "cortisol responders"; whereas a trend level was observed in "cortisol non-responders". Our findings extend the knowledge from the literature that high vagal activity during the anticipating phase of stress and the ability to restore the balance between cortisol and DHEA after a stress event could be an important feature in predicting resilience. Our findings also further support the need of combining psychological and biophysiological features in studying/predicting resilience.

Protective Effect of Hydroxysafflor Yellow A against Chronic Mild Stress-induced Memory Impairments by Suppressing Tau Phosphorylation in Mice

Chronic stress plays a critical role in the etiology of sporadic Alzheimer's disease (AD). However, there are currently no effective drugs that can target chronic stress to prevent AD. In this study, we explored the neuroprotective effect of hydroxysafflor yellow A (HSYA) against chronic mild stress (CMS)-induced memory impairments in mice and the underlying mechanism. The Morris water maze test showed that HSYA significantly reduced CMS-induced learning and memory impairments in mice. HSYA increased the expression of brain-derived neurotrophic factor (BDNF) and activated downstream tropomyosin-related kinase B (TrkB) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B(Akt)/mammalian target of rapamycin (mTOR) signaling. HSYA decreased the expression of regulator of calcineurin 1-1L (RCAN1-1L) that could promote the activity of glycogen synthase kinase-3β (GSK-3β). HSYA also attenuated tau phosphorylation by inhibiting the activity of GSK-3β and cyclin-dependent kinase-5 (Cdk5). Our data indicated that HSYA has protective effects against CMS-induced BDNF downregulation, tau phosphorylation and memory impairments. HSYA may be a promising therapeutic candidate for AD by targeting chronic stress.

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.

Positive psychological states and stress responses in caregivers of adults receiving an allogeneic bone marrow transplant: A study protocol

AIMS

This protocol directs a study that aims to: (a) describe the caregiver's experience over 8-12 weeks after an index adult patient's allogeneic bone marrow transplant (BMT) for advanced cancer using a case-oriented approach and mixed methods, with qualitative methods in the foreground; and (b) explore networks of relationships among psycho-neurological symptoms, positive psychological states and caregiver health.

DESIGN

Case-oriented longitudinal design using multiple data types and analytic approaches.

METHODS

Data will be collected from 10-12 caregivers. The sample will be recruited from a large public hospital in the southeastern United States using maximum variation sampling (e.g., caregiver race/ethnicity, relationship to patient, age, education, and number of caregiving roles). Participants will be asked to complete weekly surveys, have their blood drawn bi-weekly and participate in an interview each month during the study period (~100 days). Aim 1 analysis will include directed content analysis and case-oriented visual analysis. Aim 2 analysis will include symptom network estimation of psycho-neurological symptoms, positive psychological states, and caregiver health. Institutional review board approval was obtained August 2018.

DISCUSSION

Results will provide an in-depth description of caregivers' experiences in the 100 days after BMT. Findings will inform generation of hypotheses and identification of targets for interventions to improve caregiver's experiences after BMT.

IMPACT

This in-depth multi-method longitudinal study to describe caregivers of adult patients receiving an allogeneic BMT is an essential step in understanding caregivers' complex responses to chronic stress and the role of positive psychological states. The results from this study will inform future research on chronic stress processes, intense caregiving, and intervention development.

Episodic memory and executive functioning in informal dementia caregivers

Objectives: Informal dementia caregivers are thought to experience high levels of depression and burden, which can contribute to worse cognitive functioning. However, poorer cognitive functioning in caregivers is not always found. The current study explored whether caregivers perform better, worse, or similar to non-caregivers on tasks for executive functioning and memory. Whether sociodemographic and psychosocial characteristics are associated with caregivers' performance was also assessed.Methods: One hundred forty-five caregivers completed the Letter Fluency and Category Fluency, the Logical Memory test from the WMS-III, and five questionnaires assessing psychological characteristics. Standardized z-scores (based on age, education, and sex) were calculated using data from a matched control group (187 non-caregivers). One sample z-tests were executed to examine if the caregivers' standardized mean z-score significantly deviated from the population mean of z = 0. The z-scores were used as dependent variables in multivariable regression analyses.Results: The caregivers performed significantly better on Logical Memory - Immediate Recall than non-caregivers (z = 2.92, p = .004). The obtained z-scores on the other tasks did not deviate significantly from 0. Male sex and social reliance predicted higher scores on Category Fluency, but the F-test was non-significant, and the explained variance was low (adjusted R² = .068).Conclusions: We found no evidence for poorer cognitive performance among informal caregivers compared to non-caregivers. Our results suggest that caregiving for a loved one with dementia does not impair the caregivers' episodic memory or executive functioning when measured cross-sectionally.

