Age-related Decline In Performance Research Articles

Age-related differences in resting-state, task-related, and structural brain connectivity: graph theoretical analyses and visual search performance.

Previous magnetic resonance imaging (MRI) research suggests that aging is associated with a decrease in the functional interconnections within and between groups of locally organized brain regions (modules). Further, this age-related decrease in the segregation of modules appears to be more pronounced for a task, relative to a resting state, reflecting the integration of functional modules and attentional allocation necessary to support task performance. Here, using graph-theoretical analyses, we investigated age-related differences in a whole-brain measure of module connectivity, system segregation, for 68 healthy, community-dwelling individuals 18-78years of age. We obtained resting-state, task-related (visual search), and structural (diffusion-weighted) MRI data. Using a parcellation of modules derived from the participants' resting-state functional MRI data, we demonstrated that the decrease in system segregation from rest to task (i.e., reconfiguration) increased with age, suggesting an age-related increase in the integration of modules required by the attentional demands of visual search. Structural system segregation increased with age, reflecting weaker connectivity both within and between modules. Functional and structural system segregation had qualitatively different influences on age-related decline in visual search performance. Functional system segregation (and reconfiguration) influenced age-related decline in the rate of visual evidence accumulation (drift rate), whereas structural system segregation contributed to age-related slowing of encoding and response processes (nondecision time). The age-related differences in the functional system segregation measures, however, were relatively independent of those associated with structural connectivity.

Evidence for age-related decline in spatial memory in a novel allocentric memory task

ABSTRACT Several studies report spatial memory decline in old age. However, few studies have examined whether old adults are specifically impaired in allocentric memory tasks (testing for object-to-object spatial location memory). Thus, the present study examined the effects of age on allocentric spatial memory using a novel landmark memory task. Young (18–25 years old) and old (65 years and older) participants watched 10 short videos that displayed 180-degree viewpoints of distinct real-world locations with landmark cues. After watching each video, participants saw a snapshot from the video and were asked whether a landmark cue previously viewed in the video was to the left or right of the snapshot view. Young adults outperformed old adults on the task. This age-related decline in spatial performance was similar for men and women. These findings support that spatial ability in an allocentric task is sensitive to age-related cognitive decline in men and women.

Relationship between Eating Alone and Handgrip Strength in Korean Older Adults.

Sarcopenia is defined as an age-related decline in muscle mass, muscle strength, and physical performance. Eating alone has been linked to various health issues in older adults. This study investigated the relationship between eating alone and handgrip strength (HGS) in older adults using data from 7278 individuals (≥65 years) who participated in the 2014-2019 Korea National Health and Nutrition Examination Survey. HGS was measured using a digital grip strength dynamometer, relative HGS was calculated by dividing HGS by body mass index, and dynapenia was defined as an HGS < 28 kg for men and <18 kg for women. Multivariable logistic regression analysis showed that women who ate two meals alone were more likely to exhibit dynapenia than those who never ate alone (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.03-1.77). If the groups that never ate alone or ate one meal alone were combined as the reference group, the probability of dynapenia was higher in the combined groups that ate two or three meals alone (OR, 1.25; 95% CI, 1.04-1.50). No association was observed between eating alone and dynapenia in men. This suggests that eating alone is a modifiable related factor of dynapenia in older women.

Limits to sustained energy intake. XXXIV. Can the heat dissipation limit (HDL) theory explain reproductive aging?

According to the heat dissipation limit (HDL) theory, reproductive performance is limited by the capacity to dissipate excess heat. We tested the novel hypotheses that (1) the age-related decline in reproductive performance is due to an age-related decrease of heat dissipation capacity and (2) the limiting mechanism is more severe in animals with high metabolic rates. We used bank voles (Myodes glareolus) from lines selected for high swim-induced aerobic metabolic rate, which have also increased basal metabolic rate, and unselected control lines. Adult females from three age classes - young (4 months), middle-aged (9 months) and old (16 months) - were maintained at room temperature (20°C), and half of the lactating females were shaved to increase heat dissipation capacity. Old females from both selection lines had a decreased litter size, mass and growth rate. The peak-lactation average daily metabolic rate was higher in shaved than in unshaved mothers, and this difference was more profound among old than young and middle-aged voles (P=0.02). In females with large litters, milk production tended to be higher in shaved (least squares mean, LSM±s.e.: 73.0±4.74 kJ day-1) than in unshaved voles (61.8±4.78 kJ day-1; P=0.05), but there was no significan"t effect of fur removal on the growth rate [4.47±2.29 g (4 days-1); P=0.45]. The results provide mixed support of the HDL theory and no support for the hypotheses linking the differences in reproductive aging with either a deterioration in thermoregulatory capability or genetically based differences in metabolic rate.

