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PURPOSE: This study was intended to determine the effect of skin cooling on breath-hold duration and predicted emergency air supply duration during immersion.METHODS: While wearing a helicopter transport suit with a dive mask, 12 subjects (29 ± 10 yr, 78 ± 14 kg, 177 ± 7 cm, 2 women) were studied in 8 and 20°C water. Subjects performed a maximum breath-hold, then breathed for 90 s (through a mouthpiece connected to room air) in five skin-exposure conditions. The first trial was out of water for Control (suit zipped, hood on, mask off). Four submersion conditions included exposure of the: Partial Face (hood and mask on); Face (hood on, mask off); Head (hood and mask off); and Whole Body (suit unzipped, hood and mask off).RESULTS: Decreasing temperature and increasing skin exposure reduced breath-hold time (to as low as 10 ± 4 s), generally increased minute ventilation (up to 40 ± 15 L · min−1), and decreased predicted endurance time (PET) of a 55-L helicopter underwater emergency breathing apparatus. In 8°C water, PET decreased from 2 min 39 s (Partial Face) to 1 min 11 s (Whole Body).CONCLUSION: The most significant factor increasing breath-hold and predicted survival time was zipping up the suit. Face masks and suit hoods increased thermal comfort. Therefore, wearing the suits zipped with hoods on and, if possible, donning the dive mask prior to crashing, may increase survivability. The results have important applications for the education and preparation of helicopter occupants. Thermal protective suits and dive masks should be provided.Madu VC, Carnahan H, Brown R, Ennis K-A, Tymko KS, Hurrie DMG, McDonald GK, Cornish SM, Giesbrecht GG. Skin cooling on breath-hold duration and predicted emergency air supply duration during immersion. Aerosp Med Hum Perform. 2020; 91(7):578–585.

BACKGROUND: Helicopter hoist operators are highly skilled and critical crewmembers in search and rescue. However, hoist operator training programs are relatively underdeveloped in comparison to helicopter pilot training. It is critical that this simulator teaches the necessary skills for high-level performance given the dangers associated with helicopter hoist operation. As a result, we sought to validate and identify critical aspects of skilled hoisting.METHODS: Through expert consultation, we identified several measures of hoist operation, such as mission time, cable plumb, cable tension, cable hand position, and cable displacement. We compared hoist performance between experienced and novice hoist operators in a simulated hoisting mission with two levels of difficulty (with and without wind). The experienced group (eight men/one woman) was composed of nine active or former military hoist operators who were working in commercial search and rescue. The novice group was composed of seven subjects (two men/five women) from the general population and had no previous experience with hoisting operations or the simulator.RESULTS: We found that experienced hoist operators had faster mission time, similar cable plumb, lower tension, and less variable hand position. Further, experienced hoist operators pulled the cable inward in the wind while novice hoist operators pushed the cable away.DISCUSSION: These findings suggests that this simulator captures performance differences between skill levels and, as a result, is a first step supporting the use of this simulator for hoist operator training.King MT, Lenser S, Rogers D, Carnahan H. Helicopter hoist performance in novice and experienced hoist operators. Aerosp Med Hum Perform. 2020; 91(6):496–500.

Objective The aim of this study was to investigate the combined effect of cold and moisture on manual performance and tactile sensitivity. Background People working in the ocean environment often perform manual work in cold and wet conditions. Although the independent effects of cold and moisture on hand function are known, their combined effect has not been investigated. Method Participants completed sensory (Touch-Test, two-point discrimination) and motor (Purdue Pegboard, Grooved Pegboard, reef knot untying) tests in the following conditions: dry hand, wet hand, cold hand, and cold and wet hand. Results For the Purdue Pegboard and knot untying tasks, the greatest decrement in performance was observed in the cold-and-wet-hand condition, whereas the decrements seen in the cold-hand and wet-hand conditions were similar. In the Grooved Pegboard task, the performance decrements exhibited in the cold-and-wet-hand condition and the cold-hand condition were similar, whereas no decrement was observed in the wet-hand condition. Tactile sensitivity was reduced in the cold conditions for the Touch-Test but not the two-point discrimination test.The combined effect of cold and moisture led to the largest performance decrements except when intrinsic object properties helped with grasp maintenance. The independent effects of cold and moisture on manual performance were comparable. Application Tools and equipment for use in the cold ocean environment should be designed to minimize the effects of cold and moisture on manual performance by including object properties that enhance grasp maintenance and minimize the fine-dexterity requirements.

Purpose A number of studies has well described central cardiovascular changes caused by changing gravity levels as they occur e.g. during parabolic flight. limited data exists describing the effect of microgravity on the cerebrovascular system and brain perfusion. Methods In this study middle cerebral artery velocity (MCAv) of 16 participants was continuously monitored on a second-by-second basis during 15 consecutive parabolas (1G, 1,8G, 0G, 1,8G) using doppler ultrasound. Simultaneously central cardiovascular parameters (heart rate, mean arterial blood pressure, cardiac output) were assessed. Results Results revealed an immediate reaction of central cardiovascular parameters to changed gravity levels. In contrast, changes in MCAv only initially were in accordance with a normal cerebral autoregulation. Whereas all of the measured central cardiovascular parameters seemed to have reached a steady state after approximately 8 s of microgravity, MCAv, after an initial decrease with the onset of microgravity, increased again during the second half of the microgravity phase. Conclusion It is concluded that this increase in MCAv during the second half of the microgravity period reflects a decrease of cerebrovascular resistance caused by a pressure driven increased venous outflow and/or a contraction of precapillary sphincters in order to avoid hyperperfusion of the brain.

Previous studies showed a decrease in reaction time during the weightlessness phase of a parabolic flight. This effect was found to be stronger with increasing task complexity and was independent of previous experience of weightlessness as well as anti-nausea medication. Analysis of event related potentials showed a decreased amplitude of the N100-P200 complex in weightlessness but was not able to distinguish a possible effect of task complexity. The present study aimed to extend this previous work, by comparing behavioral (reaction time) and neurological (event related potentials analysis) performance to a simple (oddball) and a complex (mental arithmetic + oddball) task during weightlessness. 28 participants participated in two experiments. 11 participants performed a simple oddball experiment in the 1G and 0G phases of a parabolic flight. 17 participants were presented a complex arithmetic task in combination with an oddball task during the 1G and 0G phases of a parabolic flight. Reaction time as well as event related potentials (ERP) were assessed. Results revealed a reduced reaction time (p .05) for the complex task during 0G. No gravity effects on reaction time were found for the simple task. In both experiments a reduction of typical ERP amplitudes was noticeable in weightlessness. It is assumed that the weightlessness induced fluid shift to the brain is positively affecting neuro-behavioral performance.

Item does not contain fulltext Changes in gravity conditions have previously been reported to influence brain hemodynamics as well as neuronal activity. This paper attempts to identify a possible link between changes in brain blood flow and neuronal activity during microgravity. Middle cerebral artery flow velocity (MCAv) was measured using Doppler ultrasound. Brain cortical activity (i.e., cortical current density) was measured using electroencephalography. Finger blood pressure was recorded and exported to generate beat-by-beat systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), and cerebrovascular conductance index (CVCi). Seventeen participants were evaluated under normal gravity conditions and microgravity conditions, during 15 bouts of 22-s intervals of weightlessness during a parabolic flight. Although MAP decreased and CO increased, MCAv remained unchanged in the microgravity condition. CVCi as the quotient of MCAv and MAP increased in microgravity. Cortical current density showed a global decrease. Our data support earlier data reporting a decrease in the amplitude of event-related potentials recorded during microgravity. However, the general decrease in neural excitability in microgravity seems not to be dependent on hemodynamic changes.

