The locus of age x health-related physical fitness interactions in serial choice responding as a function of task complexity: central processing or motor function?

The effects of age on response time, accuracy, and shoulder/arm kinematics during hammering

The aim of this study was to investigate the effects of age on response time and accuracy during a hammering task. Older male workers aged 51-69 years (older group: OG, n = 23) and younger male reference individuals aged 25-36 years (younger group: YG, n = 16) performed the experiment. Response time, accuracy, and 3D shoulder/arm kinematics were acquired using motion capture. The effects of age were investigated using linear mixed model analysis. Response times were significantly longer for OG compared with YG (P < 0.001) while no marked differences in the accuracy was observed (P = 0.729). OG showed less hammer displacement and smaller range of motion in the shoulder. Although older workers seemed to use a less biomechanical demanding motor strategy, their response times during hammering were about twice that of younger individuals.

The impact of physical activity and sex differences on intraindividual variability in inhibitory performance in older adults

It is well-known that processing speed and executive functions decline with advancing age. However, physical activity (PA) has a positive impact on cognitive performances in aging, specifically for inhibition. Less is known concerning intraindividual variability (iiV) in reaction times. This study aims to investigate the influence of PA and sex differences on iiV in inhibitory performance during aging. Healthy adults were divided into active and sedentary groups according to PA level. To analyse iiV in reaction times, individual mean, standard deviation and the ex-Gaussian parameters were considered. An interaction between activity level and sex was revealed, sedentary females being slower and more variable than sedentary men. No sex differences were found in the active groups. These results indicate that the negative impact of sedentariness on cognitive performance in older age is stronger for females. The present findings underline the need to consider sex differences in active aging approaches.

On the preservation of vigilant attention to semantic information in healthy aging

Despite decades of research on younger adults, little is known about the way in which vigilant attention is affected by healthy aging, and the small body of work that does exist has yielded mixed findings. Prior examinations of aging and vigilant attention have focused almost exclusively on sensory/perceptual tasks despite the fact that many real-world vigilance tasks are semantic in nature and it has been shown that older adults exhibit memory and attention deficits in semantic tasks in other domains. Here, we present the first empirical investigation of vigilant attention to verbal stimuli in healthy normal aging. In Experiment 1 we find that older adults are just as able as younger adults to identify critical targets defined by category membership (both overall and over time). In Experiment 2, we increase the difficulty of the task by changing the target category from one block to the next, but again find no age-group effects in accuracy. Response time data, however, show that older adults respond more slowly and subjective ratings indicate that older adults experience higher workload and arousal compared to their younger counterparts. The practical as well as theoretical implications of these findings are discussed.

Effects of age, task complexity, and exercise on reaction time of women during ambulation tasks

PURPOSE

Reaction time (RT) is defined as the time lapse between the onset of a stimulus and the initiation of a response. The purpose of Study 1 was to compare RTs of young and elderly women during ambulation. The purpose of Study 2 was to investigate the effects of regular exercise on RTs of elderly women during ambulation tasks.

METHODS

Reaction times were measured using a portable computer, 2 transistor radios, and a radio interface box. The computer generated an auditory signal to which participants reacted by pushing a hand-held switch. Reaction times were compared in Study 1 between 17 healthy elderly women and 13 university students and in Study 2 between 15 exercising and 16 non-exercising elderly women. Testing of each participant occurred during sitting, walking on tile, and walking on foam padded carpet.

RESULTS

The results of Study 1 revealed differences in RT between the 2 groups and between the sitting and the 2 walking conditions, but no interaction between group and task complexity. The results of Study 2 revealed differences among all conditions, but not between groups.

CONCLUSIONS

The surprising result of Study 1 was that the elderly were not compromised to a greater extent than the young by increased task complexity. This suggests less age related RT decline during familiar activities. Results of Study 2 showed that level of exercise did not differentiate elderly participants' performance on RT. This may be because the active lifestyle of both groups of participants was more important in maintaining RT than a formal exercise program.

The choices, choosing model of quality of life: clinical evaluation and intervention

Two previous papers presented a conjectured model of quality of life featuring the personal management of accessing choices and choosing among them (the c-c process). Those papers made the case that this model unifies the pathways leading to impaired quality of life, especially with regard to age associated multiple co-morbidities, changes in perception and functioning, and the effects of long term care environments; it also introduces a science base for understanding and guiding interventions that can assist people to achieve their quality-of-life goals. Our aim in this paper is to outline interprofessional strategies that could relieve restrictions or distortions of the c-c process imposed by aging, ill-health, or a restricting environment. We do so by outlining potential deficits in the c-c process and matching these with restorative person-centered interprofessional interventions including interprofessional teamwork. Findings suggest that interprofessional assessment and team work is well suited to assisting the c-c process. We conclude that the groundwork has been prepared for developing training programs and clinical trials for interprofessional interventions targeting the c-c process.

The choices, choosing model of quality of life: linkages to a science base

BACKGROUND

A previous paper began with a critical review of current models and measures of quality of life and then proposed criteria for judging the relative merits of alternative models: preference was given to finding a model with explicit mechanisms, linkages to a science base, a means of identifying deficits amenable to rational restorative interventions, and with embedded values of the whole person. A conjectured model, based on the processes of accessing choices and choosing among them, matched the proposed criteria. The choices and choosing (c-c) process is an evolved adaptive mechanism dedicated to the pursuit of quality of life, driven by specific biological and psychological systems, and influenced also by social and environmental forces.

