Speed Tasks Research Articles

Cognitive performance in ISS astronauts on 6-month low earth orbit missions.

Current and future astronauts will endure prolonged exposure to spaceflight hazards and environmental stressors that could compromise cognitive functioning, yet cognitive performance in current missions to the International Space Station remains critically under-characterized. We systematically assessed cognitive performance across 10 cognitive domains in astronauts on 6-month missions to the ISS. Twenty-five professional astronauts were administered the Cognition Battery as part of National Aeronautics and Space Administration (NASA) Human Research Program Standard Measures Cross-Cutting Project. Cognitive performance data were collected at five mission phases: pre-flight, early flight, late flight, early post-flight, and late post-flight. We calculated speed and accuracy scores, corrected for practice effects, and derived z-scores to represent deviations in cognitive performance across mission phases from the sample's mean baseline (i.e., pre-flight) performance. Linear mixed models with random subject intercepts and pairwise comparisons examined the relationships between mission phase and cognitive performance. Cognitive performance was generally stable over time with some differences observed across mission phases for specific subtests. There was slowed performance observed in early flight on tasks of processing speed, visual working memory, and sustained attention. We observed a decrease in risk-taking propensity during late flight and post-flight mission phases. Beyond examining group differences, we inspected scores that represented a significant shift from the sample's mean baseline score, revealing that 11.8% of all flight and post-flight scores were at or below 1.5 standard deviations below the sample's baseline mean. Finally, exploratory analyses yielded no clear pattern of associations between cognitive performance and either sleep or ratings of alertness. There was no evidence for a systematic decline in cognitive performance for astronauts on a 6-month missions to the ISS. Some differences were observed for specific subtests at specific mission phases, suggesting that processing speed, visual working memory, sustained attention, and risk-taking propensity may be the cognitive domains most susceptible to change in Low Earth Orbit for high performing, professional astronauts. We provide descriptive statistics of pre-flight cognitive performance from 25 astronauts, the largest published preliminary normative database of its kind to date, to help identify significant performance decrements in future samples.

Assessment of embodied visuospatial perspective taking in augmented reality: insights from a reaction time task

Understanding another person’s visual perceptions is known as visuospatial perspective taking, with evidence to date demonstrating it is delineated across two levels, depending on how different that perspective is. Some strategies for visuospatial perspective taking have also been found to involve embodied cognition. However, the current generalisation of these findings is limited due to experimental setup and the use of computer monitors as the interface for experimental tasks. Augmented reality interfaces could possibly extend on the generalisation of these findings by situating virtual stimuli in the real environment, thus providing a higher degree of ecological validity and experimental standardisation. This study aimed to observe visuospatial perspective taking in augmented reality. This was achieved in participant experiments (N=24) using the Left-Right behavioural speeded decision task, which requires participants to discriminate between target objects relative to the perspective of an avatar. Angular disparity and posture congruence between the avatar and participant were manipulated between each trial to delineate between the two levels of visuospatial perspective taking and understand its potentially embodied nature. Although generalised linear mixed modeling indicated that angular disparity increased task difficulty, unexpectedly findings on posture congruence were less clear. Together, this suggests that visuospatial perspective taking in this study can be delineated across two levels. Further implications for embodied cognition and empathy research are discussed.

Crossmodal correspondences between visual and speech angularity and tactile jaggedness of response key

Several studies reported various crossmodal correspondences related to tactile features. These previous studies have investigated tactile-related correspondences through explicit matching or subjective evaluation tasks, which required participants to recognize relationships between tactile and other sensory features or rate tactile materials on scales with adjective labels related to visual or auditory features. However, these tasks are prone to occur the experimenter-expectancy effects and arbitrary categorization of tactile materials by the labels, making it difficult to assess implicit and non-arbitrary aspects of crossmodal correspondences. To address this, we used a speeded classification task to examine whether the angularity/roundedness of visual and auditory stimuli correspond to tactile jaggedness/fluffiness. Participants distinguished between angularity or roundedness (Experiment 1: visual shapes; Experiment 2: speech sounds) by pressing right- or left-positioned response keys with task-irrelevant jaggedness or fluffiness without prior instruction on which key represented jaggedness/fluffiness. Results showed faster keypresses for jagged/fluffy responses to angular/rounded stimuli, suggesting an implicit correspondence between these sensory features except for the experimenter-expectancy effects and the influence of the labels. Unlike previous studies that examined the correspondence with simple tactile features (e.g., weight, size), our findings suggest that even complex tactile-quality features, such as jaggedness/fluffiness, implicitly correspond to visual and auditory angularity/roundedness.

