Trust with increasing and decreasing reliability.

OBJECTIVE: The primary purpose was to determine how trust changes over time when automation reliability increases or decreases. A secondary purpose was to determine how task-specific self-confidence is associated with trust and reliability level. BACKGROUND: Both overtrust and undertrust can be detrimental to system performance; therefore, the temporal dynamics of trust with changing reliability level need to be explored. METHOD: Two experiments used a dominant-color identification task, where automation provided a recommendation to users, with the reliability of the recommendation changing over 300 trials. In Experiment 1, two groups of participants interacted with the system: one group started with a 50% reliable system which increased to 100%, while the other used a system that decreased from 100% to 50%. Experiment 2 included a group where automation reliability increased from 70% to 100%. RESULTS: Trust was initially high in the decreasing group and then declined as reliability level decreased; however, trust also declined in the 50% increasing reliability group. Furthermore, when user self-confidence increased, automation reliability had a greater influence on trust. In Experiment 2, the 70% increasing reliability group showed increased trust in the system. CONCLUSION: Trust does not always track the reliability of automated systems; in particular, it is difficult for trust to recover once the user has interacted with a low reliability system. APPLICATIONS: This study provides initial evidence into the dynamics of trust for automation that gets better over time suggesting that users should only start interacting with automation when it is sufficiently reliable.

Convergent validity and inter-rater reliability of a lower-limb multimodal physical function assessment in community-dwelling older adults.

Introduction: Lower-limb physical function declines with age and contributes to a greater difficulty in performing activities of daily living. Existing assessments of lower-limb function assess one dimension of movement in isolation or are not time-efficient, which discourages their use in community and clinical settings. We aimed to address these limitations by assessing the inter-rater reliability and convergent validity of a new multimodal functional lower-limb assessment (FLA). Methods: FLA consists of five major functional movement tasks (rising from a chair, walking gait, stair ascending/descending, obstacle avoidance, and descending to a chair) performed consecutively. A total of 48 community-dwelling older adults (32 female participants; age: 71 ± 6 years) completed the FLA as well as timed up-and-go, 30-s sit-to-stand, and 6-min walk tests. Results: Slower FLA time was correlated with a slower timed up-and-go test (ρ = 0.70), less sit-to-stand repetitions (ρ = -0.65), and a shorter distance in the 6-min walk test (ρ = -0.69; all, p < 0.001). Assessments by two raters were not different (12.28 ± 3.86 s versus 12.29 ± 3.83 s, p = 0.98; inter-rater reliability ρ = 0.993, p < 0.001) and were statistically equivalent (via equivalence testing). Multiple regression and relative weights analyses demonstrated that FLA times were most predicted by the timed up-and-go performance [adjusted R 2 = 0.75; p < 0.001; raw weight 0.42 (95% CI: 0.27, 0.53)]. Discussion: Our findings document the high inter-rater reliability and moderate-strong convergent validity of the FLA. These findings warrant further investigation into the predictive validity of the FLA for its use as an assessment of lower-limb physical function among community-dwelling older adults.

The Effect of Informing Participants of the Response Bias of an Automated Target Recognition System on Trust and Reliance Behavior.

OBJECTIVE: To determine how changing and informing a user of the false alarm (FA) rate of an automated target recognition (ATR) system affects the user's trust in and reliance on the system and their performance during an underwater mine detection task. BACKGROUND: ATR systems are designed to operate using a high sensitivity and a liberal decision criterion to reduce the risk of the ATR system missing a target. A high number of FAs in general may lead to a decrease in operator trust and reliance. METHODS: Participants viewed sonar images and were asked to identify mines in the images. They performed the task without ATR and with ATR at a lower and higher FA rate. The participants were split into two groups-one informed and one uninformed of the changed FA rate. Trust and/or confidence in detecting mines was measured after each block. RESULTS: When not informed of the FA rate, the FA rate had a significant effect on the participants' response bias. Participants had greater trust in the system and a more consistent response bias when informed of the FA rate. Sensitivity and confidence were not influenced by disclosure of the FA rate but were significantly worse for the high FA rate condition compared with performance without the ATR. CONCLUSION AND APPLICATION: Informing a user of the FA rate of automation may positively influence the level of trust in and reliance on the aid.

