Pattern Of Age-related Differences Research Articles

No evidence for a difference in lateralization and distinctiveness level of transcranial magnetic stimulation-derived cortical motor representations over the adult lifespan.

This study aimed to investigate the presence and patterns of age-related differences in TMS-based measures of lateralization and distinctiveness of the cortical motor representations of two different hand muscles. In a sample of seventy-three right-handed healthy participants over the adult lifespan, the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) cortical motor representations of both hemispheres were acquired using transcranial magnetic stimulation (TMS). In addition, dexterity and maximum force levels were measured. Lateralization quotients were calculated for homolog behavioral and TMS measures, whereas the distinctiveness between the FDI and ADM representation within one hemisphere was quantified by the center of gravity (CoG) distance and cosine similarity. The presence and patterns of age-related changes were examined using linear, polynomial, and piecewise linear regression. No age-related differences could be identified for the lateralization quotient of behavior or cortical motor representations of both intrinsic hand muscles. Furthermore, no evidence for a change in the distinctiveness of the FDI and ADM representation with advancing age was found. In conclusion this work showed that lateralization and distinctiveness of cortical motor representations, as determined by means of TMS-based measures, remain stable over the adult lifespan.

Use of wearable sensors to assess patterns of trunk flexion in young and old workers in the Metalworking Industry

Workers exposed to repeated trunk flexions are at risk of onset of low-back disorders and in individuals aged over 50 this issue is exacerbated by the physiologic decline of the musculoskeletal system and longer lifetime occupational exposure. In this study, we investigated the existence of possible age-related differences in patterns of trunk flexion of workers in the metalworking industry. Thirty-three subjects were monitored during an actual shift using a wearable Inertial Measurement Unit (IMU) to assess trunk flexion angles (i.e. between 30° and 60°, 60°–90° and > 90°). Results show that older workers spent less time with their trunk flexed, regardless of the class of flexion considered, with respect to their younger colleagues. Although further studies are necessary to clarify the existence of strategies aimed at optimising trunk movements during ageing, the IMU-based approach appears useful in highlighting potentially harmful conditions, especially in workers with marked signs of decline in their physical capacities. Practitioner summary: Wearable sensors, which are well tolerated and minimally intrusive, represent a valid option to continuously monitor trunk posture in workers employed in metalworking industry. The results of this study show that they provide valuable information about the patterns of flexion of young and old individuals engaged in physically demanding tasks.

Heterogeneous Indicators of Cognitive Performance and Performance Variability Across the Lifespan.

Reaction time (RT) and RT variability are core components of cognitive performance that can be captured through brief and easy-to-administer tasks of simple RT and choice RT. The current study aims to describe age-related differences in cognitive performance, toward better characterizing normative performance across the lifespan. We examined mean and variability of response times on a simple RT and choice RT tasks in a large and diverse web-based sample (10,060 visitors to TestMyBrain.org). We also examined lifespan-related differences in response time variability using multiple different approaches (raw variability, mean scaled variability, and mean residualized variability). These analyses revealed significant heterogeneity in the patterns of age-related differences in performance, across metrics and within different estimates of the same metric. Based on segmented regression analysis, age of peak performance differed significantly across metrics, with young adults having the best performance based on measures of median RT, middle age adults at peak on certain measures of RT variability (standard deviation and coefficient of variability), and older adults showing the best performance based on accuracy and mean-corrected RT variability. Our results indicate that no single measure of cognitive performance and performance variability produces the same findings with respect to age related change, with further work needed to establish the validity of particular metrics for different applications.

Patterns of frontoparietal activation as a marker for unsuccessful visuospatial processing in healthy aging.

Visuospatial abilities are sensitive to age-related decline, although the neural basis for this decline (and its everyday behavioral correlates) is as yet poorly understood. fMRI was employed to examine age-related differences in patterns of functional activation that underlie changes in visuospatial processing. All participants completed a brief neuropsychological battery and also a figure ground task (FGT) assessing visuospatial processing while fMRI was recorded. Participants included 16 healthy older adults (OA; aged 69-82years) and 16 healthy younger adults (YA; aged 20-35years). We examined age-related differences in behavioral performance on the FGT in relation to patterns of fMRI activation. OA demonstrated reduced performance on the FGT task and showed increased activation of supramarginal parietal cortex as well as increased activation of frontal and temporal regions compared to their younger counterparts. Performance on the FGT related to increased supramarginal gyrus activity and increased medial prefrontal activity in OAs, but not YAs. Our results are consistent with an anterior-posterior compensation model. Successful FGT performance requires the perception and integration of multiple stimuli and thus it is plausible that healthy aging may be accompanied by changes in visuospatial processing that mimic a subtle form of dorsal simultanagnosia. Overall, decreased visuospatial processing in OA relates to an altered frontoparietal neurobiological signature that may contribute to the general phenomenon of increasingly fragmented execution of behavior associated with normal aging.

