Stress and verbal memory in patients with Alzheimer's disease: different role of cortisol and anxiety

The relationship between perceived stigma and perceived stress in cognitive decline: a survey of persons with mild cognitive impairment and their caregivers

Introduction

While Alzheimer's disease and other causes of dementia have rapidly become a global health crisis with growing incidence that is unabated, the incidence of Mild Cognitive Impairment (MCI) far exceeds that of Alzheimer's disease. Persons with MCI demonstrate some level of cognitive impairment, but daily functions remain intact and there is no certainty that they will develop dementia. Yet, the possibility conjures a considerable amount of fear and anxiety, further fueled by a vast array of misconceptions and stigma. The pervasive nature of this stigma permeates society and culture at many levels. Persons with MCI who are at higher risk for development of dementia may be especially vulnerable to fear and stigma associated with the diagnosis. Based on this premise, the primary aim of this study was to examine the relationship between perceived stigma and perceived stress in persons with MCI and their care partners, including the relationship between income and the study variables. The secondary aim was to examine the effect of a combined cognitive rehabilitation and wellness program on these perceptions.

Methods

Thirty participants were recruited from Mayo Clinic's Health Action to Benefit Independence and Thinking (HABIT) program. MCI (n = 15) and care partner (n = 15) participants completed the Stigma Impact Scale (SIS) and the Perceived Stress Scale (PSS) before and after the HABIT program.

Results

Average SIS and PSS scores decreased in the MCI, care partner, and combined groups, both pre- and post-HABIT. Linear regression was used to assess the relationship between perceived stigma and stress, controlling for income. A significant relationship was found between perceived stigma and perceived stress both pre and post-HABIT.

Discussion

The results suggest a relationship exists between perceived stigma and perceived stress in persons with MCI and their care partners, and an educational program such as HABIT may strengthen this relationship by informing participants of potential challenges that occur in cognitive decline. Understanding these relationships may provide an opportunity to provide tools for this vulnerable population.

Reliability and validity of the electronic version of the Hopkins verbal learning test-revised in middle-aged and elderly Chinese people

Background

The aging population is increasing, making it essential to have a standardized, convenient, and valid electronic memory test that can be accessed online for older people and caregivers. The electronic version of the Hopkins Verbal Learning Test-Revised (HVLT-R) as a test with these advantages and its reliability and validity has not yet been tested. Thus, this study examined the reliability and validity of the electronic version of the HVLT-R in middle-aged and elderly Chinese people to provide a scientific basis for its future dissemination and use.

Methods

We included 1,925 healthy participants aged over 40, among whom 38 were retested after 3-6 months. In addition, 65 participants completed both the pad and paper-and-pencil versions of the HVLT-R (PAP-HVLT-R). We also recruited 42 Alzheimer's disease (AD) patients, and 45 amnestic mild cognitive impairment (aMCI) patients. All participants completed the Pad-HVLT-R, the Hong Kong Brief Cognitive Test (HKBC), the Brief Visual Memory Test-Revised (BVMT-R), and the Logical Memory Test (LM).

Results

(1) Reliability: the Cronbach's α value was 0.94, the split-half reliability was 0.96. The test-retest correlation coefficients were moderate, ranging from 0.38 to 0.65 for direct variables and 0.16 to 0.52 for derived variables; (2) Concurrent validity: the Pad-HVLT-R showed a moderate correlation with the HKBC and BVMT-R, with correlation coefficients between total recall of 0.41 and 0.54, and between long-delayed recall of 0.42 and 0.59, respectively. It also showed a high correlation with the LM, with correlation coefficients of 0.72 for total recall and 0.62 for long-delayed recall; (3) Convergent validity: the Pad-HVLT-R was moderately correlated with the PAP version, with correlation coefficients ranging from 0.29 to 0.53 for direct variables and 0.15 to 0.43 for derived variables; (4) Discriminant capacity: the Pad-HVLT-R was effective in differentiating AD patients, as demonstrated by the ROC analysis with AUC values of 0.834 and 0.934 for total recall and long-delayed recall, respectively.

