Group Of Healthy Older Adults Research Articles

Design of the VOILA-intervention study: A 12-week nutrition and resistance exercise intervention in metabolic or mobility compromised Dutch older adults and the response on immune-metabolic, gut and muscle health parameters

BackgroundExercise and nutrition interventions can slow ageing-induced decline in physiology. However, effects are heterogeneous and usually studied separately per outcome domain. In the VOILA study, we simultaneously study various health outcomes relevant for older adults and the inter-individual heterogeneity in response to a lifestyle intervention. MethodsVOILA is a 12-week lifestyle intervention in 3 groups of older adults (≥60 years), with compromised mobility (n=50), compromised metabolic health (n=50), or recovering from total knee replacement (TKR, n=70, of which 20 randomized to standard care only). The intervention includes high-intensity resistance exercise training thrice weekly, nutritional counselling, and nutritional supplements every morning and evening (including 20-25g whey protein and (evening only) 5.5g Biotis™ GOS). We measure immune-metabolic, gut health, muscle mass and physical functioning at baseline and after completion of the intervention/standard care. An additional reference group of healthy older adults (n=50) will undergo baseline measurements only. DiscussionImprovements in various physiological systems are expected, but with differences between groups/individuals. This study will provide insights into how the physiological state of older adults influences the extent of lifestyle-induced health improvements to create better tailored interventions to attenuate biological ageing and improve the health span of subgroups and individuals.

Memory benefits of daily-living-related contextual cueing for individuals with subjective cognitive decline and mild cognitive impairment.

We aimed to assess how daily-living-related contextual cueing (DLCC) affects memory performance in three groups: healthy older adults (HA), those with subjective cognitive decline (SCD), and mild cognitive impairment (MCI), while accounting for age and education. After gathering demographic information, participants underwent neuropsychological assessments including the Montreal Cognitive Assessment (MoCA), Everyday Cognition Scale (ECog-12), Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS), and Trail Making Test (TMT) to establish baseline characteristics. Participants were categorized into HA (N = 47), SCD (N = 54), and MCI (N = 43) groups based on MoCA and ECog-12 scores. Memory performance was evaluated through two components of the Contextual Memory Test (CMT): one with non-contextual cues and the other with daily-living-related contextual cues. Interaction effects between contextual cueing and group for immediate recall (p < .001), delayed recall (p < .001), and total recall (p < .001) were found. All recall scores were lower in the MCI group than in the other two groups in the contextual cueing, not non-contextual. The post-hoc results revealed that scores on immediate recall, delayed recall, and total recall were lower in the MCI group than in the other two groups in the contextual cueing condition but not in the non-contextual cueing one. Daily-living-related contextual cueing benefited HA, SCD, and younger-adult MCI groups more than older-adult MCI group, particularly enhancing delayed and total memory performance.

Using Dual-Coil TMS-EEG to Probe Bilateral Brain Mechanisms in Healthy Aging and Mild Cognitive Impairment.

A widespread observation in the cognitive neuroscience of aging is that older adults show a more bilateral pattern of task-related brain activation. These observations are based on inherently correlational approaches. The current study represents a targeted assessment of the role of bilaterality using repetitive transcranial magnetic stimulation (rTMS). We used a novel bilateral TMS-stimulation paradigm, applied to a group of healthy older adults (hOA) and older adults with mild cognitive impairment (MCI), with two aims: First, to elucidate the neurophysiological effects of bilateral neuromodulation, and second to provide insight into the neurophysiological basis of bilateral brain interactions. Electroencephalography (EEG) was recorded while participants received six forms of transcranial magnetic stimulation (TMS): unilateral and bilateral rTMS trains at an alpha (8 Hz) and beta (18 Hz) frequency, as well as two sham conditions (unilateral, bilateral) mimicking the sounds of TMS. First, time-frequency analyses of oscillatory power induced by TMS revealed that unilateral beta rTMS elicited rhythmic entrainment of cortical oscillations at the same beta-band frequency. Second, both bilateral alpha and bilateral beta stimulation induced a widespread reduction of alpha power. Lastly, healthy older adults showed greater TMS-related reductions in alpha power in response to bilateral rTMS compared to the MCI cohort. Overall, these results demonstrate frequency-specific responses to bilateral rTMS in the aging brain, and provide support for inhibitory models of hemispheric interaction across multiple frequency bands.