Age-related differences in patterns of criminal activity among a large sample of polydrug injectors in Australia

Background: The relationship between age and criminal activity among drug-using populations is poorly understood.Methods: Data from 10 years of repeat cross-sectional surveys of sentinel samples of regular people who inject drugs (PWID) across Australia (n = 5844) were used to explore the relationship between age and past-month drug dealing, property crime and violent crime, and past-year arrest. Descriptive statistics were used to explore the prevalence and frequency of each outcome. The relationship between age and each outcome was measured using multivariable Poisson regression with robust error variance.Results: After adjusting for confounding factors, each 5-year increase in age was associated with significant reductions in drug dealing (adjusted incidence rate ratio [AIRR]: 0.90, 95% confidence interval [CI]: 0.87–0.94), property crime (AIRR: 0.85, 95% CI: 0.82–0.89) and violent crime (AIRR: 0.77, 95% CI: 0.70–0.85). Older participants were also significantly less likely to report being arrested in the past 12 months (AIRR: 0.91, 95% CI: 0.88–0.93).Conclusions: Younger PWID are more heavily involved in criminal activity compared with their older counterparts. This study highlights the need for early intervention programmes to prevent offending behaviour becoming entrenched, as well as continued efforts to redirect young PWID away from the criminal justice system and into treatment and education programmes.

Age-related differences in patterns of movement during walking: a risk factor for knee osteoarthritis?

Age-related differences in patterns of movement during walking: a risk factor for knee osteoarthritis?

Effects of age on negative BOLD signal changes in the primary somatosensory cortex

In addition to a contralateral activation of the primary and secondary somatosensory cortices, peripheral sensory stimulation has been shown to elicit responses in the ipsilateral primary somatosensory cortex (SI). In particular, evidence is accumulating that processes of interhemispheric inhibition as depicted by negative blood oxygenation level dependent (BOLD) signal changes are part of somatosensory processes. The aim of the study was to analyze age-related differences in patterns of cerebral activation in the somatosensory system in general and processes of interhemispheric inhibition in particular. For this, a functional magnetic resonance imaging (fMRI) study was performed including 14 younger (mean age 23.3±0.9years) and 13 healthy older participants (mean age 73.2±8.3years). All subjects were scanned during peripheral electrical median nerve stimulation (40Hz) to obtain BOLD responses in the somatosensory system. Moreover, the individual current perception threshold (CPT) as a quantitative measure of sensory function was determined in a separate psychophysical testing. Significant increases in BOLD signal across the entire group could be measured within the contralateral SI, in the bilateral secondary somatosensory cortex (SII), the contralateral supplementary motor area and the insula. Negative BOLD signal changes were delineated in ipsilateral SI/MI as well as in the ipsilateral thalamus and basal ganglia. After comparing the two groups, only the cortical deactivation in ipsilateral SI in the early stimulation phase as well as the activation in contralateral SI and SII in the late stimulation block remained as statistically significant differences between the two groups. The psychophysical experiments yielded a significant age-dependent effect of CPT change with less difference in the older group which is in line with the significantly smaller alterations in maximal BOLD signal change in the contra- and ipsilateral SI found between the two groups. Healthy aging seems to be associated with a decrease in intracerebral inhibition as reflected by smaller negative BOLD signal changes during fMRI tasks. This finding could constitute an important link between age-related neurophysiological changes and behavioral alterations in humans.

