Biomedical subjects

Georg Bretthauer

Publications and source records attributed to Georg Bretthauer.

4 recordsLinked to original sources

PubMed2005

Automated feature assessment in instrumented gait analysis.

A methodological modular framework is presented for automated assessment of gait patterns. The processing steps of data selection, gait parameter calculation and evaluation are not limited to a specific field of application and are largely independent of case-based clinical expert knowledge. For these steps, a variety of mathematical methods was used and the validity of the approach to assess gait parameters tested by applying it to the clinical problem of Botulinum Toxin A (BTX-A) treatment of the spastic equinus foot. A set of 3670 parameters was ranked by relevance for classification of a group of 42 diplegic cerebral palsy (CP) patients and an age-matched reference group. The same procedure was performed for pre- and post-therapeutic data sets of these patients. Gait parameters of high relevance coincided well with results of previous studies based on partly manual and more subjective parameter selection. A norm distance measure is introduced to facilitate the quantification of deviations from a normal walking pattern and can be used as an overall scalar measure to evaluate differences in gait patterns or as a set of measures attributing each joint angle separately.

Automation↗

PubMed2005

A prospective randomized study to test the transfer of basic psychomotor skills from virtual reality to physical reality in a comparable training setting.

OBJECTIVE: To test whether basic skills acquired on a virtual endoscopic surgery simulator are transferable from virtual reality to physical reality in a comparable training setting. SUMMARY BACKGROUND DATA: For surgical training in laparoscopic surgery, new training methods have to be developed that allow surgeons to first practice in a simulated setting before operating on real patients. A virtual endoscopic surgery trainer (VEST) has been developed within the framework of a joint project. Because of principal limitations of simulation techniques, it is essential to know whether training with this simulator is comparable to conventional training. METHODS: Devices used were the VEST system and a conventional video trainer (CVT). Two basic training tasks were constructed identically (a) as virtual tasks and (b) as mechanical models for the CVT. Test persons were divided into 2 groups each consisting of 12 novices and 4 experts. Each group carried out a defined training program over the course of 4 consecutive days on the VEST or the CVT, respectively. To test the transfer of skills, the groups switched devices on the 5th day. The main parameter was task completion time. RESULTS: The novices in both groups showed similar learning curves. The mean task completion times decreased significantly over the 4 training days of the study. The task completion times for the control task on Day 5 were significantly lower than on Days 1 and 2. The experts' task completion times were much lower than those of the novices. CONCLUSIONS: This study showed that training with a computer simulator, just as with the CVT, resulted in a reproducible training effect. The control task showed that skills learned in virtual reality are transferable to the physical reality of a CVT. The fact that the experts showed little improvement demonstrates that the simulation trains surgeons in basic laparoscopic skills learned in years of practice.

Clinical Competence↗

PubMed2004

Two multiarticulated hydraulic hand prostheses.

PURPOSE: Consumers want new prosthetic hand designs that have increased functionality, better cosmetic appearance, and lower weight. METHODS: New lightweight hands that fulfill these demands can be designed by integrating a hydraulic system with small fluidic actuators at the digit joints. RESULTS: Two different designs of lightweight experimental prosthetic hand are presented. The weight of the first hand is reduced by 50% compared to a conventional prosthetic hand, whereas the functionality of the second hand is increased by additional prehension types. Optionally, a tactile feedback system can be integrated. Due to multiple articulated digits and flexible materials, both hands are able to conform to the shape of an object held. This significantly reduces the necessary grip force and results in stable holding of an object. For a natural appearance, the hands are covered with a cosmetic silicone rubber glove.

Artificial Limbs↗

PubMed2004

Virtual reality in laparoscopic surgery.

Although the many advantages of laparoscopic surgery have made it an established technique, training in laparoscopic surgery posed problems not encountered in conventional surgical training. Virtual reality simulators open up new perspectives for training in laparoscopic surgery. Under realistic conditions in real time, trainees can tailor their sessions with the VR simulator to suit their needs and goals, and can repeat exercises as often as they wish. VR simulators reduce the number of experimental animals needed for training purposes and are suited to the pursuit of research in laparoscopic surgery.

Austria↗