The association between music performance skills and cognitive improvement in a musical instrument training program for older adults

Recent studies have reported positive effects of music training on older adults’ executive functions. However, it is not completely known whether these outcomes were due to improvement in music performance skills or due to other components of training, such as social interaction and music listening. Here, we investigated the effect of a 10-week melodica training program on a group of healthy older adults in Japan and the relationship between their early music performance and improvements in executive functions. Participants were divided into an experimental and a passive control group; both completed a battery of executive function measures before and after the intervention. The experimental group also completed a music performance evaluation developed for the current study. We found a significant improvement in an executive function composite index for the intervention group as compared with the control group. Moreover, individual musical performance was the only factor to predict cognitive improvement. Our results suggest that musical instrument training has a positive impact on older adults’ cognition which is not solely attributed to social interaction or music listening. Further research should consider the potential of examining individual differences in music performance skills inside the experimental group to understand the effects of instrument training programs.

Normative Values of Echocardiographic Chamber Size and Function in Older Healthy Adults: The Multi-Ethnic Study of Atherosclerosis.

Echocardiographic (2-dimensional echocardiography) thresholds indicating disease or impaired functional status compared with normal physiological aging in individuals aged ≥65 years are not clearly defined. In the present study, we sought to establish standard values for 2-dimensional echocardiography parameters related to chamber size and function in older adults without cardiopulmonary or cardiometabolic conditions. In this cross-sectional study of 3032 individuals who underwent 2-dimensional echocardiography at exam 6 in the MESA (Multi-Ethnic Study of Atherosclerosis), 608 participants fulfilled our inclusion criteria of healthy aging, with normative values defined as the mean ± 1.96 standard deviation and compared across sex and race and ethnicity. Functional status measures included NT-proBNP (N-terminal pro-B-type natriuretic peptide), 6-minute walk distance, and Kansas City Cardiomyopathy Questionnaire. Prognostic performance using MESA cutoffs was compared with established guideline cutoffs using time-to-event analysis. The normative aging cohort (69.5±7.0 years, 46.2% male, 47.5% White) had lower NT-proBNP, higher 6-minute walk distance, and higher (better) Kansas City Cardiomyopathy Questionnaire summary values. Women had significantly smaller chamber sizes and better biventricular systolic function. White participants had the largest chamber dimensions, whereas Chinese participants had the smallest, even after adjustment for body size. Current guidelines identified 81.6% of healthy older adults in MESA as having cardiac abnormalities. Among a large, diverse group of healthy older adults, we found significant differences in cardiac structure and function by sex and race/ethnicity, which may signal sex-specific cardiac remodeling with advancing age. It is crucial for existing guidelines to consider the observed and clinically significant differences in cardiac structure and function associated with healthy aging. Our study highlights that existing guidelines, which grade abnormalities in echocardiographic cardiac chamber size and function based on younger individuals, may not adequately address the anticipated changes associated with normal aging.

Error monitoring in amnestic mild cognitive impairment: Cognitive correlates and relationship to measures of everyday function.

Accurate error monitoring is important for successful completion of everyday tasks and compensatory strategy use. This study examined how error awareness is impacted in amnestic mild cognitive impairment (aMCI) compared to cognitively healthy older adults (HOA). Cognitive correlates of error monitoring and relation to objective and self-reported measurement of everyday function were also evaluated. Twenty-four individuals with aMCI and 24 cognitively HOAs completed standardized cognitive measures (domains: attention, working memory, executive functioning, memory, language, visuospatial abilities); a computerized go-no-go paradigm task that evaluated error monitoring; a naturalistic, performance-based measure of everyday functioning (day-out-task; DOT); and self- and informant-report measures of everyday dysexecutive difficulties (DEX). Participants with aMCI demonstrated significantly poorer error monitoring as compared to the HOA group (Cohen's d = 1.02). Working memory and executive functioning were significantly related to error monitoring for both groups. After accounting for age and global cognitive status, hierarchical regressions revealed error monitoring significantly predicted DOT total time (but not accuracy) as well as both self- and informant-report DEX scores. Compared to HOAs, individuals with aMCI exhibited poorer conscious error awareness. Better error monitoring was associated with higher working memory and executive functioning abilities and predicted better everyday functioning. If individuals with aMCI experience difficulties recognizing performance inaccuracies, they will be unable to correct their errors, leading to mistakes in everyday task completion and difficulty implementing appropriate compensatory strategies. Findings suggest that error monitoring may be a potential target for intervention with individuals with aMCI. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reading and lexical–semantic retrieval tasks outperforms single task speech analysis in the screening of mild cognitive impairment and Alzheimer's disease

