Reliability and Validity of Inertial Sensor Assisted Reaction Time Measurement Tools among Healthy Young Adults.

The assessment of movement reaction time (RT) as a sideline assessment is a valuable biomarker for mild TBI or concussion. However, such assessments require controlled laboratory environments, which may not be feasible for sideline testing during a game. Body-worn wearable devices are advantageous as being cost-effective, easy to don and use, wirelessly transmit data, and ensure unhindered movement performance. This study aimed to develop a Drop-stick Test System (DTS) with a wireless inertial sensor and confirm its reliability for different standing conditions (Foam versus No Foam) and task types (Single versus Dual), and postures (Standing versus sitting). Fourteen healthy young participants (seven females, seven males; age 24.7 ± 2.6 years) participated in this study. The participants were asked to catch a falling stick attached to the sensor during a drop test. Reaction Times (RTs) were calculated from data for each trial from DTS and laboratory camera system (gold standard). Intraclass correlation coefficients (ICC 3,k) were computed to determine inter-instrument reliability. The RT measurements from participants using the camera system and sensor-based DTS showed moderate to good inter-instrument reliability with an overall ICC of 0.82 (95% CI 0.78-0.85). Bland-Altman plots and 95% levels of agreement revealed a bias where the DTS underestimated RT by approximately 50 ms.

Cerebral Cortical Activity During Academic Stress Amongst Undergraduate Medical Students at Kampala International University (Uganda).

Background: Stress among medical students is related to their academic lifespan; however, information on brain health among medical students from developing countries continues to be scarce. The objective of this study was to establish perceived academic stress levels, assess the ability to cope with stress, and investigate its effects on the visual reaction time (VRT), audio reaction time (ART), and tactile reaction time (TRT) in the somatosensory cortex among medical students of Uganda. Methods: This was a cross-sectional study conducted among preclinical (n = 88) and clinical (n = 96) undergraduate medical students at Kampala International University Western Campus. A standard Perceived Stress Scale (PSS) was used to categorize stress into low, moderate, and severe while the ability to cope with stress was categorized into below average, average, above average, and superior stresscoper (SS). Data on reaction time were acquired through VRT, ART, and TRT using the catch-a-ruler experiment, and this was analyzed using SPSS version 20. Results: This study shows that preclinical students are more stressed than clinical students (PSS prevalence for low stress = preclinical; clinical: 40, 60%). Moderate stress was 48.4 and 51.6% while high perceived stress was 75 and 25% among preclinical and clinical students. Among male and female students in preclinical years, higher TRT and VRT were found in clinical students showing that stress affects the tactile and visual cortical areas in the brain, although the VRT scores were only significantly (P = 0.0123) poor in male students than female students in biomedical sciences. Also, highly stressed individuals had higher TRT and ART and low VRT. SS had high VRT and ART and low TRT in preclinical students, demonstrating the importance of the visual cortex in stress plasticity. Multiple regression showed a close relationship between PSS, ability to cope with stress, age, and educational level (P < 0.05), demonstrating the importance of social and psychological support, especially in the biomedical sciences. Conclusion: Preclinical students suffer more from stress and are poorer SS than clinical students. This strongly impairs their cortical regions in the brain, thus affecting their academic productivity.

Dynamic Transitions Between Brain States Predict Auditory Attentional Fluctuations.

Achievement of task performance is required to maintain a constant level of attention. Attentional level fluctuates over the course of daily activities. However, brain dynamics leading to attentional fluctuation are still unknown. We investigated the underlying mechanisms of sustained attention using functional magnetic resonance imaging (fMRI). Participants were scanned with fMRI while performing an auditory, gradual-onset, continuous performance task (gradCPT). In this task, narrations gradually changed from one to the next. Participants pressed a button for frequent Go trials (i.e., male voices) as quickly as possible and withheld responses to infrequent No-go trials (i.e., female voices). Event-related analysis revealed that frontal and temporal areas, including the auditory cortex, were activated during successful and unsuccessful inhibition of predominant responses. Reaction-time (RT) variability throughout the auditory gradCPT was positively correlated with signal changes in regions of the dorsal attention network: superior frontal gyrus and superior parietal lobule. Energy landscape analysis showed that task-related activations could be clustered into different attractors: regions of the dorsal attention network and default mode network. The number of alternations between RT-stable and erratic periods increased with an increase in transitions between attractors in the brain. Therefore, we conclude that dynamic transitions between brain states are closely linked to auditory attentional fluctuations.