Age-Related Differences in Patterns of Increased Bordetella pertussis Antibodies

During the period 2008 to 2010, we identified 11,386 serum samples with increased (positive) levels of antibodies recognizing Bordetella pertussis antigens. We sought to characterize the distribution of positive antibody result patterns in relation to patient age. IgG and IgA antibodies recognizing pertussis toxin (PT) and filamentous hemagglutinin (FHA) were quantified using a multianalyte immunodetection assay. Four mutually exclusive positive result patterns were observed: increased FHA antibodies only, increased PT IgA but not IgG, increased PT IgG but not IgA, and increased PT IgG and IgA. In patients < 21 years old, the predominant pattern was increased PT IgG but not IgA, whereas in patients ≥ 21 years old, it was increased FHA antibodies only. The proportion of positive serum samples exhibiting increased PT IgA but not IgG was < 20% in all age categories but showed a stepwise rise with age. The proportions of positive serum samples exhibiting increased PT IgG and IgA were similar (26 to 32%) in the age categories spanning 11 to 60 years of age but lower in the < 11- and > 60-year-old groups. In 3 of 5 age categories, a significant rise in the proportion of positive serum samples exhibiting increased FHA antibodies only occurred in 2010. Patterns of positive B. pertussis antibody results varied with age. The predominance of increased FHA antibodies only in patients > 20 years old suggests that many adults thought to have B. pertussis infections actually have other infections that induce FHA-reactive antibodies. Similarly, the 2010 rise in the frequency of increased FHA antibodies only in some age groups suggests an increase in non-B. pertussis infections.

Histories of Social Engagement and Adult Cognition: Midlife in the U.S. Study

To evaluate whether social contacts, support, and social strain/conflict are related to executive function and memory abilities in middle-age and older adults. Longitudinal data on social contacts, support, and strain/conflict were examined in relation to executive function and memory at ages 35-85 years using data from the national Midlife in the U.S. (MIDUS) study. Age-related differences in patterns of association were also examined. Regression analyses, controlling for age, sex, race, education, chronic health conditions, and health behaviors, revealed significant positive associations between histories of greater social contacts and support and both executive function and episodic memory, whereas declines in social contacts were negatively associated with both outcomes. Greater average reported frequency of social exchanges characterized by strain or conflict was negatively associated with executive function but not episodic memory. Patterns were generally consistent across different age groups; where differences were seen, associations were stronger in younger age group. Positive and negative aspects of social relationships are related to cognition throughout adulthood, consistent with the hypothesis that social factors have life-long influences on cognition. Positive and negative aspects of social engagement may thus be important factors to consider in relation to efforts to promote optimal cognitive development and cognitive aging.

Age-Sensitive Design of Online Health Information: Comparative Usability Study

BackgroundOlder adults’ health maintenance may be enhanced by having access to online health information. However, usability issues may prevent older adults from easily accessing such information. Prior research has shown that aging is associated with a unique pattern of cognitive changes, and knowledge of these changes may be used in the design of health websites for older adults.ObjectiveThe goal of the current study was to examine whether older adults use of a health information website was affected by an alternative information architecture and access interface (hierarchical versus tag-based).MethodsFifty younger adults (aged 18-23) and 50 older adults (aged 60-80) navigated a health information website, which was organized hierarchically or used tags/keywords, to find answers to health-related questions while their performance was tracked. We hypothesized that older adults would perform better in the tag-based health information website because it placed greater demands on abilities that remain intact with aging (verbal ability and vocabulary).ResultsThe pattern of age-related differences in computer use was consistent with prior research with older adults. We found that older adults had been using computers for less time (F 1,98= 10.6, P= .002) and used them less often (F 1,98= 11.3, P= .001) than younger adults. Also consistent with the cognitive aging literature, younger adults had greater spatial visualization and orientation abilities (F 1,98= 34.6, P< .001 and F 1,98= 6.8, P= .01) and a larger memory span (F 1,98= 5.7, P= .02) than older adults, but older adults had greater vocabulary (F 1,98= 11.4, P= .001). Older adults also took significantly more medications than younger adults (F 1,98= 57.7, P< .001). In the information search task, older adults performed worse than younger adults (F 1,96= 18.0, P< .001). However, there was a significant age × condition interaction indicating that while younger adults outperformed older adults in the hierarchical condition (F 1,96= 25.2, P< .001), there were no significant age-related differences in the tag-based condition, indicating that older adults performed as well as younger adults in this condition.ConclusionsAccess to online health information is increasing in popularity and can lead to a more informed health consumer. However, usability barriers may differentially affect older adults. The results of the current study suggest that the design of health information websites that take into account age-related changes in cognition can enhance older adults’ access to such information.

Relative numerousness judgment and summation in young, middle-aged, and older adult orangutans (Pongo pygmaeus abelii and Pongo pygmaeus pygmaeus).

The ability to select the larger of two quantities ranging from 1 to 5 (relative numerousness judgment [RNJ[) and the ability to select the larger of two pairs of quantities with each pair ranging from 1 to 8 (summation) were evaluated in young, middle-aged, and older adult orangutans (7 Pongo pygmaeus abelii and 2 Pongo pygmaeus pygmaeus). Summation accuracy and RNJ were similar to those of previous reports in apes; however, the pattern of age-related differences with regard to these tasks was different from that previously reported in gorillas. Older orangutans were less accurate than the young and middle-aged for RNJ, and summation accuracy was equivalent among age groups. Evidence was found to suggest that the young and middle-aged based their selection of the largest quantity pair on both quantities within each pair during the summation task. These results show a relationship between subject age and the quantitative abilities of adult orangutans.