Intellectual Differences Between Boys and Girls, 35 Years of Evolution in France from WISC-R to WISC-V.

The French adaptation of the Wechsler Intelligence Scale of Children, 5th edition (WISC-V) was an opportunity to examine if some common representations of gender differences in intellectual abilities are supported by empirical evidence. The WISC-V standardization sample provided data on a wide range of cognitive tests in a large sample of 6- to 16-year-old children representative of the French population. This sample included 517 boys and 532 girls. The WISC-V data were compared to those of the French standardization samples of three previous versions of the WISC (WISC-R, WISC-III, and WISC-IV). These four standardization samples span a 35-year period. The data analysis of the WISC-V standardization sample and the three previous versions of this intelligence scale showed that the performance gaps on intellectual tests between girls and boys have gradually narrowed over time. Almost no gender differences were observed in the WISC-V standardization sample, not only in IQ but also in key facets of intelligence. Data do not support the stereotype that girls are better at verbal tasks and boys are better at visuospatial tasks. However, some statistically significant differences remain, but the magnitude was generally small with no practical implications. The only important difference is in favor of girls and concerns performance on processing speed tasks that require visual discrimination, attentional control, and writing.

Brain volume loss after cranial irradiation: a controlled comparison study between photon vs proton radiotherapy for WHO grade 2-3 gliomas.

Radiation therapy (RT) is an integral treatment component in patients with glioma but associated with neurotoxicity. Proton RT (PRT), as compared with photon RT (XRT), reduces excess radiation to nontarget tissue. We used a retrospective method to evaluate brain imaging metrics of neurotoxicity after treatment with PRT and XRT for glioma. We analyzed brain volume change in thirty-four patients with WHO grade 2-3 gliomas treated with either PRT (n = 17) or XRT (n = 17). Both groups were carefully matched by demographic/clinical criteria and assessed longitudinally for two years post-radiotherapy. Brain volume change was measured as ventricular volume expansion in the tumor free hemisphere (contralateral to RT target) as a proxy indicator of brain volume loss. We further assessed the impact of volumetric changes on cognition in PRT patients, who completed neuropsychological testing as part of an outcome study. We found significant ventricular volume increases in the contralesional hemisphere in both groups at two years post-RT (F(1, 31) = 18.45, p < 0.000, partial η2 = 0.373), with greater volume change observed in XRT (26.55%) vs. PRT (12.03%) (M = 12.03%, SD = 16.26; F(1,31) = 4.26, p = 0.048, partial η2 = 0.121). Although, there was no group-level change on any cognitive test in PRT treated patients, individual changes on cognitive screening, working memory, processing speed and visual memory tasks correlated with contralesional brain volume loss. This study suggests progressive brain volume loss following cranial irradiation, with greater severity after XRT vs. PRT. Radiation-induced brain volume loss appears to be associated with measurable cognitive changes on an individual level. Prospective studies are warranted to validate these findings and their impacts on long-term cognitive function and quality of life. An improved understanding of the structural and functional consequences of cranial radiation is essential to develop neuroprotective strategies.

A Proposal for a Noxious Stimuli-Free, Moderate-Intensity Treadmill Running Protocol to Improve Aerobic Performance in Experimental Research on Rats.