Cognitive function in soccer athletes determined by sleep disruption and self-reported health, yet not by decision-reinvestment.

Background: Sleep disruption (SD) increases sympathetic activity and cortisol secretion, and delays cognitive functions such as reaction-time (RT). Sympathetic activity of disturbed sleepers, is similar to those of so-called decision-reinvesters. Decision-reinvestment refers to traits in individuals with greater tendency to ruminate and reinvest in their decisions, with significant decrease in both motor-control and cognitive performance. Decision-making quality is a crucial attribute to athletic performance which relies on RT. Consequently, SD affects pitch-performance negatively, particularly in decision-reinvesters. This observational pilot-study examined the relationship between SD and cognitive function, perceived health, as well as reinvestment strategies. The hypothesis was that athletes with lower SD perceive their health better, report lower stress levels, perform better in cognitive tasks, and show lower tendency for decision-reinvestment. Methods: Twenty-one football player recorded their sleep with fit-trackers for 7 nights. Participants self-reported their mental and physical health, decision-reinvestment strategy, sleep behaviour, and perceived stress levels. Athletes then performed a set of cognitive tests to examine memory function (Backwards Corsi), selective attention (STROOP), and cognitive flexibility (Wisconsin Card Sorting Test, WCST). Normality was tested with a Shapiro-Wilk test, and analysed with a Pearson's or Spearman's correlation test. Results: Significant correlation appeared between extended sleep-interruptions and Backwards Corsi RT, r = 0.66, p = 0.010, as further in total sleep time and wellbeing r = 0.50, p = 0.029. A negative correlation exist in regard of pain scores and Backwards Corsi scores r = -0.57, p = 0.110. Physical health correlated with error-rates in the WCST, r = 0.69, p ≤ 0.001. Also, reinvestment negatively correlated with physical health, r = -0.80, p ≤ 0.001. Conclusion: Wellbeing relies on total sleep-time. Athletes with extended sleep-interruptions are slower in recalling memory, and those with greater reported pain have lower memory scores. Participants who rate physical health greater, have more error-rates in the WCST; indicating that cognitive flexibility is enhanced in individuals with inferior perceived health. However, individuals with lower physical health scores also have greater tendency to ruminate and reinvest in decisions, suggesting interrelation between reinvestment and physical health.

Asymmetries in Accessing Vowel Representations Are Driven by Phonological and Acoustic Properties: Neural and Behavioral Evidence From Natural German Minimal Pairs.

In vowel discrimination, commonly found discrimination patterns are directional asymmetries where discrimination is faster (or easier) if differing vowels are presented in a certain sequence compared to the reversed sequence. Different models of speech sound processing try to account for these asymmetries based on either phonetic or phonological properties. In this study, we tested and compared two of those often-discussed models, namely the Featurally Underspecified Lexicon (FUL) model (Lahiri and Reetz, 2002) and the Natural Referent Vowel (NRV) framework (Polka and Bohn, 2011). While most studies presented isolated vowels, we investigated a large stimulus set of German vowels in a more naturalistic setting within minimal pairs. We conducted an mismatch negativity (MMN) study in a passive and a reaction time study in an active oddball paradigm. In both data sets, we found directional asymmetries that can be explained by either phonological or phonetic theories. While behaviorally, the vowel discrimination was based on phonological properties, both tested models failed to explain the found neural patterns comprehensively. Therefore, we additionally examined the influence of a variety of articulatory, acoustical, and lexical factors (e.g., formant structure, intensity, duration, and frequency of occurrence) but also the influence of factors beyond the well-known (perceived loudness of vowels, degree of openness) in depth via multiple regression analyses. The analyses revealed that the perceptual factor of perceived loudness has a greater impact than considered in the literature and should be taken stronger into consideration when analyzing preattentive natural vowel processing.