Age-related cognitive impairment have increased dramatically in recent years, which has risen the interes in developing screening tools for mild cognitive impairment and Alzheimer's disease. Speech analysis allows to exploit the behavioral consequences of cognitive deficits on the patient's vocal performance so that it is possible to identify pathologies affecting speech production such as dementia. Previous studies have further shown that the speech task used determines how the speech parameters are altered. We aim to combine the impairments in several speech production tasks in order to improve the accuracy of screening through speech analysis. The sample consists of 72 participants divided into three equal groups of healthy older adults, people with mild cognitive impairment, or Alzheimer's disease, matched by age and education. A complete neuropsychological assessment and two voice recordings were performed. The tasks required the participants to read a text, and complete a sentence with semantic information. A stepwise linear discriminant analysis was performed to select speech parameters with discriminative power. The discriminative functions obtained an accuracy of 83.3% in simultaneous classifications of several levels of cognitive impairment. It would therefore be a promising screening tool for dementia.

Predicting cognitive decline using neuropsychiatric symptoms in prodromal Lewy body disease

AbstractBackgroundNeuropsychiatric symptoms (NPS) in Lewy body diseases, including dementia with Lewy bodies (DLB) and Parkinson’s disease (PD) dementia, occur frequently and at an early stage in disease progression. Such symptoms are significantly associated with quality of life, caregiver burden and functional limitations. Limited evidence exists, however, outlining the relationship between NPS and cognitive decline.MethodsData from 217 participants were derived from three cohort studies. Patients diagnosed with either MCI with Lewy bodies (MCI‐LB, n = 67), PD‐MCI (n = 56) or Alzheimer’s disease (MCI‐AD, n = 39) and a group of healthy older adults (n = 55) completed comprehensive neuropsychological and neuropsychiatric assessment and were followed up longitudinally for a median of three years. NPS identified at baseline by the Neuropsychiatric Inventory (NPI) were included as predictors in linear regressions and linear mixed effects models to assess the relationship between NPS and performance on a range of cognitive tests both at baseline and longitudinally.ResultsAt baseline, NPS were most prevalent and severe among the MCI‐LB group (49% with NPI score &gt;4 in at least one symptom) and least prevalent in controls (7% with NPI score &gt;4). Total NPI score was not related to baseline cognitive function in any domain in any group. Greater baseline total NPI score was associated with steeper rates of decline among PD‐MCI patients on a measure of processing speed (p = .01). Among healthy adults, only sleep disturbance was associated with steeper rates of decline on global cognition (p = .005). None of the patient groups showed any association between individual NPS and decline on a measure of global cognitive function.ConclusionsThe lack of a significant relationship found between NPS and either global cognitive function or decline in global cognition seen among MCI patients suggests that at this prodromal stage of disease, NPS appear to be of limited clinical impact and indicates that the mechanisms of cognitive and neuropsychiatric symptoms may differ in early Lewy body disease. Future work will investigate these mechanisms using multimodal imaging data from this cohort.