The impact of a short-period head-down tilt on executive function in younger adults.

Microgravity has been shown to be a significant stressor on the cardiovascular system and the brain due to the redistribution of fluids that occurs in the absence of gravitational force, but there is scarce literature surrounding the effects of microgravity on cerebral hemodynamics and cognition. Understanding the early effects that simulated gravity has on cognitive function is essential for developing proper physical and cognitive countermeasures to assure safe and effective cognitive/decisions making while astronauts prepare for the initial launch or when they arrive in a microgravity environment. Therefore, this study aims to determine how an acute simulation of microgravity would alter cerebral oxygenation and executive functions. Sixty-five young healthy participants (22 ± 6 years, 21 females) completed a thirty (30) minute horizontal (00 tilt) followed by a 90-min - 6° head-down-tilt (HDT) protocol. Cerebral oxygenation in the prefrontal cortex was monitored throughout the testing session using near-infrared spectroscopy. Cognition was also measured using a computerized Stroop Task. Our results demonstrate that cerebral oxygenation was higher during HDT compared to the horizontal supine position (9.11 ± 1.3 vs. 7.51 ± 1.8, p = 0.02). For the cognitive results, the non-executive performance of the Stroop task remained stable during HDT (652.46 ± 19.3 vs. 632.49 ± 14.5, p = 0.09). However, reaction time during the executive task performance was improved after the HDT (1058 ± 195-950 ± 158 ms, p < 0.01). Our results suggest that an acute bout of simulated microgravity can enhance executive functioning.

Portable wireless and fibreless fNIRS headband compares favorably to a stationary headcap-based system.

This study's purpose is to characterize the performance of a prototype functional near-infrared spectroscopy (fNIRS) headband meant to enable quick and easy measurements from the sensorimotor cortices. The fact that fNIRS is well-suited to ergonomic designs (i.e., their ability to be made wireless, their relative robustness to movement artifacts among other characteristics) has resulted in many recent examples of novel ergonomic fNIRS systems; however, the optical nature of fNIRS measurement presents an inherent challenge to measurement at areas of the brain underlying haired parts of the head. It is for this reason that the majority of ergonomic fNIRS systems that have been developed to date target the prefrontal cortex. In the present study we compared the performance of a novel, portable fNIRS headband compared with a stationary full headcap fNIRS system to measure sensorimotor activity during simple upper- and lower-extremity tasks, in healthy individuals >50 years of age. Both fNIRS systems demonstrated the expected pattern of hemodynamic activity in both upper- and lower-extremity tasks, and a comparison of the contrast-to-noise ratio between the two systems suggests the prototype fNIRS headband is non-inferior to a full head cap fNIRS system regarding the ability to detect a physiological response at the sensorimotor cortex during these tasks. These results suggest the use of a wireless and fibreless fNIRS design is feasible for measurement at the sensorimotor cortex.

The Impact of Resistance Exercise on Muscle Mass in Glioblastoma in Survivors (RESIST): Protocol for a Randomized Controlled Trial.

