The role of conscious processing of movements during balance by young and older adults.

We examined the effect of verbalization of a phylogenetic motor skill, balance, in older and young adults with a low or a high propensity for conscious verbal engagement in their movements (reinvestment). Seventy-seven older adults and 53 young adults were categorized as high or low reinvestors, using the Movement Specific Reinvestment Scale, which assesses propensity for conscious processing of movements. Participants performed a pre- and post-test balance task that required quiet standing on a force-measuring plate. Prior to the post-test, participants described their pre-test balancing performance (verbalization) or listed animals (non-verbalization). Only young adults were affected by verbalization, with participants with a high propensity for reinvestment displaying increased medial-lateral entropy and participants with a low propensity for reinvestment displaying increased area of sway and medial-lateral sway variability following the intervention. The possible explanations for these results are discussed.

Conscious Control Is Associated With Freezing of Mechanical Degrees of Freedom During Motor Learning.

This study investigated whether conscious control is associated with freezing of mechanical degrees of freedom during motor learning. Participants practiced a throwing task using either error-strewn or error-reduced practice protocols, which encourage high or low levels of conscious control, respectively. After 24 hr, participants engaged in a series of delayed retention and transfer tests. Furthermore, propensity for conscious control was assessed using participants' ratings and freezing was gauged through movement variability of the throwing arm. Performance was defined by mean radial error. In the error-strewn group, propensity for conscious control was positively associated with both freezing and performance. In the error-reduced group, propensity for conscious control was negatively associated with performance, but not with freezing. These results suggest that conscious control is associated with freezing of mechanical degrees of freedom during motor learning.

Movement pattern components and mastery of an object control skill with error-reduced learning.

OBJECTIVES: This paper reports the effects of error-reduced learning on movement components and mastery of overhand throwing in children with and without intellectual disability. METHODS: Secondary data analysis was performed on two samples of children (typically developing, TD; intellectual disability, ID) who practiced overhand throwing in either an error-reduced (ER) or error-strewn (ES) condition. Movement pattern components were assessed using a sub-skill of Test of Gross Motor Development-2. RESULTS: In TD participants, ER learners displayed improved follow-through while ES learners did not. Among children with ID, ER learners displayed greater improvements of hip/shoulder rotation and follow-through, than ES learners. Discriminant function analysis confirmed that changes in these components differentiated learning groups. Greater percentage of ER, compared to ES, participants progressed to mastery. CONCLUSIONS: With suppressed errors, the follow-through component of overhand throwing is likely to emerge, particularly in children with inferior abilities, and cognitive limitations. Error-reduced learning facilitates mastery.

Gaze-contingent training enhances perceptual skill acquisition.

The purpose of this study was to determine whether decision-making skill in perceptual-cognitive tasks could be enhanced using a training technique that impaired selective areas of the visual field. Recreational basketball players performed perceptual training over 3 days while viewing with a gaze-contingent manipulation that displayed either (a) a moving window (clear central and blurred peripheral vision), (b) a moving mask (blurred central and clear peripheral vision), or (c) full (unrestricted) vision. During the training, participants watched video clips of basketball play and at the conclusion of each clip made a decision about to which teammate the player in possession of the ball should pass. A further control group watched unrelated videos with full vision. The effects of training were assessed using separate tests of decision-making skill conducted in a pretest, posttest, and 2-week retention test. The accuracy of decision making was greater in the posttest than in the pretest for all three intervention groups when compared with the control group. Remarkably, training with blurred peripheral vision resulted in a further improvement in performance from posttest to retention test that was not apparent for the other groups. The type of training had no measurable impact on the visual search strategies of the participants, and so the training improvements appear to be grounded in changes in information pickup. The findings show that learning with impaired peripheral vision offers a promising form of training to support improvements in perceptual skill.

Multitask training promotes automaticity of a fundamental laparoscopic skill without compromising the rate of skill learning.

BACKGROUND: A defining characteristic of expertise is automated performance of skills, which frees attentional capacity to better cope with some common intraoperative stressors. There is a paucity of research on how best to foster automated performance by surgical trainees. This study examined the use of a multitask training approach to promote automated, robust laparoscopic skills. METHODS: Eighty-one medical students completed training of a fundamental laparoscopic task in either a traditional single-task training condition or a novel multitask training condition. Following training, participants' laparoscopic performance was tested in a retention test, two stress transfer tests (distraction and time pressure) and a secondary task test, which was included to evaluate automaticity of performance. The laparoscopic task was also performed as part of a formal clinical examination (OSCE). RESULTS: The training groups did not differ in the number of trials required to reach task proficiency (p = .72), retention of skill (ps > .45), or performance in the clinical examination (p = .14); however, the groups did differ with respect to the secondary task (p = .016). The movement efficiency (number of hand movements) of single-task trainees, but not multitask trainees, was negatively affected during the secondary task test. The two stress transfer tests had no discernable impact on the performance of either training group. CONCLUSION: Multitask training was not detrimental to the rate of learning of a fundamental laparoscopic skill and added value by providing resilience in the face of a secondary task load, indicative of skill automaticity. Further work is needed to determine the extent of the clinical utility afforded by multitask training.