Contributions of macrostructural and microstructural white matter damage to apathy in people with Alzheimer’s disease

AbstractBackgroundApathy is the most common neuropsychiatric symptom in Alzheimer’s disease (AD) that affects patients’ quality of life and prognosis. Previous functional neuroimaging studies have found multiple cerebral alterations suggesting a conceptualisation of apathy as a symptom resulting from a communication breakdown among functional neural networks involved in motivational‐affective processing. To test this hypothesis, this study investigated the association between white matter (WM) structural connectivity and apathy in AD.MethodSixty‐one patients with (AD‐AP) and 61 without apathy (AD‐NA) were identified from the ADNI database and matched for diagnosis, cognitive status, age and education. A group of 61 matched healthy older adults (HOA) was also included. Data on cognitive performance, cerebrospinal fluid (CSF) biomarkers, brain volumes and mean DTI indices of 50 WM tracts were extracted for all participants. Cognitive profiles and volumetric/DTI data were compared across groups using general linear models including sex as a covariate. Post hoc analyses were performed to investigate pair‐wise differences in all outcome measures.ResultBoth patient groups showed widespread cognitive deficits and neural alterations, lower amyloid beta and higher phosphorylated tau CSF levels compared to the HOA group. The direct AD‐AP vs AD‐NA comparison showed no significant differences in CSF biomarkers and MRI outcomes, but the AD‐AP group had more severe neuropsychiatric symptoms, lower scores on the Clock Test – copy and relied more on cues in the Logical Memory test – delayed recall. When the patient groups were compared to the HOA independently, the AD‐AP group had more extensive WM damage: 1) reduced WM and larger WM hyperintensity volume; 2) increased radial diffusivity and reduced fractional anisotropy primarily in the cingulum, superior longitudinal and inferior fronto‐occipital fasciculi and genu of the corpus callosum.ConclusionAD‐AP patients had WM damage mildly more severe than that observed in AD‐NA, especially in associative tracts in the frontal lobes and the cingulum. Such disruption in structural connectivity might affect crucial functional inter‐network communication resulting in motivational deficits and worse cognitive decline. These findings warrant further investigations to ascertain the relationship between WM damage and disruption of functional brain network dynamic interactions in AD patients with apathy.

Molecular imaging of the association between serotonin degeneration and beta-amyloid deposition in mild cognitive impairment

BackgroundDegeneration of the serotonin system has been observed in Alzheimer’s disease (AD) and in mild cognitive impairment (MCI). In transgenic amyloid mouse models, serotonin degeneration is detected prior to widespread cortical beta-amyloid (Aβ) deposition, also suggesting that serotonin degeneration may be observed in preclinical AD. MethodsThe differences in the distribution of serotonin degeneration (reflected by the loss of the serotonin transporter, 5-HTT) relative to Aβ deposition was measured with positron emission tomography in a group of individuals with MCI and a group of healthy older adults. A multi-modal partial least squares (mmPLS) algorithm was applied to identify the spatial covariance pattern between 5-HTT availability and Aβ deposition. ResultsForty-five individuals with MCI and 35 healthy older adults were studied, 22 and 27 of whom were included in the analyses who were “amyloid positive” and “amyloid negative”, respectively. A pattern of lower cortical, subcortical and limbic 5-HTT availability and higher cortical Aβ deposition distinguished the MCI from the healthy older control participants. Greater expression of this pattern was correlated with greater deficits in memory and executive function in the MCI group, not in the control group. ConclusionA spatial covariance pattern of lower 5-HTT availability and Aβ deposition was observed to a greater extent in an MCI group relative to a control group and was associated with cognitive impairment in the MCI group. The results support the application of mmPLS to understand the neurochemical changes associated with Aβ deposition in the course of preclinical AD.

Verbal Fluency Performance in Older Adults on a Novel Computerized Test Battery

AbstractBackgroundPrevious studies have suggested that impaired verbal fluency is a sensitive measure of semantic impairment in dementia that appears several years prior to diagnosis. This early impairment has been associated with neural changes and altered activation in key regions of bilateral temporal and frontal cortex.MethodIn the current study, we report verbal fluency findings from a large group of healthy older adults (n = 270, ages 56–89) on a new computerized neuropsychological battery that utilizes advanced automatic speech recognition and transcription software. In an ongoing longitudinal study, we are testing healthy older participants on the California Cognitive Assessment Battery (CCAB) every six months for three years, in order to track changes in cognition associated with aging, including evolution of mild cognitive impairment (MCI) and dementia. The CCAB includes six semantic categories: Animals, vegetables, countries, sports, furniture, and fruit. Participants are given one minute per category to generate as many exemplars as possible. Online speech‐to‐text transcription was implemented using consensus automatic speech recognition (CASR) software, which utilizes six different speech recognition systems and chooses the most common transcription.ResultOverall verbal fluency performance was significantly predicted by age. However, this effect depended on the semantic category. For example, females and more educated participants generated more exemplars for the category “countries.”ConclusionFindings from the current study enhance understanding of aging effects on verbal fluency and serve as a critical baseline against which to monitor alterations in performance that coincide with the development of MCI and dementia in older adults.