Neuropsychological consequences of chronic stress: the case of informal caregivers

Introduction: Caring for a family member with a long-term illness is a significant source of chronic stress that might significantly accelerate the cognitive ageing of informal caregivers. Nevertheless, the absence of a defined theoretical body of literature on the neuropsychology of this population makes it difficult to understand what the characteristic neuropsychological deficits of these caregivers are.Aims: The main aim of this study is to carry out a systematic review of studies of cognitive deficits present in informal caregivers of people with several chronic pathologies, and analyse the effects of cognitive-behavioural interventions on caregivers' cognition.Methods: The scientific literature was reviewed following the PRISMA quality criteria for reviews using the following digital databases: PubMEd, PsycINFO, and Dialnet.Results: Identification of 2046 abstracts and retrieval of 211 full texts led to the inclusion of 38 papers. The studies showed heterogeneous results, but most of the cross-sectional studies reviewed that employed neuropsychological assessments concluded that informal caregivers reported a generalized cognitive deterioration, especially memory dysfunctions (i.e. learning verbal, visuospatial, and digit information). Moreover, they also presented low selective attention and capacity for inhibition, along with slow processing speed. Longitudinal studies confirmed that caregivers whose care situation was more prolonged showed a marked deterioration in their overall cognitive state, memory, processing speed, and vocabulary richness. However, although the patient's death does not seem to reverse the neuropsychological alterations in caregivers, cognitive-behavioural interventions that employ techniques to reduce stress levels, cognitive biases, and inadequate adaptation schemas seem to improve some of the aforementioned cognitive abilities.Conclusions: Results from this synthesis and critical analysis of neuropsychological deficits in informal caregivers offer guidelines for diagnosing caregivers' cognitive status by including a test battery covering all the domains considered relevant. Finally, given the ability of cognitive behavioural interventions to improve cognition in caregivers, further studies on their long-term effects on caregivers are warranted.Chronic stress entails an acceleration of the cognitive ageingCross-sectional studies concluded that informal caregivers reported a generalized cognitive deteriorationCognitive-behavioural interventions seem to improve cognitive abilities of caregivers.

Minimally-invasive methods for examining biological changes in response to chronic stress: A scoping review

BACKGROUND

Nurse researchers are increasingly interested in incorporating biological indicators related to chronic stress, or repeated or constant exposure to psychological stressors. Minimally invasive collection methods may improve access to vulnerable populations.

OBJECTIVE

To map biological indicators measured through minimally invasive methods investigating biological changes in response to chronic stress.

DESIGN, DATA SOURCES, AND METHODS

The paper seeks to answer two questions: What are the characteristics of the minimally-invasive methods used to measure the biological correlates of chronic stress? What are the limitations regarding the use of the minimally-invasive methods and/or biological indicators identified above? Authors completed a scoping review following guidelines from the Joanna Briggs Institute Manual and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews. A literature search was completed in PubMed, PsycINFO, and Scopus. 2518 articles were screened and 145 studies were included. Data were extracted using a standardized extraction tool, compiled, and coded.

RESULTS

Studies included minimally-invasive methods to measure the hypothalamic-adrenal-pituitary axis (N = 173), immune and inflammatory markers (N = 118), and adult neurogenesis (N = 6). Cortisol was most frequently measured (N = 136), usually in saliva (N = 86). Studies included a variety of limitations for the methods and indicators, including concerns about timing and accuracy of collection, frequency of sampling, and controlling for acute stressors.

CONCLUSIONS

Nurse researchers have access to many minimally-invasive methods to measure altered biological processes related to chronic stress. A gap identified by this review is the paucity of minimally-invasive methods for investigating neurogenesis; the measurement of brain derived neurotrophic factor in plasma is a distal proxy and further research is needed to test the response of peripheral levels to psychosocial stress interventions. Additionally, while this scoping review allows nurse researchers to consider possible biological indicators to include in their research, future research is still needed on some of the basic premises of stress research, including agreement on the conceptualization of chronic stress.

Mood, lifestyle and cardiovascular risk factors among older caregivers of patients with Alzheimer's disease dementia: a case-control study

BACKGROUND

Caregivers may have a higher risk of cardiovascular diseases and have high rates of anxiety and depression.

AIMS

The objective of this study was to evaluate mood, lifestyle and the presence of cardiovascular risk factors in older women caregivers of patients with Alzheimer´s disease (AD) dementia compared to non-caregivers living in the neighborhood.