Examining Movement-Specific Reinvestment and Performance in Demanding Contexts.

Two experiments examined the roles of the dimensions of movement-specific reinvestment (movement self-consciousness and conscious motor processing) on performance under demanding conditions. In Experiment 1, novice golfers practiced a golf putting task and were tested under low- and high-anxiety conditions. Conscious motor processing was not associated with putting proficiency or movement variability; however, movement self-consciousness was positively associated with putting proficiency and appeared to be negatively associated with variability of impact velocity in low-anxiety conditions, but not in high-anxiety conditions. Increased anxiety and effort possibly left few attention resources for movement self-consciousness under high anxiety. In Experiment 2, participants performed a quiet standing task in single- and dual-task conditions. Movement self-consciousness was positively associated with performance when attention demands were low (single task) but not when attention demands were high (dual task). The findings provide insight into the differential influence of the two dimensions of movement-specific reinvestment under demanding conditions.

Exploring personality dimensions that influence practice and performance of a simulated laparoscopic task in the objective structured clinical examination.

BACKGROUND: Surgical educators have encouraged the investigation of individual differences in aptitude and personality in surgical performance. An individual personality difference that has been shown to influence laparoscopic performance under time pressure is movement specific reinvestment. Movement specific reinvestment has 2 dimensions, movement self-consciousness (MS-C) (i.e., the propensity to consciously monitor movements) and conscious motor processing (CMP) (i.e., the propensity to consciously control movements), which have been shown to differentially influence laparoscopic performance in practice but have yet to be investigated in the context of psychological stress (e.g., the objective structured clinical examination [OSCE]). OBJECTIVE: This study investigated the role of individual differences in propensity for MS-C and CMP in practice of a fundamental laparoscopic skill and in laparoscopic performance during the OSCE. Furthermore, this study examined whether individual differences during practice of a fundamental laparoscopic skill were predictive of laparoscopic performance during the OSCE. METHODS: Overall, 77 final-year undergraduate medical students completed the movement specific reinvestment scale, an assessment tool that quantifies the propensity for MS-C and CMP. Participants were trained to proficiency on a fundamental laparoscopic skill. The number of trials to reach proficiency was measured, and completion times were recorded during early practice, later practice, and the OSCE. RESULTS: There was a trend for CMP to be negatively associated with the number of trials to reach proficiency (p = 0.064). A higher propensity for CMP was associated with fewer trials to reach proficiency (ß = -0.70, p = 0.023). CMP and MS-C did not significantly predict completion times in the OSCE (p > 0.05). Completion times in early practice (ß = 0.05, p = 0.016) and later practice (ß = 0.47, p < 0.001) and number of trials to reach proficiency (ß = 0.23, p = 0.003) significantly predicted completion times in the OSCE. CONCLUSION: It appears that a higher propensity for CMP predicts faster rates of learning of a fundamental laparoscopic skill. Furthermore, laparoscopic performance during practice is indicative of laparoscopic performance in the challenging conditions of the OSCE. The lack of association between the 2 dimensions of movement specific reinvestment and performance during the OSCE is explained using the theory of reinvestment as a framework. Overall, consideration of personality differences and individual differences in ability during practice could help inform the development of individualized surgical training programs.

Cathodal Transcranial Direct Current Stimulation Over Left Dorsolateral Prefrontal Cortex Area Promotes Implicit Motor Learning in a Golf Putting Task.

BACKGROUND: Implicit motor learning is characterized by low dependence on working memory and stable performance despite stress, fatigue, or multi-tasking. However, current paradigms for implicit motor learning are based on behavioral interventions that are often task-specific and limited when applied in practice. OBJECTIVE: To investigate whether cathodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) area during motor learning suppressed working memory activity and reduced explicit verbal-analytical involvement in movement control, thereby promoting implicit motor learning. METHODS: Twenty-seven healthy individuals practiced a golf putting task during a Training Phase while receiving either real cathodal tDCS stimulation over the left DLPFC area or sham stimulation. Their performance was assessed during a Test phase on another day. Verbal working memory capacity was assessed before and after the Training Phase, and before the Test Phase. RESULTS: Compared to sham stimulation, real stimulation suppressed verbal working memory activity after the Training Phase, but enhanced golf putting performance during the Training Phase and the Test Phase, especially when participants were required to multi-task. CONCLUSION: Cathodal tDCS over the left DLPFC may foster implicit motor learning and performance in complex real-life motor tasks that occur during sports, surgery or motor rehabilitation.