BACKGROUND: Glioblastoma is the most common primary brain malignancy in adults, accounting for approximately 48% of all brain tumors. Standard treatment includes radiation and temozolomide chemotherapy. Glioblastomas are highly vascular and can cause vasogenic brain edema and mass effect, which can worsen the neurologic symptoms associated with the disease. The steroid dexamethasone (DEX) is the treatment of choice to reduce vasogenic edema and intracranial pressure associated with glioblastoma. However high-dose DEX or long-term use can result in muscle myopathy in 10%-60% of glioblastoma patients, significantly reducing functional fitness and quality of life (QOL). There is a wealth of evidence to support the use of exercise as an adjuvant therapy to improve functional ability as well as help manage treatment-related symptoms. Specifically, resistance training has been shown to increase muscle mass, strength, and functional fitness in aging adults and several cancer populations. Although studies are limited, research has shown that exercise is safe and feasible in glioblastoma populations. However, it is not clear whether resistance training can be successfully used in glioblastoma to prevent or mitigate steroid-induced muscle myopathy and associated loss of function. OBJECTIVE: The primary purpose of this study is to establish whether an individualized circuit-based program will reduce steroid-induced muscle myopathy, as indicated by maintained or improved functional fitness for patients on active treatment and receiving steroids. METHODS: This is a 2-armed, randomized controlled trial with repeated measures. We will recruit 38 adult (≥18 years) patients diagnosed with either primary or secondary glioblastoma who are scheduled to receive standard radiation and concurrent and adjuvant temozolomide chemotherapy postsurgical debulking and received any dose of DEX through the neurooncology clinic and the Nova Scotia Health Cancer Center. Patients will be randomly allocated to a standard of care waitlist control group or standard of care + circuit-based resistance training exercise group. The exercise group will receive a 12-week individualized, group and home-based exercise program. The control group will be advised to maintain an active lifestyle. The primary outcome, muscle myopathy (functional fitness), will be assessed using the Short Physical Performance Battery and hand grip strength. Secondary outcome measures will include body composition, cardiorespiratory fitness, physical activity, QOL, fatigue, and cognitive function. All measures will be assessed pre- and postintervention. Participant accrual, exercise adherence, and safety will be assessed throughout the study. RESULTS: This study has been funded by the Canadian Cancer Society Atlantic Cancer Research Grant and the J.D. Irving Limited-Excellence in Cancer Research Fund (grant number 707182). The protocol was approved by the Nova Scotia Health and Acadia University's Research Ethics Boards. Enrollment is anticipated to begin in March 2022. CONCLUSIONS: This study will inform how individualized circuit-based resistance training may improve functional independence and overall QOL of glioblastoma patients. TRIAL REGISTRATION: ClinicalTrails.gov NCT05116137; https://www.clinicaltrials.gov/ct2/show/NCT05116137. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/37709.

The role of at home workstation ergonomics and gender on musculoskeletal pain.

BACKGROUND: The recent mandate for university faculty and staff to work-from-home (WFH) during the COVID-19 pandemic has forced employees to work with sub-optimal ergonomic workstations that may change their musculoskeletal discomfort and pain. As women report more work-related musculoskeletal discomfort (WMSD), this effect may be exacerbated in women. OBJECTIVE: The purpose of this study was to describe university employee at-home office workstations, and explore if at-home workstation design mediates the effect of gender on musculoskeletal pain. METHODS: University employees completed a survey that focused on the WFH environment, at home workstation design and musculoskeletal pain. Descriptive statistics and regression analysis were used to analyze the responses. RESULTS: 61% of respondents reported an increase in musculoskeletal pain, with the neck, shoulders and lower back being reported most frequently. Women reported significantly greater musculoskeletal pain, but this relationship was significantly mediated by poor ergonomic design of the home workstation. Improper seat-height and monitor distance were statistically associated with total-body WMSD. CONCLUSIONS: WFH has worsened employee musculoskeletal health and the ergonomic gap between women and men in the workspace has persisted in the WFH environment, with seat height and monitor distance being identified as significant predictors of discomfort/pain.

fMRI neurofeedback in the motor system elicits bidirectional changes in activity and in white matter structure in the adult human brain.

