Using error-estimation to probe the psychological processes underlying contextual interference effects.

Although the learning benefits of interleaved practice schedules relative to blocked schedules are well-reported, the mechanisms underlying these effects are not fully understood. Researchers have generally suggested that random schedules of practice increase task-related information processing which arises due to switching between variations of the same task (or switching between different tasks). Thus, one potentially useful way to both probe and manipulate contextual interference is to pair it with error estimation during practice. Forced error estimation increases task-related information processing and recording these estimates provides insight into learners' self-awareness of their errors. In the present study, 84 participants were randomly allocated to four groups. Participants practiced a timing task under blocked or random schedules, with and without error estimations prior to feedback. During the acquisition phase, three target times were trained (1500, 1700, 1900 ms), with feedback delivered after every trial. We used delayed post-tests (24 hrs later) to evaluate the retention of these target times and their transfer to two new target times (1600, 1800 ms). Participants who practiced with a random schedule performed worse (i.e., greater absolute error) than those with a blocked schedule during acquisition (p = .006); however, randomly scheduled participants also showed reduced error (p = .004) on the retention and transfer tests. Although prompting error estimations led to greater self-reported mental effort being invested on the task (p = .001), error estimation was not reliably associated with superior learning (p = .133). The accuracy of error estimations did not differ as a function of practice structure (p = .070), although the accuracy of error estimations improved during acquisition (p = .006). Findings highlight the robustness of the contextual interference effect, but we did not find evidence that error estimations moderated the effect on this task. It is in some ways surprising that we found an effect of contextual interference, as past-work suggests that interference effects are attenuated (or eliminated) when participants switch between different parameters of the same task. We speculate that this might be due to the difficulty of the task; even though participants switched between parametric variations of the same task, the distinction between parameters was subtle (i.e., tenths of a second).

A Comparison of Three Different Warm-Ups on 800-Meter Running Performance in Elite Division I Track Athletes - A Pilot Study.

Track and Field athletes perform different types of warm-ups at varying levels of volume and/or intensity prior to competition. Theoretically, this prepares sport specific muscles for activity by increasing muscle temperature, thus mitigating the chance for injury. There is a paucity of information regarding the optimum level for warm-ups regarding maximizing performance in middle distance events. The aim of this study was to examine the effects of three different warm-ups on 800-meter performance. Thirteen Division I student-athletes (seven males and six females) from the Southeastern Conference (SEC) who were middle distance runners participated in this study. We utilized a randomized, cross-over study design to test low, medium, and high-volume warm-up protocols on 800-meter performance. Trials were conducted over a span of three weeks on a SEC University outdoor track. We used a 2 (Sex) x 3 (Warm-Up Protocol) mixed-factor ANOVA, and our results show a main effect of warm-up volume that is not moderated by sex. Post-hoc tests reveal a high-volume warm-up yields superior results for the 800-meter run in comparison to a medium volume warm-up, which provides better results than a low-volume warm-up. These findings may be of value in providing information in program design for coaches on the most effective warm-up protocols for 800-meter runners. Identifying the best warm-up protocol to prime an 800-meter runner for peak performance may not only assist in preventing injury, but enhance performance thus leading to an increased of achievement, and confidence in personal ability.

Exploring the reliability and sensitivity of the EEG power spectrum as a biomarker.

INTRODUCTION: The slope of the electroencephalography (EEG) power spectrum (also referred to as 1/f noise) is an important consideration when calculating narrow-band power. However, psychophysiological data also suggest this slope is a meaningful signal itself, not merely background activity or noise. We present two different methods for quantifying the slope of the power spectrum and assess their reliability and sensitivity. METHODS: We used data from N = 60 participants who had EEG collected during rest, a videogame task, and a second period of rest. At all phases of the experiment, we calculated the "spectral slope" (a regression-based method fit to all datapoints) and the "aperiodic slope" (estimated with the fitting oscillations with 1/f algorithm FOOOF). For both methods we assessed: their reliability, their sensitivity to the transition from rest to task, their sensitivity to changes during the videogame task itself, and the agreement between the two measures. RESULTS: Across resting phases, both spectral and aperiodic slopes showed a high degree of reliability. Both methods also showed a steepening of the power spectrum on-task compared to rest. There was also a high degree of consistency between the two methods in their estimate of the underlying slope, but FOOOF explained more variance in the power spectra across regions and type of activity (rest versus task). CONCLUSION: The slope of the power spectrum is a highly reliable individual difference and sensitive to within-subject changes across two different methods of estimation. Moving forward, we generally recommend the use of the FOOOF algorithm for its ability to account for narrow-band signals, but these data show how regression-based approaches produce similar estimates of the spectral slope, which may be useful in some applications.

