Effect of additional tasks on the reaction time of braking responses in simulated car driving: beyond the PRP effect.

The presentation of one task increases the reaction time on a subsequent task, if stimulus onset asynchrony (SOA) between tasks is short. This psychological refractory period (PRP) effect is typically leveling off as SOA approaches 1 s, which has been documented both in classical laboratory paradigms and in simulated car driving. Here we report a more persistent effect on the subsequent task that goes well beyond the typical duration of the PRP effect. In a driving simulator, 120 healthy older participants followed a lead car that mostly drove at a constant speed. They had to maintain a regular distance from the lead car and had to brake when the lead car braked. Participants also engaged in several additional tasks during driving (two types of tasks: typing three-digit numbers, stating arguments on public issues). SOA between the braking task and the last preceding additional task was 11.49 s ± 1.99 (mean and standard deviation). In a control condition, the braking task was administered without additional tasks. Main performance outcome was Braking Reaction Time (RT, in s), as the interval between onset of brake lights of the lead car and the moment participants released the gas pedal. Additionally, foot movement time (MT, in s), i.e., the difference between gas pedal release and brake pedal onset, was considered for possible compensation behavior. Inter-vehicle distance to the lead car (in m) was taken into account as a moderator. We found that RT averaged 0.77 s without additional tasks, but averaged 1.45 s with additional tasks. This RT difference was less pronounced at smaller inter-vehicle distances, and was not compensated for by faster MT from the gas pedal to the brake pedal. We conclude that detrimental effects of additional tasks on subsequent braking responses can be more persistent than suggested by the PRP effect, possibly because of maintaining multiple task sets, requiring increased executive control. We further conclude that potential detrimental effects can be ameliorated at small inter-vehicle distances by mobilizing extra cognitive resources when response urgency is higher. As a practical implication of our study, distracting stimuli can have persisting detrimental effects on traffic safety.

Chronic exercise effects on overall depression severity and distinct depressive symptoms in older adults: A protocol of a systematic and meta-analytic review.

INTRODUCTION: There is high evidence that chronic exercise benefits overall depression severity in older adults. However, late-life depression is characterized by considerable heterogeneity in clinical manifestation emphasizing the need for more individualized exercise intervention programs. Therefore, the objective of the proposed review is to investigate the effects of chronic exercise on overall depression severity and on different symptoms of depression in randomized controlled trials (RCTs) including older adults with a mean age of at least 60 years, and by considering the moderating effects of intervention characteristics and individual characteristics. METHODS: This protocol is guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P). We will use the Population-Intervention-Comparator-Outcomes-Study design (PICOS) criteria for study inclusion and will search the following database sources for relevant RCTs: Web of Science, Academic Search Complete, CINAHL, APA Psycinfo, SPORTDiscuss, Cochrane. Two independent reviewers will conduct the study selection, data extraction, and quality assessment. Disagreement will be solved by a third reviewer. Primary outcome will be changes in overall depression severity and secondary outcomes will encompass changes in symptoms of depression as defined by the DSM-5, such as sleep quality, fatigue, anxiety, mood, apathy, changes in weight, information processing speed, and executive functions, from baseline until the end of the intervention and to any available intermediary measurement or follow up. Meta-analysis will be undertaken to synthesize the effects of chronic exercise on primary and secondary outcomes. Subgroup analysis will investigate the moderating effects of intervention characteristics (frequency, intensity, duration, type of exercise, cognitive demand, social interactions, exercise supervision, behavioral change techniques, compliance, study design, dropout-rate, type of control group) and individual characteristics (age, sex, education, functional capacity, global cognition, population) on primary and secondary outcomes. Additionally, we plan to assess quality of evidence and publication bias, and to carry out sensitivity analysis. CONCLUSION: The results of the proposed review are anticipated to have a substantial impact on research and clinical practice. On the one hand, the review's conclusions could form the foundation for developing evidence-based recommendations for individualized exercise programs that alleviate depression in older adults. On the other hand, by revealing research gaps, the review results could encourage the formulation of research questions for further RCTs. PROTOCOL REGISTRATION NUMBER: This protocol has been published in the Prospero repository (PROSPERO 2022 CRD42022361418, available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022361418).

Inefficient frontal and parietal brain activation during dual-task walking in a virtual environment in older adults.

