Obesity reduces hippocampal structure and function in older African Americans with the APOE-ε4 Alzheimer’s disease risk allele

IntroductionExcess body weight and Alzheimer’s disease (AD) disproportionately affect older African Americans. While mid-life obesity increases risk for AD, few data exist on the relationship between late-life obesity and AD, or how obesity-based and genetic risk for AD interact. Although the APOE-ε4 allele confers a strong genetic risk for AD, it is unclear if late-life obesity poses a greater risk for APOE-ε4 carriers compared to non-carriers. Here we assessed: (1) the influence of body mass index (BMI) (normal; overweight; class 1 obese; ≥ class 2 obese) on cognitive and structural MRI measures of AD risk; and (2) the interaction between BMI and APOE-ε4 in older African Americans.MethodsSeventy cognitively normal older African American participants (Mage = 69.50 years; MBMI = 31.01 kg/m2; 39% APOE-ε4 allele carriers; 86% female) completed anthropometric measurements, physical assessments, saliva collection for APOE-ε4 genotyping, cognitive testing, health and lifestyle questionnaires, and structural neuroimaging [volume/surface area (SA) for medial temporal lobe subregions and hippocampal subfields]. Covariates included age, sex, education, literacy, depressive symptomology, and estimated aerobic fitness.ResultsUsing ANCOVAs, we observed that individuals who were overweight demonstrated better hippocampal cognitive function (generalization of learning: a sensitive marker of preclinical AD) than individuals with normal BMI, p = 0.016, ηp2 = 0.18. However, individuals in the obese categories who were APOE-ε4 non-carriers had larger hippocampal subfield cornu Ammonis region 1 (CA1) volumes, while those who were APOE-ε4 carriers had smaller CA1 volumes, p = 0.003, ηp2 = 0.23.DiscussionThus, being overweight by BMI standards may preserve hippocampal function, but obesity reduces hippocampal structure and function in older African Americans with the APOE-ε4 Alzheimer’s disease risk allele

Examining the efficacy of a cardio-dance intervention on brain health and the moderating role of ABCA7 in older African Americans: a protocol for a randomized controlled trial

IntroductionAfrican Americans are two to three times more likely to be diagnosed with Alzheimer’s disease (AD) compared to White Americans. Exercise is a lifestyle behavior associated with neuroprotection and decreased AD risk, although most African Americans, especially older adults, perform less than the recommended 150 min/week of moderate-to-vigorous intensity exercise. This article describes the protocol for a Phase III randomized controlled trial that will examine the effects of cardio-dance aerobic exercise on novel AD cognitive and neural markers of hippocampal-dependent function (Aims #1 and #2) and whether exercise-induced neuroprotective benefits may be modulated by an AD genetic risk factor, ABCA7 rs3764650 (Aim #3). We will also explore the effects of exercise on blood-based biomarkers for AD.Methods and analysisThis 6-month trial will include 280 African Americans (≥ 60 years), who will be randomly assigned to 3 days/week of either: (1) a moderate-to-vigorous cardio-dance fitness condition or (2) a low-intensity strength, flexibility, and balance condition for 60 min/session. Participants will complete health and behavioral surveys, neuropsychological testing, saliva and venipuncture, aerobic fitness, anthropometrics and resting-state structural and functional neuroimaging at study entry and 6 months.DiscussionResults from this investigation will inform future exercise trials and the development of prescribed interventions that aim to reduce the risk of AD in African Americans

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

Interventions to Improve Older Driver Safety

Increased longevity coupled with age-related declines that compromise driving safety and fragility render older adults as vulnerable road users (Oxley & Whelan, 2008). To address this public health concern, researchers continue to investigate interventions to improve older driver safety. The current dissertation consists of two papers examining: a) the state of the literature on older driver interventions and b) the efficacy of one approach, Useful Field of View cognitive training, to reduce at-fault crash involvement. The first paper sought to identify and quantify the effects of different interventions among older adults on outcomes of crashes, on-road driving performance, self-reported outcomes (errors and crashes), and driving simulator performance in a systematic review and meta-analysis (k = 31). Skill-specific interventions (i.e., physical retraining/exercise, visual-perceptual training) and combined approaches demonstrated medium to large effects on driving performance among those trained across studies, ds = 0.564–1.061, ps \u3c .050. Cognitive training approaches reduced at-fault crashes by almost 30%, OR = 0.729, 95% CI [0.553, 0.962], p = .026. Education and context-specific approaches were not efficacious to improve driving safety outcomes. The second paper examined the longitudinal impact of adaptive Useful Field of View cognitive training on at-fault crash involvement. Results showed that cognitive training did not significantly reduce at-fault crashes per person-year of travel across 10 years as compared to the control group, RR = 0.672, 95% CI [0.326, 1.385], p = .281. However, this paper was limited by inadequate power due to a relatively low base rate of at-fault crashes. Future directions include identifying components within skill-specific and combined training approaches that contribute to improved driving safety and evaluating the durability of adaptive Useful Field of View cognitive training to reduce at-fault crashes among high-risk drivers in an adequately powered study