Association between vitamin D status, physical performance, sex, and lifestyle factors: a cross-sectional study of community-dwelling Kosovar adults aged 40years and older.

Vitamin D status and its association with age-related decline in physical performance and strength have already been highlighted in various ways, but data on the situation in developing countries are scarce. This study aimed to investigate vitamin D status, its association with muscle mass and function, and other potential determinants such as age, sex, lifestyle factors (physical activity, dietary behavior), self-perceived health status, medication intake, education and financial situation in adults from Kosovo. This cross-sectional study included 297 participants (54.5% women), aged ≥ 40years. Serum 25-hydroxyvitamin D (25(OH)D) concentration, hand grip strength and physical performance tests, body composition, vitamin D dietary intake and knowledge were assessed. The interaction between serum 25(OH)D status, lifestyle factors and muscle traits was investigated. Vitamin D deficiency (< 50nmol/L) was observed in 47.5% of the total population, of whom 14.7% of them were severely deficient (< 30nmol/L). No associations were found between 25(OH)D concentration and age. Daily dietary intake ofvitamin D was low (1.89 ± 0.67µg) and 87.6% of individuals did not take vitamin D supplements. However, vitamin D supplementation was the only variable that added statistical significance (p < 0.05) to the prediction of vitamin D status (3.8%). On the other hand, age, medication intake and vitamin D level contributed significantly to the overall regression model, explaining 24.9% of the 30-s chairstand performance as an indicator of lower-body strength endurance. Vitamin D deficiency is highly prevalent among community-dwelling adults in Kosovo and low serum 25(OH)D has been associated with low muscle strength. This implies an urgent need for the development of comprehensive prevention strategies, focusing on pharmacological (supplementation) but alsoon non-pharmacological strategies such as education, foodfortification or lifestyle advices.

Ab. No. 69 Comparative Study on Effect of Square Stepping Exercises With Conventional Balance Exercises on Balance in Community Dwelling Elderly Population: A Randomized Control Trial

Introduction: Determining &amp; comparing the effects of Square Stepping Exercises (SSE) versus Conventional balance exercises after 4 weeks training in the older adults. To tackle age-related decline in balance performance in elderly, physical interventions are essential. SSE is a novel intervention that can enhance balance and reduce the risk of falls. Methods: 40 healthy community dwelling older individuals of age 60 years &amp; more with ability to walk backwards for 3 meters were included in the study. Participants were randomly allocated into two groups of 20 each using sealed envelope method. Limits of Stability (LOS) and Mini-BES Test were assessed as outcome measures prior to and after the 4 weeks of training. Non-Parametric test were used to analyze the data of Mini BESTest as the data was not normally distributed. Whereas the rest of the data (LOS) were normally distributed, hence parametric tests were used to analyze. Results: Both the groups showed statistically significant results when compared to their pre-intervention scores (p&lt;0.0001) The between group comparison did not show any statistically significant difference on balance components (p&gt;0.05). Conclusions: Both Conventional balance training exercises and Square stepping exercises were found to be equally effective in improving balance in elderly. Implications: SSE does not have an advantage over the conventional balance exercises, however it can be used as an adjunct to the conventional balance training to introduce variety in training of community dwelling elderly with adequate safety measures in place.

Age-related decline in balance performance and changes in relevant white matter tracts

Age-related decline in balance performance and changes in relevant white matter tracts

Parsing memory and nonmemory contributions to age-related declines in mnemonic discrimination performance: a hierarchical Bayesian diffusion decision modeling approach.