Background/Objectives: Animal models can help understand human physiological responses, including the response to exercise and physical activity. However, many of these models incorporate noxious stimuli for various scientific purposes. We propose a noxious stimuli-free treadmill running training program for Rattus norvegicus species to study adaptations to aerobic exercise. Methods: In this study, rats were randomly allocated to training (n = 20) and sedentary (n = 20) groups. The training group underwent a program consisting of 30-50 min of treadmill running at 60% intensity, three times per week for 8 weeks. Maximum speed tasks (Tmax) were conducted to determine, adjust, and evaluate changes in fitness conditions. The rats had one week of familiarization with the treadmill, and a rubber ball was used at the back wall of the lane as a painless stimulus to encourage running. All assessments were conducted by two independent researchers in a double-blind manner, with data analysis conducted by a third-blind investigator. Results: A significant effect of time (η2p = 0.430, p < 0.001, large effect) could be found, showing differences between Tmax1 and Tmax2, and between Tmax1 and Tmax3 in both groups. The training group significantly outperformed the sedentary group (η2p = 0.266, p < 0.001, large effect). There was a significant interaction between time and condition (η2p = 0.152, p < 0.001, large effect). Conclusions: The proposed moderate-intensity treadmill running program could effectively differentiate between trained and sedentary conditions within both the short period of 4 weeks and the extended period of 8 weeks. This protocol can be used as a model for running on a treadmill for Rattus norvegicus species without the use of noxious stimuli.

Rapid instructed task learning is impaired after stroke and associated with impairments in prepotent inhibition and processing speed.

Motor rehabilitation is a central contributor to motor recovery after stroke. Rehabilitation could be hampered by stroke-associated cognitive impairments such as the decreased ability to follow instructions. Rapid instructed task learning (RITL) was never directly studied in older adults and subjects with stroke. The aim of this study was to assess RITL following stroke and its underlying cognitive determinants. Thirty-one subjects with chronic stroke and 36 age-matched controls completed a computerized cognitive examination that included an antisaccade task for measuring prepotent inhibition and processing speed and stimulus-response association task (NEXT) for measuring RITL and proactive inhibition. RITL abilities were impaired after stroke (d = 0.72), together with prepotent inhibition (d = 0.71) and processing speed (d = 1.12). A correlation analysis revealed that RITL is associated with prepotent inhibition abilities and with processing speed. Subjects with stroke show impairments in the ability to follow instructions, that may be related to their impaired prepotent inhibition and processing speed. The causal effect of RITL impairments on the responsivity to rehabilitation and on motor recovery should be examined. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Valence sound symbolism facilitates classification of vowels and emotional facial expressions.

Research on iconicity or sound symbolism chronicles associations between aspects of word meaning and word form. In valence sound symbolism, specifically, vowels were demonstrated to be associated with valence, so that the vowel /i/ (as in English sea) is judged to fit positively valenced stimuli, whereas the vowel /o/ (as in German Boot) is judged to fit negatively valenced stimuli. However, because previous findings were based on judgments or name invention tasks, they may reflect deliberate strategies. The present research aims to demonstrate the automaticity of valence sound symbolism in online language processing by means of a speeded response task. A total of 163 participants performed a speeded categorization task in which they were requested to classify one of two simultaneously presented stimuli, pseudowords containing the vowels /i/ or /o/ and pictures with positive or negative emotional facial expressions. Thus, stimulus pairings could be either congruent (/i/-words and positive expressions; /o/-words and negative expressions) or incongruent (/i/-words and negative expressions; /o/-words and positive expressions). We observed faster and more accurate responses for congruent over incongruent combinations (the simple effects were significant for positive but not for negative expressions). Thus, sound symbolic congruency (vs. incongruency) of an irrelevant stimulus facilitated responses, which accords with an automatic process contributing to valence sound symbolism and indicates that valence sound symbolism is deeply engrained in the human cognitive system. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Disparate trajectories of cognitive aging among American Indian and Alaskan Native people with and without HIV.

This study describes trajectories of cognitive aging among American Indian/Alaskan Native (AI/AN) adults with and without HIV and the role of immunosenescence longitudinally. We characterized trajectories of cognitive aging in a sample of 333 AI/AN and 309 non-Hispanic White (NHW) adults who were followed longitudinally for up to 20 years by the HIV Neurobehavioral Research Program (HNRP) across six U.S. research sites. We used growth curve modeling with autoregressive Lag-1 structures and heterogeneous residual variances to assess the role of ethnoracial identity and HIV grouping upon decline in trajectories of cognitive aging. HIV- AI/AN adults demonstrated earlier and steeper decline in normative trajectories of cognitive aging on tasks of processing speed, timed tasks of attention/working memory, executive function, and psychomotor speed in comparison to HIV- NHW adults. Accentuated trajectories of cognitive aging were evident in both HIV+ and HIV+ immunosuppressed groups in comparison to HIV- peers and were primarily driven by the role of immunosenescence. AI/AN disparities in trajectories of cognitive aging are evident and are likely explained by the interplay of biopsychosociocultural factors, including immunosenescence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Deep reinforcement learning-based low-latency task offloading for mobile-edge computing networks