Variaciones de los tiempos de reacción frente a cambios de perspectiva y tamaño de los estímulos 2D y 3D en atención selectiva / RVariations of reaction times explained by stimuli changes in size and perspective in 2D and 3D for selective attention

Resumen Frente a un estímulo objetivo, las personas procesan mediante la atención selectiva antes de realizar toma de decisiones. Si ese estímulo sufre algún cambio en su configuración 2D o 3D, ¿en qué casos una persona reacciona más rápido o más lento? La presente investigación evaluó la influencia de los cambios en las características de los estímulos en experimentos de tiempos de reacción en tareas de atención visual en videojuegos creados en Unity 3D. Para estudiar esas características, se realizó una comparación entre dos experimentos de videojuegos. El primer experimento se dividió en dos bloques: uno mostraba estímulos en 2D y otro en 3D. Se recolectó el tiempo de reacción de los participantes frente a esos estímulos y se obtuvo que el tiempo de reacción fue mayor en 3D en 28.33 ms. En el segundo experimento se incrementaron los bloques (de dos a ocho) para explicar las diferencias de los tiempos de reacción obtenidas en el primer experimento sea por el tamaño o el ángulo relativo que otorga una diferente perspectiva geométrica de presentación de los estímulos en 3D, para lo cual se modificaron algunas características de los estímulos del primer experimento. Los resultados después de comparar los distintos escenarios muestran que la modificación de las características tiene una influencia en la atención selectiva, pues los tiempos de reacción del primer experimento varían en comparación a los del segundo experimento dependiendo del cambio realizado (entre 65 y 67 ms de diferencia para 2D y entre 53 y 77 ms para 3D). En la discusión, se analiza el ámbito de los estímulos en 2D y 3D en el neuromarketing o el deporte ante los cambios de tamaño y ángulo de la cámara. En ambos escenarios, el presente trabajo sugiere evaluar para cada caso la modificación en sus presentaciones o herramientas en un consiguiente incremento del tiempo de reacción de los potenciales usuarios o equivalentemente en un nivel bajo de atención.

Abstract When facing a goal-stimulus, people have a certain degree of attention. Therefore, when stimulus has changes in 2D or 3D configuration, in which cases one would react faster or slower? The present research evaluated the influence of the changes in the characteristics of the stimuli in reaction time experiments in visual attention tasks in videogames made in Unity 3D. For this, a comparison was made between two videogame experiments. The first videogame experiment was divided into two blocks that showed stimuli a block in 2D videogame and another in 3D videogame respectively to the participants and collected their reaction times against these stimuli. The second videogame experiment increase the number of blocks (from two to eight) to explain the differences in the reaction times obtained in the first experiment either by the size or the relative angle of 3D presentation of the stimuli, for which some characteristics of the blocks of the first experiment. The results, after comparing the different scenarios, have shown that the modification of the characteristics changed selective attention, because the reaction times of the first experiment vary in comparison to those of the second experiment depending on the change made (between 65 and 67 ms of difference for 2D and between 53 and 77 ms for 3D). On the discussion, one can question the commercial spheres of 2D stimuli in the so-called neuromarketing or sports. In both scenarios, the present work suggests evaluating for each case changes in their presentations or tools in a consequent control the reaction time of potential users, and this translates into a level of attention control.

Attention regulation in women with ADHD and women with bipolar disorder: An ex-Gaussian approach.

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) show certain overlapping features, such as increased reaction time variability. Here, we tested whether more detailed ex-Gaussian reaction time distribution measures identify shared or disorder-specific impairments in ADHD and BD. The total assessed sample consisted of 60 women (20 each in ADHD, BD and control groups). We compared the groups on ex-Gaussian measures of mu, sigma, and tau from a flanker task (congruent and incongruent conditions), an oddball task, and a four-choice reaction time task (baseline and fast-incentive conditions of the `fast task'). The ex-Gaussian measures mu and sigma reflect the speed and variability of typical responses, while tau captures variability in infrequent slow responses. Compared to controls, both ADHD and BD groups showed significantly increased tau in the fast task baseline condition. Participants with BD further showed a significantly increased sigma compared to ADHD and control groups in the flanker task incongruent condition. Our findings indicate that the ex-Gaussian approach is informative in detecting shared and disorder-specific cognitive impairments in ADHD and BD that may represent objective markers of these two disorders.