METHODS

Paired case-control (1:1). Volunteers responded to a questionnaire with information about physical and leisure activities, smoking, alcohol use, and daily hours of care. Blood pressure (BP) was measured on 5 days with the Home Blood Pressure Monitoring (HBPM) system, and mood was assessed with the Geriatric Depression Scale (GDS) and Mini International Neuropsychiatric Interview (MINI). Laboratory testing for cardiovascular risk factors was performed.

RESULTS

Sixty-two volunteers were evaluated. Total cholesterol levels were higher among caregivers, with an odds ratio (OR) of 3.57 (95% CI 1.2-11, p = 0.03). There was no difference in BP. A positive screening for depression was obtained for 58% of caregivers and for 16% of control subjects (OR = 6.62, 95% CI 1.9-22.6, p < 0.01). The MINI revealed that 38.7% of caregivers had an actual depressive episode as compared to 9.7% of controls (9.7%) (OR = 5.42, 95% CI 1.3-22.7, p = 0.02); 35.5% of caregivers and 6% of controls had a diagnosis of anxiety disorder (OR = 4.79, 95% CI 1.2-19.1, p = 0.03).

DISCUSSION

The cardiovascular risk markers and lifestyle were similar in caregivers and non-caregivers, but there was a higher prevalence of depression and anxiety among caregivers.

CONCLUSIONS

Older women caregivers of patients with AD have more mental health symptoms and disorders and need to be treated.

BDNF and Cortisol integrative system - Plasticity vs. degeneration: Implications of the Val66Met polymorphism

BDNF is the neurotrophin mediating pro-neuronal survival and plasticity. Cortisol (COR), in turn, is engaged in the coordination of several processes in the brain homeostasis. Stress-responsive, both factors show an integrative role through their receptor's dynamics in neurophysiology. Furthermore, the Val66Met BDNF polymorphism may play a role in this mechanism.

AIM

to investigate BDNF-COR interaction in the human neurophysiology context.

METHODS

We collected all papers containing BDNF and COR parameters or showing COR analyses in genotyped individuals in a PubMed search - full description available on PROSPERO - CRD42016050206.

DISCUSSION

BDNF and COR perform distinct roles in the physiology of the brain whose systems are integrated by glucocorticoid receptors dynamics. The BDNF polymorphism appears to have an influence on individual COR responsivity to stress. BDNF and COR play complementary roles in the nervous system where COR is a regulator of positive/negative effects. Exercise positively regulates both factors, regardless of BDNF polymorphism.

Psychological characteristics and physiological reactivity to acute stress in mothers of children with autism spectrum disorder

Stress related to parenting a child with autism spectrum disorder can differently affect caregiver's physiological reactivity to acute stress. Here, parental stress levels, psychological characteristics, and coping strategies were assessed alongside measures of heart rate, heart rate variability, and cortisol during a psychosocial stress test in mothers of children with ASD (M-ASD, n = 15) and mothers of typically developing children (n = 15). M-ASD reported significantly higher levels of parental stress, anxiety, negative affectivity, social inhibition, and a larger preference for avoidance strategies. M-ASD showed larger heart rate and cortisol responses to the psychosocial stress test. A positive relationship was found between parental stress levels and the magnitude of the cortisol stress response in both groups. The present findings indicate exaggerated physiological reactivity to acute psychosocial stress in M-ASD and prompt further research to explore the role of individual differences in mediating the effects of parental stress on physiological stress responses.

Mental health in familial caregivers of Alzheimer's disease patients: are the effects of chronic stress on cognition inevitable?

Familial caregivers of Alzheimer's disease (AD) patients experience an emotional and physical burden which characterizes a chronic stress condition. The resulting hypothalamic-pituitary-adrenal axis dysfunction favors an imbalance of neurotoxic/neuroprotective factors and causes cognitive impairments, increasing the caregivers' risk for cognitive decline and compromising their ability to provide adequate care of the patient. Therefore, the present study aimed to investigate the reversibility of the cognitive impairments of familial caregivers of AD patients during their caregiving-related chronic stress condition. Thirty-three caregivers (61.42 + 2.68 years; 27 women) and thirty-four controls (57.91 ± 2.16 years, 20 women) were evaluated for their cognitive functioning (attention, executive function, processing speed and memory) with a neuropsychological battery (Digit-span, Trail Making, Stroop and the Logical Memory tests). Subjects' cortisol/dehydroepiandrosterone (DHEA) ratios were determined by radioimmunoassay, and their brain-derived neurotrophic factor (BDNF) levels were analyzed by ELISA. An incidental contextual memory task, with or without an associative encoding instruction, was used to investigate if caregivers have a cognitive reserve prone to rehabilitation. The contextual memory impairment of caregivers was associated with prefrontal and hippocampal cognitive dysfunctions, alterations of the cortisol/DHEA ratio and lower BDNF levels. Even so, the contextual memory impairment could be improved by the associative encoding condition. This study suggests that the cognitive impairments of caregivers are not necessarily irreversible, as indicated by the results obtained for contextual memory, which could be improved despite the ongoing chronic stress and associated hormonal and neurotrophin dysfunctions. Lay summary The support of a relative with Alzheimer's Disease submits the familial caregivers to a chronic stress condition that increases their own risk of cognitive decline. This study suggests that, irrespective to their alterations on cortisol/DHEA ratio and BDNF levels, caregivers have a cognitive reserve that could probably be engaged to limit the negative effects of chronic stress on cognition.