White matter (WM) plasticity supports skill learning and memory. Up- and downregulation of brain activity in animal models lead to WM alterations. But can bidirectional brain-activity manipulation change WM structure in the adult human brain? We employ fMRI neurofeedback to endogenously and directionally modulate activity in the sensorimotor cortices. Diffusion tensor imaging is acquired before and after two separate conditions, involving regulating sensorimotor activity either up or down using real or sham neurofeedback (n = 20 participants × 4 scans). We report rapid opposing changes in corpus callosum microstructure that depend on the direction of activity modulation. Our findings show that fMRI neurofeedback can be used to endogenously and directionally alter not only brain-activity patterns but also WM pathways connecting the targeted brain areas. The level of associated brain activity in connected areas is therefore a possible mediator of previously described learning-related changes in WM.

Automation Use and Dis-Use in Golf: The Impact of Distance Measuring Devices on Trust in Technology and Confidence in Determining Distance.

An athlete's decision to use technology depends on trust in the automation, and confidence in their abilities. Distance measuring devices (DMD) are used in golf to estimate yardage. The purpose of these studies was to examine how DMD usage affects trust in the DMD, confidence in determining yardage manually, and golf performance over time. In study 1, DMD non-users played four rounds of golf, two with the DMD and two without. In study 2, DMD users played five rounds, three with the device, and two without. Participants' trust in automation, confidence, and performance were recorded by online survey at baseline and following each round. Giving a DMD to non-users influenced trust in automation and confidence. When DMD users relinquished the device, confidence decreased briefly but rebounded quickly, trust in automation was unaffected. Performance was unchanged in both groups. These studies provide information about how confidence in abilities and trust in automation interact.

High-Intensity Interval Training Improves Cognitive Flexibility in Older Adults.

Introduction: Regular aerobic exercise is associated with better executive function in older adults. It is unclear if high-intensity-interval-training (HIIT) elicits moderate-intensity continuous training (MICT) or resistance training (RT). We hypothesized that HIIT would augment executive function more than MICT and RT. Methods: Sixty-nine older adults (age: 68 ± 7 years) performed six weeks (three days/week) of HIIT (2 × 20 min bouts alternating between 15 s intervals at 100% of peak power output (PPO) and passive recovery (0% PPO); n = 24), MICT (34 min at 60% PPO; n = 19), or whole-body RT (eight exercise superior improvements in executive function of older adults than moderate-intensity-continuous-training, 2 × 10 repetitions; n = 26). Cardiorespiratory fitness (i.e., V˙O2max) and executive function were assessed before and after each intervention via a progressive maximal cycle ergometer protocol and the Stroop Task, respectively. Results: The V˙O2max findings revealed a significant group by time interaction (p = 0.001) in which all groups improved following training, but HIIT and MICT improved more than RT. From pre- to post-training, no interaction in the naming condition of the Stroop Task was observed (p > 0.10). However, interaction from pre- to post-training by group was observed, and only the HIIT group exhibited a faster reaction time (from 1250 ± 50 to 1100 ± 50 ms; p < 0.001) in switching (cognitive flexibility). Conclusion: Despite similar improvements in cardiorespiratory fitness, HIIT, but not MICT nor RT, enhanced cognitive flexibility in older adults. Exercise programs should consider using HIIT protocols in an effort to combat cognitive decline in older adults.

The role of visual error and reward feedback in learning to aim to an optimal movement endpoint.

When presented with a target circle horizontally overlapped by a penalty circle, participants initially aim closer to the penalty circle than optimal and with experience and feedback shift their endpoint horizontally to the optimal endpoint. Our purpose was to determine whether solely reward feedback or reward feedback in combination with visual error feedback of the movement and final movement endpoint is necessary for participants to learn to aim to the optimal endpoint. Participants received money for hitting the target but lost money for hitting the penalty region. In a critical No Feedback group, the target/penalty configuration would disappear on movement initiation, but participants were told the number of points received or lost after each trial. Similar to groups receiving various amounts of visual error feedback (target never disappeared, or reappeared upon screen contact), participants in the No Feedback group shifted the endpoint horizontally with experience, but they vertically undershot the horizontal meridian that contained the optimal endpoint. The region of the vertical undershoot, although suboptimal, was associated with less variance in the value of the expected outcomes. We suggest that reward feedback encourages participants to aim toward this less risky region, whereas receiving full visual error feedback leads participants to aim to the more advantageous horizontal meridian. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Choices in a key press decision-making task are more optimal after gaining both aiming and reward experience.