P3b as an electroencephalographic index of automatic associations of exercise-related images.

OBJECTIVE: Interest in automatic associations of exercise and physical activity as potential contributors to behavior is rising. However, the measurement of these associations presents a challenge, since the reliability and validity of behavioral tests (despite their widespread usage) is unsatisfactory by most accounts. As a possible alternative, an electroencephalographic (EEG) index (i.e., P3b amplitude) was examined in the present study. DESIGN: We used a mixed-factor design, with one group of insufficiently and one group of sufficiently physically active participants being compared across different experimental conditions. METHODS: Thirty-seven insufficiently and thirty-six sufficiently active participants viewed exercise-related images presented within series of negative, neutral, or positive images and rated all images as negative (unpleasant) or positive (pleasant) while EEG recordings were obtained. The amplitude of the P3b component of the EEG-derived event-related potential, time-locked to the onset of exercise images in each context (series), was extracted as the dependent variable. RESULTS: Insufficiently active participants rated the exercise-related images as neutral-to-positive, whereas sufficiently active participants rated the images as positive. However, all participants exhibited the smallest P3b amplitude when the images were presented in the neutral context, suggesting that the images were registering as neutral. CONCLUSION: Exercise-related images may evoke neutral automatic associations, but these associations may differ from how individuals reflectively rate the same images. P3b amplitude may be useful in detecting such discrepancies and potentially a promising (evidence-based) option for assessing automatic associations of exercise stimuli.

Does learning a skill with the expectation of teaching it impair the skill's execution under psychological pressure if the skill is learned with analogy instructions?

OBJECTIVE: Having learners practice a motor skill with the expectation of teaching it (versus an expectation of being tested on it) has been revealed to enhance skill learning. However, this improvement in skill performance is lost when the skill must be performed under psychological pressure due to 'choking under pressure.' The present study will investigate whether this choking effect is caused by an accrual of declarative knowledge during skill practice and could be prevented if a technique (analogy instructions) to minimize the accrual of declarative knowledge during practice is employed. DESIGN: We will use a 2 (Expectation: teach/test) x 2 (Instruction: analogy/explicit) x 2 (Posttest: high-pressure/low-pressure) mixed-factor design, with repeated measures on the last factor. METHODS: A minimum of 148 participants will be quasi-randomly assigned (based on sex) to one of four groups. Participants in the teach/analogy and teach/explicit groups will practice golf putting with the expectation of teaching putting to another participant, and analogy instructions or explicit instructions, respectively. Participants in the test/analogy and test/explicit groups will practice golf putting with the expectation of being tested on their putting, and analogy instructions or explicit instructions, respectively. The next day all participants will complete low- and high-pressure putting posttests, with their putting accuracy serving as the dependent variable.

Adverse Childhood Experiences, Depressive Symptoms, Functional Dependence, and Physical Activity: A Moderated Mediation Model.