Sound application of clinical reasoning (CR) by the physical therapist is critical to achieving optimal patient outcomes. As such, it is important for institutions granting certification in orthopaedic manual physical therapy (OMPT) to ensure that the assessment of CR is sufficiently robust. At present, the dearth of validated instruments to assess CR in OMPT presents a serious challenge to certifying institutions. Moreover, the lack of documentation of the development process for instruments that measure CR pose additional challenges. The purpose of this study is to evaluate the sensibility of a newly developed instrument for assessing written responses to a test of CR in OMPT; a ‘pilot’ phase that examines instrument feasibility and acceptability. Using a sequential mixed-methods approach, Canadian OMPT examiners were recruited to first review and use the instrument. Participants completed a sensibility questionnaire followed by semi-structured interviews, the latter of which were used to elaborate on questionnaire responses regarding feasibility and acceptability. Eleven examiners completed the questionnaire and interviews. Questionnaire results met previously established sensibility criteria, while interview data revealed participants' (dis)comfort with exerting their own judgment and with the rating scale. Quantitative and qualitative data provided valuable insight regarding content validity and issues related to efficiency in assessing CR competence; all of which will ultimately inform further psychometric testing. While results suggest that the new instrument for assessing clinical reasoning in the Canadian certification context is sensible, future research should explore how rater judgment can be utilized effectively and the mental workload associated with appraising clinical reasoning.

Colonoscopy performance is typically assessed by a supervisor in the clinical setting. There are limitations of this approach, however, because it allows for rater bias and increases supervisor workload demand during the procedure. Video-based assessment of recorded procedures has been proposed as a complementary means by which to assess colonoscopy performance. This study sought to investigate the reliability, validity, and feasibility of video-based assessments of competence in performing colonoscopy compared with live assessment.Novice (50 previous colonoscopies), intermediate (50-500), and experienced (1000) endoscopists from 5 hospitals participated. Two views of each colonoscopy were videotaped: an endoscopic (intraluminal) view and a recording of the endoscopist's hand movements. Recorded procedures were independently assessed by 2 blinded experts using the Gastrointestinal Endoscopy Competency Assessment Tool (GiECAT), a validated procedure-specific assessment tool comprising a global rating scale (GRS) and checklist (CL). Live ratings were conducted by a non-blinded expert endoscopist. Outcomes included agreement between live and blinded video-based ratings of clinical colonoscopies, intra-rater reliability, inter-rater reliability and discriminative validity of video-based assessments, and perceived ease of assessment.Forty endoscopists participated (20 novices, 10 intermediates, and 10 experienced). There was good agreement between the live and video-based ratings (total, intra-class correlation [ICC] = 0.847; GRS, ICC = 0.868; CL, ICC = 0.749). Intra-rater reliability was excellent (total, ICC = 0.99; GRS, ICC = 0.99; CL, ICC = 0.98). Inter-rater reliability between the 2 blinded video-based raters was high (total, ICC = 0.91; GRS, ICC = 0.918; CL, ICC = 0.862). GiECAT total, GRS, and CL scores differed significantly among novice, intermediate, and experienced endoscopists (P .001). Video-based assessments were perceived as "fairly easy," although live assessments were rated as significantly easier (P .001).Video-based assessments of colonoscopy procedures using the GiECAT have strong evidence of reliability and validity. In addition, assessments using videos were feasible, although live assessments were easier.

Context In health professions education, tests have traditionally been used to assess the skills and knowledge of learners. More recently, research in psychology and education has shown that tests can also be used to enhance student memory; a phenomenon called the ‘testing effect’. Much of the research in this domain has focused on enhancing rote memory of simple facts, and not on the deeper comprehension and application of complex theoretical knowledge necessary to diagnose and manage patients. The purpose of this study was to examine the effects of testing on students' comprehension of the basic science mechanisms and diagnostic accuracy. Methods Undergraduate dental and dental hygiene students (n = 112) were taught the radiographic features and pathophysiology underlying four intrabony abnormalities. Participants were divided into two groups: the test-enhanced (TE) condition and the study (ST) condition. Following the learning phase, the TE condition group completed an interventional test that tested the basic science mechanisms and the ST condition group was given additional study passages without being tested. Participants in both groups then completed a diagnostic test and a memory test immediately after the learning phase and 1 week later. Results A main effect of testing condition was found. The participants in the TE condition group outperformed those in the ST condition group on immediate and delayed testing. Unlike the diagnostic test, the memory test showed no difference between the groups. Conclusion The inclusion of the basic science test appears to have improved the students' understanding of the underlying disease mechanisms learned and also improved their performance on a test of diagnostic accuracy.

Trainees could benefit from practicing orthotic fabrication on simulated hands with joint deformities. As a first step toward such training, we explored the use of a nonpathological model hand. Twenty-one participants were randomized into one of two groups that practiced using a person’s right hand or a model right hand. One week later, all participants returned for a transfer test in which they made one orthosis on a person’s left hand. All participants’ performance and orthoses were evaluated using a validated checklist and a global rating scale (GRS). Fabrication time for each orthosis also was recorded. The GRS score and fabrication time changed significantly over the course of practice. Trainees who practiced with the model hand made better orthoses during practice and on the transfer test, as measured with the checklist’s final product subscore. Instructional and contextual factors that may affect trainees’ performance and learning are discussed.

Surgical instructors often predetermine the details of training sessions, such as the order of practised tasks, the duration of practice, and timing and type of feedback, while the trainee remains relatively passive. Such training environments are often not tailored to the informational needs of individual learners and, as such, are likely to be suboptimal learning environments. However, as surgical training programs contend with limited instructor availability and time allotted to teach fundamental technical skills, there is a trend toward the use of self-directed learning modules (e.g., CD-ROM and online programs) that require learners to be more active and independent. Recent research suggests that self-directed practice might assist surgical educators in creating learning environments that better support trainees’ motivation to practise by meeting changing informational needs.1 A study conducted by Jowett and colleagues2 demonstrated that skill performance for tying knots was unaffected by practice enforced after trainees decided they had reached proficiency and did not require further practice. These researchers speculated that the learning environment (e.g., simulation model and instructions) remained unchanged after the trainees reached a certain proficiency on the skill and therefore did not provide any additional benefit to learning. Studies using laboratory, sporting and surgical tasks have shown that motor learning can be facilitated if the learner is able to self-direct various aspects of their training experience, such as frequency of feedback,3–6 access to video instruction6,7 and order of practised tasks.1 Surgical educators have also begun to consider how other aspects of the training environment, such as distribution and schedule of practice, can be optimized to enhance motor learning within time constraints.8 With respect to practice schedules, the literature has shown that performance during acquisition of related tasks practised in a random or unsystematic order (e.g., ACB, BAC, ABC, for 3 tasks A, B and C) is impaired compared with performance of tasks in blocked or drill-type order (e.g., AAA, BBB, CCC). Interestingly, however, after a rest period, performance is better on a delayed test for random practice compared with blocked practice. This phenomenon is referred to as the contextual interference effect9 and is often explained by the forgetting hypothesis,10 which suggests that practice that forces the learner to repetitively forget and recall the required skills, such as random practice, will enhance delayed performance. This is important because, unlike immediate postpractice performance, which often represents transient practice effects, delayed tests are more likely to reflect relatively permanent improvement in ability (i.e., learning).11 Since the motor learning literature has shown the contextual interference effect to be greatest for simple laboratory tasks,12,13 researchers have begun to explore its applicability to more complex tasks in the surgical domain. While these studies have shown divergent results,14–16 they highlight the fact that, in the surgical domain, interactions between performance and practice variability can be affected by task difficulty. While there is some evidence supporting random and self-directed practice in the surgical domain, to our knowledge, no studies have examined both practice schedule and the selection of practice schedule for the same surgical skill. The purpose of this study was to determine how practice schedule (random or blocked) and selection of practice schedule (self-directed or prescribed) contribute to learning of suturing skills. We hypothesized that self-directed and random practice schedules would produce better postpractice performance than the other prescribed practice schedules.

