Age differences in vigilance as a function of health-related physical fitness and task demands

Cardiorespiratory fitness is associated with sustained neurocognitive function during a prolonged inhibitory control task in young adults: An ERP study

Although beneficial associations between cardiorespiratory fitness and cognitive function have been established, whether cardiorespiratory fitness is related to behavioral and neuroelectric indices of performance during a prolonged inhibitory control task remains unknown. Young adults, categorized into High and Low Fitness groups, completed a 60-min Stroop task, while the N1 and P3 components of event-related potentials were measured. The results showed that the High Fitness group demonstrated shorter response times, regardless of the Stroop task congruency or time-on-task, than Low Fitness group. The High Fitness group also exhibited larger P3 amplitudes than the Low Fitness group, but no differences in N1 amplitudes were observed. These findings suggest that cardiorespiratory fitness during young adulthood has beneficial effects on task performance and attention allocation during an inhibitory control task, and these benefits can be sustained for 60 min.

Effect of Physical Exercise Program Based on Active Breaks on Physical Fitness and Vigilance Performance

The scientific literature has shown the beneficial effects of chronic Physical Exercise (PE) on a wide range of tasks that involve high-order functioning. For this reason, the present study aimed to investigate the effects of active breaks on physical fitness and vigilance performance in high school students through eight weeks of physical training. A total of 42 healthy students (age = 16.50 ± 0.59 years; height = 171.08 ± 8.07 cm; weight = 67.10 ± 13.76 kg) from one Andalusian high school (Spain) were assigned for convenience and matched into two groups, a Control Group (CG) and an Active-Break Group (ABG). The ABG performed two active breaks (based on strength and self-loading exercises) during the school day, first at 10:00 a.m. and second at 12:30 p.m. The participants were assessed before and after the training program using the Alpha-Fitness test battery and the Psychomotor Vigilance Task (PVT). Significant differences were observed in the post-training PVT results, compared with the pretraining PVT, showing ABG responding faster than CG. Thus, the presents study demonstrated that eight weeks of physical training affects vigilance performance (compared to CG) and improves the efficiency of vigilance in high school students, contributing to enhancement of quality of education.

Response Time Consistency Is an Indicator of Executive Control Rather than Global Cognitive Ability

OBJECTIVES

Intraindividual variability increases with age, but the relative strength of association with cognitive domains is still unclear. The objective of this study was to examine the relation between cognitive domains and the shape and spread of response time (RT) distributions as indexed by intraindividual standard deviation (ISD), and ex-Gaussian parameters (μ, σ, τ).

METHODS

Healthy adults (40 young [aged 18-30 years], 40 young-old [aged 65-74 years], and 41 old-old [aged 75-85 years]) completed neuropsychological testing and a touch-screen attention task from which ISD and ex-Gaussian parameters were derived. The relation between RT performance and cognitive domains (memory, processing speed, executive functioning) was examined with structural equation modeling (SEM), and the predictive power of RT distribution indices over age was investigated with linear regression.

RESULTS

ISD, μ, and τ, but not σ, showed a linear increase with age group. An SEM showed that independent of age, τ was most strongly associated with executive functioning, while μ exhibited less critical associations. Linear regression indicated that μ and τ explained a significant portion of variance in processing speed and executive ability in addition to age group. Memory was more parsimoniously predicted by age, without any significant contribution of ex-Gaussian parameters.

CONCLUSIONS

The findings suggest that exceptionally slow responses convey attention lapses through wavering of cognitive control, which strongly correspond to executive functioning tests. General slowing and extremely slow responses predicted processing speed and executive performance beyond age group, indicating that RT metrics are sensitive to differences in cognitive ability. (JINS, 2018, 24, 456-465).

Individual and Combined Associations of Cognitive and Mobility Limitations on Mortality Risk in Older Adults

OBJECTIVE

To evaluate the potential independent and combined associations of cognitive and mobility limitations on risk of all-cause mortality in a representative sample of the US older adult population who, at baseline, were free of cardiovascular and cerebrovascular disease.

PATIENTS AND METHODS

Data from the 1999 to 2002 National Health and Nutrition Examination Survey were used to identify 1852 adults (age, 60-85 years) with and without mobility and/or cognitive limitations. Hazard ratios (HRs) for mortality risk were calculated for 4 mutually exclusive groups: no limitation (group 1 as reference), mobility limitation only (group 2), cognitive limitation only (group 3), both cognitive and mobility limitations (group 4).