Walking while performing an additional cognitive task (dual-task walking; DT walking) is a common yet highly demanding behavior in daily life. Previous neuroimaging studies have shown that performance declines from single-task (ST) to DT conditions are accompanied by increased prefrontal cortex (PFC) activity. This increment is particularly pronounced in older adults and has been explained either by compensation, dedifferentiation, or inefficient task processing in fronto-parietal circuits. However, there is only limited evidence for the hypothesized fronto-parietal activity changes measured under real-life conditions such as walking. In this study, we therefore assessed brain activity in PFC and parietal lobe (PL), to investigate whether higher PFC activation during DT walking in older adults is related to compensation, dedifferentiation, or neural inefficiency. Fifty-six healthy older adults (69.11 ± 4.19 years, 30 female) completed three tasks (treadmill walking at 1 m/s, Stroop task, Serial 3's task) under ST and DT conditions (Walking + Stroop, Walking + Serial 3's), and a baseline standing task. Behavioral outcomes were step time variability (Walking), Balance Integration Score BIS (Stroop), and number of correct calculations S3corr (Serial 3's). Brain activity was measured using functional near-infrared spectroscopy (fNIRS) over ventrolateral and dorsolateral PFC (vlPFC, dlPFC) and inferior and superior PL (iPL, sPL). Neurophysiological outcome measures were oxygenated (HbO2) and deoxygenated hemoglobin (HbR). Linear mixed models with follow-up estimated marginal means contrasts were applied to investigate region-specific upregulations of brain activation from ST to DT conditions. Furthermore, the relationships of DT-specific activations across all brain regions was analyzed as well as the relationship between changes in brain activation and changes in behavioral performance from ST to DT. Data indicated the expected upregulation from ST to DT and that DT-related upregulation was more pronounced in PFC (particularly in vlPFC) than in PL regions. Activation increases from ST to DT were positively correlated between all brain regions, and higher brain activation changes predicted higher declines in behavioral performance from ST to DT. Results were largely consistent for both DTs (Stroop and Serial 3's). These findings more likely suggest neural inefficiency and dedifferentiation in PFC and PL rather than fronto-parietal compensation during DT walking in older adults. Findings have implications for interpreting and promoting efficacy of long-term interventions to improve DT walking in older persons.

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.

Cognitive-motor multitasking in older adults: a randomized controlled study on the effects of individual differences on training success.

BACKGROUND: Multitasking is an essential part of our everyday life, but performance declines typically in older age. Many studies have investigated the beneficial effects of cognitive, motor and combined cognitive-motor training on multitasking performance in older adults. Previous work, however, has not regarded interindividual differences in cognitive functioning and motor fitness that may affect training benefits. The current study aims to identify whether different training programs may have differential effects on multitasking performance depending on the initial level of cognitive functioning and motor fitness. METHODS: We conduct a 12-week single-blinded randomized controlled trial. A total of N = 150 healthy older adults are assigned to either a single cognitive, a single motor, or a simultaneous cognitive-motor training. Participants are trained twice per week for 45 min. A comprehensive test battery assesses cognitive functions, motor and cardiovascular fitness, and realistic multitasking during walking and driving in two virtual environments. We evaluate how multitasking performance is related not only to the training program, but also to participants' initial levels of cognitive functioning and motor fitness. DISCUSSION: We expect that multitasking performance in participants with lower initial competence in either one or both domains (cognitive functioning, motor fitness) benefits more from single-task training (cognitive training and/or motor training). In contrast, multitasking performance in participants with higher competence in both domains should benefit more from multitask training (simultaneous cognitive-motor training). The results may help to identify whether tailored training is favorable over standardized one-size-fits all training approaches to improve multitasking in older adults. In addition, our findings will advance the understanding of factors that influence training effects on multitasking. TRIAL REGISTRATION: DRKS (German Clinical Trials Register), DRKS00022407. Registered 26/08/2020 - Retrospectively registered at https://www.drks.de/drks_web/setLocale_EN.do.

Lifestyle Matters: Effects of Habitual Physical Activity on Driving Skills in Older Age.