Using an entorhinal cortex‐based virtual reality navigation task to differentiate between individuals with and without subjective cognitive decline

AbstractBackgroundEntorhinal cortex is vulnerable to neurodegenerative changes in the earliest stages of AD. However, this early AD stage cannot be detected by currently available neuropsychological tests. The entorhinal cortex contains spatial modulated cells, known as grid cells, that play a key role in supporting path integration (PI), a crucial component of spatial navigation that supports continuous integration of self‐motion information and in combination with environmental cues provides accurate internal representation of space. Previously, PI deficits were associaed with impaired grid cell function in healthy older adults and in young APOE‐E4 carriers. Importantly, PI performance has successfully discriminated between biomarker positive and negative mild cognitive impairment patients and between healthy older adults at higher and lower risk of AD. In this study, we tested whether performance on an immersive virtual reality PI task can differentiate between patients with and without subjective cognitive decline (SCD).MethodA group of healthy older adults and SCD patients will perform an immersive virtual reality PI task. In this task, participants are immersed in an open‐field virtual environment and are guided along short, curved paths. At certain points they are asked to stop and indicate their initial heading orientation and the location of an object, providing information about distance and orientation coding. During the task participants have access to multisensory self‐motion cues (visual, vestibular and proprioceptive), all of which are pivotal for supporting grid cell function. Additionally, participants will be screened for presence of objective cognitive impairments and will undergo an assessment of their visuospatial working memory and balance.ResultWe will compare if SCD patients perform worse than healthy older controls in the general PI performance measures (e.g., PI error, response time). Furthermore, we will apply a recently developed computational model to identify multiple sources of PI error. This approach allows for a very nuanced characterization of PI deficits, and, as a result, provides additional, potentially even more sensitive markers of very early AD compared to typical PI performance measures.ConclusionThe results will be discussed with reference to the utility of immersive virtual PI as a sensitive biomarker for early, preclinical, AD manifestation.

Executive functioning and attention in amnestic mild cognitive impairment are related to widespread grey matter integrity

AbstractBackgroundMemory problems that are characteristic of amnestic mild cognitive impairment (aMCI) are often accompanied by difficulties in attention and executive functions (EF). Studies have consistently reported atrophy of the hippocampus and its association with memory decline in aMCI. However, it is less clear whether differences in grey matter volume (GMV) also contribute to difficulties in attention and EF. To that end, we investigated whether GMV is related to performance on a series of cognitive tests in people with aMCI.MethodGMV of 29 people with aMCI (mean age = 73.8 ± 7.6 Y, 5 F) was measured with voxel‐based morphometry and regressed against measures of task‐switching (Trail Making B‐A), inhibition (Stroop interference score), working memory (Symbol Digit Modalities), and attention (Vienna Reaction Time S1, S2, S3). Analyses were controlled for age and total intracranial volume. Because of the small sample, we used a lenient significance threshold of p &lt; 0.001 (uncorrected) and cluster size (k) &gt;= 20.ResultBetter task performance was related to higher GMV in widespread cortical regions. Task‐switching was mainly related to GMV in the bilateral insula (k = 924, 456, Z = 4.87, 3.79) and prefrontal areas (k = 846, Z = 4.35). Inhibition was related to volume in left posterior areas (k = 302, 300, Z = 3.93, 3.62), and working memory to volume in left temporal, parietal, and frontal cortices (k = 21‐88, Z = 3.28‐3.67). Attention to visual stimuli was associated with GMV of cerebellar (k = 20‐281, Z = 3.36‐3.59) and parieto‐occipital regions (k = 20‐76, Z = 3.28‐4.17), and attention to auditory stimuli mainly with prefrontal regions (k = 113, 49, Z = 3.96, 3.53). Interestingly, slower reactions to complex stimuli were related to higher GMV in occipital gyri (k = 28, Z = 3.56).ConclusionOur results suggest that EF and attention in people with aMCI are related to integrity of regions beyond those normally implicated in memory decline (e.g. the hippocampus). As investigation into aMCI is crucial for preventing disease progression, our findings should be further investigated by studies with a control group of healthy older adults.