RESULTS

Compared with group 1, the adjusted HRs (95% CI) for groups 2, 3, and 4 were 1.72 (1.24-2.38), 2.00 (1.37-2.91), and 2.18 (1.57-3.02), respectively. The mortality risk when comparing group 4 (HR, 2.18) with group 3 (HR, 2.00), however, was not statistically significant (P=.65). Similarly, the mortality risk when comparing group 4 (HR, 2.18) with group 2 (HR, 1.72) was not statistically significant (P=.16).

CONCLUSION

Although the highest mortality risk occurred in those with both limitations (group 4), this point estimate was not statistically significantly different when compared with those with cognitive or mobility limitations alone.

The relationship between sustained attention and aerobic fitness in a group of young adults

BACKGROUND

A growing set of studies has shown a positive relationship between aerobic fitness and a broad array of cognitive functions. However, few studies have focused on sustained attention, which has been considered a fundamental cognitive process that underlies most everyday activities. The purpose of this study was to investigate the role of aerobic fitness as a key factor in sustained attention capacities in young adults.

METHODS

Forty-four young adults (18-23 years) were divided into two groups as a function of the level of aerobic fitness (high-fit and low-fit). Participants completed the Psychomotor Vigilance Task (PVT) and an oddball task where they had to detect infrequent targets presented among frequent non-targets.

RESULTS

The analysis of variance (ANOVA) showed faster responses for the high-fit group than for the low-fit group in the PVT, replicating previous accounts. In the oddball task, the high-fit group maintained their accuracy (ACC) rate of target detection over time, while the low-fit group suffered a significant decline of response ACC throughout the task.

DISCUSSION

Importantly, the results show that the greater sustained attention capacity of high-fit young adults is not specific to a reaction time (RT) sustained attention task like the PVT, but it is also evident in an ACC oddball task. In sum, the present findings point to the important role of aerobic fitness on sustained attention capacities in young adults.

Differences in Sustained Attention Capacity as a Function of Aerobic Fitness

PURPOSE

We investigated the relationship between aerobic fitness and sustained attention capacity by comparing task performance and brain function, by means of event-related potentials (ERP), in high- and low-fit young adults.

METHODS

Two groups of participants (22 higher-fit and 20 lower-fit) completed a 60-min version of the Psychomotor Vigilance Task (PVT). Behavioral (i.e., reaction time) and electrophysiological (ERP) (i.e., contingent negative variation and P3) were obtained and analyzed as a function of time-on-task. A submaximal cardiorespiratory fitness test confirmed the between-groups difference in terms of aerobic fitness.

RESULTS

The results revealed shorter reaction time in higher-fit than in lower-fit participants in the first 36 min of the task. This was accompanied by larger contingent negative variation amplitude in the same period of the task in higher-fit than in lower-fit group. Crucially, higher-fit participants maintained larger P3 amplitude throughout the task compared to lower-fit, who showed a reduction in the P3 magnitude over time.

CONCLUSIONS

Higher fitness was related to neuroelectric activity suggestive of better overall sustained attention demonstrating a better ability to allocate attentional resources over time. Moreover, higher fitness was related to enhanced response preparation in the first part of the task. Taken together, the current data set demonstrated a positive association between aerobic fitness, sustained attention, and response preparation.

Transient autonomic responses during sustained attention in high and low fit young adults

Maintaining vigilance over long periods of time is especially critical in performing fundamental everyday activities and highly responsible professional tasks (e.g., driving, performing surgery or piloting). Here, we investigated the role of aerobic fitness as a crucial factor related to the vigilance capacity. To this end, two groups of young adult participants (high-fit and low-fit) were compared in terms of reaction time (RT) performance and event-related heart rate responses in a 60′ version of the psychomotor vigilance task. The results showed shorter RTs in high-fit participants, but only during the first 24′ of the task. Crucially, this period of improved performance was accompanied by a decelerative cardiac response pattern present only in the high-fit group that also disappeared after the first 24′. In conclusion, high aerobic fitness was related to a pattern of transient autonomic responses suggestive of an attentive preparatory state that coincided with improved behavioural performance, and that was sustained for 24′. Our findings highlight the importance of considering the role of the autonomic nervous system reactivity in the relationship between fitness and cognition in general, and sustained attention in particular.