Alzheimers' disease and caregiving: a meta-analytic review comparing the mental health of primary carers to controls

OBJECTIVES

To quantitatively review the literature comparing depressed mood, anxiety and psychological distress in caregivers (CGs) of older adults with Alzheimer's disease (AD) with non-caregivers (NCGs) Methods: Eighteen independent studies comparing AD CGs (N = 2378) with NCGs (N = 70,035) were evaluated in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Standardised mean differences (Hedges' g) with associated 95% confidence intervals and p-values were calculated using a random-effects model.

RESULTS

Studies generally conformed to STROBE criteria in terms of their methodological and procedural detail, although data management issues that may contribute to methodological bias were identified. Pooled effect estimates revealed medium to large group differences in depression (g_w = 1.01 [CI: 0.73, 1.29] p < 0.01) and anxiety (g_w = 0.64 [CI: 0.39, 0.89] p < 0.01): AD caregivers reported higher symptom severity. Gender was a significant moderator: female caregivers experienced poor self-reported mood (g_w = 1.58 [CI: 1.11, 2.05], p < 0.01), although this analysis was limited in power given the small number of contributing studies.

DISCUSSION

Caregivers of patients with AD experience poor mental health in comparison to the general population, with female caregivers being disproportionately affected. Further exploration of the psychosocial variables that contribute to these group differences is needed to inform effective support services and, in turn, help caregivers manage the emotional demands of AD.

Dehydroepiandrosterone: Molecular mechanisms and therapeutic implications in osteoarthritis

Dehydroepiandrosterone (DHEA), a 19-carbon steroid hormone primarily synthesized in the adrenal gland, exerts a chondroprotective effect against osteoarthritis (OA) and has been considered an effective candidate of disease-modifying OA drugs (DMOADs) that slow disease progression. We and others previously demonstrated that DHEA exerted a beneficial effect on osteoarthritic cartilage by positively modulating the balance between anabolic and catabolic factors (e.g., MMPs/TIMP-1, ADAMTS/TIMP-3 and cysteine proteinases/cystatin C), inhibiting catabolic signaling pathways (e.g., Wnt/β-catenin), and suppressing proinflammatory cytokines-mediated low-grade synovial inflammation (e.g., IL-1β). However, the full picture of the pharmacological molecular mechanism(s) underlying the activity of DHEA against OA is still incomplete, and a comprehensive and up-to-date review article in this field is unavailable. In this review, recent findings (apart from the well documented pathogenesis of OA) regarding disease-related mechanisms involving low grade synovial inflammation, cartilage matrix stiffness, chondrocyte autophagy and the roles of a variety of catabolic cellular signaling pathways are discussed. Moreover, the possible relationship between these disease-related mechanisms and DHEA action is discussed. Emerging evidence from in vivo and in vitro studies were scrutinized and are concisely presented to demonstrate the investigational and putative mechanisms underlying the anti-OA potential of DHEA.

Mild cognitive dysfunction of caregivers and its association with care recipients' end-of-life plans and preferences

Little is known about the association between cognitive dysfunction among informal caregivers and patients’ plans and preferences for patients’ end of life care. We report on the frequency of cognitive dysfunction among both patients and caregivers and examine associations between caregivers’ cognitive screening scores and end of life plans and preferences of patients with advanced cancer. The current sample was derived from a National Cancer Institute- and National Institute of Mental Health-funded study of patients with distant metastasis who had disease progression on at least first-line chemotherapy, and their informal caregivers (n = 550 pairs). The Pfeiffer Short Portable Mental Status, a validated cognitive screen, was administered to patients and caregivers. Patients were interviewed about their end of life plans and preferences. Logistic regression models regressed patients’ advance care planning and treatment preferences on caregivers’ cognitive screen scores. Patients’ cognitive screen scores were included as covariates. Most caregivers (55%) were spouses. Almost 30% of patients scored worse on the cognitive screen than their caregivers and 12% of caregivers scored worse than the patients. For each additional error that caregivers made on the cognitive screen, patients were more likely (AOR = 1.59, p = 0.002) to report that they preferred that everything possible be done to keep them alive and were less likely (AOR = 0.75, p = 0.04) to have a living will or a health care proxy/durable power of attorney. Worse caregiver cognitive screening scores were associated with higher likelihood of patients’ reporting that they wanted everything done to save their lives and a lower likelihood of having a living will or other type of advanced care plan. Future studies should confirm these findings in other populations and determine the mechanisms that may underlie the identified relationships.