The effect of exercising in different environments on heart rate and power output among older adults-a randomized crossover study.

A growing body of evidence suggests that exposure to nature is beneficial for human health. However, the observed health effect of nature may be mediated by physical activity and that humans are physically active at a higher intensity outdoors compared to when they are physical active indoors. This study examines the variation of heart rate and power output for a fixed rating of perceived exertion in a group of healthy older adults in three different environments representing three levels of exposure to nature. To this randomized, 3-by-3 crossover design study, healthy older adults (≥65 years) were recruited from local gyms. All participants participated in three experimental conditions; indoors, simulated outdoors and outdoor environments, in a randomized order. The participants exercised for 20 minutes at an intensity equivalent to a rating of 11-13 on the Borg scale for perceived exertion (RPE). Measurements of heart rate, power output (Watt) and ratings of perceived exertion were taken at minutes 1 to 6 and at minute 20. To examine the effect of the environment on heart rate and power, linear mixed models were used. In all, 48 participants (56% females) were included in the analysis. No significant main effects on the outcomes were observed for power output (p = 0.073, η2 = 0.04) or heart rate (p = 0.067, η2 = 0.04). No significant effect on the outcomes was observed. However, borderline significant outcomes for power output or heart rate outdoors in nature, along with previous studies in the field, indicates that such an effect cannot be completely ruled out, but any effect is likely to be small. Future research examining health benefits of the independent exposure to nature are encouraged to adjust for the dose of physical activity. ID: ISRCTN22230544.

Successful wayfinding in age: A scoping review on spatial navigation training in healthy older adults.

IntroductionSpatial navigation is a complex cognitive function that declines in older age. Finding one’s way around in familiar and new environments is crucial to live and function independently. However, the current literature illustrates the efficacy of spatial navigation interventions in rehabilitative contexts such as pathological aging and traumatic injury, but an overview of existing training studies for healthy older adults is missing. This scoping review aims to identify current evidence on existing spatial navigation interventions in healthy older adults and analyze their efficacy.MethodsTo identify spatial navigation interventions and assessments and investigate their effectiveness, four electronic databases were searched (Pubmed, Web of Science, CINAHL and EMBASE). Two independent reviewers conducted a screening of title, abstract and full-texts and performed a quality assessment. Studies were eligible if (1) published in English, (2) the full text was accessible, (3) at least one group of healthy older adults was included with (4) mean age of 65 years or older, (5) three or more spatial navigation-related training sessions were conducted and (6) at least one spatial ability outcome was reported.ResultsTen studies were included (N = 1,003, age-range 20–95 years, 51.5% female), only healthy older adults (n = 368, mean age ≥ 65) were assessed further. Studies differed in sample size (n = 22–401), type of training, total intervention duration (100 min–50 h), and intervention period (1–16 weeks).ConclusionThe spatial navigation abilities addressed and the measures applied to elicit intervention effects varied in quantity and methodology. Significant improvements were found for at least one spatial ability-related outcome in six of 10 interventions. Two interventions achieved a non-significant positive trend, another revealed no measurable post-training improvement, and one study did not report pre-post-differences. The results indicate that different types of spatial navigation interventions improve components of spatial abilities in healthy older adults. The existing body of research does not allow conclusions on transferability of the trained components on everyday life spatial navigation performance. Future research should focus on reproducing and extending the promising approaches of available evidence. From this, valuable insights on healthy aging could emerge.Trial RegistrationThis scoping review was preregistered at Open Science Framework (https://osf.io/m9ab6).