The mnemonic discrimination task (MDT) is a widely used cognitive assessment tool. Performance in this task is believed to indicate an age-related deficit in episodic memory stemming from a decreased ability to pattern-separate among similar experiences. However, cognitive processes other than memory ability might impact task performance. In this study, we investigated whether nonmnemonic decision-making processes contribute to the age-related deficit in the MDT. We applied a hierarchical Bayesian version of the Ratcliff diffusion model to the MDT performance of 26 younger and 31 cognitively normal older adults. It allowed us to decompose decision behavior in the MDT into different underlying cognitive processes, represented by specific model parameters. Model parameters were compared between groups, and differences were evaluated using the Bayes factor. Our results suggest that the age-related decline in MDT performance indicates a predominantly mnemonic deficit rather than differences in nonmnemonic decision-making processes. In addition, this mnemonic deficit might also involve a slowing in processes related to encoding and retrieval strategies, which are relevant for successful memory as well. These findings help to better understand what cognitive processes contribute to the age-related decline in MDT performance and may help to improve the diagnostic value of this popular task.

Openness to Experience is associated with neural andperformance measures ofmemory inolder adults.

Age-related decline in episodic memory performance is a well-replicated finding across numerous studies. Recent studies focusing on aging and individual differences found that the Big Five personality trait Openness to Experience (hereafter: Openness) is associated with better episodic memory performance in older adults, but the associated neural mechanisms are largely unclear. Here, we investigated the relationship between Openness and memory network function in a sample of 352 participants (143 older adults, 50-80 years; 209 young adults, 18-35 years). Participants underwent functional magnetic resonance imaging (fMRI) during a visual memory encoding task. Functional memory brain-network integrity was assessed using the similarity of activations during memory encoding (SAME) scores, which reflect the similarity of a participant's memory network activity compared to prototypical fMRI activity patterns of young adults. Openness was assessed using the NEO Five-Factor Inventory. Older vs young adults showed lower memory performance and higher deviation of fMRI activity patterns (i.e.lower SAME scores). Specifically in older adults, high Openness was associated with better memory performance, and mediation analysis showed that this relationship was partially mediated by higher SAME scores. Our results suggest that trait Openness may constitute a protective factor in cognitive aging by better preservation of the brain's memory network.

Age-related changes in mobility assessments correlate with repetitive goal-directed arm-movement performance

BackgroundThere is ample evidence that mobility abilities between healthy young and elderly people differ. However, we do not know whether these differences are based on different lower leg motor capacity or instead reveal a general motor condition that could be detected by monitoring upper-limb motor behavior. We therefore captured body movements during a standard mobility task, namely the Timed Up and Go test (TUG) with subjects following different instructions while performing a rapid, repetitive goal-directed arm-movement test (arm-movement test). We hypothesized that we would be able to predict gait-related parameters from arm motor behavior, even regardless of age.MethodsSixty healthy individuals were assigned to three groups (young: mean 26 ± 3 years, middle-aged 48 ± 9, old 68 ± 7). They performed the arm-movement and TUG test under three conditions: preferred (at preferred movement speed), dual-task (while counting backwards), and fast (at fast movement speed). We recorded the number of contacts within 20 s and the TUG duration. We also extracted TUG walking sequences to analyze spatiotemporal gait parameters and evaluated the correlation between arm-movement and TUG results.ResultsThe TUG condition at preferred speed revealed differences in gait speed and step length only between young and old, while dual-task and fast execution increased performance differences significantly among all 3 groups. Our old group’s gait speed decreased the most doing the dual-task, while the young group’s gait speed increased the most during the fast condition. As in our TUG results, arm-movements were significant faster in young than in middle-aged and old. We observed significant correlations between arm movements and the fast TUG condition, and that the number of contacts closely predicts TUG timefast and gait speedfast. This prediction is more accurate when including age.ConclusionWe found that the age-related decline in mobility performance that TUG reveals strongly depends on the test instruction: the dual-task and fast condition clearly strengthened group contrasts. Interestingly, a fast TUG performance was predictable by the performance in a fast repetitive goal-directed arm-movements test, even beyond the age effect. We assume that arm movements and the fast TUG condition reflect similarly reduced motor function.Trial registrationGerman Clinical Trials Register (DRKS) number: DRKS00016999, prospectively registered on March, 26, 2019.