The Role of Biomarkers in Research on Caregivers for Cancer Patients: A Scoping Review

BACKGROUND

Biomarkers can be used as prognostic, predictive, or monitoring indicators of an associated outcome. The purpose of this review was to provide a comprehensive summary of the research examining the use of biomarkers as surrogate end points for clinical outcomes in family caregivers for cancer patients, identify gaps, and make recommendations for future research.

METHODS

A scoping review, a process of mapping the existing literature, was conducted. Studies comparing biomarkers across caregivers and controls and/or examining relationships between biomarkers and psychological health were reviewed.

RESULTS

The studies ( N = 18) of caregivers for cancer patients who were identified used biomarkers to predict outcomes ( n = 13) and to monitor the efficacy of interventions ( n = 6). Biomarkers were divided into two categories based on physiological systems involved: (1) neuroendocrine function (sympathetic-adrenal-medullary axis activity, hypothalamic-pituitary-adrenal axis activity) and (2) immune function. Predictive biomarkers were sensitive to differences between caregivers and controls. The biomarkers were used to evaluate outcomes frequently associated with stress, depression, and anxiety. Cortisol was the biomarker most commonly measured to monitor the efficacy of interventions.

DISCUSSION

Biomarkers are most commonly incorporated into caregiver studies to predict group membership and psychological health. Neuroendocrine biomarkers, specifically cortisol, are most frequently assessed. Future research should include biomarkers of other physiologic functions (e.g., cardiovascular function, cognitive dysfunction, and cell aging) and those that serve as multisystem indicators. Expanding the scientific study of biomarkers will contribute to our understanding of the mechanisms through which stress may influence caregiver health.

Specific protein biomarker patterns for Alzheimer's disease: improved diagnostics in progress

This short review looks at Alzheimer's disease (AD) diagnosis through my own point of view, going from imaging through cerebrospinal fluid to blood proteins. Over the last couple of years, we have published two papers targeted at Alzheimer's diagnosis. In one paper, we took an approach of selecting a specific target, namely, activity-dependent neuroprotective protein (ADNP), and our results tightened the association of ADNP blood expression with intelligence. In another paper, we took an unbiased approach of analysis of all genes expressed in lymphoblastoid cells lines and discovered changes in expression of the regulator of G-protein signaling 2 (RGS2) as a potential AD predictor. This review will assess our data in comparison to selected independent studies focusing on blood protein biomarkers as well as assessing saliva and urine samples with potential predictive value for AD. Furthermore, the review will provide directions for a combination of innovative markers, stratifying the population toward disease prevention and personalized medicine.

Multimodal physical activity increases brain-derived neurotrophic factor levels and improves cognition in institutionalized older women

Physical activity has been proposed as a promising intervention to improve cognition and decrease the risk of dementia in older adults. Brain-derived neurotrophic factor (BDNF) appears to mediate, at least partially, these effects of exercise. However, intervention studies of the effects of multimodal exercises on cognition and BDNF levels are scarce and composed by small samples. Thus, the generalization of the conclusions of these studies depends on the reproducibility of the results. In order to contribute to the knowledge on the field, the present study evaluated the effects of a physical activity intervention composed by muscle strengthening and aerobic conditioning on BDNF levels and cognition in older women. Independent and non-demented subjects (≥75 years) were assigned to a 3-month physical activity intervention (n = 22, 60 min exercise sessions three times a week) or to a control condition (n = 10, no exercise). Clinical (anxiety and depression symptoms), neuropsychological (Digit Span, Stroop, Trail Making, and Contextual Memory tests), physical (upper and lower limb strength, aerobic conditioning), and physiological (serum BDNF) parameters were evaluated immediately before, 1 month, and 3 months after starting intervention. Results indicated that controls had stable levels for all measured variables, whereas the intervention group improved on physical fitness, depressive symptoms, cognitive performance, and BDNF levels. Moreover, a linear regression identified an association between aerobic conditioning and BDNF levels. In conclusion, combined muscle strengthening and aerobic conditioning was able to improve cognitive performance and increase BDNF levels. Aerobic conditioning seems to be an important mediator of these outcomes.