OBJECTIVE

In this paper the c-c model is examined for its potential to strengthen the science base for the field of quality of life and thus to unify many approaches to concept and measurement.

CONCLUSIONS

A third paper in this set will lay out a guide to applying the c-c model in evaluating impairments of quality of life and will tie this evaluation to corresponding interventions aimed at relieving restrictions or distortions of the c-c process; thus helping people to preserve and improve their quality of life. The fourth paper will demonstrate empirical analyses of the relationship between health imposed restrictions of options for living and conventional indicators of diminished quality of life.

A meta-regression to examine the relationship between aerobic fitness and cognitive performance

Many studies have been conducted to test the potentially beneficial effects of physical activity on cognition. The results of meta-analytic reviews of this literature suggest that there is a positive association between participation in physical activity and cognitive performance. The design of past research demonstrates the tacit assumption that changes in aerobic fitness contribute to the changes in cognitive performance. Therefore, the purpose of this meta-analysis was to use meta-regression techniques to statistically test the relationship between aerobic fitness and cognitive performance. Results indicated that there was not a significant linear or curvilinear relationship between fitness effect sizes (ESs) and cognitive ESs for studies using cross-sectional designs or posttest comparisons. However, there was a significant negative relationship between aerobic fitness and cognitive performance for pre-post comparisons. The effects for the cross-sectional and pre-post comparisons were moderated by the age group of the participants; however, the nature of this effect was not consistent for the two databases. Based on the findings of this meta-analytic review, it is concluded that the empirical literature does not support the cardiovascular fitness hypothesis. To confirm the findings of this review, future research should specifically test the dose-response relationship between aerobic fitness and cognitive performance. However, based upon the findings of this review, we also encourage future research to focus on other physiological and psychological variables that may serve to mediate the relationship between physical activity and cognitive performance.

Ageing and midline crossing inhibition

Age-related deficits of lower extremity lateral movements were investigated to identify a specific age range for the reappearance of midline crossing inhibition (MCI) along a developmental continuum. Ten individuals (five men and five women) representing each decade between the ages of 40 and 89 (five age groups) performed 108 seated trials on a lower extremity apparatus that measured choice reaction time and movement time. Midline crossing inhibition was operationally defined as statistically slower contralateral reaction times when compared to ipsilateral reaction times. The two eldest age groups (70- and 80-year-olds) exhibited MCI only on the first day of testing. Practice may facilitate cross lateral integration in normal ageing adults, even those of advanced age. There were no significant differences for movement times across age groups.

Inconsistency in serial choice decision and motor reaction times dissociate in younger and older adults

Intraindividual variability (inconsistency) in reaction time (RT) latencies was investigated in a group of younger (M=25.46 years) and older (M=69.29 years) men. Both groups performed 300 trials in 2-, 4-, and 8-choice RT conditions where RTs for decision and motor components of the task were recorded separately. A dissociation was evident in that inconsistency was greater in older adults for decision RTs when task demands relating to the number of choices and fatigue arising from time-on-task were high. For younger persons, a weak trend toward greater inconsistency in motor RTs was evident. The results are consistent with accounts suggesting that inconsistency in neurobiological mechanisms increases with age, and that attentional lapses or fluctuations in executive control contribute to RT inconsistency.

Utilization of Cognitive Support in Episodic Free Recall as a Function of Apolipoprotein E and Vitamin B₁₂ or Folate Among Adults Aged 75 Years and Older

Apolipoprotein E (APOE), vitamin B12, and folate were examined in relation to free recall among 167 community-based older adults. Cognitive support at encoding and retrieval was also taken into account. Participants were classified as APOE e4 or non-epsilon4 allele carriers and as either low or normal vitamin B12 or folate status. A significant association was identified between low vitamin B12 and the epsilon4 genotype in respect to free recall, but only in circumstances of low cognitive support. This result remained after removing dementia cases that occurred up to 6 years after testing. A similar, but nonsignificant, trend was evident in relation to folate. The research is discussed with reference to vulnerability models and genetic influences on brain reserves.

Components of Response Time as a Function of Age, Physical Activity, and Aerobic Fitness

Research suggests that there are differences in response time (RespT) as a function of age but that aerobic fitness might have a facilitatory effect on RespT. This study was designed to examine this relationship while addressing methodological issues from past research. Men from 3 age groups completed speeded tasks, a physical activity questionnaire, and an aerobic-fitness test. Results indicated that age has a negative impact on RespT (specifically premotor time and movement time). The interaction of aerobic fitness by age was also a significant predictor of RespT (specifically movement time) such that aerobic fitness was positively related to speed of performance for older participants. It is concluded that aerobic fitness might serve a preservative function for speeded tasks in older adults.

Physical activity, physiological, and psychomotor performance: a study of variously active older adult men

This research examined varying levels of physical activity and psychomotor and physiological function in variously active older men. Very active moderately active, and low active participants were tested on simple (SRT) and choice reaction time (CRT), coincidence-anticipation timing (CAT), and VO2max. No significant differences for age or height were found, although percentage of fat, and weight were statistically different. Active groups were leaner and lighter. VO2max was significantly different between groups, as physically active groups yielded geater values. SRT and CAT also yielded significantly different results with more active participants showing better performance. No between-groups significant differences resulted for CRT. Generally, increased levels of physical activity were related to superior physiological outcomes and improved psychomotor peformance.