Mitochonic acid 5 attenuates age-related neuromuscular dysfunction associated with mitochondrial Ca2+ overload in Caenorhabditis elegans

Mitochonic acid-5 ameliorates the pathophysiology of human mitochondrial-disease fibroblasts and Caenorhabditis elegans Duchenne muscular dystrophy and Parkinson’s disease models. Here, we found that 10 μM MA-5 attenuates the age-related decline in motor performance, loss of muscle mitochondria, and degeneration of dopaminergic neurons associated with mitochondrial Ca2+ overload in C. elegans. These findings suggest that MA-5 may act as an anti-aging agent against a wide range of neuromuscular dysfunctions in metazoans.

Childhood growth, current age, and waist circumference predict biological reserve capacity, physical performance, and rapid aging in Bangladeshi women

Background: The UK Bangladeshi community is socially disadvantaged, and many adults suffer from obesity, diabetes, and other chronic illnesses. Rapid aging has been noted.&#x0D; Objectives: Analyse biosocial trade-offs in growth, adult body composition, and reproduction, which are risk factors for age-related decline in physical performance, more rapid aging, frailty, and death.&#x0D; Methods: Sample: 40 Bangladeshi mothers (40-70 years old), one of their adult daughters (N=37, 18-36 years old) in the United Kingdom (UK), and 22 mother-daughter pairs of the same age range in Bangladesh (BD). Measurements: anthropometry, including knee height, migration, demographic history, education level, current menstruation (yes/no), and a 7-component lower body physical function score (PFS). Analysis: ridge regression and St Nikolas House Analysis (SNHA).&#x0D; Results: All the women are of short stature (x̄=150cm), with especially low knee height. Daughters who migrated to the UK have shorter knee height than daughters born in the UK. Marriage age was 16-18 years and total pregnancies of ~6 per mother, ~3 per daughter. UK mothers have higher fatness and lower PFS than BD women. Greater knee height predicts greater PFS, and that greater waist circumference and older age predict a lower PFS. SNHA finds that knee height is the most direct predictor of PFS.&#x0D; Conclusion: Adult knee height may serve as a sensitive indicator of early life physical and emotional well-being and predict physical performance, a risk factor for frailty and death. International migration of daughters is associated with poorer health status and physical performance at later ages.

A physiological comparison of the new-over 70 years of age-marathon record holder and his predecessor: A case report.

Purpose: This study assessed the body composition, cardiorespiratory fitness, fiber type and mitochondrial function, and training characteristics of a 71-year-old runner who broke the world record marathon of the men's 70-74 age category and held several other world records. The values were compared to those of the previous world-record holder. Methods: Body fat percentage was assessed using air-displacement plethysmography. , running economy, and maximum heart rate were measured during treadmill running. Muscle fiber typology and mitochondrial function were evaluated using a muscle biopsy. Results: Body fat percentage was 13.5%, was 46.6mlkg-1min-1, and maximum heartrate was 160beats∙min-1. At the marathon pace (14.5kmh-1), his running economy was 170.5mlkg-1km-1. The gas exchange threshold and respiratory compensation point occurred at 75.7% and 93.9% of the , i.e., 13kmh-1 and 15kmh-1, respectively. The oxygen uptake at the marathon pace corresponded to 88.5% of . Vastus lateralis fiber content was 90.3% type I and 9.7% type II. Average distance was 139km∙w-1 in the year prior to the record. Conclusion: The 71-year-old world-record holder marathon showed a relatively similar , lower percentage of at marathon pace, but a substantially better running economy than his predecessor. The better running economy may result from an almost double weekly training volume compared to the predecessor and a high type I fiber content. He trained every day in the last ∼1.5years and achieved international performance in his age group category with a small (<5% per decade) age-related decline in marathon performance.