Objective and Subjective Cognitive Problems among Caregivers and Matched Non-caregivers

Purpose of the study

Caregivers (CGs) have been shown to do more poorly than non-caregivers (NCGs) on objective cognitive tests (Trails B and Digit Symbol Test, DST), but less is known about whether these groups differ in: (a) reports of subjective cognitive problems (SCPs, memory complaints, etc.) and (b) relationships of SCPs with objective cognitive tests, depression, and stress exposure. Such relationships are important because researchers/clinicians use SCPs as proxies for objective cognitive tests.

Design and methods

One hundred and twenty-two spouse CGs of persons with Alzheimer's disease and 117 demographically matched NCG spouses were compared on Trails B and DST at baseline (T1), 1 year later (T2), and 2 years later (T3) and on SCPs at T1.

Results

Trails B was slower in CGs than NCGs and DST declined in CGs relative to NCGs. CGs reported more SCPs than NCGs. Depression mediated group differences in Trails and DST and was also associated with SCPs. Trails B and DST explained variance in SCPs in NCGs, but not in CGs. Hours of care explained variance in SCPs in CGs, but not in NCGs.

Implications

When using SCPs to make inferences about CG cognitive function, researchers/clinicians should consider the possible influence of stress exposures and depression. The lack of associations of objective and subjective cognitive measures may be a reflection of poorer self-monitoring among CGs, a potential new area of CG research.

Reduced cardiovascular activation following chronic stress in caregivers of people with anorexia nervosa

Caring for offspring diagnosed with eating disorders (EDs) puts caregivers under high levels of chronic stress, which have negative consequences for their health. Unfortunately, caregivers have received little attention from mental health professionals. Chronic stress experienced by informal caregivers has been associated with the alteration of body homeostasis, and therefore, the functioning of various physiological systems. This could be the basis of health problems in informal caregivers of people with EDs. The main objective of this study was to analyze physiological response, in terms of heart rate (HR) and heart rate variability (HRV), to an acute laboratory stressor in a sample of informal caregivers of individuals with anorexia nervosa (n = 24) compared to a sample of noncaregivers (n = 26). In addition, the relationship between depressive mood and the aforementioned cardiovascular response parameters was analyzed in the group of caregivers. Caregivers had higher high-frequency (HF) power HRV, and lower HR, low-frequency (LF) power HRV and LF/HF ratio values than noncaregivers, which suggests lower cardiovascular reactivity to the acute stressor than noncaregivers. Moreover, a blunted HR response to stress was associated with high depressive mood scores in caregivers. Hence, it seems that the worse the mood the lower the cardiovascular reactivity to stressful events in this population. Developing and implementing psychotherapeutic interventions focused on stress management would help caregivers to reduce their stress levels and cope more effectively with stressors.

Psychological distress is associated with altered cognitive functioning in family caregivers of patients with disorders of consciousness

OBJECTIVES

To analyse the possible presence of reduced cognitive efficiency in family caregivers of patients with prolonged disorders of consciousness (DOC).

SUBJECTS

The participants were 27 caregivers of 25 patients with DOC admitted to the severe brain injury units of the ICS Maugeri, Institutes of Telese Terme and Sciacca, Italy.

METHODS

We examined cognitive functions such as short- and long-term memory, executive functions and attention by means of standardized tests. We also assessed features of psychological distress such as anxiety, depression, psychophysiological symptoms, prolonged grief disorder, psychological burden and quality of life. All scores on neuropsychological tests were compared with those of the 15 matched control subjects.

RESULTS

Enrolled family caregivers showed high frequency of clinically relevant depressive symptoms and anxiety; half of them met the criteria for prolonged grief disorder. Caregivers achieved scores lower than the matched controls on tests for selective attention, verbal fluency and long-term spatial memory.

CONCLUSIONS

Family caregivers' burden is associated with a reduced efficiency of selected executive measures and visuospatial learning. These results emphasize the need for appropriate psychological and cognitive supporting therapies for family caregivers of patients with DOC, also considering their delicate involvement in clinical decision-making and in providing care.

Cognitive reserve and self-efficacy as moderators of the relationship between stress exposure and executive functioning among spousal dementia caregivers

BACKGROUND

A substantial literature has reported that stress negatively impacts on cognitive processes. As dementia caregiving can be stressful, it has been hypothesized that the challenges of dementia care may increase caregivers' own vulnerability to cognitive decline. Prefrontal processes are thought to be most vulnerable to stress; however, few studies have examined whether greater caregiver stress predicts poorer executive dysfunction, and no previous research has considered potential moderators of this relationship. We examined (1) whether greater psychological stress mediated a relationship between caregiver stress exposure and executive functioning and (2) whether greater self-efficacy and cognitive reserve (CR) moderated this relationship.