The Way We Do the Things We Do: How Cognitive Contexts Shape the Neural Dynamics of Motor Areas in Humans.

In spontaneously triggered movements the nature of the executed response has a prominent effect on the intensity and the dynamics of motor areas recruitment. Under time pressure, the time course of motor areas recruitment is necessarily shorter than that of spontaneously triggered movements because RTs may be extremely short. Moreover, different classes of RT tasks allow examining the nature and the dynamics of motor areas activation in different cognitive contexts. In the present article, we review experimental results obtained from high temporal resolution methods (mainly, but not exclusively EEG ones), during voluntary movements; these results indicate that the activity of motor areas not only depends on the nature of the executed movement but also on the cognitive context in which these movements have to be executed.

Ayurvedic approach for improving reaction time of attention deficit hyperactivity disorder affected children.

Attention deficit/hyperactivity disorder (ADHD) is a behavioral disorder of children. It is the most common neurological disorder of childhood. The present study was conducted to examine the increase in attention span in 43 ADHD-affected children treated with different approaches. The reaction time was measured using a Vernier chronoscope (electronic). Selected children of both sexes in the age-group of 6-16 years were divided into three groups. In group A, 17 patients received syrup Ayurvedic compound I; in group B, 14 patients were treated with syrup Ayurvedic compound I + Shirodhara with milk; and in group C, 12 patients received syrup Ayurvedic compound II (placebo). The dose of the drug was 1.0 ml/kg body weight and the duration of treatment was 3 months. Group B showed highly significant (P<.001) improvement in total reaction time, while in group C the change was statistically nonsignificant P > 0.10. It was found that while the drug and Shirodhara were both effective in improving the reaction time of ADHD-affected children, the drug combined with Shirodhara was superior to the drug used alone.

Study of word naming reaction time of reading Chinese in patients with mild Alzheimer disease and mild cognitive impairment / 中国康复理论与实践

@#ObjectiveTo explore the pattern and the time course changes of semantic and phonological processing during Chinese language cognition study in patients with mild Alzheimer's disease(AD) and mild cognitive impairment (MCI).MethodsPatients with mild AD and MCI and normal controls matched with age, gender, level of education were enrolled in the single-character words naming task, which applied short and long stimulus onset asynchrony (SOA). Semantic, homophonic, semihomophonic and unrelated primes preceded the words as well as nonwords targets. Subjects were asked to read the targets aloud. Semantic and phonological priming effects were analyzed by comparing reaction time of semantic, homophonic or semihomophonic related targets to unrelated targets. The reaction time and accuracy for each response were recorded.ResultsThe mean reaction time of mild AD and MCI patients were prolonged for all types of priming in contrast with normal controls. Responses of the normal controls were faster during the long SOA comparing to short SOA, whereas the mild AD group's reaction time was longer for long SOA than for short SOA. Normal controls exhibited homophonic priming, whereas mild AD and MCI groups exhibited tonal inhibition effects.ConclusionThe speed of Chinese language cognitive processing decreased in mild AD and MCI patients. The phonological encoding and accessing ability may be impaired in mild AD and MCI.

The mechanism of the latent reacyion time in the elderly men. Differance by the task completions / 体力科学

The mechanism of the latent reaction time in task completion in elderly men was investigated by comparing the reaction time (RT), EMG-RT and motor time (MT) in young and elderly men. The motor performance was recorded as task completion through as a WS-RS, simple reaction or a choice reaction for each movement using a handgrip and switch.<BR>In this study, we found that the RT and EMG-RT of elderly men in all movements of WS-RS and choice reaction tasks were significantly longer than those of young men, especially in the choice reaction tasks were striking. Moreover, the MT of elderly men in all tasks was significantly longer than those of young men.<BR>These findings suggest that the latent RT and EMG-RT in a choice reaction task may be due to relayed information processing through as the discrimination and cognition functions in the brain, and that it may be also influenced by the mechanism of the latent reaction time of task completion in elderly men.