A retrospective study of premorbid ability and aging differences in cognitive clusters of schizophrenia

This retrospective, cross-sectional study evaluated whether age-related differences in patterns of cognitive deficit exist among four cognitively based schizophrenia subgroups. These subgroups had previously been identified through cluster analyses of a battery of abstraction and problem-solving tests in large samples. Evaluation of estimated premorbid intellectual ability and postmorbid cognitive functioning stratified by decade from the twenties through the fifties revealed different patterns across the schizophrenia subgroups and a clinical comparison sample. A near normal cognitive subgroup demonstrated relatively high premorbid intellectual ability and a pattern of age differences similar to the comparison sample, with the exception of deficits on the Wisconsin Card Sorting Test that were detectable in the twenties and remained stable thereafter. In contrast, a subgroup characterized by severe, pervasive cognitive deficit demonstrated low premorbid intellectual ability and extremely low test scores across the four decades studied. The remaining clusters were characterized by moderate cognitive impairment and showed age differences suggestive of a decline in cognitive function around the time of illness onset that remained stable. Results provide further support for the validity of these subgroups and encourage continued efforts to identify cognitively based candidate schizophrenia subtypes.

Effects of Age, Domain, and Processing Demands on Memory Span: Evidence for Differential Decline

Analysis of cross-sectional data from the normative sample of the Wechsler Memory Scale - Third Edition (WMS-III) revealed different patterns of age-related differences in memory span measures depending on the type of memory item, processing demands, and the age of the older adult group. Regression of memory span on age revealed that the slope for Spatial Span raw scores was significantly more negative than the slope for Digit Span raw scores. There was no significant difference, however, either between the slopes for forward and backward Digit Span or between the slopes for forward and backward Spatial Span. Regression of Letter-Number Sequencing raw scores on age showed a distinctive, curvilinear pattern. Taken together, the present findings suggest that at least two mechanisms are involved in age-related differences in memory span. One mechanism, associated with a relatively linear decrease in memory span as a function of age, may differentially affect the storage of different types of information (e.g., sequences of digits vs. spatial locations). The other mechanism, evidenced by the curvilinear trend in Letter-Number Sequencing scores, may be tentatively attributed to a decline in executive aspects of working memory that becomes increasingly pronounced with age.

Age-Related Prostate Cancer Metastases

Objectives. Metastatic prostate cancer results in significant patient morbidity, health care expenditure, and ultimately in mortality. We sought to identify patient and treatment factors predictive of distant metastases in patients completing external beam radiotherapy. Methods. Five hundred sixty-seven patients completing external beam radiotherapy at Fox Chase Cancer Center, Philadelphia, Pennsylvania between March 1987 and November 1994 for Stage T1 to T3 tumors were analyzed. Distant metastases were detected by radionuclide bone scans. Estimates of rates for distant metastases as a first failure were conducted using cumulative incidence methods and predictors of failure were analyzed univariately and multivariately. Results. The median follow-up was 46 months. On univariate analysis, the following were statistically significant predictors of distant metastases at 5 years: patient age greater than 65 years, pretreatment prostate-specific antigen (PSA) level, advanced stage, lower radiation dose, and Gleason score 7 to 10. Multivariate testing confirmed that age greater than 65 years, high pretreatment PSA level, lower radiation dose, and advanced stage were significant independent predictors of distant metastases. Conclusions. Men over the age of 65 years are more likely to experience distant failure than are younger men. The discovery of age-related differences in patterns of failure has significant therapeutic implications with regard to patient selection, trial design, and adjuvant therapy recommendations. Furthermore, age-related differences in failure may influence comparison of outcome data for radiotherapy series, which tend to have older patients, to surgical reports that usually include significantly younger men.