Research on multitasking driving has suggested age-related deterioration in driving performance. It has been shown that physical and cognitive functioning, which are related to driving performance and decline with aging, are positively associated with physical activity behavior. This study aimed to explore whether driving performance decline becomes severe with advancing age and whether physical activity behavior modifies age-related deterioration in driving performance. A total of one hundred forty-one healthy adults were categorized into three groups based on their age; old-old (74.21 ± 2.33 years), young-old (66.53 ± 1.50 years), and young adults (23.25 ± 2.82 years). Participants completed a realistic multitasking driving task. Physical activity and cardiorespiratory fitness levels were evaluated. Older groups drove more slowly and laterally than young adults, and old-old adults drove slower than young-old ones across the whole driving course. Physical activity level did not interact with the aging effect on driving performance, whereas cardiovascular fitness interacted. Higher-fitness young-old and young adults drove faster than higher-fitness old-old adults. Higher-fitness old adults drove more laterally than higher-fitness young adults. The present study demonstrated a gradual decline in driving performance in old adults, and cardiorespiratory fitness interacted with the aging effect on driving performance. Future research on the interaction of aging and physical activity behavior on driving performance in different age groups is of great value and may help deepen our knowledge.

Distracting tasks have persisting effects on young and older drivers' braking performance.

It is well established that car driving performance suffers when the driver concurrently engages in a distracting activity, such as talking on a cell phone. The present study investigates whether the effects of driver distraction are short-lived, or rather persist for some time. Age-related differences are evaluated as well. Sixty-three young and 61 older adults were tested in a driving simulator. They were asked to follow a lead car that drove at a constant speed, and to concurrently engage in a pseudorandom sequence of distracting tasks (typing, reasoning, memorizing). When the lead car braked, participants had to brake as well to prevent a collision. The stimulus onset asynchrony between the braking task and the last preceding distraction was 11.49 ± 1.99 s. Each person was tested once in a multitasking condition (as described above), and once in a control condition without distracting tasks. Outcome measures quantified distance keeping and lane keeping while participants braked to the lead car. We found that braking responses differed significantly between conditions; this difference could be interpreted as a combination of performance deficits and compensatory strategies in the multitasking condition compared to the control condition. We also found significant differences between age groups, which could be interpreted similarly. Differences between age groups were less pronounced in the multitasking than in the control condition. All observed effects were associated with participants' executive functioning. Our findings confirm that distractions have an impact on braking responses, and they document for the first time that this impact can persist for about 11.5 s. We attribute this persistence to a task set effect, and discuss the practical relevance of our findings.

The Relationship Between the Perceived Movement Quality and the Kinematic Pattern of Complex Skills in Gymnastics.

The study aimed to investigate the relationship between the perceived movement quality of a gymnastics skill and its kinematic pattern, as well as the influence of expertise. Thirty participants with different levels of gymnastics expertise (n = 10 visual experts, n = 10 motor experts and n = 10 novices) were recruited for the study. They were instructed to compare the movement quality of eleven video sequences, showing different handstand - back handspring performances. To extract the kinematics, the performances were digitized. By means of an ongoing cluster analysis, the kinematic pattern as well as the pattern of the perceived movement quality of the skills were determined for each experimental group. The results of the cluster analysis of the different experimental groups were analyzed and compared. Expertise differences were found regarding the pattern of the perceived movement quality. There was a significant correlation between the dendrograms of the visual experts and the motor experts (p = .021), as well as between the dendrograms of the visual experts and the novices (p = .011). There was no significant correlation between the dendrograms of the motor experts and the novices (p = .173). The pattern of the perceived movement quality was not correlated with the holistic kinematic pattern of judged skills (p > .143). These results suggest perceptual and cognitive differences of the participants due to their different previous visual and motor experience.

Exploring Cognitive and Perceptual Judgment Processes in Gymnastics Using Essential Kinematics Information.

The aim of the current study was to transfer the method of using isolated kinematics information combined with the examination of perceptual-cognitive processes to gymnastics judging and thereby investigating the informational underpinnings of skilled perception and judgment. More specifically, a combination of process-tracing methods that include both the gaze pattern (via eye tracking) and the performance judgment (via ratings on a six-point Likert scale) of participants with different gymnastics expertise (visual experts, n = 14, motor experts, n = 17, novices, n = 18) was employed for gymnastics performances of a floor routine (round off, back handspring, back layout somersault), which were shown as videos in original or in stick-figure format. Gaze pattern was analyzed for the whole floor routine as well as for the particular temporal-spatial windows of the three motor skills. Differences between visual experts, motor experts, and novices could be found concerning the judgment score, ηp 2 = .242, and the judgment accuracy, ηp 2 = .196, but not the gaze pattern. The significant interaction effects between skill and format for the gaze pattern show the importance of the last skill in the judgment processes. Further research should investigate the influence of judgment instruction on the gaze pattern as well as the importance of the last skill for the judgment score.