Conclusion

(1) The electronic version of HVLT-R has good reliability and validity in middle-aged and elderly Chinese people; (2) The electronic version of HVLT-R can be used as an effective tool to distinguish AD patients from healthy people.

Mild acute stress prevents the memory impairment induced by long-term isoflurane anesthesia

Objectives

Long-term isoflurane anesthesia exposure could result in postoperative cognitive dysfunction (POCD). Preoperative stress is also reported to be a risk factor of POCD. However, it is unknown whether acute stress could impair memory after long-term isoflurane anesthesia.

Methods

In this study, we categorized the mice with acute stress into mild (30 min restraint stress), moderate (60 min restraint stress), and severe (120 min restraint stress) stress groups and then we used Open-Field Test (OFT) to detect whether different scales of acute restraint stress successfully induced acute stress in mice. The memory performance of mice was measured using contextual and cued memory test, and the brain-derived neurotrophic factor protein levels of hippocampus was detected by Western blot.

Results

We verified that mild stress has pro-cognitive effect, but severe stress has amnestic effect. Moreover, we found that mild and moderate other than severe acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

Conclusion

Mild and moderate acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

Lifetime stress exposure, cognition, and psychiatric wellbeing in women

Objectives:Although life stress has been associated with worse cognitive and psychiatric functioning, few studies on this topic have examined these associations in older adults and no studies to date have assessed lifetime stress exposure in this context.Method:To address this important issue, we investigated associations between lifetime stress exposure, cognition, and psychiatric wellbeing in 44 women aged 60 and older who completed a comprehensive lifetime stress exposure inventory, two memory tasks, and a complete psychiatric assessment.Results:As hypothesized, greater acute and chronic lifetime stress exposure were both related to poorer psychiatric functioning and more somatic health complaints. Greater lifetime stress exposure was also associated with poorer subjective cognition as indicated by memory and thought problems but not objective indices of memory function.Conclusion:Screening for high life stress exposure may therefore help identify older women at increased risk of experiencing negative psychiatric and cognitive outcomes.

Multitarget 2'-hydroxychalcones as potential drugs for the treatment of neurodegenerative disorders and their comorbidities

The complex nature of neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD) and Parkinson's disease (PD) calls for multidirectional treatment. Restoring neurotransmitter levels by combined inhibition of cholinesterases (ChEs) and monoamine oxidases (MAOs, MAO-A and MAO-B), in conjunction with strategies to counteract amyloid β (Aβ) aggregation, may constitute a therapeutically strong multi-target approach for the treatment of NDDs. Chalcones are a subgroup of flavonoids with a broad spectrum of biological activity. We report here the synthesis of 2'-hydroxychalcones as MAO-A and MAO-B inhibitors. Compounds 5c (IC50 = 0.031 ± 0.001 μM), 5a (IC50 = 0.084 ± 0.003 μM), 2c (IC50 = 0.095 ± 0.019 μM) and 2a (IC50 = 0.111 ± 0.006 μM) were the most potent, selective and reversible inhibitors of human (h)MAO-B isoform. hMAO-B inhibitors 1a, 2a and 5a also inhibited murine MAO-B in vivo in mouse brain homogenates. Molecular modelling rationalised the binding mode of 2'-hydroxychalcones in the active site of hMAO-B. Additionally, several derivatives inhibited murine acetylcholinesterase (mAChE) (IC50 values from 4.37 ± 0.83 μM to 15.17 ± 6.03 μM) and reduced the aggregation propensity of Aβ. Moreover, some derivatives bound to the benzodiazepine binding site (BDZ-bs) of the γ-aminobutyric acid A (GABAA) receptors (1a and 2a with Ki = 4.9 ± 1.1 μM and 5.0 ± 1.1 μM, respectively), and exerted sedative and/or anxiolytic like effects on mice. The biological results reported here on 2'-hydroxychalcones provide an extension to previous studies on chalcone scaffold and show them as a potential treatment strategy for NDDs and their associated comorbidities.