When presented with two different target-penalty configurations of similar maximum expected gain (MEG), participants prefer aiming to configurations with more advantageous spatial, rather than more advantageous gain parameters-perhaps due to the motor system's inherent prioritisation of spatial information during movements with high accuracy demands such as aiming. To test this hypothesis, participants in the present studies chose between target-penalty configurations via key presses to reduce the importance of spatial parameters of the response and performance-related feedback. Configurations varied in spatial (target-penalty region overlap) and gain parameters (negative penalty values) and could have similar or different MEG. Choices were made without prior aiming experience (Experiment 1), after aiming experience provided information of movement variability (Experiment 2), or after aiming experience provided information of movement variability and outcome feedback (Experiment 3). Overall, configurations with advantageous spatial or gain parameters were chosen equally (Both-Similar condition) in all experiments. However, average behaviour at the group level was not reflective of the behaviour of most individual participants with three subgroups emerging: those with a value preference, distance preference, or no preference. In Experiments 1 and 2, these individual differences cannot be explained by MEG differences between configurations or participants' movement variability, but these variables predicted choice behaviour in Experiment 3. Further in the Both-Different condition, participants only selected the larger MEG configuration at a level above chance when both variability and outcome information were given prior to the key press task (Experiment 3). In sum, the data indicate that prioritisation of spatial information did not emerge at the group level when performing key presses and more optimal behaviour emerged when information regarding movement variability and outcome feedback were given.

The impact of athletic clothing style and body awareness on motor performance in women.

The type of clothing worn, revealing versus concealing, can affect the performance of women on cognitive tasks. This difference in performance may arise because of changes in body awareness that may draw cognitive resources from the goal task. The present study investigated the influence of the style of athletic clothing and body awareness on visual-motor performance in women. Participants (women ages 18-35 years) were randomly assigned to wear tight and revealing (TR group, n = 40) or loose and concealing (LC group, n = 40) athletic clothing. All participants completed the same visual-motor aiming task to assess spatiotemporal measures of motor performance. In addition to the clothing, participants were primed to be conscious of their bodies via measurements of height, weight, and waist circumference; photographs taken of their bodies; a computerized body-size distortion task; and a mirror in the testing chamber. Results revealed that the TR group had increased movement time variability and did not show performance improvements relative to the LC group. These differences suggest that style of clothing may influence motor performance in women by reallocating cognitive resources towards the body and away from the motor task at hand. This research highlights the interactions between cognitive and motor processes and, potentially, the importance of considering the impact of clothing on performance in many different contexts.

Efficacy of low-cost wireless neurofeedback to modulate brain activity during motor imagery.

OBJECTIVES: Motor imagery can be used as an adjunct to traditional stroke rehabilitation therapies for individuals who have hand and arm impairment resulting from their stroke. The provision of neurofeedback during motor imagery allows individuals to receive real time information regarding their motor imagery-related brain activity. However, the equipment required to administer this feedback is expensive and largely inaccessible to many of the individuals who could benefit from it. Available EEG-based technology provides an accessible, low-cost, wireless alternative to traditional neurofeedback methods, with the tradeoff of lower gain and channel count resulting in reduced signal quality. This study investigated the efficacy of this wireless technology for the provision of motor imagery-related neurofeedback. APPROACH: Twenty-eight healthy individuals participated in a 2-group, double-blinded study which involved imagining performing a unimanual button pressing task while receiving neurofeedback that is either a direct transform of their motor imagery-related brain activity (i.e., real) or is related to someone else's brain activity (i.e., sham). The change in amplitude of 15-30 Hz (beta) rhythmic brain activity elicited during the task blocks was calculated and analyzed across sessions and groups. MAIN RESULTS: We found that individuals who received real neurofeedback showed a statistically significant positive trajectory in modulating the amplitude of the beta rhythm across sessions, while those who received sham feedback showed a negative trajectory. Our results did not indicate a trend of increased lateralization across sessions, as has been shown in previous studies. SIGNIFICANCE: Our main findings replicated previous results with research-grade equipment indicating that there is potential for introducing this wireless technology for the provision of neurofeedback. Given the marginal longitudinal effect of neurofeedback in our study, further study is required to address the limitations associated with this technology before our protocol can be implemented in a clinical setting.

