Search

The introduction of simulators for the practice of endoscopic-surgery sensori-motor skills opens a wide range of design options. An obvious one is augmented visual information early in practice, in particular a direct view of the site instead of the endoscopic view. We studied the effects of such augmented visual information on the simulated ablation of tissue with straight, horizontal and parallel cuts. Direct view had an immediate beneficial effect on performance as compared with endoscopic-view practice. However, in subsequent tests with endoscopic view the benefits disappeared and turned into costs for some aspects of performance, e.g., duration. This finding highlights for a simulated surgical task that optimisation of practice by a performance criterion may not result in optimisation by a transfer criterion. Practitioner Summary: Endoscopic surgery represents a challenge for human sensori-motor skills, but new simulator-based training methods give leeway for optimisation. A candidate is augmented visual feedback, in particular a direct rather than endoscopic view of the site. However, performance becomes dependent on the augmented feedback so that the costs outweigh the benefits. [ABSTRACT FROM PUBLISHER]

Objective: We explored constraints in responding to spatially variable stimuli when hand movements are transformed into inverse movements of a tool.Background: Generally, the spatial compatibility between stimuli and responses is a powerful determinant of performance. However, many tasks require the use of simple tools such as first-class levers that transform hand movements into inverted movements of a tool. What types of compatibility effects arise with such tools?Method: Participants moved the tip of a pointer to the left or right according to the color of a stimulus. The pointer was manipulated either directly, so that a hand movement caused a pointer movement in the corresponding direction, or indirectly, so that the hand moved the pointer in the opposite direction.Results: Responding was faster when the location of stimulus and the movement direction of the tool corresponded than when they did not correspond, independent of the movement direction of the hand. This occurred when stimulus location was task relevant (Experiment 1) as well as when it was task irrelevant (Experiment 2). Furthermore, responding was delayed when the hand and the relevant end of the tool moved in noncorresponding rather than corresponding directions.Conclusion: These results point to two distinct compatibility effects in tool use: one that relates to the transformation of stimuli into goals and one that relates to the transformation of goals into movements.Application: Potential applications of this research include the prediction and possibly manipulation of unwanted "fulcrum effects" in laparoscopic surgery and other first-class lever movements. [ABSTRACT FROM AUTHOR]

During the last two decades two potent groups of predictors for work-related musculoskeletal problems have been identified: physical work load and poor psychosocial working conditions. However, little is known about their combined effects. In this study the buffering effect of control at work with respect to the negative effects of psychological demands and physical work load on musculoskeletal problems is examined. All study variables were sampled from 431 people working in geriatric nursing homes in Germany by means of questionnaires. Main effects and interactions were tested with multiple regression analysis. The results showed that control buffered the effects of high psychological demands, but not of high physical work load; the buffering effect of control was observed only when physical work load was low. The combined effects of demands and physical work load were over-additive. Thus, the power of different predictors for musculoskeletal symptoms depended on the level of other predictors. This suggests that the efficiency of certain strategies for the prevention of musculoskeletal problems is likely to depend on the level of risk factors, with different strategies being appropriate for different levels of risk. [ABSTRACT FROM AUTHOR]