The contributions of central and peripheral vision to expertise in basketball: How blur helps to provide a clearer picture.

The main purpose of this study was to examine the relative roles of central and peripheral vision when performing a dynamic forced-choice task. We did so by using a gaze-contingent display with different levels of blur in an effort to (a) test the limit of visual resolution necessary for information pick-up in each of these sectors of the visual field and, as a result, to (b) develop a more natural means of gaze-contingent display using a blurred central or peripheral visual field. The expert advantage seen in usual whole field visual presentation persists despite surprisingly high levels of impairment to central or peripheral vision. Consistent with the well-established central/peripheral differences in sensitivity to spatial frequency, high levels of blur did not prevent better-than-chance performance by skilled players when peripheral information was blurred, but they did affect response accuracy when impairing central vision. Blur was found to always alter the pattern of eye movements before it decreased task performance. The evidence accumulated across the 4 experiments provides new insights into several key questions surrounding the role that different sectors of the visual field play in expertise in dynamic, time-constrained tasks.

Conscious motor processing and movement self-consciousness: two dimensions of personality that influence laparoscopic training.

BACKGROUND: Identifying personality factors that account for individual differences in surgical training and performance has practical implications for surgical education. Movement-specific reinvestment is a potentially relevant personality factor that has a moderating effect on laparoscopic performance under time pressure. Movement-specific reinvestment has 2 dimensions, which represent an individual's propensity to consciously control movements (conscious motor processing) or to consciously monitor their 'style' of movement (movement self-consciousness). OBJECTIVE: This study aimed at investigating the moderating effects of the 2 dimensions of movement-specific reinvestment in the learning and updating (cross-handed technique) of laparoscopic skills. METHODS: Medical students completed the Movement-Specific Reinvestment Scale, a psychometric assessment tool that evaluates the conscious motor processing and movement self-consciousness dimensions of movement-specific reinvestment. They were then trained to a criterion level of proficiency on a fundamental laparoscopic skills task and were tested on a novel cross-handed technique. Completion times were recorded for early-learning, late-learning, and cross-handed trials. RESULTS: Propensity for movement self-consciousness but not conscious motor processing was a significant predictor of task completion times both early (p = 0.036) and late (p = 0.002) in learning, but completion times during the cross-handed trials were predicted by the propensity for conscious motor processing (p = 0.04) rather than movement self-consciousness (p = 0.21). CONCLUSION: Higher propensity for movement self-consciousness is associated with slower performance times on novel and well-practiced laparoscopic tasks. For complex surgical techniques, however, conscious motor processing plays a more influential role in performance than movement self-consciousness. The findings imply that these 2 dimensions of movement-specific reinvestment have a differential influence in the learning and updating of laparoscopic skills.

Taking aim at the Müller-Lyer goalkeeper illusion: an illusion bias in action that originates from the target not being optically specified.

Van der Kamp and Masters (2008) reported that goalkeeper postures that mimic the Müller-Lyer (1889) illusion affect the location of handball penalty throws. In four experiments, we aimed to verify that the effects on throwing are consistent with an illusory bias (Experiments 1 and 2), and to examine how these observations can be understood in the context of Milner and Goodale's (1995, 2008) two-visual systems model (Experiments 3 and 4). Experiments 1 and 2 confirmed that the goalkeeper Müller-Lyer posture may indeed induce an illusory bias in throwing, implying that allocentric information is used in far-aiming action tasks. Experiment 3 demonstrated that the bias was not related to a participant's throwing skill. Experiment 4 suggested that an absence of visual information to instantaneously specify target location may have induced use of context-dependent allocentric information, causing the throwing bias. The results are discussed in the context of recent debates about the roles of the two-visual systems in perception and action. It is suggested that the two systems are first and foremost perceptual systems that serve the pickup of different sources of information.

The role of central and peripheral vision in expert decision making.