The effects of cardiorespiratory fitness on executive function and prefrontal oxygenation in older adults.

Reviews on cardiovascular fitness and cognition in older adults suggest that a higher level of cardiorespiratory fitness may protect the brain against the effects of aging. Although studies reveal positive effects of cardiorespiratory fitness on executive function, more research is needed to clarify the underlying mechanisms of these effects in older adults. The aim of the current study was to assess the association between cardiorespiratory fitness level, cerebral oxygenation, and cognitive performance in older adults (OAs). Seventy-four OAs (68 ± 6.3 years) gave their written, informed consent to participate in the study. Complete data was collected from 66 participants. All participants underwent a cycle ergometer maximal continuous graded exercise test in order to assess their peak power output (PPO) and a neuropsychological paper and pencil tests (Trail Making Test A and B) while changes in left prefrontal cortex oxygenation were measured with functional near-infrared spectroscopy (fNIRS). The results reveal increased cardiorespiratory fitness was associated with decreased response time (i.e., better performance) on the Trail Making Test (B) (standardized ß = - 0.42, p < 0.05). Cerebral oxygenation in higher fit older adults mediated the relationship with improved executive functioning (standardized ß = - 0.08, p < 0.05). Specifically, in older adults with higher cardiorespiratory fitness (based on a median split), cerebral oxygenation was related to executive functioning but no such relationship existed in lower fit adults.

No one knows what attention is.

In this article, we challenge the usefulness of "attention" as a unitary construct and/or neural system. We point out that the concept has too many meanings to justify a single term, and that "attention" is used to refer to both the explanandum (the set of phenomena in need of explanation) and the explanans (the set of processes doing the explaining). To illustrate these points, we focus our discussion on visual selective attention. It is argued that selectivity in processing has emerged through evolution as a design feature of a complex multi-channel sensorimotor system, which generates selective phenomena of "attention" as one of many by-products. Instead of the traditional analytic approach to attention, we suggest a synthetic approach that starts with well-understood mechanisms that do not need to be dedicated to attention, and yet account for the selectivity phenomena under investigation. We conclude that what would serve scientific progress best would be to drop the term "attention" as a label for a specific functional or neural system and instead focus on behaviorally relevant selection processes and the many systems that implement them.

Symbolic, non-directional predictive cues affect action execution.

Predictive cues may help us to plan an action in anticipation of what will come next. Some cues such as arrows contain directional information to orient the actor. Other cues, however, may contain no spatial information that directly orients the actor to the upcoming action. Non-directional predictive cues have been shown to increase performance in visual search tasks but have not been explored in the planning and execution of actions. The first aim of this study is to determine whether participants can implicitly learn to associate symbolic cues with an upcoming action target location. The second aim is whether this association leads to transient or sustained activation of the action associated with the predicted target location. High and low predictive cues preceded target appearance at long cue-target-onset asynchronies (1,100-2,000 ms). The trajectories of participants' reaching movements were analyzed depending on whether they aimed at the predicted or the non-predicted side within each of the cue type conditions. For the highly predictive cue, participants' trajectories veered further toward the opposite target location when participants aimed for the predicted target location compared to when they aimed for the non-predicted target location. These results indicate that participants can associate an upcoming action with non-directional predictive cues but the predicted response was inhibited in the long intervening time between the cue and target. This finding is similar to the response to peripheral-onset cues in inhibition of return type paradigms.

