Assessing colonoscopic inspection skill using a virtual withdrawal simulation: a preliminary validation of performance metrics.

Background: The effectiveness of colonoscopy for diagnosing and preventing colon cancer is largely dependent on the ability of endoscopists to fully inspect the colonic mucosa, which they achieve primarily through skilled manipulation of the colonoscope during withdrawal. Performance assessment during live procedures is problematic. However, a virtual withdrawal simulation can help identify and parameterise actions linked to successful inspection, and offer standardised assessments for trainees.

A novel training device for tip control in colonoscopy: preliminary validation and efficacy as a training tool.

Background: Effective control of the colonoscope tip is one of the most fundamental components of colonoscopy skill. Mastering fine tip control can be problematic for novice trainees, yet no validated training regimes exist for developing this specific skill component in isolation. We aimed to conduct a preliminary validation of a novel training device for colonoscopic tip control, and to assess its efficacy as a training tool.

The efficacy of training insertion skill on a physical model colonoscopy simulator.

Prior research supports the validity of performance measures derived from the use of a colonoscopy simulator - the (Kyoto Kagaku Co. Ltd., Kyoto, Japan) - for assessing insertion skill.

Assessment of colorectal polyp recognition skill: development and validation of an objective test.

Background: The quality of colonoscopy is known to vary. The extent to which colonoscopists can recognize the presence of subtle colorectal lesions by visually distinguishing them from the surrounding mucosa (i.e.

Construct validation of a physical model colonoscopy simulator.

Background: Previous studies have demonstrated the construct validity of virtual reality colonoscopy simulators by showing that they can distinguish between users according to their level of endoscopic experience. Although physical model simulators are known to simulate looping more realistically than these devices, they lack published validation evidence.

Objective: To assess the construct validity of a physical model simulator, the Kyoto Kagaku Colonoscope Training Model (Kyoto Kagaku Co.

The influence of visual motion on interceptive actions and perception.

Visual information is an essential guide when interacting with moving objects, yet it can also be deceiving. For instance, motion can induce illusory position shifts, such that a moving ball can seem to have bounced past its true point of contact with the ground. Some evidence suggests illusory motion-induced position shifts bias pointing tasks to a greater extent than they do perceptual judgments.

Assessing the realism of colonoscopy simulation: the development of an instrument and systematic comparison of 4 simulators.

Background: No useful comparative data exist on the relative realism of commercially available devices for simulating colonoscopy.

Objectives: To develop an instrument for quantifying realism and provide the first wide-ranging empiric comparison.

Design: Repeated measures, observational study.

The effect of priming on interceptive actions.

Time constraints in ball sports encourage players to take advantage of any relevant advance information available to prepare their actions. Advance information, therefore, can serve to prime movement parameters (e.g.

Delayed inhibition of an anticipatory action during motion extrapolation.

Background: Continuous visual information is important for movement initiation in a variety of motor tasks. However, even in the absence of visual information people are able to initiate their responses by using motion extrapolation processes. Initiation of actions based on these cognitive processes, however, can demand more attentional resources than that required in situations in which visual information is uninterrupted.

The time course of direction specification in brief interceptive actions.

In fastball sports such as baseball and tennis people are required to produce accurate responses following brief observations of the ball. This limits the time available to prepare the movement. To cope with constrained viewing periods which precede the interception of fast approaching balls, performers are likely to prepare their responses in advance.

Preparation and inhibition of interceptive actions.

Two experiments aimed to provide an estimate of the last moment at which visual information needs to be obtained in order for it to be used to initiate execution of an interceptive movement or to withhold execution of such a movement. In experiment 1, we sought to estimate the minimum time required to suppress the movement when the participants were first asked to intercept a moving target. In experiment 2, we sought to determine the minimum time required to initiate an interceptive movement when the participants were initially asked to keep stationary.

The utilisation of visual information in the control of rapid interceptive actions.

When intercepting a moving target, accurate timing depends, in part, upon starting to move at the right moment. It is generally believed that this is achieved by triggering motor command generation when a visually perceived quantity such as the target's time-to-arrival reaches a specific criterion value. An experimental method that could be used to determine the moment when this visual event happens was introduced by Whiting and coworkers in the 1970s, and it involves occluding the vision of the target at different times prior to the time of movement onset (MO).

Reducing contrast makes speeds in a video-based driving simulator harder to discriminate as well as making them appear slower.

We investigated the effect of reducing image contrast on speed perception using a video-based driving simulator in which participants viewed pairs of scenes and were asked to judge whether the second scene was faster or slower than the first scene. We predicted two outcomes: (i) that vehicle speeds would become harder to discriminate, and (ii) that vehicle speeds would appear slower. There is previous evidence confirming the latter prediction in a less realistic computer-based driving simulation, but none demonstrating the former.

Auditory feedback influences perceived driving speeds.

Reducing the level of internal noise is seen as a goal when designing modern cars. One danger of such a philosophy is that one is systematically attempting to alter one of the cues that can be used by drivers to estimate speed and this could bias speed judgments and driving behaviour. Seven participants were presented with pairs of video-based driving scenes and asked to judge whether the second scene appeared faster or slower than the first (2-alternative forced-choice task using the method of constant stimuli).

The time course of amplitude specification in brief interceptive actions.

The interception of fast moving objects typically allows the object to be seen for only a short period of time. This limits the time available to prepare the movement. To deal with short preparation intervals, performers are likely to prepare a motor program in advance.

Systematic changes in the duration and precision of interception in response to variation of amplitude and effector size.

The results of two experiments are reported that examined how performance in a simple interceptive action (hitting a moving target) was influenced by the speed of the target, the size of the intercepting effector and the distance moved to make the interception. In Experiment 1, target speed and the width of the intercepting manipulandum (bat) were varied. The hypothesis that people make briefer movements, when the temporal accuracy and precision demands of the task are high, predicts that bat width and target speed will divisively interact in their effect on movement time (MT) and that shorter MTs will be associated with a smaller temporal variable error (VE).

The attentional demands of preferred and non-preferred gait patterns.

The purpose of this study was to determine the attentional demands of natural and imposed gait, as well as the attentional costs of transitions between the walking and running co-ordination patterns. Seven healthy young men and four healthy young women undertook an auditory probe reaction time task concurrently with self-selected gait (Experiment 1) and imposed walking and running (Experiment 2) at different speeds on a motor-driven treadmill. In Experiment 1, where participants were free to choose their own movement pattern to match the speed of travel of the treadmill, normal gait control was shown to have a significant attentional cost, and hence not be automatic in the classical sense.