Background Little is known with regard to how acupuncture skills are optimally taught, learnt and evaluated despite clear evidence that technical skill acquisition is important to trainee success in health professions. Objectives This study reports an investigation of the sensorimotor aspects of the acupuncture lifting-thrusting skill in order to highlight the important kinematic and kinetic features of the action. The study also explores the role of perceptual acuity in accurate acupuncture performance. Methods Twelve novice and 12 expert acupuncturists watched a standardised video demonstrating the mild reinforcing and reducing technique of lifting-thrusting on an acupuncture point and then performed 10 trials of the technique on an artificial skin pad mounted on a six-axis force transducer with an infrared light-emitting diode affixed to the index finger of their dominant hand. The force transducer measured the force applied by participants as they needled the acupuncture point while an optoelectric camera measured the position of the diode. Subsequently, the participants engaged in two tests of general perceptual acuity. Results Repeated measures analyses of variance indicated that experts are more consistent in their trial-by-trial amplitude (p=0.03) and lifting-thrusting velocity (p=0.029) than novices. Measures of perceptual acuity revealed no differences between novices and experts. Conclusions Movement amplitude and velocity consistency are the action features of the mild reinforcing and reducing lifting-thrusting skill that differentiate the performances of experts from novices. The acquisition of acupuncture expertise is a function of extended practice rather than any inherent perceptual ability.

While the ultimate goal of simulation training is to enhance learning, cost-effectiveness is a critical factor. Research that compares simulation training in terms of educational- and cost-effectiveness will lead to better-informed curricular decisions. Using previously published data we conducted a cost-effectiveness analysis of three simulation-based programs. Medical students (n = 15 per group) practiced in one of three 2-h intravenous catheterization skills training programs: low-fidelity (virtual reality), high-fidelity (mannequin), or progressive (consisting of virtual reality, task trainer, and mannequin simulator). One week later, all performed a transfer test on a hybrid simulation (standardized patient with a task trainer). We used a net benefit regression model to identify the most cost-effective training program via paired comparisons. We also created a cost-effectiveness acceptability curve to visually represent the probability that one program is more cost-effective when compared to its comparator at various ‘willingness-to-pay’ values. We conducted separate analyses for implementation and total costs. The results showed that the progressive program had the highest total cost (p < 0.001) whereas the high-fidelity program had the highest implementation cost (p < 0.001). While the most cost-effective program depended on the decision makers’ willingness-to-pay value, the progressive training program was generally most educationally- and cost-effective. Our analyses suggest that a progressive program that strategically combines simulation modalities provides a cost-effective solution. More generally, we have introduced how a cost-effectiveness analysis may be applied to simulation training; a method that medical educators may use to investment decisions (e.g., purchasing cost-effective and educationally sound simulators).

L'impact de l'exposition au froid sur les aptitudes motrices individuelles exige une meilleure comprehension de la facon dont le froid influence les performances psychomotrices et haptiques. Dans cette etude, les differentes facettes de la performance psychomotrice ont ete analysees afin de determiner les effets de l'exposition au froid ambiant sur les personnes âgees. Des personnes et jeunes et plus âgees en bonne sante ont effectue une batterie de tests psychomoteurs haptiques aux temperatures ambiantes (23° C) et froids (1° C) pour determiner les effets de l'exposition au froid ambiant sur les personnes âgees. Les resultats indiquent que les personnes âgees n'achevent pas les resultats aussi forts que ceux des personnes plus jeunes a travers la batterie de tests, et qu'une temperature froide degrade davantage leur dexterite pour les tâches (par exemple, leur niveau dans le Minnesota Manual Dexterity Test: F [1, 16] = 10,23, p Abstract: The impact of exposure to cold on individuals' motor skills demands a deeper understanding of the ways in which cold weather influences psychomotor and haptic performance. In this study, various facets of psychomotor performance were evaluated in order to determine the impacts of ambient cold exposure on older persons. Healthy younger and older persons performed a battery of haptic psychomotor tests at room (23° C) and cold (1° C) ambient temperatures. The results indicate that older individuals do not perform as well as younger persons across the battery of tests, with cold temperature further degrading their performance in dexterity tasks (in, for example, Minnesota Manual Dexterity test placing: F [1, 16] = 10.23, p F [1, 16] = 18.97, p

Self-assessment is important for life-long learning and a recommended assessment method for endoscopy skills. Prior literature has not investigated self-assessment accuracy of colonoscopic competence in the clinical setting. This study aimed to determine the self-assessment accuracy of novice, intermediate, and experienced endoscopists.Novice (performed 50 previous colonoscopies), intermediate (50-500), and experienced (1000) endoscopists from 5 hospitals each performed a clinical colonoscopy. Video recordings of procedures were independently assessed by 2 blinded expert endoscopists by using the Gastrointestinal Endoscopy Competency Assessment Tool (GiECAT). Externally assessed and self-assessed GiECAT scores were defined as the mean of the 2 video-based ratings and as participants' own assigned ratings, respectively. Self-assessment accuracy between the externally assessed and self-assessed scores was evaluated by using absolute difference scores, intraclass correlation coefficients, and the Bland-Altman analysis.Twenty novice, 10 intermediate, and 10 experienced endoscopists participated. There was moderate agreement of externally assessed and self-assessed GiECAT scores, with an intraclass correlation coefficient of 0.65 (95% confidence interval, 0.44-0.80). The absolute difference scores among the 3 groups were significantly different (P = .002), with experienced endoscopists demonstrating a more accurate self-assessment ability compared with novices (P = .002). Bland-Altman plots suggest that novice and experienced endoscopists tend to overrate and underrate their clinical competence, respectively; no specific trends were associated with intermediates.Participants demonstrated moderate self-assessment accuracy of clinical competence. Endoscopist experience was positively associated with self-assessment accuracy; novices demonstrated lower self-assessment accuracy compared with experienced endoscopists. Moreover, novices tended to overestimate their performances. Novice endoscopists may benefit from targeted interventions to improve self-assessment accuracy.

Feedback is an important feature of simulation-based education. This study investigated the optimal timing of feedback for technical skills learning in novices.Thirty novice endoscopists were pretested on a colonoscopy simulator task. Participants then received feedback either during (concurrent) or after (terminal) each of their 12 practice trials. Effectiveness of training was assessed using an immediate posttest and one week later on retention and transfer tests. Measures included execution time and blinded expert assessments.Both groups performed similarly on the pre-, post-, and retention tests. At transfer, the terminal feedback group performed significantly better as measured by execution time, checklist, and global rating scores. The concurrent feedback group's performance decreased significantly on the transfer test as compared with the posttest and retention test.Not all feedback conditions seem equally effective. The use of terminal feedback resulted in better learning as demonstrated by superior performance during transfer.