Increasing Lateralized Motor Activity in Younger and Older Adults using Real-time fMRI during Executed Movements.

Neurofeedback training involves presenting an individual with a representation of their brain activity and instructing them to alter the activity using the feedback. One potential application of neurofeedback is for patients to alter neural activity to improve function. For example, there is evidence that greater laterality of movement-related activity is associated with better motor outcomes after stroke; so using neurofeedback to increase laterality may provide a novel route for improving outcomes. However, we must demonstrate that individuals can control relevant neurofeedback signals. Here, we performed two proof-of-concept studies, one in younger (median age: 26years) and one in older healthy volunteers (median age: 67.5years). The purpose was to determine if participants could manipulate laterality of activity between the motor cortices using real-time fMRI neurofeedback while performing simple hand movements. The younger cohort trained using their left and right hand, the older group trained using their left hand only. In both studies participants in a neurofeedback group were able to achieve more lateralized activity than those in a sham group (younger adults: F(1,23)=4.37, p<0.05; older adults: F(1,15)=9.08, p<0.01). Moreover, the younger cohort was able to maintain the lateralized activity for right hand movements once neurofeedback was removed. The older cohort did not maintain lateralized activity upon feedback removal, with the limitation being that they did not train with their right hand. The results provide evidence that neurofeedback can be used with executed movements to promote lateralized brain activity and thus is amenable for testing as a therapeutic intervention for patients following stroke.

Clinical Model of Exercise-Related Dyspnea in Adult Patients With Cystic Fibrosis.

PURPOSE: Dyspnea is a highly distressing symptom of pulmonary disease that can make performing physical activities challenging. However, little is known regarding the strongest predictors of exercise-related dyspnea in adult cystic fibrosis (CF). Therefore, the purpose of the present study was to determine the best clinical model of exercise-related dyspnea in this patient group. METHODS: A retrospective analysis of pulmonary function and cardiopulmonary exercise testing data from patients with CF being followed up at the Adult CF Program at St Michael's Hospital, Toronto, Canada, from 2002 to 2008 were used for the analysis. RESULTS: Patients (n = 88) were male 66%; aged 30.4 ± 9.4 years; body mass index (BMI) 23.1 ± 3.3 kg/m; forced expiratory volume in 1 second (FEV1) 70% ± 19% predicted; and peak oxygen uptake 74% ± 20% predicted. A multivariate linear regression model assessing the effects of age, sex, BMI, airway obstruction (FEV1), perceived muscular leg fatigue, and dynamic hyperinflation explained 54% of the variance in dyspnea severity at peak exercise (P < .01). Relative importance analysis showed that the presence of dynamic hyperinflation and perceived muscular leg fatigue were the largest contributors. CONCLUSIONS: Pulmonary rehabilitation programs may consider strategies to reduce dynamic hyperinflation and promote muscular function to best improve exercise-related dyspnea in this patient group.

The Role of Consistent Context in Rapid Movement Planning: Suboptimal Endpoint Adjustment to Changing Rewards.

The authors' purpose was to determine if participants adjusted their endpoint during a rapid aiming task in the context of changing rewards and whether participants needed consistent feedback to do so. Participants aimed to a target that was overlapped by a penalty region. Participants gained points for hitting the target but lost points for hitting the penalty region. The reward value associated with target contact either changed trial to trial, reducing consistent feedback (variable condition) or changed between blocks of trials (blocked condition) with the repetition of reward value within a block increasing the consistency of feedback. Participants adjusted their endpoints with changing reward value in the blocked but not variable condition indicating consistent feedback is needed to adjust endpoint to changing rewards.