Wireless Mobile Edge Computing (MEC) is an emerging solution to facilitate users’ computing. However, there are still some drawbacks, such as slow learning speed and high task latency. To overcome these difficulties, a deep reinforcement learning (DRL)-based task offloading (DRTO) framework is proposed, taking into account the time-varying nature of wireless channels and the unpredictability of task arrivals in multi-user MEC systems. Many deep neural networks (DNNs) are also used as scalable solutions to quickly determine the best offloading strategy by combining the perceptual capabilities of deep learning with the decision making capabilities of reinforcement learning (RL). Additionally, the concept of a minimum upper bound on the target Q-value is utilized to address the value overestimation problem that occurs during offload policy updates. This approach aims to minimize the latency of offload decisions by considering different channel environments, variable latency constraints among many users, and limited computational resources. Simulation results show that the algorithm reduces computation time and latency while achieving near-optimal performance compared to traditional Deep Deterministic Policy Gradient (DDPG) and Q-learning optimization methods. In addition, DRTO achieves more than 99.6% computational speedup compared to current almost ideal benchmarking techniques. Thus, the DRTO computational offload approach offers great potential for reducing overall system latency and improving the user experience.

Age-based stereotype threat effects on dynamic balance in healthy older adults.

Stereotype threat can lead older adults to perceive their experiences in a biased manner, giving rise to interfering thoughts and negative emotions that generate stress and anxiety. Negative beliefs about aging may serve as an additional factor that increases the need for attentional demand, potentially resulting in a performance level below their actual capabilities. In the present study, we asked whether negative aging stereotypes influence a dynamic balance task and explored the means to counteract them in healthy elderly participants. The performance of balance was compared in two groups of participants aged 65 to 75 years (n = 22) under stereotype threat or reduced-threat situation. Balance abilities were tested under dynamic conditions, requiring participants to maintain balance on a moving platform and using a gradient of difficulty (with eyes open or closed, without or with foam). Postural performance was evaluated by means of posturographic evaluation of the center of pressure displacement and motion analysis. Additionally, we investigated the effects of stereotype threat on a preferred walking speed task and on the Timed Up and Go (TUG) test. Participants under stereotype threat showed poorer balance, particularly in challenging conditions (eyes closed, on foam), with less effective body segments stabilization. Their postural stabilization on foam was worse compared to a solid surface. Conversely, those in the reduced threat condition maintained better body segment stabilization across all conditions, indicating consistent postural control regardless of the presence of foam. Stereotype threat did not affect preferred walking speed or the time to complete the "Time Up and Go" test. This study provides the first description of age-based stereotype threat effects on a dynamic balance task and how to counteract them in healthy older adults. We suggest that the decrease in postural performance observed in participants exposed to stereotype threat can be attributed to a split in attentional focus between negative intrusive thoughts and the attention needed for maintaining balance. These findings open new perspectives on how to overcome negative expectations when evaluating and training physical abilities, thereby contributing to fall prevention among older adults.

Cognitive Speed in Neurodegenerative Disease: Comparing Mean Rate and Inconsistency Within and Across the Alzheimer's and Lewy Body Spectra in the COMPASS-ND Study.