Directed self-guidance, whereby trainees independently practice a skill-set in a structured setting, may be an effective technique for novice training. Currently, however, most evaluation methods require an expert to be present during practice. The study aim was to determine if absolute symmetry error, a clinically important measure that can be assessed by the trainee, is a feasible assessment tool for self-guided learning of suturing skill. Forty-eight undergraduate medical trainees independently practiced suturing and knot tying skills using a benchtop model. Performance on a pretest, posttest, retention test and a transfer test was assessed using (1) the validated final product analysis (FPA), (2) the surgical efficiency score (SES), a combination of the FPA and hand motion analysis and (3) absolute symmetry error, a new measure that assesses the symmetry of the final product. Absolute symmetry error, along with the other objective assessment tools, detected improvements in performance from pretest to posttest (P

Basic changes in environmental conditions are fundamental to understanding brain cortical mechanisms. Several studies have reported impairment of central nervous processes during weightlessness. There is ongoing debate as to whether these impairments are attributable to primary physiological effects or secondary psychological effects of the weightlessness environment. This study evaluates the physiological effects of changed gravity conditions on brain cortical activity. In a first experiment, EEG activity of seven participants was recorded at normal, increased and zero gravity during a parabolic flight. Additionally an EEG under normal gravity conditions preflight was recorded. In a second experiment, 24 participants were exposed to a supine, seated and 9 degree head-down tilt position while EEG was recorded. Data were analysed using low resolution brain electromagnetic tomography (LORETA). Beta-2 EEG activity (18-35 Hz) was found to be increased in the right superior frontal gyrus under normal gravity conditions inflight. By exposure to weightlessness a distinct inhibition of this activity within the same areas could be noticed. As the tilt experiment showed changes in the left inferior temporal gyrus in supine and tilted positions we conclude that the observed changes under weightlessness are not explainable by hemodynamic changes but rather reflect emotional processes related to the experience of weightlessness. These findings suggest that weightlessness has a major impact on electro cortical activity and may affect central nervous and adaptation processes.

Previous studies showed that changing forces of gravity as they typically occur during parabolic flights might be responsible for adaptional processes of the CNS. However, until now it has not been differentiated between primary influences of weightlessness and secondary influences due to psycho-physiological factors (e.g., physical or mental strain). With the aim of detecting parabolic flight related changes in central cortical activity, a resting EEG was deduced in 16 subjects before, during and after parabolic flights. After subdividing EEG into alpha-, beta-,delta- and theta-wave bands, an increase in beta-power was noticeable inflight, whereas alpha(1)-power was increased postflight. No changes could be observed for the control group. To control possible effects of cortical activation, a manual tracking task with mirror inversion was performed during either the phase of weightlessness or during the normal gravity phase of a parabolic flight. No differences in performance nor in adaptation could be observed between both groups. A third group, performing under normal and stress-free conditions in a lab showed similar tracking values. We assume that the specific increase in brain activity is a sign of an increase in arousal inflight. This does support previous assumptions of non-specific stressors during parabolic flights and has to be considered as a relevant factor for experiments on central nerve adaptation. Although no influences of stress and/or weightlessness on motor performance and adaptation could be observed, we suggest that an "inflight" control group seems to be more adequate than a laboratory control group to investigate gravity-dependent changes in motor control.

Numerous studies have shown significant effects of weightlessness on adaptational processes of the CNS, cardiovascular and/or muscular system. Most of these studies have been carried out during parabolic flights, using the recurring 20 s of weightlessness at each parabola. Although some of these studies reported on potential influences not only of weightlessness but also of the stressful situation within a parabolic flight, especially provoked by the ongoing changes between 1.8, 1 and 0 G, so far there seems to be only marginal information about objective parameters of stress evoked by parabolic flights. By collecting blood samples from a permanent venous catheter several times during parabolic flights, we were able to show an increase of prolactin, cortisol and ACTH in the course of a 120 min flight. We conclude, therefore, that previous reported effects of weightlessness on adaptational processes may be affected not only by weightlessness but also by the exposure to other stressors experienced within the environment of a Zero-G airbus.

In this article, we report on two experiments that examined the haptic perception of slipperiness. The first experiment aimed to determine whether the type of finger motion across a surface influenced the ability to accurately judge the frictional coefficient (or slipperiness) of that surface. Results showed that when using static contact, participants were not as good at distinguishing between various surfaces, compared with when their finger moved across the surface. This raises the issue of how humans are able to generate the appropriate forces in response to friction during grasping (which involves static finger contact). In a second study, participants lifted objects with surfaces of varying coefficients of friction. The participants were able to accurately perceive the slipperiness of the surfaces that were lifted; however, the grasping forces were not scaled appropriately for the friction. That is, there was a dissociation between haptic perception and motor output.

Rigorously developed and validated direct observational assessment tools are required to support competency-based colonoscopy training to facilitate skill acquisition, optimize learning, and ensure readiness for unsupervised practice.To examine reliability and validity evidence of the Gastrointestinal Endoscopy Competency Assessment Tool (GiECAT) for colonoscopy for use within the clinical setting.Prospective, observational, multicenter validation study. Sixty-one endoscopists performing 116 colonoscopies were assessed using the GiECAT, which consists of a 7-item global rating scale (GRS) and 19-item checklist (CL). A second rater assessed procedures to determine interrater reliability by using intraclass correlation coefficients (ICCs). Endoscopists' first and second procedure scores were compared to determine test-retest reliability by using ICCs. Discriminative validity was examined by comparing novice, intermediate, and experienced endoscopists' scores. Concurrent validity was measured by correlating scores with colonoscopy experience, cecal and terminal ileal intubation rates, and physician global assessment.A total of 116 colonoscopies performed by 33 novice (50 previous procedures), 18 intermediate (50-500 previous procedures), and 10 experienced (1000 previous procedures) endoscopists from 6 Canadian hospitals.Interrater and test-retest reliability, discriminative, and concurrent validity.Interrater reliability was high (total: ICC=0.85; GRS: ICC=0.85; CL: ICC=0.81). Test-retest reliability was excellent (total: ICC=0.91; GRS: ICC=0.93; CL: ICC=0.80). Significant differences in GiECAT scores among novice, intermediate, and experienced endoscopists were noted (P.001). There was a significant positive correlation (P.001) between scores and number of previous colonoscopies (total: ρ=0.78, GRS: ρ=0.80, CL: Spearman's ρ=0.71); cecal intubation rate (total: ρ=0.81, GRS: Spearman's ρ=0.82, CL: Spearman's ρ=0.75); ileal intubation rate (total: Spearman's ρ=0.82, GRS: Spearman's ρ=0.82, CL: Spearman's ρ=0.77); and physician global assessment (total: Spearman's ρ=0.90, GRS: Spearman's ρ=0.94, CL: Spearman's ρ=0.77).Nonblinded assessments.This study provides evidence supporting the reliability and validity of the GiECAT for use in assessing the performance of live colonoscopies in the clinical setting.