Sex-specific changes in autosomal methylation rate in ageing common terns

Senescence, an age-related decline in survival and/or reproductive performance, occurs in species across the tree of life. Molecular mechanisms underlying this within-individual phenomenon are still largely unknown, but DNA methylation changes with age are among the candidates. Using a longitudinal approach, we investigated age-specific changes in autosomal methylation of common terns, relatively long-lived migratory seabirds known to show senescence. We collected blood at 1-, 3- and/or 4-year intervals, extracted DNA from the erythrocytes and estimated autosomal DNA methylation by mapping Reduced Representative Bisulfite Sequencing reads to a de novo assembled reference genome. We found autosomal methylation levels to decrease with age within females, but not males, and no evidence for selective (dis)appearance of birds of either sex in relation to their methylation level. Moreover, although we found positions in the genome to consistently vary in their methylation levels, individuals did not show such strong consistent variance. These results pave the way for studies at the level of genome features or specific positions, which should elucidate the functional consequences of the patterns observed, and how they translate to the ageing phenotype.

The association of executive functions and physical fitness with cognitive-motor multitasking in a street crossing scenario

Age-related decline in cognitive-motor multitasking performance has been attributed to declines in executive functions and physical fitness (motor coordinative fitness and cardiovascular fitness). It has been suggested that those cognitive and physical resources strongly depend on lifestyle factors such as long-term regular physical activity and cognitive engagement. Although research suggests that there is covariation between components of executive functions and physical fitness, the interdependence between these components for cognitive-motor multitasking performance is not yet clear. The aim of the study was to examine the contribution and interrelationship between executive functions, motor coordinative fitness, and cardiovascular fitness on street crossing while multitasking. We used the more ecologically valid scenario to obtain results that might be directly transferable to daily life situation. Data from 50 healthy older adults (65–75 years, 17 females, recruited in two different cities in Germany) were analyzed. Participants’ executive functions (composite score including six tests), motor coordinative fitness (composite score including five tests), and cardiovascular fitness (spiroergometry), as well as their street crossing performance while multitasking were assessed. Street crossing was tested under single-task (crossing a two-line road), and multitask conditions (crossing a two-line road while typing numbers on a keypad as simulation of mobile phone use). Street crossing performance was assessed by use of cognitive outcomes (typing, crossing failures) and motor outcomes (stay time, crossing speed). Linear mixed-effects models showed beneficial main effects of executive functions for typing (p = 0.004) and crossing failures (p = 0.023), and a beneficial main effect of motor coordinative fitness for stay time (p = 0.043). Commonality analysis revealed that the proportion of variance commonly explained by executive functions, motor coordinative fitness, and cardiovascular fitness was small for all street crossing outcomes. For typing and crossing failures (cognitive outcomes), the results further showed a higher relative contribution of executive functions compared to motor coordinative fitness and cardiovascular fitness. For stay time (motor outcome), the results correspondingly revealed a higher relative contribution of motor coordinative fitness compared to executive functions and cardiovascular fitness. The findings suggest that during cognitive-motor multitasking in everyday life, task performance is determined by the components of executive functions and physical fitness related to the specific task demands. Since multitasking in everyday life includes cognitive and motor tasks, it seems to be important to maintain both executive functions and physical fitness for independent living up to old age.

Age-related differences in frontoparietal activation for target and distractor singletons during visual search.

Age-related decline in visual search performance has been associated with different patterns of activation in frontoparietal regions using functional magnetic resonance imaging (fMRI), but whether these age-related effects represent specific influences of target and distractor processing is unclear. Therefore, we acquired event-related fMRI data from 68 healthy, community-dwelling adults ages 18-78 years, during both conjunction (T/F target among rotated Ts and Fs) and feature (T/F target among Os) search. Some displays contained a color singleton that could correspond to either the target or a distractor. A diffusion decision analysis indicated age-related increases in sensorimotor response time across all task conditions, but an age-related decrease in the rate of evidence accumulation (drift rate) was specific to conjunction search. Moreover, the color singleton facilitated search performance when occurring as a target and disrupted performance when occurring as a distractor, but only during conjunction search, and these effects were independent of age. The fMRI data indicated that decreased search efficiency for conjunction relative to feature search was evident as widespread frontoparietal activation. Activation within the left insula mediated the age-related decrease in drift rate for conjunction search, whereas this relation in the FEF and parietal cortex was significant only for individuals younger than 30 or 44 years, respectively. Finally, distractor singletons were associated with significant parietal activation, whereas target singletons were associated with significant frontoparietal deactivation, and this latter effect increased with adult age. Age-related differences in frontoparietal activation therefore reflect both the overall efficiency of search and the enhancement from salient targets.