Alzheimer's disease (AD) and Lewy body disease (LBD) are characterized by early and gradual worsening perturbations in speeded cognitive responses. Using simple and choice reaction time tasks, we compared two indicators of cognitive speed within and across the AD and LBD spectra: mean rate (average reaction time across trials) and inconsistency (within person variability). The AD spectrum cohorts included subjective cognitive impairment (SCI, n = 28), mild cognitive impairment (MCI, n = 121), and AD (n = 45) participants. The LBD spectrum included Parkinson's disease (PD, n = 32), mild cognitive impairment in PD (PD-MCI, n = 21), and LBD (n = 18) participants. A cognitively unimpaired (CU, n = 39) cohort served as common benchmark. We conducted multivariate analyses of variance and discrimination analyses. Within the AD spectrum, the AD cohort was slower and more inconsistent than the CU, SCI, and MCI cohorts. The MCI cohort was slower than the CU cohort. Within the LBD spectrum, the LBD cohort was slower and more inconsistent than the CU, PD, and PD-MCI cohorts. The PD-MCI cohort was slower than the CU and PD cohorts. In cross-spectra (corresponding cohort) comparisons, the LBD cohort was slower and more inconsistent than the AD cohort. The PD-MCI cohort was slower than the MCI cohort. Discrimination analyses clarified the group difference patterns. For both speed tasks, mean rate and inconsistency demonstrated similar sensitivity to spectra-related comparisons. Both dementia cohorts were slower and more inconsistent than each of their respective non-dementia cohorts.

Dual-task costs in speed tasks: a comparison between elite ice hockey, open-skill and closed-skill sports athletes.

Ice hockey is a high pace sports game that requires players to integrate multiple skills. Players face perceptive, cognitive, and motor tasks concurrently; hence, players are regularly exposed to dual- or multi-task demands. Dual-tasking has been shown to lead to decreased performance in one or both performed tasks. The degree of performance reductions might be modulated by the exhaustion of cognitive resources. Literature on dual-task paradigms that combine sport-relevant elements is scarce. Therefore, a novel paradigm combining cyclical speed of the lower extremities and concurrent visuo-verbal speed reading was tested and validated. Additionally, to understand the nature of dual-task costs, the relationship between these costs and cognitive performance was assessed. We hypothesized occurrence of dual-task costs in all athletes without relationship to single task performance. Differences in dual-task cost were expected between open-skill and closed-skill sports, as well as differing expertise levels. Level of cognitive function was expected to explain some variance in dual-task cost. A total of 322 elite athletes (120 ice hockey, 165 other team sports, 37 closed-skill sports) participated in this study. Each athlete performed a tapping task, a visuo-verbal speed-reading task, and both tasks simultaneously. All ice hockey athletes performed additional cognitive tests assessing processing speed, spatial working memory, sustained attention, two choice reaction time, and motor inhibition. The results of paired-sample t-tests confirmed significant dual-task costs for all sport groups (p < 0.001). Single-task performance and dual-task costs correlated weakly in a positive direction. A one-way ANOVA revealed significantly greater costs in closed-skill sports athletes than in ice hockey and other sports athletes. No significant differences in dual-task costs were found between teams of differing expertise levels. Lastly, no significant regression model was found to predict dual-task costs from cognitive test performance. Our study suggests that this novel dual-task paradigm was successful in inducing dual-task costs for all elite athletes. Since it distinguishes between closed-skill and open-skill sports athletes, it might be a valuable diagnostic tool for performance and for talent development of open-skill athletes. Dual-task costs could not be relevantly predicted via cognitive performance measures, questioning cognitive resource theories as an explanation for dual-task costs.

Cognitive Dysfunction in Non-CNS Metastatic Cancer: Comparing Brain Metastasis, Non-CNS Metastasis, and Healthy Controls

Limited research has compared cognition of people with non-central nervous system metastatic cancer (NCM) vs. metastatic brain cancer (BM). This prospective cross-sectional study was comprised 37 healthy controls (HC), 40 NCM, and 61 BM completing 10 neuropsychological tests. The NCM performed below HCs on processing speed and executive functioning tasks, while the BM group demonstrated lower performance across tests. Tasks of processing speed, verbal fluency, and verbal memory differentiated the clinical groups (BM < NCM). Nearly 20% of the NCM group was impaired on at least three neuropsychological tests whereas approximately 40% of the BM group demonstrated the same level of impairment.

Sex differences in motor learning flexibility are accompanied by sex differences in mushroom spine pruning of the mouse primary motor cortex during adolescence.