BACKGROUND: Adverse childhood experiences, depressive symptoms, and functional dependence are interrelated. However, the mechanisms underlying these associations remain unclear. The authors investigated the potential of depressive symptoms to mediate the effect of adverse childhood experiences on functional dependence in older age and whether physical activity moderated this mediation. METHOD: Data from 25,775 adults aged 62 (9) years from the Survey of Health Ageing and Retirement in Europe were used in adjusted linear mixed-effects models to test whether depressive symptoms mediated the associations between adverse childhood experiences and functional dependence in activities of daily living (ADL) and instrumental ADL (IADL) and whether physical activity moderated these mediations. RESULTS: The results showed a graded association between the number of adverse childhood experiences (0 vs 1 and 0 vs ≥2) and the number of functional limitations in both ADL (bs = 0.040 and 0.067) and IADL (bs = 0.046 and 0.076). These associations were mediated by depressive symptoms. Physical activity reduced the effect of adverse childhood experiences on depressive symptoms (bs = -0.179 and -0.515) and tempered the effect of depressive symptoms on functional dependence both in ADL (b = -0.073) and IADL (b = -0.100). As a result of these reductions, the effect of adverse childhood experiences and depressive symptoms on functional dependence in ADL (Ps > .081) and IADL (Ps > .528) was nonsignificant in physically active participants. CONCLUSIONS: These findings suggest that, after age 50, engaging in physical activity more than once a week protects functional independence from the detrimental effects of adverse childhood experiences and depression. In inactive individuals, the detrimental effects of adverse childhood experiences on functional dependence are mediated by depressive symptoms.

Physically active individuals look for more: An eye-tracking study of attentional bias.

Attentional capture by exercise-related stimuli is important for the regulation of physical activity. Attentional processing underlying this capture has been investigated with indirect behavioral measures based on reaction times. To investigate more direct measures of visual spatial attention toward physical activity (vs. inactivity) stimuli, we used eye-tracking and a visual dot probe task in 77 young adults with various level of physical activity. Reaction times to detect a dot appearing in the area previously occupied by a physical activity (vs. inactivity) stimulus were an indirect measure of attentional bias. The first picture gaze and viewing time were more direct measures of attentional orienting and attentional engagement, respectively. Pupil dilation was an indicator of arousal. Reaction times revealed a two-way interaction between the location of the dot and participants' usual level of physical activity. Only participants with a high level of physical activity more quickly detected a dot when it appeared in the area previously occupied by a physical activity stimulus. Eye-tracking results showed greater odds of first gazing at physical activity stimuli and for a longer time, and a greater decrease in pupil size when viewing physical activity stimuli when usual level of physical activity was moderate or high, but not low. The variance explained in the outcomes ranged from 13.9% (pupil dilation) to 40% (reaction times). Overall, as hypothesized, compared to less physically active participants, participants who were more physically active demonstrated indirect (reaction times) and direct (first gaze, viewing time) evidence of a more pronounced attentional bias toward physical activity. Physical activity stimuli biased attention, with a pronounced effect when the level of physical activity was higher. These findings suggest that physical activity stimuli are relevant to the current concerns of moderately and highly active individuals.

Design and Refinement of a Data Quality Assessment Workflow for a Large Pediatric Research Network.

BACKGROUND: Clinical data research networks (CDRNs) aggregate electronic health record data from multiple hospitals to enable large-scale research. A critical operation toward building a CDRN is conducting continual evaluations to optimize data quality. The key challenges include determining the assessment coverage on big datasets, handling data variability over time, and facilitating communication with data teams. This study presents the evolution of a systematic workflow for data quality assessment in CDRNs. IMPLEMENTATION: Using a specific CDRN as use case, the workflow was iteratively developed and packaged into a toolkit. The resultant toolkit comprises 685 data quality checks to identify any data quality issues, procedures to reconciliate with a history of known issues, and a contemporary GitHub-based reporting mechanism for organized tracking. RESULTS: During the first two years of network development, the toolkit assisted in discovering over 800 data characteristics and resolving over 1400 programming errors. Longitudinal analysis indicated that the variability in time to resolution (15day mean, 24day IQR) is due to the underlying cause of the issue, perceived importance of the domain, and the complexity of assessment. CONCLUSIONS: In the absence of a formalized data quality framework, CDRNs continue to face challenges in data management and query fulfillment. The proposed data quality toolkit was empirically validated on a particular network, and is publicly available for other networks. While the toolkit is user-friendly and effective, the usage statistics indicated that the data quality process is very time-intensive and sufficient resources should be dedicated for investigating problems and optimizing data for research.