Investigating sustained attention ability in the elderly by using two different approaches: inhibiting ongoing behavior versus responding on rare occasions

Previous studies on sustained attention ability in the elderly produced inconsistent results. The aim of this study was to evaluate sustained attention performance in younger and older individuals by using, in a within-subjects design, two versions of the same task (the sustained attention to response task, SART) in which only in the response mode differed: in a traditionally formatted task (TFT), subjects had to respond to rare targets, and in a Go/No-Go task they had to withhold response to rare targets. Results showed that in the TFT SART only the older group exhibited a vigilance decrement. On the contrary, only young individuals showed a vigilance decrement in the Go/No-Go SART. These results showed that older individuals, who also reported less mind wandering and a higher level of motivation, exhibited preserved sustained attention ability in the Go/No-Go SART, which could be explained by increased engagement of cognitive control mechanisms in this population. The discrepancy in performance depending on the approach used also underlines the need for further studies on the nature of attention failures and their underlying mechanisms.

Sustained attention in the elderly: what do we know and what does it tell us about cognitive aging?

The ability to achieve and maintain the focus of cognitive activity on a given stimulation source or task, in other words to sustain attention or vigilance, is a fundamental component of human cognition. Given the omnipresent need for sustained attention in people's daily lives, a precise knowledge of the effects of normal aging on sustained attention is crucial. Findings in this topic are currently not consistent since they highlight either alteration or preservation or even the two, depending on the experimental approach used. Actually, the two existing approaches do not involve bottom-up and top-down processes at the same extent, which may in part account for this inconclusiveness. This review presents and attempts to explain these results by putting them into perspective with our current knowledge on cognitive aging and the two competing vigilance decrement theories, and discusses how they could inform us on our problems with sustaining attention over time.

Quadriceps strength and executive functions in older women

OBJECTIVE

The aim of this study is to answer the question whether the strength of the knee extensor musculus quadriceps (m. quadriceps), in particular, is related to specific executive functions and whether this relationship is independent of aerobic fitness. The clinical relevance of this question is that the m. quadriceps can still be trained in older people and executive functions are the most vulnerable to processes of aging.

DESIGN

In 41 cognitively intact older women, cognitive functioning was assessed by neuropsychological tests; isometric and isotonic quadriceps strength by the Quadrisotester and the 30-sec chair-stand test, respectively; and aerobic fitness by the 6-min walk test.

RESULTS

A significant proportion of the total variance of the executive functions, attention/working memory and inhibition, were explained by isometric/isotonic knee extensor strength and aerobic fitness, respectively. Extensor muscle strength, aerobic fitness, or one or more interactions did not explain a significant proportion of the total variance of other cognitive functions.

CONCLUSIONS

These data suggest that in older women, quadriceps strength is associated with the executive function, attention/working memory, and that this effect is independent of aerobic fitness, which seems to be associated more strongly with inhibition, another executive function.

Effects of Age and Task Complexity on EEG and Performance in Relation to Psychological States

The purpose of the present study is to analyse the effects of task complexity on the EEG spectral parameters and the extent to which age modulates this relationship. Subjects were divided into a junior and a senior group and engaged in a simple and a complex version of “Go/No go” tasks. Cognitive, subjective and electrophysiological data were combined. Our results indicated that there was an increase in alpha power over time only in the junior group in the simple task and the senior group in the complex one, suggesting that, depending on age, the increase in alpha band vary in a different way according with the degree of task complexity and could reflect some different phenomena. Cognitive performance were independent of age but for the main dimensions of motivation, seniors had higher scores, and they were less sleepy than juniors. Finally, this study showed correlations between cognitive performance, subjective evaluations and electrophysiological measures, and their value for understanding the subject’s engagement in a task.

Intraindividual Variability in Vigilance Performance: Does Degrading Visual Stimuli Mimic Age-Related “Neural Noise”?

Intraindividual performance variability, or inconsistency, has been shown to predict neurological status, physiological functioning, and age differences and declines in cognition. However, potential moderating factors of inconsistency are not well understood. The present investigation examined whether inconsistency in vigilance response latencies varied as a function of time-on-task and task demands by degrading visual stimuli in three separate conditions (10%, 20%, and 30%). Participants were 24 younger women aged 21 to 30 years (M = 24.04, SD = 2.51) and 23 older women aged 61 to 83 years (M = 68.70, SD = 6.38). A measure of within-person inconsistency, the intraindividual standard deviation (ISD), was computed for each individual across reaction time (RT) trials (3 blocks of 45 event trials) for each condition of the vigilance task. Greater inconsistency was observed with increasing stimulus degradation and age, even after controlling for group differences in mean RTs and physical condition. Further, older adults were more inconsistent than younger adults for similar degradation conditions, with ISD scores for younger adults in the 30% condition approximating estimates observed for older adults in the 10% condition. Finally, a measure of perceptual sensitivity shared increasing negative associations with ISDs, with this association further modulated as a function of age but to a lesser degree by degradation condition. Results support current hypotheses suggesting that inconsistency serves as a marker of neurological integrity and are discussed in terms of potential underlying mechanisms.