METHOD

Spousal dementia caregivers (n = 253) completed the Neuropsychiatric Inventory Questionnaire (stress exposure), the Perceived Stress Scale, the National Adult Reading Test (CR), the Fortinsky dementia-specific caregiver self-efficacy scale, and the Color Trails Test (executive functioning). Moderated mediation was tested using the PROCESS macro. Age, gender, and dementia risk factors were included as covariates.

RESULTS

Greater stress exposure indirectly predicted executive functioning through psychological stress. Stronger relationships between greater psychological stress and poorer executive functioning were observed among caregivers with lower CR; there was no evidence that self-efficacy moderated the relationship between stress exposure and psychological stress.

CONCLUSIONS

Our findings are in line with the idea that greater psychological stress in response to challenges associated with dementia care predicts poorer caregiver executive functioning, particularly among caregivers with low CR. However, these findings are cross sectional; it is also possible that poorer executive functioning contributes to greater caregiver stress.

Decreased peripheral brain-derived neurotrophic factor levels in Alzheimer's disease: a meta-analysis study (N=7277)

Studies suggest that dysfunction of brain-derived neurotrophic factor (BDNF) is a possible contributor to the pathology and symptoms of Alzheimer's disease (AD). Several studies report reduced peripheral blood levels of BDNF in AD, but findings are inconsistent. This study sought to quantitatively summarize the clinical BDNF data in patients with AD and mild cognitive impairment (MCI, a prodromal stage of AD) with a meta-analytical technique. A systematic search of Pubmed, PsycINFO and the Cochrane Library identified 29 articles for inclusion in the meta-analysis. Random-effects meta-analysis showed that patients with AD had significantly decreased baseline peripheral blood levels of BDNF compared with healthy control (HC) subjects (24 studies, Hedges' g=-0.339, 95% confidence interval (CI)=-0.572 to -0.106, P=0.004). MCI subjects showed a trend for decreased BDNF levels compared with HC subjects (14 studies, Hedges' g=-0.201, 95% CI=-0.413 to 0.010, P=0.062). No differences were found between AD and MCI subjects in BDNF levels (11 studies, Hedges' g=0.058, 95% CI=-0.120 to 0.236, P=0.522). Interestingly, the effective sizes and statistical significance improved after excluding studies with reported medication in patients (between AD and HC: 18 studies, Hedges' g=-0.492, P<0.001; between MCI and HC: 11 studies, Hedges' g=-0.339, P=0.003). These results strengthen the clinical evidence that AD or MCI is accompanied by reduced peripheral blood BDNF levels, supporting an association between the decreasing levels of BDNF and the progression of AD.

The exercise-glucocorticoid paradox: How exercise is beneficial to cognition, mood, and the brain while increasing glucocorticoid levels

Exercise is known to have beneficial effects on cognition, mood, and the brain. However, exercise also activates the hypothalamic-pituitary-adrenal axis and increases levels of the glucocorticoid cortisol (CORT). CORT, also known as the "stress hormone," is considered a mediator between chronic stress and depression and to link various cognitive deficits. Here, we review the evidence that shows that while both chronic stress and exercise elevate basal CORT levels leading to increased secretion of CORT, the former is detrimental to cognition/memory, mood/stress coping, and brain plasticity, while the latter is beneficial. We propose three preliminary answers to the exercise-CORT paradox. Importantly, the elevated CORT, through glucocorticoid receptors, functions to elevate dopamine in the medial prefrontal cortex under chronic exercise but not chronic stress, and the medial prefrontal dopamine is essential for active coping. Future inquiries may provide further insights to promote our understanding of this paradox.

A systematic review of the psychobiological burden of informal caregiving for patients with dementia: Focus on cognitive and biological markers of chronic stress

As the physiological impact of chronic stress is difficult to study in humans, naturalistic stressors are invaluable sources of information in this area. This review systematically evaluates the research literature examining biomarkers of chronic stress, including neurocognition, in informal dementia caregivers. We identified 151 papers for inclusion in the final review, including papers examining differences between caregivers and controls as well as interventions aimed at counteracting the biological burden of chronic caregiving stress. Results indicate that cortisol was increased in caregivers in a majority of studies examining this biomarker. There was mixed evidence for differences in epinephrine, norepinephrine and other cardiovascular markers. There was a high level of heterogeneity in immune system measures. Caregivers performed more poorly on attention and executive functioning tests. There was mixed evidence for memory performance. Interventions to reduce stress improved cognition but had mixed effects on cortisol. Risk of bias was generally low to moderate. Given the rising need for family caregivers worldwide, the implications of these findings can no longer be neglected.