Prevalence of psychiatric morbidity in elderly hospitalized patients

Background: Improved healthcare extends life expectancy, but social and economic issues including poverty, family breakdown, and insufficient help for the elderly put people's mental health in danger. Because of feelings of loneliness and natural age-related decline in physiological and physical performance, the elderly are more prone to psychological disorders. With this aim in mind, the study of the prevalence of psychiatric morbidity in elderly hospitalized patients was taken up. Methods: A cross-sectional analytical study was carried out in a tertiary hospital in Pune on 200 hospitalized patients of 65 years of age and more from July 2019 to July 2021. Subjects with known psychiatric disorders were excluded. Subjects were evaluated with a sociodemographic proforma, mini-international neuropsychiatric interview (MINI), depression anxiety stress scale-21 (DASS-21), and the multidimensional scale of perceived social support (MSPSS). Results: A total of 35.5% of elderly subjects admitted to non-psychiatric wards were found to be suffering from psychiatric disorders, most commonly major depressive disorder, generalized anxiety disorders (GADs), and social anxiety disorders. On DASS-21, 55.5% of patients had stress, 24% anxiety, and 15.5% had depression. On the MSPSS scale, 53% had a high level of support. A mean score of 5.94 was obtained for family support, 5.413 for support from friends, and 3.486 for support from significant others. Males received higher support. Conclusion: We found that elderly patients admitted in non-psychiatric wards had psychiatric disorders. The most common psychiatric disorders were GAD (16.5%) and major depressive disorder (15%). It is more beneficial when physicians/surgeons also screen or refer their elderly patients to their psychiatrist colleagues to help alleviate their suffering to the extent possible.

Physical performance reference values for Japanese oldest old: a SONIC study

BackgroundThe oldest old, defined as those aged 90 or over, is now the fastest-growing population sector. This study aimed to determine reference values for several physical performance measures (PPMs) among 90-year-olds using internationally standardized measurements and to clarify the characteristics of these indices by comparing their results for 90-year-olds with those for older people 70 and 80.MethodsWe used the Septuagenarians, Octogenarians, and Nonagenarians Investigation with Centenarians (SONIC) study data from 2010 to 2018. The study subjects were 70, 80, and 90-year-olds in the target area eligible to participate in the venue. Excluding those certified for long-term care, the final number of eligible persons is 70s cohort 1000 (2010), 80s cohort 973 (2011), and 90s cohort 690. 90s cohort only consisted of three survey waves: 2012, 2015, and 2018. We used hand grip strength and score on the Short Physical Performance Battery (SPPB) for our physical performance measurements. In addition, we statistically analyzed sex and age differences.ResultThe simple mean ± standard deviation (SD) for the 90-year-old respondents were in men, 24.1 ± 5.4 kg in hand grip strength, 0.80 ± 0.22 m/s in usual gait speed, 17.2 ± 6.73 s in 5times chair stand, 5.89 ± 4.42 s in tandem balance, and 8.3 ± 2.2 in SPPB respectively and in women, 14.4 ± 4.0 kg in hand grip strength, 0.72 ± 0.20 m/s in usual gait speed, 17.8 ± 7.89 s in 5times chair stand, 4.72 ± 4.35 s in tandem balance, and 7.5 ± 2.4 in SPPB, respectively. For all PPMs, the age 90 cohort was statistically significantly different from the age 70 and 80 cohorts (all trends P < 0.001). Hand grip strength decreased with a similar gradient with age cohort increase of 10 years for both sexes. In contrast, SPPB lower limb score showed a larger drop between the age 80 and 90 cohorts than between the age 70 and 80 cohorts. We also constructed sex-specific appraisal standards according to quintiles.ConclusionsOur study yielded inclusive sex-specific reference values and appraisal standards for major physical performance measures not certified as requiring long-term care, community-dwelling, oldest old Japanese. The characteristics of age-related decline in physical performance differed between the upper and lower extremity assessments.