Natural History of Cardiomyopathy in Adult Dogs With Golden Retriever Muscular Dystrophy.

Background Duchenne muscular dystrophy (DMD) is an X-linked disease that causes progressive muscle weakness. Affected boys typically die from respiratory or cardiac failure. Golden retriever muscular dystrophy (GRMD) is genetically homologous with DMD and causes analogous skeletal and cardiac muscle disease. Previous studies have detailed features of GRMD cardiomyopathy in mostly young dogs. Cardiac disease is not well characterized in adult GRMD dogs, and cardiac magnetic resonance (CMR) imaging studies have not been completed. Methods and Results We evaluated echocardiography and CMR in 24 adult GRMD dogs at different ages. Left ventricular systolic and diastolic functions, wall thickness, and myocardial strain were assessed with echocardiography. Features evaluated with CMR included left ventricular function, chamber size, myocardial mass, and late gadolinium enhancement. Our results largely paralleled those of DMD cardiomyopathy. Ejection fraction and fractional shortening correlated well with age, with systolic dysfunction occurring at ≈30 to 45 months. Circumferential strain was more sensitive than ejection fraction in early disease detection. Evidence of left ventricular chamber dilatation provided proof of dilated cardiomyopathy. Late gadolinium enhancement imaging showed DMD-like left ventricular lateral wall lesions and earlier involvement of the anterior septum. Multiple functional indexes were graded objectively and added, with and without late gadolinium enhancement, to give cardiac and cardiomyopathy scores of disease severity. Consistent with DMD, there was parallel skeletal muscle involvement, as tibiotarsal joint flexion torque declined in tandem with cardiac function. Conclusions This study established parallels of progressive cardiomyopathy between dystrophic dogs and boys, further validating GRMD as a model of DMD cardiac disease.

Neural and Attentional Correlates of Intrinsic Motivation Resulting from Social Performance Expectancy.

Some models of motivation distinguish between intrinsic and extrinsic motivation. While past work has examined the neural and cognitive correlates of extrinsic motivation, research on intrinsic motivation has relied primarily on behavioral measures of performance and learning. In particular, no past work has examined the neural and cognitive correlates of social performance expectancy, which is linked to intrinsic motivation. The current study manipulated expectancy of difficult (vs. easy) trials on a cued flanker task and assessed attentional scope and performance. EEG was used to examine motor-action preparation as measured by suppression of beta band activity over the motor cortex and feedback processing as measured by the Reward Positivity (RewP). Results revealed expectancy of difficult (vs. easy) trials narrowed attentional scope, reduced beta activity over the motor cortex, and enhanced RewP amplitudes to win feedback. These findings suggest that enhancing intrinsic motivation through expectancies of positive social comparison engages similar neural and cognitive correlates as extrinsic motivators high in motivational intensity.

A Comparison of Mental Workload in Individuals with Transtibial and Transfemoral Lower Limb Loss during Dual-Task Walking under Varying Demand.

OBJECTIVES: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand. METHODS: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e., varying physical demand). RESULTS: The findings revealed both groups of participants (TT LL vs. TF LL) exhibited a similar EEG theta synchrony response as either the cognitive or the physical demand increased. Also, while individuals with TT LL maintained similar performance on the cognitive task during seated and walking conditions, those with TF LL exhibited performance decrements (slower response times) on the cognitive task during the walking in comparison to the seated conditions. Furthermore, those with TF LL neither exhibited regional differences in EEG low-alpha power while walking, nor EEG high-alpha desynchrony as a function of cognitive task difficulty while walking. This lack of alpha modulation coincided with no elevation of theta/alpha ratio power as a function of cognitive task difficulty in the TF LL group. CONCLUSIONS: This work suggests that both groups share some common but also different neurocognitive features during dual-task walking. Although all participants were able to recruit neural mechanisms critical for the maintenance of cognitive-motor performance under elevated cognitive or physical demands, the observed differences indicate that walking with a prosthesis, while concurrently performing a cognitive task, imposes additional cognitive demand in individuals with more proximal levels of amputation.