Global analysis of ginsenoside Rg1 protective effects in β-amyloid-treated neuronal cells

BACKGROUND

A number of reports have described the protective effects of ginsenoside Rg1 (Rg1) in Alzheimer's disease (AD). However, the protective mechanisms of Rg1 in AD remain elusive.

METHODS

To investigate the potential mechanisms of Rg1 in β-amyloid peptide-treated SH-SY5Y cells, a comparative proteomic analysis was performed using stable isotope labeling with amino acids in cell culture combined with nano-LC-MS/MS.

RESULTS

We identified a total of 1,149 proteins in three independent experiments. Forty-nine proteins were significantly altered by Rg1 after exposure of the cells to β-amyloid peptides. The protein interaction network analysis showed that these altered proteins were clustered in ribosomal proteins, mitochondria, the actin cytoskeleton, and splicing proteins. Among these proteins, mitochondrial proteins containing HSD17B10, AARS2, TOMM40, VDAC1, COX5A, and NDUFA4 were associated with mitochondrial dysfunction in the pathogenesis of AD.

CONCLUSION

Our results suggest that mitochondrial proteins may be related to the protective mechanisms of Rg1 in AD.

Age Effects on Cognitive and Physiological Parameters in Familial Caregivers of Alzheimer's Disease Patients

Objectives

Older familial caregivers of Alzheimer’s disease patients are subjected to stress-related cognitive and psychophysiological dysfunctions that may affect their quality of life and ability to provide care. Younger caregivers have never been properly evaluated. We hypothesized that they would show qualitatively similar cognitive and psychophysiological alterations to those of older caregivers.

Method

The cognitive measures of 17 young (31–58 years) and 18 old (63–84 years) caregivers and of 17 young (37–57 years) and 18 old (62–84 years) non-caregiver controls were evaluated together with their salivary cortisol and dehydroepiandrosterone (DHEA) levels, as measured by radioimmunoassays and ELISA assays of brain-derived neurotrophic factor (BDNF) in serum.

Results

Although younger caregivers had milder impairments in memory and executive functions than older caregivers, their performances fell to the same or lower levels as those of the healthy older controls. Decreases in DHEA and BDNF levels were correlated with the cognitive dysfunctions observed in the older and younger caregivers, respectively. Cortisol at 10PM increased in both caregiver groups.

Discussion

Younger caregivers were prone to cognitive impairments similar to older caregivers, although the degree and the neuropsychological correlates of the cognitive dysfunctions were somewhat different between the two groups. This work has implications for caregiver and care-recipient health and for research on the neurobiology of stress-related cognitive dysfunctions.

Cognitive Health Assessment and Establishment of a Virtual Cohort of Dementia Caregivers

Background

Many factors impact caregivers’ cognitive health and, by extension, their ability to provide care. This study examined the relationship between psychosocial factors and cognitive performance among dementia caregivers and established a virtual cohort of caregivers for future research.

Methods

Data on 527 caregivers were collected via a Web-based survey that assessed cognitive performance. Caregiver data were compared to corresponding data from 527 age-, race-, gender-, and education-matched controls from a normative database. Caregiver self-reported sleep, stress, health, and social support were also assessed.

Results

Caregivers performed significantly worse than controls on 3 of 5 cognitive subtests. Stress, sleep, perceived support, self-rated health, years of caregiving, race, and gender were significant predictors of cognitive performance.

Conclusion

In this sample of dementia caregivers, psychosocial factors interacted in complex ways to impact cognitive performance. Further investigation is needed to better understand how these factors affect cognitive performance among caregivers. This could be accomplished by the establishment of a virtual cohort that facilitates the development of digital tools to support the evaluation and management of caregiver needs in a manner that helps them remain effective in their caregiving roles.

Higher chronic stress is associated with a decrease in temporal sensitivity but not in subjective duration in healthy young men

Maintaining accurate and precise temporal perception under conditions of stress is important. Studies in animal models and clinic patients have suggested that time perception can change under chronic stress. Little is known, however, about the relationship between chronic stress and time perception in healthy individuals. Here, a sample of 62 healthy young men completed Cohen’s Perceived Stress Scale (PSS) as a measure of chronic stress levels, while time perception was measured using a temporal bisection task. This task used short (400 ms) and long (1600 ms) visual signals as anchor durations. Participants were presented with a range of intermediate probe durations and were required to judge whether the durations were more similar to the short or the long anchor. Results showed that chronic stress was negatively related to temporal sensitivity indexed by the Weber ratio. However, there was no significant correlation between chronic stress and subjective duration indexed by the bisection point. These results demonstrate that higher chronic stress is associated with lower temporal sensitivity and thus provide evidence for a link between chronic stress and time perception in healthy adults.