Impaired sensitivity to spatial configurations in healthy aging

Healthy aging is associated with decline in social, emotion, and identity perception, which is frequently attributed to deterioration of structures involved in social inference. It is believed that this decline is unlikely to be a result of perceptual aberrations due to intact (corrected) visual acuity. Nevertheless, the present studies examine whether more particular perceptual aberrations may be present in healthy aging, that could in principle contribute to such difficulties. The present study examined the possibility that particular deficits in configural processing impair the perception of faces in healthy aging. Across two signal detection experiments, we required a group of healthy older adults and matched younger adults to detect changes in images of faces that could differ either at the local, featural level, or in configuration of these features. In support of our hypothesis, older adults were particularly impaired in detecting configural changes, relative to detecting changes in features. The impairments were found for both upright and inverted faces and were similar in a task with images of inanimate objects (houses). Drift diffusion modelling suggested that this decline related to reduced evidence accumulation rather than a tendency to make configural judgments based on less evidence. These findings indicate that domain-general problems processing configural information contribute to the difficulties with face processing in healthy aging, and may in principle contribute to a range of higher-level social difficulties – with implications also for other groups exhibiting similar patterns in perception and understanding.

Acute High-Intensity Interval Exercise Modulates Corticospinal Excitability in Older Adults.

Acute exercise can modulate the excitability of the nonexercised upper limb representation in the primary motor cortex (M1). Measures of M1 excitability using transcranial magnetic stimulation (TMS) are modulated after various forms of acute exercise in young adults, including high-intensity interval training (HIIT). However, the impact of HIIT on M1 excitability in older adults is currently unknown. Therefore, the purpose of the current study was to investigate the effects of lower limb cycling HIIT on bilateral upper limb M1 excitability in older adults. We assessed the impact of acute lower limb HIIT or rest on bilateral corticospinal excitability, intracortical inhibition and facilitation, and interhemispheric inhibition of the nonexercised upper limb muscle in healthy older adults (mean age 66 ± 8 yr). We used single and paired-pulse TMS to assess motor evoked potentials, short-interval intracortical inhibition, intracortical facilitation, and the ipsilateral silent period. Two groups of healthy older adults completed either HIIT exercise or seated rest for 23 min, with TMS measures performed before (T0), immediately after (T1), and 30 min after (T2) HIIT/rest. Motor evoked potentials were significantly increased after HIIT exercise at T2 compared with T0 in the dominant upper limb. Contrary to our hypothesis, we did not find any significant change in short-interval intracortical inhibition, intracortical facilitation, or ipsilateral silent period after HIIT. Our findings demonstrate that corticospinal excitability of the nonexercised upper limb is increased after HIIT in healthy older adults. Our results indicate that acute HIIT exercise impacts corticospinal excitability in older adults, without affecting intracortical or interhemispheric circuitry. These findings have implications for the development of exercise strategies to potentiate neuroplasticity in healthy older and clinical populations.

Increased cost of cognitive effort in preclinical Alzheimer’s disease

AbstractBackgroundScores on neuropsychological tests depend on willingness to expend the necessary cognitive effort to complete each task. Group differences on cognitive test scores may partially reflect differences in perceived cognitive cost, or the willingness to exert cognitive effort, which will obscure estimates of “true” cognitive ability. It is critical, therefore, to obtain estimates of cognitive effort during neuropsychological testing. Subjective, questionnaire‐based measures of effort are prone to self‐report bias, so we administered an objective measure of cognitive effort (Cognitive Effort Discounting: COGED) to participants at the Knight ADRC. In COGED, participants complete increasingly difficult levels of a working memory task (the N‐Back) and then are asked to rate which “level” they would complete again for a given amount of monetary reward. We hypothesized that objective (COGED) but not subjective measures of effort would decrease in preclinical AD and this would be related to cognitive performance.MethodSixty‐five healthy older adults (Clinical Dementia Rating = 0) completed both the COGED task and a subjective effort rating scale (the NASA task load index). Participants were classified as amyloid‐positive (N=24) or negative (N=41) based either on amyloid PET scan or CSF Ab42/Ab40 ratio. Group differences on the effort task were analyzed using linear regression.ResultEffort ratings decreased across levels of N‐back (p&lt;0.001), indicating the task accurately tracks perceived effort. As expected, amyloid‐positive participants scored lower on the N‐back task (p=.03) but more importantly, they also scored lower on COGED than the amyloid‐negative group (Figure 1, p=0.05), after controlling for age, education and working memory. There were no group differences on the NASA (Figure 2). Surprisingly, neither COGED scores nor the NASA were related to performance on the N‐back, suggesting that effort ratings are independent of task performance.ConclusionWe successfully adapted the COGED paradigm for remote assessment and administered the task to a group of healthy older adults from the Knight ADRC. This task accurately reflects effort / reward processing. Objective (but not subjective) measures of the ability to make these computations decline in preclinical AD but does not appear to affect concurrent cognitive assessments.