In 3 experiments, the authors investigated and described how individuals control manual interceptive movements to slowly moving targets. Participants (N = 8 in each experiment) used a computer mouse and a graphics tablet assembly to manually intercept targets moving across a computer screen toward a marked target zone. They moved the cursor so that it would arrive in the target zone simultaneously with the target. In Experiment 1, there was a range of target velocities, including some very slow targets. In Experiment 2, there were 2 movement distance conditions. Participants moved the cursor either the same distance as the target or twice as far. For both experiments, hand speed was found to be related to target speed, even for the very slowly moving targets and when the target-to-cursor distance ratios were altered, suggesting that participants may have used a strategy similar to tracking. To test that notion, in Experiment 3, the authors added a tracking task in which the participants tracked the target cursor into the target zone. Longer time was spent planning the interception movements; however, there was a longer time in deceleration for the tracking movements, suggesting that more visually guided trajectory updates were made in that condition. Thus, although participants scaled their interception movements to the cursor speed, they were using a different strategy than they used in tracking. It is proposed that during target interception, anticipatory mechanisms are used rather than the visual feedback mechanism used when tracking and when pointing to stationary targets.

Participants generated manual interception movements toward a target cursor that moved across a computer screen. The target reached its peak velocity either during the first third, at the midpoint, or during the last third of the movement. In Experiment 1 the view of the target was available for either the first 316, 633, 950, or 1267 ms, after which it disappeared. Results showed that for all viewing conditions, the timing of the interception velocity was related to the temporal properties of the target's trajectory. In Experiment 2, when the portion of the target trajectory that was viewed was reversed (such that participants did not see the first 316, 633, 950, or 1267 ms of the trajectory, but instead saw only the later portions of the trajectory), there was no clear relationship between the target trajectory and the timing of the aiming trajectory. These results suggest that participants use visual information early in the target's trajectory to form a representation of the target motion that is used to facilitate manual interception.

The goal of the present study was to understand which characteristics (movement time or velocity) of target motion are important in the control and coordination of the transport and grasp-preshape components of prehensile movements during an interception task. Subjects were required to reach toward, grasp and lift an object as it entered a target area. Targets approached along a track at four velocities (500, 750, 1000 and 1250 mm/s) which were presented in two conditions. In the distance-controlled condition, targets moving at all velocities traveled the same distance. In the viewing-time-controlled condition, combinations of velocity and starting distances were performed such that the moving target was visible for 1000 ms for all trials. Analyses of kinematic data revealed that when, target distance was controlled, velocity affected all transport-dependent measures; however, when viewing time was controlled, these dependent measures were no longer affected by target velocity. Thus, the use of velocity information was limited in the viewing-time-controlled condition, and subjects used other information, such as target movement time, when generating the transport component of the prehensile movement. For the grasp-preshape component, both peak aperture and peak-aperture velocity increased as target velocity increased, regardless of condition, indicating that target velocity was used to control the spatial aspects of aperture formation. However, the timing of peak aperture was affected by target velocity in the distance-controlled condition, but not in the viewing-time-controlled condition. These results provide evidence for the autonomous generation of the spatial and temporal aspects of grasp preshape. Thus, an independence between the transport and grasp-preshape phases was found, whereby the use of target velocity as a source of information for generating the transport component was limited; however, target velocity was an important source of information in the grasp-preshape phase.

To observe the features of acupuncture needle twirling manipulations in order to promote the development of objective and quantitative performance standards of acupuncture manipulation.Twelve expert acupuncturists and 12 novices were enrolled in this study. Everyone of them was instructed to perform 10 trials of the uniform reinforcing and reducing technique of acupuncture on an artificial skin-pad that was mounted to a six-axis force transducer and each subject had his or her dominant hand index finger affixed with an infrared light emitting diode for acquiring parameters of acupuncture needle manipulation. The force transducer was used to measure the force the participant applied as they held an acupuncture needle to stimulate the skin-pad, and at the mean time, an optoelectric camera was employed to measure the position of the diode.In comparison with the expert acupuncturist group, the straggling coefficient of needle-twirling frequency was significantly bigger in the novice group (P0.01), suggesting a higher consistency in the trial-by-trial needle-twirling operation of the expert acupuncturists. Comparison of the needle-twirling force showed that the force values of the Z-axis in both expert group and novice group were considerably higher than those of the X-axis and Y-axis in the same one group (P0.01). The time of pre-needle-twirling of the novice group was markedly longer than that of the expert group (P0.01), suggesting a skilled operation technique of the expert acupuncturists. No significant differences were found between the expert acupuncturist group and novice group in the needle-twirling amplitude, frequency, force and total operation time (P0.05).Movement frequency consistency and temporal efficiency are the action features of expert acupuncturists in performing the uniform reducing-reinforcing twirling skill, which differentiates the performances of experts from novices. The assessment and training of this acupuncture skill should focus on these kinematic features.

Two experiments were conducted to examine the influence of target motion on the control and coordination of reaching and grasping movements. In Experiment 1 all the measures which reflected the transport or reaching phase of prehension (movement time, peak velocity, time to peak velocity, and transport tau margin) were sensitive to the velocity of the target, with subjects moving even slower than during the stationary trials, when the target was moving very slowly. Measures which reflected grasp formation such as the size of maximum aperture and the grasping tau margin were not influenced by target speed. To further investigate this dissociation between grasp and transport, different object sizes and even slower object speeds were introduced in Experiment 2. Transport results similar to those found in the first study were observed. However, in Experiment 2, both size of peak aperture and the grasping tau margin were sensitive to target movement. The results of these two studies are discussed in terms of the limitations of optic variables in the visual regulation of movement, and the independence of the control of the reach and grasp phases of prehension.

OBJECTIVE. Pencil grasps other than the dynamic tripod may be functional for handwriting. This study examined the impact of grasp on handwriting speed and legibility. METHOD. We videotaped 120 typically developing fourth-grade students while they performed a writing task. We categorized the grasps they used and evaluated their writing for speed and legibility using a handwriting assessment. Using linear regression analysis, we examined the relationship between grasp and handwriting. RESULTS. We documented six categories of pencil grasp: four mature grasp patterns, one immature grasp pattern, and one alternating grasp pattern. Multiple linear regression results revealed no significant effect for mature grasp on either legibility or speed. CONCLUSION. Pencil grasp patterns did not influence handwriting speed or legibility in this sample of typically developing children. This finding adds to the mounting body of evidence that alternative grasps may be acceptable for fast and legible handwriting.

The authors investigated the effects of hand function and aging on the ability to manipulate different hearing instrument controls. Over the past quarter century, hearing aids and hearing aid controls have become increasingly miniaturized. It is important to investigate the aging hand and hearing aid ergonomics because most hearing aid wearers are adults aged 65 years and above, who may have difficulty handling these devices.In Experiment 1, the effect of age on the ability to manipulate two different open-fit behind-the-ear style hearing aids was investigated by comparing the performance of 20 younger (18-25 years of age), 20 young-old (60-70 years of age), and 20 older adults (71-80 years of age). In Experiment 2, ability to manipulate 11 different hearing instrument controls was investigated in 28 older adults who self-reported having arthritis in their hand, wrist, or finger and 28 older adults who did not report arthritis. For both experiments, the relationship between performance on the measures of ability to manipulate the devices and performance on a battery of tests to assess hand function was investigated.In Experiment 1, age-related differences in performance were observed in all the tasks assessing hand function and in the tasks assessing ability to manipulate a hearing aid. In Experiment 2, although minimal differences were observed between the two groups, significant differences were observed depending on the type of hearing instrument control. Performance on several of the objective tests of hand function was associated with the ability to manipulate hearing instruments.The overall pattern of findings suggest that haptic (touch) sensitivity in the fingertips and manual dexterity, as well as disability, pain, and joint stiffness of the hand, all contribute to the successful operation of a hearing instrument. However, although aging is associated with declining hand function and co-occurring declines in ability to manipulate a hearing instrument, for the sample of individuals in this study, including those who self-reported having arthritis, only minimal declines were observed.