Color-Word Stroop test performance across the adult life span

In the Color-Word Stroop test (CWST), the basic task is to name the ink color of rows of XXXs, and performance in this condition is compared with performance in naming the ink-color of color words under conditions where word meanings and ink colors mismatch or are incongruent (e. g., the word red printed in green ink). The present study investigated whether Stroop test interference, defined as the cost associated with ink-color naming in the incongruous stimulus condition versus in the basic color-naming condition, provides positive evidence for a kind of processing qualitatively different than that which is required for color naming or for word reading. Does the pattern of age-related differences in Stroop interference force the conclusion that the incongruous condition taps a qualitatively different kind of processing than that required for color naming or for word reading? We gave the CWST to 310 healthy adults. Their performance in each condition of the test replicates and extends previous findings. Structural equation modeling of the data showed a significant, direct link between age and performance in the latent factor associated with the incongruent condition. However, this direct link with age produced a relatively small increase in the model's fit; it amounted to only a .024 increase in the proportion of variance explained in the incongruent condition. In light of this small direct influence due to age, the most parsimonious explanation of our findings is that age effects in Stroop interference are due to age-related slowing (which is also indexed by color naming and by word reading) primarily; the findings do not provide positive evidence for a qualitatively different kind of processing that declines with age.

Offspring growth in the California gull: reproductive effort and parental experience hypotheses

Measures of adult feeding and foraging behaviour in the California gull, Larus californicus, were related to the growth of their offspring. Offspring showed significantly higher growth when average feeding interval, a measure of the time interval between feedings, and feeding latency following foraging decreased. The amount of time parents foraged was positively related to offspring growth and negatively correlated with average feeding interval. Either (1) increased foraging efficiency with parental age, or (2) increased reproductive effort with age, could explain age-related differences in patterns of feeding behaviour and their impact on offspring growth. However, data on foraging time support only the hypothesis of increased reproductive effort with parental age.

Recent Trends in Hospital Mortality of Acute Myocardial Infarction—the Worcester Heart Attack Study

While age-related differences in patterns of care for acute myocardial infarction have been demonstrated, temporal trends in clinical outcome for patients in different age groups have not been carefully examined. We analyzed data collected as part of an ongoing communitywide study of 5480 patients hospitalized with validated acute myocardial infarction in Worcester, Mass, during 7 selected years spanning a 15-year period (1975 through 1990). Patients were stratified into three age groups: less than 65 years (n = 2220), 65 through 74 years (n = 1595), and 75 years or older (n = 1665). Within each age group, the odds of in-hospital death were determined by study year, with adjustments for selected demographic, clinical, and hospital characteristics. For patients less than age 65 years, the odds of dying during the acute hospital phase of myocardial infarction were reduced for all study years relative to the reference year (1975), reaching their lowest level in 1990 (adjusted odds ratio [OR], 0.16; 95% confidence interval [CI], 0.06 to 0.48). For patients aged 65 through 74 years, the odds of dying declined among patients hospitalized in 1978 (adjusted OR, 0.71; 95% CI, 0.39 to 1.29) and 1981 (adjusted OR, 0.36; 95% CI, 0.19 to 0.66) but remained essentially unchanged during the subsequent study years through 1990. For patients 75 years of age or older, the odds of dying declined through 1984 (adjusted OR, 0.42; 95% CI, 0.25 to 0.72) but increased over the following study years: 1986, 1988, and 1990. While the risk of in-hospital death following acute myocardial infarction has recently declined for patients less than 65 years of age, improvements have not been realized for older age groups. Current patterns of management of acute myocardial infarction in older patients require reexamination.

The pattern of age-related differences in electrophysiological activity of healthy males and females

—Age-related differences in quantified electrophysiological measures were examined in 202 subjects (109 females; 93 males) ages 30–80 all of whom were judged to be optimally healthy on a wide variety of criteria. The study utilized both absolute and relative measures from EEG spectral analysis as well as additional measures from long latency-evoked potentials. The same findings were noted for the 109 newly studied females as were reported for 63 previously studied male subjects. Results indicate that there is a broad trend for decreased EEG slow and increased fast activity with age, however, some of the measures change linearly and others are best represented by nonlinear functions. There is no decade where activities remain stable. Overall the pattern of change for males and females is similar, however, gender differences in both the EEG and EP data were present. The females had higher magnitudes for almost all absolute spectral and fast relative spectral measures. However, females demonstrated lower absolute alpha amplitude, lower relative slow activity, and lower late-latency EP data. Moreover, the absolute slow activity measure showed a gender × age interaction, indicating that the females had a different change in pattern of activity with increasing age than the males. Thus, gender-related findings were complex and could not be expressed as simple differences in overall amplitude. Age-related change is not a simple linear process but differs for differing EEG spectral bands, relative, and absolute spectral measures and for males and females. The overall findings contradict the common wisdom that EEG and alpha slow with age and that age related EEG change is on a continuum with findings in Alzheimer's disease where increased slowing predominates.