Error relationship to an everyday monitoring in mild cognitive impairment: Cognitive correlates and task

AbstractBackgroundAccurate error monitoring is important for successful completion of everyday tasks and use of compensatory strategies. This work examined error monitoring in individuals with amnestic MCI (aMCI) as compared to healthy older adults (HOA) using a computerized task. We also examined cognitive domains associated with error monitoring and the contribution of error monitoring to objective and self‐reported measurement of everyday functioning.MethodsTwenty‐four individuals with aMCI and 24 HOAs were administered a battery of neuropsychological tests (domains assessed: attention, working memory, executive functioning, memory, language, visuospatial abilities); a sustained attention task that included an error‐monitoring score (Sustained Attention to Response Task; SART); a naturalistic, performance‐based measure of everyday functioning (Day Out Task; DOT); and self‐ and informant‐report measures that captured everyday dysexecutive difficulties (DEX).Results T‐test comparisons revealed the aMCI group (M = 0.48; SD = 0.22) exhibited poorer error monitoring (measured by the number of accurately self‐corrected errors on the SART divided by total errors) compared to the HOA group (M = 0.71; SD = 0.23), d = 1.02. Partial correlation analyses with age as a covariate revealed significant correlations between the error monitoring score and the cognitive domains of working memory and executive functioning for both the aMCI group and the HOA group. Hierarchical regression analyses revealed that after accounting for age and global cognitive status, the SART error monitoring score significantly predicted DOT total time, but not accuracy, as well as both self‐ and informant DEX scores.ConclusionThis study revealed that the ability to recognize errors was significantly poorer in individuals with aMCI compared to HOAs and most associated with the cognitive domains of executive functioning and working memory. After controlling for age and general cognitive status, error monitoring predicted performance in everyday functioning as assessed by a naturalistic, performance‐based test and questionnaires assessing everyday dysexecutive difficulties. This suggests that if individuals with aMCI do not recognize performance inaccuracies, they will not be able to correct errors, leading to mistakes in everyday task completion and reduction in implementation of appropriate compensatory strategies. These results implicate error monitoring as a potential target for early interventions with individuals with aMCI.

Adaptations in Reactive Balance Strategies in Healthy Older Adults After a 3-Week Perturbation Training Program and After a 12-Week Resistance Training Program.

Both resistance training (RT) and perturbation-based training (PBT) have been proposed and applied as interventions to improve reactive balance performance in older adults. PBT is a promising approach but the adaptations in underlying balance-correcting mechanisms through which PBT improves reactive balance performance are not well-understood. Besides it is unclear whether PBT induces adaptations that generalize to movement tasks that were not part of the training and whether those potential improvements would be larger than improvements induced by RT. We performed two training interventions with two groups of healthy older adults: a traditional 12-week RT program and a 3-week PBT program consisting of support-surface perturbations of standing balance. Reactive balance performance during standing and walking as well as a set of neuro-muscular properties to quantify muscle strength, sensory and motor acuity, were assessed pre- and post-intervention. We found that both PBT and RT induced training specific improvements, i.e., standing PBT improved reactive balance during perturbed standing and RT increased strength, but neither intervention affected reactive balance performance during perturbed treadmill walking. Analysis of the reliance on different balance-correcting strategies indicated that specific improvements in the PBT group during reactive standing balance were due to adaptations in the stepping threshold. Our findings indicate that the strong specificity of PBT can present a challenge to transfer improvements to fall prevention and should be considered in the design of an intervention. Next, we found that lack of improvement in muscle strength did not limit improving reactive balance in healthy older adults. For improving our understanding of generalizability of specific PBT in future research, we suggest performing an analysis of the reliance on the different balance-correcting strategies during both the training and assessment tasks.