Changes in saccadic reaction time while maintaining neck flexion in the elderly

We investigated changes in saccadic reaction time during maintenance of neck flexion in elderly individuals. Subjects comprised 49 volunteers, including 19 young adults and 30 elderly adults. Elderly subjects were separated into 2 groups (trained group: n=18; untrained group: n=12) based on responses to a questionnaire concerning activities of daily living. Saccadic reaction time was measured at angles of neck flexion of 0 degrees (resting position), 10 degrees and 20 degrees , with the chin either resting on a stand (chin-on) or not (chin-off). Reaction time was determined as the latency to the beginning of eye movement toward the lateral target, which was moved at random intervals in jumps of 20 degrees amplitude. In the chin-on posture, the angle of neck flexion had no significant effect on reaction time in any group. In the chin-off posture, the flexion angle significantly affected reaction time in both young and elderly trained groups. Significant shortenings of the reaction time were obtained at 10 degrees and 20 degrees neck flexion in the young group, and at 20 degrees neck flexion in the elderly trained group. No significant shortening of reaction time was noted in the elderly untrained group. These findings suggest that neural function associated with shortening of saccadic reaction time due to neck extensor activity decreases with age, and the decrements become more marked with inactivity in daily life.

Physical activity and executive functions in the elderly with mild cognitive impairment

The primary goal of the present study was to examine whether in the elderly with mild cognitive impairment (MCI), the effect of physical activity measured directly following treatment, was reflected in an improvement in cognitive functioning in general or in executive functions (EF) in particular. Secondly, this study aimed to compare the effectiveness of two types of intervention, with varying intensities: walking and hand/face exercises. Forty-three frail, advanced elderly subjects (mean age: 86) with MCI were randomly divided into three groups, namely, a walking group (n=15), a group performing hand and face exercises (n=13), and a control group (n=15). All subjects received individual treatment for 30 minutes a day, three times a week, for a period of six weeks. A neuropsychological test battery, administered directly after cessation of treatment, assessed cognitive functioning. The results show that although a (nearly) significant improvement in tasks appealing to EF was observed in both the walking group and the hand/face group compared to the control group, the results should be interpreted with caution. Firm conclusions about the effectiveness of mild physical activity on EF in the oldest old can only be drawn after studies with larger number of subjects.

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.

Cognitive support at encoding attenuates age differences in recollective experience among adults of lower frontal lobe function

Free recall and recollective experience were investigated in relation to low and high cognitive support at encoding and to neuropsychological measures of frontal lobe function (FLF) in 105 healthy adults divided into 3 age groups (young, young-old, old). Statistically significant main effects suggested free recall was inferior with increasing age and lower FLF. For recollective experience however, a significant interaction between age and FLF was modified by the provision of cognitive support at encoding. Recognition measures classified as familiar did not vary according to age, neuropsychological function, or encoding condition. The results suggest that the neural systems of the prefrontal cortex underlie age differences in recollective experience and that cognitive support modifies the influence of those systems in old age.

Age differences in perceived workload across a short vigil

The main objective of this research was to investigate age differences in the perceived workload associated with the performance of a demanding, high event rate, vigilance task. Younger participants (n=26) aged 16 to 35 years (M=27.8) and older participants (n=24) aged 45 to 65 years (M=52.2) completed perceived workload scales (NASA-TLX) following a brief practice session (pretest) on the vigilance task, and then again following a test session (posttest) lasting nine minutes. In relation to the vigilance task, a statistically significant performance decrement was identified, but there was no evidence that performance differed according to age in respect to that decrement. However, a dissociation was found in relation to the perceived workload ratings: while no age differences were found in vigilance performance, the workload ratings revealed older participants to perceive a significantly greater increase in workload from pretest to posttest. These findings are considered theoretically in relation to the demands placed upon attentional resources, and their implications for both laboratory-based vigilance research, and workplace systems monitoring situations, are discussed.