Introduction Educators often simplify complex tasks by setting learning objectives that focus trainees on isolated skills rather than the holistic task. We designed 2 sets of learning objectives for intravenous catheterization using goal setting theory. We hypothesized that setting holistic goals related to technical, cognitive, and communication skills would result in superior holistic performance, whereas setting isolated goals related to technical skills would result in superior technical performance. Methods We randomly assigned practicing health care professionals to set holistic (n = 14) or isolated (n = 15) goals. All watched an instructional video and studied a list of 9 goals specific to their group. Participants practiced independently in a hybrid simulation (standardized patient combined with an arm simulator). The first and the last practice trials were videotaped for analysis. One-week later, participants completed a transfer test in another hybrid simulation scenario. Blinded experts evaluated performance on all 3 trials using the Direct Observation of Procedural Skills tool. Results The holistic group scored higher than the isolated group on the holistic Direct Observation of Procedural Skills score for all 3 trials [mean (SD), 45.0 (9.16) vs. 38.4 (9.17); P = 0.01]. The isolated group did not perform better than the holistic group on the technical skills score [10.3 (2.73) vs. 11.6 (3.01); P = 0.11]. Conclusions Our results suggest that asking learners to set holistic goals did not interfere with their attaining competent holistic and technical skills during hybrid simulation training. This exploratory trial provides preliminary evidence for how to consider integrating hybrid simulation into medical curricula and for the design of learning goals in simulation-based education.

Aim: To investigate the impact of common pencil grasp patterns on the speed and legibility of handwriting after a 10-minute copy task, intended to induce muscle fatigue, in typically developing children and in those non-proficient in handwriting. Methods: A total of 120 Grade 4 students completed a standardised handwriting assessment before and after a 10-minute copy task. The students indicated the perceived difficulty of the handwriting task at baseline and after 10 minutes. The students also completed a self-report questionnaire regarding their handwriting proficiency upon completion. Results: The majority of the students rated higher effort after the 10-minute copy task than at baseline (rank sum: P = 0.00001). The effort ratings were similar for the different grasp patterns (multiple linear regression: F = 0.37, P = 0.895). For both typically developing children and those with handwriting issues, the legibility of the writing samples decreased after the 10-minute copy task but the speed of writing increased. Conclusions and Significance of the Study: The quality of the handwriting decreased after the 10-minute copy task; however, there was no difference in the quality or speed scores among the different pencil grasps before and after the copy task. The dynamic tripod pencil grasp did not offer any advantage over the lateral tripod or the dynamic or lateral quadrupod pencil grasps in terms of quality of handwriting after a 10-minute copy task. These four pencil grasp patterns performed equivalently. Our findings question the practice of having students adopt the dynamic tripod pencil grasp.

Technical and communicative skills are both important features for one's perception of practitioner competence.This research examines how trainees' perceptions of practitioner competence change as they view health care practitioners who vary in their technical and communicative skill proficiencies.Occupational therapy students watched standardized encounters of a practitioner performing a patient transfer in combinations of low and high technical and communicative proficiency and then reported their perceptions of practitioner competence.The reports indicate that technical and communicative skills have independently identifiable impacts on the perceptions of practitioner competency, but technical proficiency has a special impact on the students' perceptions of practitioner communicative competence.The results are discussed with respect to the way in which students may evaluate their own competence on the basis of either technical or communicative skill. The issue of how this may lead trainees to dedicate their independent learning efforts to an incomplete set of features needed for the development of practitioner competency is raised.

Visual and haptic integration has been examined extensively, however little is known about alternative premovement sensory information to help in the anticipatory control of prehension. This study explored the concept of using auditory cues as an alternative premovement cue. Individuals lifted champagne flutes filled with various levels of water; and one group was given a sound cue before lifting. Sounds provided a precue regarding fluid level and hence mass. Results showed that auditory cues were used to predict the “target force” required to lift the masses, as evidenced by scaling of grip rates as a function of mass in the auditory cue group only. It was hypothesized that individuals used the auditory cues to preprogram the grasping forces produced during the lifting movement.

Objective: To determine the contribution of the loss of tactile sensitivity, glove flexibility, glove thickness, and changes in finger geometry to force decrement and increased effort during gloved power grip. Background: Gloved work has been shown to increase the effort required to perform manual tasks. Method: A battery of maximal and submaximal gripping tasks was performed while grip force and surface electromyography of seven forearm muscles were recorded. Participants performed power grips while wearing three different thicknesses of rubber gloves (differing only in thickness; maximum 3.1 mm), wearing interdigital spacers between the fingers (matched to the glove thicknesses), and with a bare hand. Results: Decreases in maximum grip force compared with the bare hand were observed for the thickest glove (—31.0 ± 6.8%, p < .05) and for the thickest interdigital spacers (—9.7 ± 5.9 %, p < .05). Participants increased their grip force with increasing glove thickness for a submaximal object-lifting task ( p < .01). To maintain an unloaded grip posture and to create a fixed submaximal force, participants increased muscle activation ( p < .05) for all muscles with increasing glove thickness. Conclusion: Decreases in maximal grip force and increased effort in submaximal tasks could be attributed to a combination of reduced tactile sensitivity, the effort to bend the gloves, and interdigital separation. Application: Although the values obtained are specific to the rubber gloves tested, the results give insights into factors important in the design and selection of gloves.

Objectives Mounting evidence suggests that trainees acquire psychomotor skills better when they are allowed self-guided access to instructional material and when they set goals that are related to performance processes rather than performance outcomes. The present study assessed whether self-guided access to instruction and the setting of process goals lead to better acquisition of clinical technical skills. Methods To learn wound closure skills, 48 medical students were randomly assigned to one of four groups in a 2 × 2 study design. Self-guided participants were able to access the instructional video freely, whereas control participants were restricted to watching only those video segments accessed by their matched self-guided participant. Each group was further divided into two subgroups, comprising a process goal subgroup, where participants set goals focused on performance mechanisms, and an outcome goal subgroup, where participants set goals focused on performance products. Performance on pre-, post-, retention and transfer tests was assessed with hand motion measures and expert evaluations. Group differences were evaluated using one-way anovas. Results The self-guided group with process goals showed greater skill retention than its matched control group, whereas the self-guided group with outcome goals did not. Furthermore, the groups with process goals performed better on the transfer test than the outcome goal groups. Outcome goal participants accessed the instructional video most frequently. Conclusions Our findings advance the study of independent learning in medical education. Trainees used interactive and structured instructional materials to effectively self-guide their learning of clinical technical skills. However, a self-guided benefit was demonstrated only when trainees set process goals.