Although males excel at motor tasks requiring strength, females exhibit greater motor learning flexibility. Cognitive flexibility is associated with low baseline mushroom spine densities achieved by pruning which can be triggered by α4βδ GABAA receptors (GABARs); defective synaptic pruning impairs this process. We investigated sex differences in adolescent pruning of mushroom spine pruning of layer 5 pyramidal cells of primary motor cortex (L5M1), a site essential for motor learning, using microscopic evaluation of Golgi stained sections. We assessed α4GABAR expression using immunohistochemical and electrophysiological techniques (whole cell patch clamp responses to 100 nM gaboxadol, selective for α4βδ GABARs). We then compared performance of groups with different post-pubertal mushroom spine densities on motor learning (constant speed) and learning flexibility (accelerating speed following constant speed) rotarod tasks. Mushroom spines in proximal L5M1 of female mice decreased >60% from PND35 (puberty onset) to PND56 (Pubertal: 2.23 ± 0.21 spines/10 μm; post-pubertal: 0.81 ± 0.14 spines/10 μm, P < 0.001); male mushroom spine density was unchanged. This was due to greater α4βδ GABAR expression in the female (P < 0.0001) because α4 -/- mice did not exhibit mushroom spine pruning. Although motor learning was similar for all groups, only female wild-type mice (low mushroom spine density) learned the accelerating rotarod task after the constant speed task (P = 0.006), a measure of motor learning flexibility. These results suggest that optimal motor learning flexibility of female mice is associated with low baseline levels of post-pubertal mushroom spine density in L5M1 compared to male and female α4 -/- mice.

Neurocognitive outcomes in young adults with cochlear implants: The role of early language access and crossmodal plasticity

Many children with profound hearing loss have received cochlear implants (CI) to help restore some sense of hearing. There is, however, limited research on long-term neurocognitive outcomes in young adults who have grown up hearing through a CI. This study compared the cognitive outcomes of early-implanted (n = 20) and late-implanted (n = 21) young adult CI users, and typically hearing (TH) controls (n=56), all of whom were enrolled in college. Cognitive fluidity, nonverbal intelligence, and American Sign Language (ASL) comprehension were assessed, revealing no significant differences in cognition and nonverbal intelligence between the early and late-implanted groups. However, there was a difference in ASL comprehension, with the late-implanted group having significantly higher ASL comprehension. Although young adult CI users showed significantly lower scores in a working memory and processing speed task than TH age-matched controls, there were no significant differences in tasks involving executive function shifting, inhibitory control, and episodic memory between young adult CI and young adult TH participants. In an exploratory analysis of a subset of CI participants (n = 17) in whom we were able to examine crossmodal plasticity, we saw greater evidence of crossmodal recruitment from the visual system in late-implanted compared with early-implanted CI young adults. However, cortical visual evoked potential latency biomarkers of crossmodal plasticity were not correlated with cognitive measures or ASL comprehension. The results suggest that in the late-implanted CI users, early access to sign language may have served as a scaffold for appropriate cognitive development, while in the early-implanted group early access to oral language benefited cognitive development. Furthermore, our results suggest that the persistence of crossmodal neuroplasticity into adulthood does not necessarily impact cognitive development. In conclusion, early access to language – spoken or signed – may be important for cognitive development, with no observable effect of crossmodal plasticity on cognitive outcomes.

Neurocognitive and psychiatric outcomes associated with postacute COVID-19 infection without severe medical complication: a meta-analysis

BackgroundCognitive symptoms are often reported by those with a history of COVID-19 infection. No comprehensive meta-analysis of neurocognitive outcomes related to COVID-19 exists despite the influx of studies after the...

Lower-Body Power, Body Composition, Speed, and Agility Performance among Youth Soccer Players.

Speed and agility have been described as crucial abilities for soccer players. The purpose of this study was to analyze, in detail, the variance in speed and agility tasks explained by lower-body power after controlling for age and body composition. The participants were 96 male soccer players aged 16.1 ± 1.6 years. Body composition (stature, body fat percentage-BF%, body mass, and fat-free mass-FFM), lower-body power (countermovement jump-CMJ, and squat jump-SJ), speed (5-, 10-, and 35 m sprints), and agility (t-test) were assessed. Among body composition parameters, BF% presented the highest number of significant relationships with speed and agility, with the strength of correlations ranging from small (5 m sprint, r = 0.25) to large (35 m sprint, r = 0.52). The strongest correlation coefficient emerged between FFM and the 35 m sprint (r = -0.65). Significant correlations were found between vertical jump performance and the 35 m sprint (CMJ: r = -0.68; SJ: r = -0.69), followed by the t-test (CMJ: r = -0.35; SJ: r = -0.47). The hierarchical multiple regression model could explain 22% to 67% of the variance observed in agility scores and speed. BF% remained the most statistically significant negative predictor of all regression models. The CMJ remained a statistically significant positive predictor of the 35 m sprint (β = -0.581, p ≤ 0.01) after controlling for age and body composition. Integrating programs targeting lower-body power might be important to enhance speed and agility performance in youth soccer. On the other hand, future research based on multidisciplinary approaches to investigate the effects of nutritional strategies in reducing or preventing gains in BF% is still needed, which remained a significant predictor of sprint and agility performance in the final models.