Cerebral cortical networking for mental workload assessment under various demands during dual-task walking.

While several studies have examined attentional reserve (via event-related potentials) and mental effort (via EEG spectral content) from various cortical regions during dual-task walking, none have assessed changes in the magnitude of interregional (cortico-cortical) communication as a measure of mental workload. Therefore, by deploying a traditional montage of electrode sites centered over the motor planning region as well as a more comprehensive graph theory-based approach encompassing the entire scalp, this study aimed to systematically examine changes in the magnitude of functional connectivity underlying cortico-cortical communication to assess changes in mental workload under various levels of challenge. Specifically, the Weighted Phase Lag Index (WPLI) was computed to assess the changes in magnitude of functional connectivity as participants performed a cognitive task under two demands (low and high) and two conditions (seated and walking). The results revealed enhanced fronto-centro-temporo-parietal theta connectivity during dual-task walking relative to being seated as well as a reduced inhibition of fronto-centro-temporo-parieto-occipital alpha networking as the demand on the secondary cognitive task increased. Collectively, these findings may reflect greater recruitment of task relevant processes to respond to increased cognitive-motor demands and thus an elevation of mental workload in an effort to maintain performance under varying levels of challenge. This work has the potential to inform future mental workload assessment applications in patient populations, including those who employ prostheses during cognitive-motor performance under various task demands.

Cognitive resources moderate the adverse impact of poor perceived neighborhood conditions on self-reported physical activity of older adults.

Poor neighborhood conditions are associated with lower levels of physical activity for older adults but socio-ecological models posit that physical activity depends on both environmental and individual factors. Older adults' ability to overcome environmental barriers to physical activity may partially rely on cognitive resources. However, evidence on the moderating role of these cognitive resources in the associations between environmental barriers and physical activity is still lacking. We analyzed cross-national and longitudinal data on 28,393 adults aged 50 to 96 years as part of the SHARE. Lack of access to services and neighborhood nuisances were used as indicators of poor neighborhood conditions. Delayed recall and verbal fluency were used as indicators of cognitive resources. Confounder-adjusted generalized estimation equations were conducted to test associations between neighborhood conditions and self-reported moderate physical activity, as well as the moderating role of cognitive resources. Results showed that poor neighborhood conditions reduced the odds of engagement in physical activity. Cognitive resources robustly reduced the adverse influence of poor neighborhood conditions on physical activity. Participants with lower cognitive resource scores showed lower odds of engaging in physical activity when neighborhood conditions were poorer, whereas these conditions were not related to this engagement for participants with higher cognitive resource scores. These findings suggest that cognitive resources can temper the detrimental effect of poor neighborhood conditions on physical activity. Public policies should target both individual and environmental factors to tackle the current pandemic of physical inactivity more comprehensively.

Opportunities to sit and stand trigger equivalent reward-related brain activity.

A recent theory contends that behaviors minimizing energetic cost are rewarding (Cheval et al., 2018). However, direct experimental evidence supporting this theory is lacking. To fill this knowledge gap, we investigated the effect of energy expenditure on reward-related brain activity in a pre-registered study. This preregistered study included thirty-one participants who were equipped with an electroencephalography (EEG) cap and performed a monetary incentive delay task. After attempting to quickly respond to a target, participants were given feedback instructing them to retrieve a token (reward condition) or to wait (no reward condition). In half of the rewarding trials, participants stood up to retrieve a token, thereby increasing energy expenditure. In the other half, participants just had to extend their arm to retrieve a token, thereby minimizing energy expenditure. The contingent negative variation event-related potential (ERP) component preceding the motor response was used as an indicator of reward pursuit. The reward positivity ERP component time-locked to feedback onset was used to determine reward valuation. Results showed that response time, contingent negative variation, and the reward positivity were not influenced by energy expenditure (remaining seated vs. standing up). This null effect of conditions was confirmed using equivalence tests. These results do not support the theory of energetic cost minimization but the equivalent effect of sitting and standing on reward-related brain activity is new knowledge that could contribute to shed light on the neural processes underlying the pandemic of physical inactivity.