An increasing number of studies within the recent years connected physical exercise with changes in brain cortical activity. Most of this data (1) refers to aerobic exercise and (2) does not correlate to psychological parameters although it is well known that exercise has a positive effect on mood. In times where health activities play a major role it is increasingly necessary to connect somato-physiological and somatopsychological components of physical activity. This study aimed to find changes in EEG activity and mood after low, preferred and high intensity running. EEG and actual state of mood were recorded before and after exercise. Results showed an effect for the preferred and high intensity velocity in both, EEG and mood. As only the higher frequency areas N18 Hz showed persisting decreases post-exercise we concluded that this might be a sign of outlasting effects of exercise on brain cortical activity which may have influences on general well-being. We could also show that there is a clear relationship between EEG activity and mood reflecting a basic principle of cortical excitation.

It is well known that sensorimotor memories are built and updated through experience with objects. These representations are useful to anticipatory and feedforward control processes that preset grip and load forces during lifting. When individuals lift objects with qualities that are not congruent with their memory-derived expectations, feedback processes adjust motor plans to achieve successful lifts and contribute to the updating of the stored representations. The two experiments presented examine motor adaptation to an illusory size–weight lifting task, and the transfer of this motor adaptation to the unexposed hand. In Experiment 1, performers acquired motor adaptation with their right hand and transfer was measured on their left hand. In Experiment 2, adaptation was acquired with the left hand and transfer was measured on the right hand. In order to investigate the persistence of sensorimotor memories, these experiments measure adaptation, retention, and transfer after 15 min and 24 h delay periods. Both experiments confirm that experience with objects leads to adaptation of force scaling processes, that these adaptations transcend effector and are persistent. The results are discussed in terms favouring interpretations that describe motor adaptations to illusion as being centrally available.

The purpose of our study was to investigate the impact of distracting noise on the performance on a simulated orthopedic bone drilling skill when that noise blocks routine auditory feedback associated with the sounds of the drill.Medical students (n=11), intermediate residents (postgraduate years 3-5, n=10) and surgeons (n=8) each drilled 20 bicortical holes in a femur bone from a lamb: 10 holes without and 10 holes with the presence of distracting noise. We quantified surgical outcome in the form of plunge depth using computer-assisted objective methods.Novice participants plunged more than did the intermediate trainees and surgeons (p0.001). With the addition of distracting noise, the plunges of both intermediate residents and surgeons were affected.Distracting noise impairs orthopedic bone drilling performance, and the ability to use drilling sounds to guide drilling motions is part of surgical expertise.

Mental and perceptual motor performance has been reported to be impaired during hypergravity. Current research has focused on physiological explanations (e.g., deficient proprioceptive feedback) and neglected psycho-physiological effects (e.g., arousal, emotion, cognitive engagement). This study aims at localising changes in brain cortical activity by using a distributed source localisation algorithm (sLORETA) to model the probable neural generators of changes in scalp voltage under hypergravity conditions. Brain cortical activity was measured by EEG before, during and after exposure to three time terrestrial gravity (3G z ) on ten naive subjects aged 29 ± 5 years. Changes in EEG activity were localised using standardised low resolution brain electromagnetic tomography (sLORETA) for alpha-1 [7.5–10 Hz], alpha-2 [10–12.5 Hz], beta-1 [12.5–18 Hz], beta-2 [18–35 Hz] and gamma [35–45 Hz] activities. Individual concentrations of blood cortisol and perceived psychological strain were related to changes in cortical current density. An increase in alpha-1 activity occurred in the right inferior frontal lobe, beta-1 activity was found to be increased in the limbic lobe during 3G z . Post acceleration alpha-2 and beta-1 activities declined in frontal, temporal and limbic lobes. Changes in blood cortisol concentrations and perceived strain showed a clear relationship to changes in right sided frontal alpha-1 activity. We conclude that frontal activity during hypergravity may serve as a marker of anxiety. This puts a new light on the debate as to whether cognitive and sensorimotor impairments are attributable to primary physiological effects or secondary psychological effects of a hypergravity environment.

It has been suggested that the central and peripheral neural processes (CPNP) are affected by gravitational changes. Based on the previous experiments during parabolic flights, central and peripheral changes may not only be due to the changed gravitational forces but also due to neuroendocrine reactions related to the psycho-physiological consequences of gravitational changes. The present study focuses on the interaction of neuroendocrine changes and the physical and mental states after acceleration to three-time terrestrial gravity (3Gz). Eleven participants (29.4+/-5.1 [SD] years (male (n=8): 30+/-5.1 years; female (n=3): 27.7+/-2.1 years) underwent a 15 min acceleration to 3Gz in a human centrifuge. Before and after the acceleration to 3Gz circulating stress hormone concentrations (cortisol, adrenocorticotropic hormone (ACTH), prolactin, epinephrine, norepinephrine) and perceived physical and mental states were recorded. A second control group of 11 participants underwent the same testing procedure in a laboratory session. Serum cortisol concentration during exposure to the centrifugal acceleration increased by 70%, plasma concentration of ACTH increased threefold, prolactin twofold, epinephrine by 70% and norepinephrine by 45%, whereas the perceived physical well-being decreased. These findings demonstrate that psycho-physiological changes have to be regarded as a relevant factor for the changes in CPNP during phases of hypergravity exposure.

Objective: The aim of this project was to compare texture discrimination when both touch and vision were perturbed. Background: Texture discrimination is important in the workplace. How textures are identified with the finger and with instruments when vision is magnified with lenses or video cameras is unclear. Method: Sandpaper was explored with the index finger or a metal instrument (hemostat), using normal or magnified vision. The forces generated during exploration were measured, and participants rated surface roughness. Results: With the finger, the perception of roughness was unaffected with magnification; with the instrument, magnified surfaces were perceived as rougher ( p < .05). Forces during finger exploration were unaffected by magnification; forces with the instrument increased under magnification ( p < .05). Conclusion: Visual characteristics of the working field can influence the exploration and perception of materials. With the finger, mechanoreceptors that directly detect textures are activated, and with the instrument, receptors sensitive to vibrations are stimulated. Application: The higher forces produced when using instruments under magnification could lead to material damage. Attenuated perception of texture when exploring with tools may lead to difficulty in accurate touch perception. This could create problems in industrial tasks such as grading wool or identifying surface imperfections on manufactured materials, as well as in clinical settings such as dentistry or surgery in which instruments are used during tissue identification.

The purpose of this study was to investigate the ability to discriminate friction during surface exploration using a finger and surgical instrument under normal vision and when vision was absent. Participants explored surfaces with either with the finger or with an instrument and rated the slipperiness. Results showed that the explorations with the instrument were estimated to be more slippery and less sensitive than those for the finger. There were no effects for visual condition. This study showed that novices who use instruments to make estimations of tissue slipperiness require practice and training in order to adequately perceive friction. Novices' reduced ability to perceive friction with instruments should be integrated into simulator design.

Compare different protocols for blood processing to be used during parabolic flights.Measurement of cortisol (COR), prolactin (PRL), adrenocorticotropic hormone (ACTH), epinephrine (EP) and norepinephrine (NOR) concentrations stored at different temperatures and intervals before analysis.COR, PRL and NOR showed no changes in concentration between analysis protocols. ACTH dropped by 60% when not analysed within 24 h.A standardised processing protocol that includes a 4-h delay following blood collection is suitable for the assessment of serum stress hormone concentrations.