Age-associated Decline In 20-sec Stepping Test Performance In Independent, Community-dwelling Older Women

PURPOSE: To determine if there is an age-related decline in ST performance in independent, community-dwelling women (age 66-89 yrs; n = 1163). METHODS: Subjects completed an eyes open, 20-sec ST and fitness testing. ST measures included head total movement distance (TMD), head greatest placement (MMD), knee total movement distance (KMD) and stepping rate (STEP) determined with a KINECTTM infrared depth sensor. Ratio of KMD/TMD is an index of upper-body sway relative to lower-body. Fitness was defined by self-selected walking speed (NW), fast-walking speed (FW), timed up and go (UPGO), chair stand five-times (CS), and maximum voluntary knee extension force (MVC). Subjects were divided into age groups 65-69 (n = 178), 70-74 (n = 293), 75-79 (n = 417), 80-84 (n = 251), and > 85 (n = 24) yrs and differences examined by ANOVA; significance p < 0.05. Associations between age and ST measures were evaluated using Pearson product moment correlation. RESULTS: Individuals between 75-79 and 85+ groups were shorter, while body mass declined across each group, leveling off at 80 yrs. % body fat was greater, but equal in 80-84 and 85+ groups. TMD was greatest in 80-84 group; all others were similar. TMD and KMD increased in 75-79 through 85+ group. MMD was not different among groups. KMD/TMD was similar and greater in 75-79 and 80-84 yrs, while, 85+ was greater than all groups. Sway per STEP (TMD/KMD/STEP) increased progressively across groups. There was a progressive reduction in fitness variables beginning with 75-79 group. ST variables, except MMD, were significantly correlated with age, but coefficients were low (r = -0.23-0.12, p < 0.05). CONCLUSIONS: Age-related decline in ST performance observed primarily as a progressive increase in sway (KMD/TMD, and KMD/TMD/STEP) indicates reduced balance in accordance with our previous findings. Progressive reduction in static/dynamic balance negatively affects physical function (e.g. decrements in walking speed, TUG etc.) as observed here. This supports our recent findings that ST differentiates physical disability, indicates risk of falling, and “need for assistance”. Supported by JSPS (Grant number: 20 K11656)

Targeting the frontoparietal network using bifocal transcranial alternating current stimulation during a motor sequence learning task in healthy older adults

BackgroundHealthy older adults show a decrease in motor performance and motor learning capacity as well as in working memory (WM) performance. WM has been suggested to be involved in motor learning processes, such as sequence learning. Correlational evidence has shown the involvement of the frontoparietal network (FPN), a network underlying WM processes, in motor sequence learning. However, causal evidence is currently lacking. Non-invasive brain stimulation (NIBS) studies have focused so far predominantly on motor-related areas to enhance motor sequence learning while areas associated with more cognitive aspects of motor learning have not yet been addressed. HypothesisIn this study, we aim to provide causal evidence for the involvement of WM processes and the underlying FPN in the successful performance of a motor sequence learning task by using theta transcranial alternating current stimulation (tACS) targeting the FPN during a motor sequence learning task. MethodsIn a cohort of 20 healthy older adults, we applied bifocal tACS in the theta range to the FPN during a sequence learning task. With the use of a double-blind, cross-over design, we tested the efficacy of active compared to sham stimulation. Two versions of the motor task were used: one with high and one with low WM load, to explore the efficacy of stimulation on tasks differing in WM demand. Additionally, the effects of stimulation on WM performance were addressed using an N-back task. The tACS frequency was personalized by means of EEG measuring the individual theta peak frequency during the N-back task. ResultsThe application of personalized theta tACS to the FPN improved performance during the motor sequence learning task with high WM load (p < .001), but not with low WM load. Active stimulation significantly improved both speed (p < .001), and accuracy (p = .03) during the task with high WM load. In addition, the stimulation paradigm improved performance on the N-back task for the 2-back task (p = .013), but not for 1-back and 3-back. ConclusionThe performance during a motor sequence learning task can be enhanced by means of personalized bifocal theta tACS to the FPN when WM load is high, indicating that the efficacy of this stimulation paradigm is dependent on the cognitive demand during the learning task. These data provide further causal evidence for the critical involvement of WM processes and the FPN during the execution of a motor sequence learning task in healthy older. These findings open new exciting possibilities to counteract the age-related decline in motor performance, learning capacity and WM performance.