Does limiting pre-movement time during practice eliminate the benefit of practicing while expecting to teach?

Past research has revealed practicing and studying a motor skill with the expectation of teaching it to another person increases the amount of time participants spend preparing for movement during practice trials of the skill. However, it is unknown whether the increased motor preparation time explains the benefit of expecting to teach on motor learning. To address this question, we had participants practice golf putting with the expectation of teaching the skill to another participant the following day or the expectation of being tested on the skill the following day. We limited the motor preparation time for half of the participants who expected to teach and half of the participants who expected to test, and allowed the remaining participants to take as much motor preparation time as they liked. All participants were tested on their putting the next day. We predicted that participants who expected to teach would exhibit superior posttest performance, but this benefit would be exclusive to those participants who also practiced with unlimited motor preparation. Although the current data did not support this hypothesis, we also conducted an exploratory analysis in which we aggregated data from two prior experiments. This cumulative analysis suggested that expecting to teach does indeed enhance motor learning, but not through motor preparation during practice.

Challenge, motivation, and effort: Neural and behavioral correlates of self-control of difficulty during practice.

Self-control of task-relevant parameters during practice results in superior learning. However, the mechanisms underlying this effect remain unclear. To investigate these effects, we collected frontal alpha asymmetry (ΔFAS) and midline frontal theta (ΔMFT). Sixty novice participants were randomized into a self-controlled group, controlling difficulty for each block in a videogame task, or a yoked group, with difficulty matched to a self-controlled counterpart. ΔMFT decreased with better performance and increased at higher levels of difficulty, but the effect of difficulty was moderated by group. There was also a Block x Group interaction for ΔMFT. Changing difficulty depended on a participant's group and score, and participant engagement in the self-controlled group. This pattern of results suggests that self-controlled participants were better prepared to deal with more difficult environments. These data provide insight into the physiological factors that might explain self-controlled learning effects.

Learning a skill with the expectation of teaching it impairs the skill's execution under psychological pressure.

When practicing a motor skill, learners who are expecting to teach it to another person exhibit superior gains in skill execution and declarative knowledge. Since skills acquired with large gains in declarative knowledge are highly susceptible to decrement under psychological pressure, it is possible the advantage of expecting to teach is lost when performing the learned skill under pressure. To test this hypothesis, we had 40 participants practice golf putting with the expectation of teaching (teach group) and 42 participants practice with the expectation of being tested (test group). The next day, all participants performed low- and high-pressure posttests. The teach group outperformed the test group under low pressure but not high pressure, where the teach group's performance declined to that of the test group. Further, the teach group reported using more declarative knowledge during the posttests than the test group, but declarative knowledge use did not mediate the performance decline from low- to high-pressure posttest. Taken together, results suggest expecting to teach benefits skill learning, but this advantage is lost when performing the skill under high pressure. However, whether skill breakdown under high pressure is caused by an increase in declarative knowledge use remains an open question. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effects of a Multi-Ingredient Energy Supplement on Cognitive Performance and Cerebral-Cortical Activation.

This study assessed whether a multi-ingredient energy supplement (MIES) could enhance cerebral-cortical activation and cognitive performance during an attention-switching task. Cerebral-cortical activation was recorded in 24 young adults (12 males, 12 females; 22.8 ± 3.8 yrs) via electroencephalography (EEG) both at rest and during the attention-switching task before (pretest) and 30 min after (posttest) consumption of a single serving of a MIES (MIES-1), two servings of a MIES (MIES-2), or a placebo (PL) in a double-blinded, randomized crossover experimental design. EEG upper-alpha power was assessed at rest and during the task, wherein d' (Z[hit rate]-Z[false alarm rate]) and median reaction time (RT) for correct responses to targets on attention-hold and attention-switch trials were analyzed. For both d' and RT, the Session (MIES-1, MIES-2, PL) × Time (pretest, posttest) interaction approached statistical significance (p = .07, η2p = 0.106). Exploring these interactions with linear contrasts, a significant linear effect of supplement dose on the linear effect of time was observed (ps ≤.034), suggesting the pretest-to-posttest improvement in sensitivity to task target stimuli (d') and RT increased as a function of supplement dose. With respect to upper-alpha power, the Session × Time interaction was significant (p < .001, η2p = 0.422). Exploring this interaction with linear contrasts, a significant linear effect of supplement dose on the linear effect of time was observed (p < .001), suggesting pretest-to-posttest increases in cerebral-cortical activation were a function of supplement dose. In conclusion, our findings suggest that MIES can increase cerebral-cortical activation and RT during task performance while increasing sensitivity to target stimuli in a dose-dependent manner.