Computer-assisted analysis of wrist movement has recently emerged as an objective laparoscopic performance evaluation method. The first purpose of this study was to assess the differences in motion characteristics between the tip of the instrument and the wrist. The second purpose was to describe the control strategies used to move laparoscopic instruments. During a bead transfer task, motions of a laparoscopic needle driver's tip, heel, and the participants' wrist were monitored. Results showed that large amplitude movements were best described by movements of the wrist, and small amplitude movements were evidenced by motions of the instrument tip. Thus, for describing expertise, and for evaluation and feedback, motion of the tip of the laparoscopic instrument should be quantified, in addition to motion of the wrist. The motions of the instrument were controlled by utilizing the flexibility of the skin of the laparoscopic trainer in addition to using the fulcrum, and sliding through the trocar. In order to increase fidelity, virtual reality trainers should simulate the flexibility of the real structures around the insertion of the instrument.

Background Ensuring competence remains a seminal objective of endoscopy training programs, professional organizations, and accreditation bodies; however, no widely accepted measure of endoscopic competence currently exists. Objective By using Delphi methodology, we aimed to develop and establish the content validity of the Gastrointestinal Endoscopy Competency Assessment Tool for colonoscopy. Design An international panel of endoscopy experts rated potential checklist and global rating items for their importance as indicators of the competence of trainees learning to perform colonoscopy. After each round, responses were analyzed and sent back to the experts for further ratings until consensus was reached. Main Outcome Measurements Consensus was defined a priori as ≥80% of experts, in a given round, scoring ≥4 of 5 on all remaining items. Results Fifty-five experts agreed to be part of the Delphi panel: 43 gastroenterologists, 10 surgeons, and 2 endoscopy managers. Seventy-three checklist and 34 global rating items were generated through a systematic literature review and survey of committee members. An additional 2 checklist and 4 global rating items were added by Delphi panelists. Five rounds of surveys were completed before consensus was achieved, with response rates ranging from 67% to 100%. Seven global ratings and 19 checklist items reached consensus as good indicators of the competence of clinicians performing colonoscopy. Limitations Further validation required. Conclusion Delphi methodology allowed for the rigorous development and content validation of a new measure of endoscopic competence, reflective of practice across institutions. Although further evaluation is required, it is a promising step toward the objective assessment of competency for use in colonoscopy training, practice, and research.

The withdrawal of vision of the arm during a manual aiming task has been found to result in a large increase in aiming error, regardless of the amount of practice in normal vision before its withdrawal. In the present study, the authors investigated whether the increase in error reflects the domination of visual afferent information over the movement representation developed during practice to the detriment of other sources of afferent information or whether it reflects only transformation errors of the location of the target from an allocentric to an egocentric frame of reference. Participants (N = 40) performed aiming movements with their dominant or nondominant arm in a full-vision or target- only condition. The results of the present experiment supported both of those hypotheses. The data indicated that practice does not eliminate the need for visual information for optimizing movement accuracy and that learning is specific to the source or sources of afferent information more likely to ensure optimal accuracy during practice. In addition, the results indicated that movement planning in an allocentric frame of reference might require simultaneous vision of the arm and the target. Finally, practice in a target-only condition, with knowledge of results, was found to improve recoding of the target in an egocentric frame of reference.

Prior research on large-fibre skin mechanoreceptors in humans and monkeys has demonstrated their sensitivity to perpendicular skin indentation and to the rate of force application. Although some studies have examined skin afferent responses to stretch, relatively few investigations have examined the neural and perceptual correlates of shear forces applied tangentially to the skin. The present study assessed the ability of human subjects to scale different levels of tangential force applied to the distal pad of the index finger. Subjects were instructed to choose their own magnitude estimation scale. Seven force levels ranging from 0.15 to 0.70 N were delivered randomly at rates of 0.10 N/s, 0.15 N/s or 0.30 N/s. Tangential forces were produced with a smooth metal spatula coated with an adhesive to insure a shear force on the underlying skin without slip. The same procedures were also used to generate skin indentation with normal forces. The results showed that most human subjects were able to scale different magnitudes of both tangential and normal forces applied to the tip of the index finger. The rate of force change did not influence the perception of the applied forces. These results highlight the potentially important role of tangential forces in haptic perception.

Milner and Goodale (1995) have proposed that visuomotor and perceptual processes are mediated by discrete visual systems that reflect the functional independence of action and perception. The visuomotor system is proposed to be insensitive to pictorial illusions of object size, whereas the perceptual system is reliably "tricked" by such figures. Brenner and Smeets (1996) and Jackson and Shaw (2000) demonstrated that grasp preshaping, but not grasping force, is immune to the Ponzo visual illusion, suggesting that not all visuomotor processes operate independently of the perceptual system. The present study investigated the effect of illusory object size on prehension kinematics and grasping dynamics (i.e., grip force and load force) as well as perceptual judgements of object size. Unlike previous investigations, object mass was held constant independent of changes in size. The Ponzo figure reliably affected perceptual estimates of object size, but this effect was restricted to one form of the illusion. Some aspects of the prehension movement were sensitive to veridical but not illusory object size (peak grip aperture, peak grip force, peak vertical wrist acceleration), whereas other movement parameters demonstrated illusory size effects (movement time, peak wrist velocity). Still other movement parameters were not sensitive to veridical or illusory object size (peak load force). Together the data suggest that certain prehension components are immune to pictorial illusions of object size, whereas others are not. Complex interactions between the perceptual and visuomotor systems appear to underlie the anticipatory scaling of grasping forces in prehension.

The effect of the horizontal-vertical illusion on the visual and visuomotor systems was investigated. Participants (N = 8) viewed horizontal and vertical lines in an inverted-T stimulus and judged whether the two line segments were the same or different lengths. Participants also reached out and grasped either the vertical or the horizontal line segment of the stimulus. Perceptually, participants succumbed to the illusion; that is, they judged Ts of equal horizontal and vertical line lengths to be different and Ts of unequal line lengths to be the same. When reaching toward the same stimuli, however, the size of their grip aperture was scaled appropriately for the various line lengths. Thus, whereas the perceptual system succumbed to the illusion, the visuomotor system did not. Those results support a model proposed by M. A. Goodale and A. D. Milner (1992), who posited separate cortical pathways for visual perception and visually guided action.

Neuromuscular adaptation at the onset of resisted exercise can be observed as increases in torque and surface electromyography. The effect of learning the motor task has been hypothesized to contribute to these early increases, especially for older people. Thus, the purpose of this study was to investigate the facilitatory effects of practice on motor performance in older adults during short-term isokinetic training of the ankle dorsiflexors (DF). Twenty-eight men and women (M = 76.3 +/- 4.6 years) volunteered for a 2-week, 3-days/week strength training program. They were tested in a sitting position on a KinCom isokinetic dynamometer at 30, 90, and 180 degrees s-1 through 40 degrees of DF movement (concentric and eccentric contractions). Criterion curves of lever arm angle patterns were cross-correlated with subject-generated angle patterns, showing significantly better correlations on posttest versus baseline. Smoothness and proficiency of muscle contraction improved with practice by fewer hesitations in movement and increased ability to change between concentric and eccentric muscle contractions. Increased agonist electromyography and torque were hypothesized to be secondary to greater neural drive and/or synchronization of motor unit firing rate and/or recruitment during maximal voluntary contraction, improved coordination, and adapted neural control of concentric and eccentric muscle contraction.