Exploring the challenges of avoiding collisions with virtual pedestrians using a dual-task paradigm in individuals with chronic moderate to severe traumatic brain injury.

Individuals with a moderate-to-severe traumatic brain injury (m/sTBI), despite experiencing good locomotor recovery six months post-injury, face challenges in adapting their locomotion to the environment. They also present with altered cognitive functions, which may impact dual-task walking abilities. Whether they present collision avoidance strategies with moving pedestrians that are altered under dual-task conditions, however, remains unclear. This study aimed to compare between individuals with m/sTBI and age-matched control individuals: (1), the locomotor and cognitive costs associated with the concurrent performance of circumventing approaching virtual pedestrians (VRPs) while attending to an auditory-based cognitive task and; (2) gaze behaviour associated with the VRP circumvention task in single and dual-task conditions. Twelve individuals with m/sTBI (age = 43.3 ± 9.5 yrs; >6 mo. post injury) and 12 healthy controls (CTLs) (age = 41.8 ± 8.3 yrs) were assessed while walking in a virtual subway station viewed in a head-mounted display. They performed a collision avoidance task with VRPs, as well as auditory-based cognitive tasks (pitch discrimination and auditory Stroop), both under single and dual-task conditions. Dual-task cost (DTC) for onset distance of trajectory deviation, minimum distance from the VRP, maximum lateral deviation, walking speed, gaze fixations and cognitive task accuracy were contrasted between groups using generalized estimating equations. In contrast to CTLs who showed locomotor DTCs only, individuals with m/sTBI displayed both locomotor and cognitive DTCs. While both groups walked slower under dual-task conditions, only individuals with m/sTBI failed to modify their onset distance of trajectory deviation and maintained smaller minimum distances and smaller maximum lateral deviation compared to single-task walking. Both groups showed shorter gaze fixations on the approaching VRP under dual-task conditions, but this reduction was less pronounced in the individuals with m/sTBI. A reduction in cognitive task accuracy under dual-task conditions was found in the m/sTBI group only. Individuals with m/sTBI present altered locomotor and gaze behaviours, as well as altered cognitive performances, when executing a collision avoidance task involving moving pedestrians in dual-task conditions. Potential mechanisms explaining those alterations are discussed. Present findings highlight the compromised complex walking abilities in individuals with m/sTBI who otherwise present a good locomotor recovery.

Examining the Impact of Reading Fluency on Lexical Decision Results in French 6th Graders.

How does lexical decision behavior vary in students with the same grade level (all students were in their first year of middle-school), but different levels of reading fluency? Here, we tested a prediction of the dual-route model: as fluency increases, variations in the results may reflect a decreasing reliance on decoding and an increasing reliance on the lexical route. 1,501 French 6th graders passed a one-minute speeded reading-aloud task evaluating fluency, and a ten-minute computerized lexical decision task evaluating the impact of lexicality, length, word frequency and pseudoword type. As predicted, the word length effect varied dramatically with reading fluency, with the least fluent students showing a length effect even for frequent words. The frequency effect also varied, but solely in proportion to overall reading speed, suggesting that frequency affects the decision stage similarly in all readers, while length disproportionately impacts poor readers. Response times and errors were also affected by pseudoword type (e.g., letter substitutions or transpositions), but these effects showed minimal variation with fluency. Overall, lexical decision variables were excellent predictors of reading fluency (r = 0.62). Our results highlight the variability in middle-school reading ability and describe how a simple lexical decision task can be used to assess students' mental lexicon (vocabulary) and the automatization of reading skills.