The purpose of this study was to investigate the role of central and peripheral vision in expert decision making. A gaze-contingent display was used to selectively present information to the central and peripheral areas of the visual field while participants performed a decision-making task. Eleven skilled and eleven less-skilled male basketball players watched video clips of basketball scenarios in three different viewing conditions: full-image control, moving window (central vision only), and moving mask (peripheral vision only). At the conclusion of each clip participants were required to decide whether it was more appropriate for the ball-carrier to pass the ball or to drive to the basket. The skilled players showed significantly higher response accuracy and faster response times compared with their lesser-skilled counterparts in all three viewing conditions, demonstrating superiority in information extraction that held irrespective of whether they were using central or peripheral vision. The gaze behaviour of the skilled players was less influenced by the gaze-contingent manipulations, suggesting they were better able to use the remaining information to sustain their normal gaze behaviour. The superior capacity of experts to interpret dynamic visual information is evident regardless of whether the visual information is presented across the whole visual field or selectively to either central or peripheral vision alone.

Cutting errors in surgery: experience limits underestimation bias in a simulated surgical environment.

OBJECTIVE: Error management is crucial in surgery and needs to be developed through appropriate training and education. Research suggests that perceptual errors may be more likely in laparoscopic environments. The objective of this work is to investigate error management by novices compared with experienced surgeons when performing a simple simulated incision in a visually challenging environment. METHODS: Novices (n = 20) and experienced surgeons (n = 11) viewed pairs of horizontal lines on a laparoscopic monitor. Participants were asked to replicate the line lengths by making simulated incisions. The task was completed with or without online visual feedback of the incising hand. In a second phase of the study, the task was complicated by embedding the lines within a perceptual illusion (i.e., Ponzo illusion). RESULTS: Incision lengths generally were shorter than the actual lengths of the viewed lines for all participants. For the novices, however, this underestimation bias was exacerbated when visual feedback of the incising hand was unavailable (p < 0.001), whereas the surgeons were not affected by loss of vision of the incising hand (p = 0.864). Furthermore, novices were influenced by the perceptual illusion designed to alter perceptions of line length (p = 0.021), whereas the surgeons did not appear to be influenced by the illusion (p = 0.945). CONCLUSIONS: A perceptual bias towards incision length underestimation may be present when surgery involves a laparoscopic monitor; however, surgical experience may protect against accentuation of the underestimation bias when the task becomes more visually challenging. The bias is discussed using the framework of error management theory.

Conscious monitoring and control (reinvestment) in surgical performance under pressure.

BACKGROUND: Research on intraoperative stressors has focused on external factors without considering individual differences in the ability to cope with stress. One individual difference that is implicated in adverse effects of stress on performance is "reinvestment," the propensity for conscious monitoring and control of movements. The aim of this study was to examine the impact of reinvestment on laparoscopic performance under time pressure. METHODS: Thirty-one medical students (surgery rotation) were divided into high- and low-reinvestment groups. Participants were first trained to proficiency on a peg transfer task and then tested on the same task in a control and time pressure condition. Outcome measures included generic performance and process measures. Stress levels were assessed using heart rate and the State Trait Anxiety Inventory (STAI). RESULTS: High and low reinvestors demonstrated increased anxiety levels from control to time pressure conditions as indicated by their STAI scores, although no differences in heart rate were found. Low reinvestors performed significantly faster when under time pressure, whereas high reinvestors showed no change in performance times. Low reinvestors tended to display greater performance efficiency (shorter path lengths, fewer hand movements) than high reinvestors. CONCLUSION: Trained medical students with a high individual propensity to consciously monitor and control their movements (high reinvestors) displayed less capability (than low reinvestors) to meet the demands imposed by time pressure during a laparoscopic task. The finding implies that the propensity for reinvestment may have a moderating effect on laparoscopic performance under time pressure.

Development and validation of a surgical workload measure: the surgery task load index (SURG-TLX).

BACKGROUND: The purpose of the present study was to develop and validate a multidimensional, surgery-specific workload measure (the SURG-TLX), and to determine its utility in providing diagnostic information about the impact of various sources of stress on the perceived demands of trained surgical operators. As a wide range of stressors have been identified for surgeons in the operating room, the current approach of considering stress as a unidimensional construct may not only limit the degree to which underlying mechanisms may be understood but also the degree to which training interventions may be successfully matched to particular sources of stress. METHODS: The dimensions of the SURG-TLX were based on two current multidimensional workload measures and developed via focus group discussion. The six dimensions were defined as mental demands, physical demands, temporal demands, task complexity, situational stress, and distractions. Thirty novices were trained on the Fundamentals of Laparoscopic Surgery (FLS) peg transfer task and then completed the task under various conditions designed to manipulate the degree and source of stress experienced: task novelty, physical fatigue, time pressure, evaluation apprehension, multitasking, and distraction. RESULTS: The results were supportive of the discriminant sensitivity of the SURG-TLX to different sources of stress. The sub-factors loaded on the relevant stressors as hypothesized, although the evaluation pressure manipulation was not strong enough to cause a significant rise in situational stress. CONCLUSIONS: The present study provides support for the validity of the SURG-TLX instrument and also highlights the importance of considering how different stressors may load surgeons. Implications for categorizing the difficulty of certain procedures, the implementation of new technology in the operating room (man-machine interface issues), and the targeting of stress training strategies to the sources of demand are discussed. Modifications to the scale to enhance clinical utility are also suggested.