Biomechanical and neurocognitive performance outcomes of walking with transtibial limb loss while challenged by a concurrent task.

Individuals who have sustained loss of a lower limb may require adaptations in sensorimotor and control systems to effectively utilize a prosthesis, and the interaction of these systems during walking is not clearly understood for this patient population. The aim of this study was to concurrently evaluate temporospatial gait mechanics and cortical dynamics in a population with and without unilateral transtibial limb loss (TT). Utilizing motion capture and electroencephalography, these outcomes were simultaneously collected while participants with and without TT completed a concurrent task of varying difficulty (low- and high-demand) while seated and walking. All participants demonstrated a wider base of support and more stable gait pattern when walking and completing the high-demand concurrent task. The cortical dynamics were similarly modulated by the task demand for both groups, to include a decrease in the novelty-P3 component and increase in the frontal theta/parietal alpha ratio power when completing the high-demand task, although specific differences were also observed. These findings confirm and extend prior efforts indicating that dual-task walking can negatively affect walking mechanics and/or neurocognitive performance. However, there may be limited additional cognitive and/or biomechanical impact of utilizing a prosthesis in a stable, protected environment in TT who have acclimated to ambulating with a prosthesis. These results highlight the need for future work to evaluate interactions between these cognitive-motor control systems for individuals with more proximal levels of lower limb loss, and in more challenging (ecologically valid) environments.

User Testing an Information Foraging Tool for Ambulatory Surgical Site Infection Surveillance.

BACKGROUND: Surveillance for surgical site infections (SSIs) after ambulatory surgery in children requires a detailed manual chart review to assess criteria defined by the National Health and Safety Network (NHSN). Electronic health records (EHRs) impose an inefficient search process where infection preventionists must manually review every postsurgical encounter (< 30 days). Using text mining and business intelligence software, we developed an information foraging application, the SSI Workbench, to visually present which postsurgical encounters included SSI-related terms and synonyms, antibiotic, and culture orders. OBJECTIVE: This article compares the Workbench and EHR on four dimensions: (1) effectiveness, (2) efficiency, (3) workload, and (4) usability. METHODS: Comparative usability test of Workbench and EHR. Objective test metrics are time per case, encounters reviewed per case, time per encounter, and retrieval of information meeting NHSN definitions. Subjective measures are cognitive load using the National Aeronautics and Space Administration (NASA) Task Load Index (NASA TLX), and a questionnaire on system usability and utility. RESULTS: Eight infection preventionists participated in the test. There was no difference in effectiveness as subjects retrieved information from all cases, using both systems, to meet the NHSN criteria. There was no difference in efficiency in time per case between the Workbench and EHR (8.58 vs. 7.39 minutes, p = 0.36). However, with the Workbench subjects opened fewer encounters per case (3.0 vs. 7.5, p = 0.002), spent more time per encounter (2.23 vs. 0.92 minutes, p = 0.002), rated the Workbench lower in cognitive load (NASA TLX, 24 vs. 33, p = 0.02), and significantly higher in measures of usability. CONCLUSION: Compared with the EHR, the Workbench was more usable, short, and reduced cognitive load. In overall efficiency, the Workbench did not save time, but demonstrated a shift from between-encounter foraging to within-encounter foraging and was rated as significantly more efficient. Our results suggest that infection surveillance can be better supported by systems applying information foraging theory.