Biomedical subjects

W B Verwey

Publications and source records attributed to W B Verwey.

7 recordsLinked to original sources

PubMed2006

Validation of open-surgery VR trainer.

VREST (Virtual Reality Educational Surgical Tools) is developing a universal and autonomous simulation platform which can be used for training and assessment of medical students and for continuing education of physicians. With the VREST - Virtual Lichtenstein Trainer, simulating the open surgery procedure of the inguinal hernia repair according to Lichtenstein, the validation of the simulator is ongoing. Part of this trajectory is the evaluation of the transfer of training of the virtual incision making. One group of students trained incision making on the VREST platform where the control group did not. In an experiment both groups has to perform several incision tasks on a manikin. The results are not available yet but will be presented at the MMVR14 conference.

Computer Simulation↗

PubMed2006

Open surgery in VR: inguinal hernia repair according to Lichtenstein.

VREST (Virtual Reality Educational Surgical Tools) is developing a universal and autonomous simulation platform which can be used for training and assessment of medical students and for continuing education of physicians. A workstation consisting of two haptic devices and a 3D vision system is part of the VREST platform. Another part of the platform is a generic software environment in which lessons can be built by the teacher and performed by their students. Using the platform one can see, feel and decide as in reality. With the assessment tool the progress and skills of the students can be supervised. The first lesson build on the VREST platform is an inguinal hernia repair according to Lichtenstein. This is an open surgery procedure. The VREST platform is used prior to the first operating room surgery of the resident. Interactive models and case dependent feedback is used to enlarge the residents' cognition. This should reduce the training time in the operating room.

Computer Simulation↗

PubMed2001

Concatenating familiar movement sequences: the versatile cognitive processor.

Earlier studies demonstrated that practicing a series of key presses in a fixed order yields memory representations (i.e., motor chunks) that can be selected and used for sequence execution as if familiar key pressing sequences are single responses. In order to examine whether these motor chunks are robust in different situations and whether preparation for one sequence may overlap with execution of another one, two experiments were carried out in which participants executed two highly practiced keying sequences in rapid succession in response to two simultaneously presented stimuli. The results confirmed robustness of motor chunks, even when the sequences included only two elements, and showed that preparation (and in particular, selection) of a forthcoming sequence may occur during execution of the earlier sequence. Sequences including only two keys appeared to be slowed more by concurrent preparation than longer sequences. Together these results suggest that the execution of familiar keying sequences is predominantly carried out by a dedicated motor processor, and that the cognitive processor can be allocated to preparing a forthcoming sequence (e.g., during execution of an earlier sequence) or, some times, to selecting individual sequence elements in parallel to the motor processor.

Adult↗

PubMed2000

On-line driver workload estimation. Effects of road situation and age on secondary task measures.

In order to develop a driver-car interface that adapts the presentation of messages generated by in-vehicle information systems to driver workload, two experiments investigated potential determinants of driver visual and mental workload as indicated by performance on two secondary tasks. Experiment 1 suggested that road situation is a major determinant of visual and mental workload of the driver and that the processing resources of older drivers are somewhat more limited than those of younger and middle-aged drivers. Familiarity with the area of driving (when guided) and time of day (associated with traffic density) showed no secondary task effects. Experiment 2 showed that the categorization of road situations, proposed in Experiment 1, could underlie adaptation of visually loading messages to the workload incurred by driving. This was not found with respect to mentally loading messages.

Adult↗

PubMed1999

Preventing drowsiness accidents by an alertness maintenance device.

The reported experiment investigated in an advanced driving simulator whether drivers' alertness can be maintained in drowsiness-inducing conditions by a special game-like system, a 'gamebox'. Drowsiness was assessed by self-rating and eye-closures. Mental effort was assessed by a subjective workload rating scale and by a physiological measure (the 0.1 Hz component of heart rate). Driving quality and safety were assessed by steering movements, time-to-line crossings, and by the occurrence of safety-related driving errors--solid line crossings, driving off-road incidents and accidents. When driving with the gamebox, drivers reported a lower degree of drowsiness and fewer instances of sleep episodes as compared to a control condition. Driving with the device resulted in fewer incidents and accidents, and these occurred later in the session. The quality of vehicle control deteriorated progressively over the course of the session, but less so in the gamebox condition. Hence, the results corroborate the notion that mental activity counteracts drowsiness in prolonged driving.

Accidents, Traffic↗

PubMed1997

Fatigue, workload and adaptive driver systems.

This paper is directed to the further understanding of the problems of fatigue and workload and their role in diminishing driving capability. We present a specific strategy designed to defend against the adverse effects of fatigue and workload extremes through the use of adaptive driver systems. To begin, the work presents a brief critique of Muscio's constraints on developing a test of fatigue. In criticizing these constraints, we point to the commonalities between all energetic reflections of human performance and use advances in stress theory to explain the problems of and resolution to the question of fatigue. We link fatigue and chronic workload and use this coadunation as a basis for the operation of adaptive driver systems which are specifically designed to combat driving impairment. A specific program is then explained in detail and illustrations are given as to how an extension of previous efforts can address the problem of the drowsy and chronically fatigued driver. Future recommendations are articulated.

Accidents, Occupational↗

PubMed1993

Effects of extended practice in a one-finger keypressing task.

This paper addresses skilled operations underlying the initiation and execution of rapid movement sequences in a task consisting of three sequential keypresses made with one finger. It sought to provide evidence for the notion that, as a result of practice, processes required to produce a keypressing sequence become concurrent. The results of the experiment show, first, that unpacking of the third keypress in a three-keypress sequence, which is assumed to occur normally after execution of the second keypress, is shifted in time during practice so as to occur during or before actual depression of the second key. Second, no evidence was found that selection of a stimulus-dependent key occurring later in the sequence could be performed during execution of earlier, stimulus-independent keypresses. Third, the pattern of dual-task interference suggested that attention is required for preparing as well as for executing movement sequences. Dual-task interference hardly reduced with practice which was interpreted as evidence for the notion that reduction of attentional demands of keypressing with practice is used only for increasing the amount of concurrent unpacking. In conclusion, the present experiment suggests that a major reason that movement sequences are executed faster with practice is that the reduction of attentional demands of individual subprocesses is utilized to increase the amount of concurrent processing.

Adult↗