A systematic review and meta-analysis of older driver interventions

The purpose of this systematic review and meta-analysis was to summarize and quantify the effects of different driving interventions among older adults on outcomes of crashes, on-road driving performance, self-reported outcomes of errors and crashes, and driving simulator performance. Randomized controlled trials examining the effects of a driving intervention among older adults ≥ 50 years of age were included. Thirty-one studies were identified using a systematic literature review, and 26 were included in meta-analyses. The following types of driving interventions were identified: physical retraining/exercise (e.g., flexibility and coordination training); visual-perceptual training (e.g., improving figure-ground discrimination); cognitive training (e.g., Useful Field of View cognitive training); education (e.g., classroom driver refresher course); context-specific training (i.e., on-road training in car, driving simulator training); combined intervention approaches (e.g., education and context-specific training combined). Effect sizes were calculated for each driving intervention type relative to control groups using random-effects. Physical retraining/exercise, visual-perceptual training, and combined intervention approaches demonstrated medium to large effects on on-road driving performance, ds = 0.564–1.061, ps .050. In summary, skill-specific interventions (physical retraining/exercise, visual-perceptual training, cognitive training) and combined intervention approaches improved on-road driving performance and reduced at-fault crashes. Optimizing interventions that target age-related functional declines and combined intervention approaches is recommended

Cognitive Training Enhances Auditory Attention Efficiency in Older Adults

TesisEl presente trabajo de investigación titulado: Sistema de detracciones y la reinversión en las MYPES de arrendamiento de bienes: Ayacucho, 2015, tiene como objetivo determinar como afecta el sistema de detracciones a la reinversión en las Mypes de arrendamiento de bienes en la ciudad de Ayacucho. Su importancia radica en el análisis de la conveniencia de mantener dinero en la cuenta de detracciones, las desventajas y las pérdidas que genera a las Mypes. El tipo de investigación es aplicada, el nivel y diseño de investigación es descriptiva - no experimental. La muestra de esta investigación está conformada por 30 empresas que operan en la ciudad de Ayacucho cuyas actividades económicas se centran en el arrendamiento de bienes (servicios). Los datos estadísticos provienen de los resultados obtenidos después de la aplicación de instrumentos de recolección, se utilizó fichas de registros para obtener información de los estados financieros y las declaraciones mensuales de impuestos, se realiza un análisis a los ratios financieros y al costo de oportunidad del dinero detraído; además de la realización de una entrevista estructurada a la muestra establecida; la conclusión principal es: existe una tendencia creciente de los montos detraídos que mantienen las empresas y esto afecta significativamente los niveles de reinversión de las empresas de arrendamiento de bienes en la ciudad de Ayacucho

Cognitive training enhances auditory attention efficiency in older adults.

Auditory cognitive training (ACT) improves attention in older adults; however, the underlying neurophysiological mechanisms are still unknown. The present study examined the effects of ACT on the P3b event-related potential reflecting attention allocation (amplitude) and speed of processing (latency) during stimulus categorization and the P1-N1-P2 complex reflecting perceptual processing (amplitude and latency). Participants completed an auditory oddball task before and after 10 weeks of ACT (n = 9) or a no contact control period (n = 15). Parietal P3b amplitudes to oddball stimuli decreased at post-test in the trained group as compared to those in the control group, and frontal P3b amplitudes show a similar trend, potentially reflecting more efficient attentional allocation after ACT. No advantages for the ACT group were evident for auditory perceptual processing or speed of processing in this small sample. Our results provide preliminary evidence that ACT may enhance the efficiency of attention allocation, which may account for the positive impact of ACT on the everyday functioning of older adults

Cognitive training enhances auditory attention efficiency in older adults.

Auditory cognitive training (ACT) improves attention in older adults; however, the underlying neurophysiological mechanisms are still unknown. The present study examined the effects of ACT on the P3b event-related potential reflecting attention allocation (amplitude) and speed of processing (latency) during stimulus categorization and the P1-N1-P2 complex reflecting perceptual processing (amplitude and latency). Participants completed an auditory oddball task before and after 10 weeks of ACT (n = 9) or a no contact control period (n = 15). Parietal P3b amplitudes to oddball stimuli decreased at post-test in the trained group as compared to those in the control group, and frontal P3b amplitudes show a similar trend, potentially reflecting more efficient attentional allocation after ACT. No advantages for the ACT group were evident for auditory perceptual processing or speed of processing in this small sample. Our results provide preliminary evidence that ACT may enhance the efficiency of attention allocation, which may account for the positive impact of ACT on the everyday functioning of older adults

Comparison of Subjective and Objective Measures of Hearing, Auditory Processing, and Cognition Among Older Adults With and Without Mild Cognitive Impairment

Purpose: The aims of the study were to compare the Cognitive Self-Report Questionnaire (CSRQ; Spina, Ruff, & Mahncke, 2006) Hearing and Cognitive subscale ratings among older adults with and without probable mild cognitive impairment (MCI) and to examine whether self-report, as measured by the CSRQ, is associated with objective measures of hearing, auditory processing, and cognition. Method: Data analyses included 97 older adults of ages 61–91 years. Participants completed the CSRQ self-report measure as well as a battery of objective measures, including pure-tone audiometry, degraded speech understanding, temporal processing, and memory. Results: Older adults with probable MCI rated their cognitive abilities more poorly than those without MCI (p = .002), but ratings of hearing and auditory abilities did not differ between the two groups (p = .912). Age and CSRQ Hearing subscale ratings explained a significant proportion of variance in objective measures of hearing and degraded speech understanding (R2 = .39, p \u3c .001). Age, sex, mental status, and CSRQ Cognition subscale ratings explained a significant proportion of variance in objective memory performance (R2 = .55, p \u3c .001). Conclusions: Taken together, these results suggest that the CSRQ is an appropriate self-report measure of hearing, cognition, and some aspects of auditory processing for older adults with and without probable MCI