Implicit motor learning promotes neural efficiency during laparoscopy.

BACKGROUND: An understanding of differences in expert and novice neural behavior can inform surgical skills training. Outside the surgical domain, electroencephalographic (EEG) coherence analyses have shown that during motor performance, experts display less coactivation between the verbal-analytic and motor planning regions than their less skilled counterparts. Reduced involvement of verbal-analytic processes suggests greater neural efficiency. The authors tested the utility of an implicit motor learning intervention specifically devised to promote neural efficiency by reducing verbal-analytic involvement in laparoscopic performance. METHODS: In this study, 18 novices practiced a movement pattern on a laparoscopic trainer with either conscious awareness of the movement pattern (explicit motor learning) or suppressed awareness of the movement pattern (implicit motor learning). In a retention test, movement accuracy was compared between the conditions, and coactivation (EEG coherence) was assessed between the motor planning (Fz) region and both the verbal-analytic (T3) and the visuospatial (T4) cortical regions (T3-Fz and T4-Fz, respectively). RESULTS: Movement accuracy in the conditions was not different in a retention test (P = 0.231). Findings showed that the EEG coherence scores for the T3-Fz regions were lower for the implicit learners than for the explicit learners (P = 0.027), but no differences were apparent for the T4-Fz regions (P = 0.882). CONCLUSIONS: Implicit motor learning reduced EEG coactivation between verbal-analytic and motor planning regions, suggesting that verbal-analytic processes were less involved in laparoscopic performance. The findings imply that training techniques that discourage nonessential coactivation during motor performance may provide surgeons with more neural resources with which to manage other aspects of surgery.

A comparison of evaluation, time pressure, and multitasking as stressors of psychomotor operative performance.

BACKGROUND: There is gathering interest in determining the typical sources of stress for an operating surgeon and the effect that stressors might have on operative performance. Much of the research in this field, however, has failed to measure stress levels and performance concurrently or has not acknowledged the differential impact of potential stressors. Our aim was to examine empirically the influence of different sources of stress on trained laparoscopic performance. METHODS: A total of 30 medical students were trained to proficiency on the validated Fundamentals of Laparoscopic Surgery peg transfer task, and then were tested under 4 counterbalanced test conditions: control, evaluation threat, multitasking, and time pressure. Performance was assessed via completion time and a process measure reflecting the efficiency of movement (ie, path length). Stress levels in each test condition were measured using a multidimensional approach that included the State-Trait Anxiety Inventory (STAI) and the subject's heart rate while performing a task. RESULTS: The time pressure condition caused the only significant increase in stress levels but did not influence completion time or the path length of movement. Only the multitasking condition significantly increased completion time and path length, despite there being no significant increase in stress levels. Overall, the STAI and heart rate measures were not correlated strongly. CONCLUSION: Recommended measures of stress levels do not necessarily reflect the demands of an operative task, highlighting the need to understand better the mechanisms that influence performance in surgery. This understanding will help inform the development of training programs that encourage the complete transfer of skills from simulators to the operating room.

Attention and time constraints in perceptual-motor learning and performance: instruction, analogy, and skill level.

We sought to gain more insight into the effects of attention focus and time constraints on skill learning and performance in novices and experts by means of two complementary experiments using a table tennis paradigm. Experiment 1 showed that skill-focus conditions and slowed ball frequency disrupted the accuracy of experts, but dual-task conditions and speeded ball frequency did not. For novices, only speeded ball frequency disrupted accuracy. In Experiment 2, we extended these findings by instructing novices either explicitly or by analogy (implicit motor learning technique). Explicitly instructed novices were less accurate in skill-focused and dual-task conditions than in single-task conditions. Following analogy instruction novices were less accurate in the skill-focused condition, but maintained accuracy under dual-task conditions. Participants in both conditions retained accuracy when ball frequency was slowed, but lost accuracy when ball frequency was speeded, suggesting that not attention, but motor dexterity, was inadequate under high temporal constraints.