Intact circadian rhythm despite cortisol hypersecretion in Alzheimer's disease: A meta-analysis

Hypersecretion of the glucocorticoid steroid hormone cortisol by individuals with Alzheimer's disease (AD) has been suspected for several decades, during which time dozens of examinations of this phenomenon have been conducted and published. The goals of this investigation were to summarize this sizeable body of literature, test whether participant and methodological characteristics modify the magnitude of the AD-associated basal cortisol hypersecretion, and examine whether cortisol circadian rhythmicity is maintained among individuals with AD. To this end, the present meta-analysis and systematic review examined over 300 comparisons of indices of basal HPA-axis functioning between individuals with AD and cognitively normal older adults. AD was associated with basal cortisol elevations (g = 0.45) but the magnitude of the effect was not systematically impacted by any of the participant characteristics considered or the time-of-day of the cortisol sampling. Further, there was no evidence of group differences among direct indices of circadian rhythmicity such as the cortisol awakening response or the diurnal cortisol slope. These results suggest that basal hypersecretion of cortisol, but not circadian dysrhythmia, is characteristic of individuals with AD. Mechanistically, the observed hypersecretion is consistent with the theorized AD-driven deterioration of the hippocampus and subsequent reduction in hypothalamic-pituitary-adrenal axis inhibition. Further investigation is warranted to elucidate the role and timing of cortisol elevations in the progression of AD.

Acculturation in Context: The Relationship Between Acculturation and Socioenvironmental Factors With Level of and Change in Cognition in Older Latinos

OBJECTIVES

Latinos are 1.5 times as likely to develop Alzheimer's dementia as non-Latino Whites. This health disparity may arise from multiple influences with culturally relevant factors receiving increasing attention. Models of acculturation stress the importance of considering acculturation-related factors within the context of socioenvironmental factors to better capture the Latino experience in the United States.

METHODS

We measured 10 acculturation and contextually-related variables in 199 Latinos (age 69.7 years) without dementia participating in Rush Alzheimer's Disease Center studies. We tested the relationship between these variables via Principal Component Analysis (PCA), then investigated how resulting components associated with level of and longitudinal change in global and domain-specific cognition using separate linear mixed-effects models adjusted for relevant confounders and their interactions with time.

RESULTS

The PCA revealed a 3-factor unrotated solution (variance explained ~70%). Factor 1, representing acculturation-related aspects of nativity, language- and social-based acculturation, was positively associated with level, but not change, in global cognition, semantic memory, and perceptual speed. Factor 2, representing contextually-related socioenvironmental experiences of discrimination, social isolation, and social networks, was negatively associated with level of global cognition, episodic and working memory, and faster longitudinal decline in visuospatial ability. Factor 3 (familism only) did not associate with level or change in any cognitive outcome.

DISCUSSION

Acculturation- and contextually-related factors differentiated from each other and differentially contributed to cognition and cognitive decline in older Latinos. Providers should query acculturation and lived experiences when evaluating cognition in older Latinos.

Frailty and cognitive decline

Frailty and cognitive impairment are among the 2 most common geriatric syndromes. Their presence poses major risks to the elderly including greater disability, reduced quality of life, and higher morbi-mortality. Recent evidence suggest that frailty can be a risk factor for incident dementia. The opposite is also true since subjects with Alzheimer's disease and other dementia also present with more severe frailty measures. The mechanisms for the association between frailty and cognitive impairment is not clear, but possibly involves abnormalities in biological processes related to aging. Here, we will review the current evidence of the association between frailty and cognitive impairment. We will also review the possible biological mechanistic links between the 2 conditions. Finally, we will address potential therapeutic targets and interventions that can mitigate both conditions.