Biomedical subjects

Rüdiger Rupp

Publications and source records attributed to Rüdiger Rupp.

7 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

EEG-based neuroprosthesis control: a step towards clinical practice.

This case study demonstrates the coupling of an electroencephalogram (EEG)-based Brain-Computer Interface (BCI) with an implanted neuroprosthesis (Freehand system). Because the patient was available for only 3 days, the goal was to demonstrate the possibility of a patient gaining control over the motor imagery-based Graz BCI system within a very short training period. By applying himself to an organized and coordinated training procedure, the patient was able to generate distinctive EEG-patterns by the imagination of movements of his paralyzed left hand. These patterns consisted of power decreases in specific frequency bands that could be classified by the BCI. The output signal of the BCI emulated the shoulder joystick usually used, and by consecutive imaginations the patient was able to switch between different grasp phases of the lateral grasp that the Freehand system provided. By performing a part of the grasp-release test, the patient was able to move a simple object from one place to another. The results presented in this work give evidence that Brain-Computer Interfaces are an option for the control of neuroprostheses in patients with high spinal cord lesions. The fact that the user learned to control the BCI in a comparatively short time indicates that this method may also be an alternative approach for clinical purposes.

Adult↗

PubMed2004

Influence of passive leg movements on blood circulation on the tilt table in healthy adults.

BACKGROUND: One problem in the mobilization of patients with neurological diseases, such as spinal cord injury, is the circulatory collapse that occurs while changing from supine to vertical position because of the missing venous pump due to paralyzed leg muscles. Therefore, a tilt table with integrated stepping device (tilt stepper) was developed, which allows passive stepping movements for performing locomotion training in an early state of rehabilitation. The aim of this pilot study was to investigate if passive stepping and cycling movements of the legs during tilt table training could stabilize blood circulation and prevent neurally-mediated syncope in healthy young adults. METHODS: In the first experiment, healthy subjects were tested on a traditional tilt table. Subjects who had a syncope or near-syncope in this condition underwent a second trial on the tilt stepper. In the second experiment, a group of healthy subjects was investigated on a traditional tilt table, the second group on the tilt ergometer, a device that allows cycling movements during tilt table training. We used the chi-square test to compare the occurrence of near-syncope/syncope in both groups (tilt table/tilt stepper and tilt table/tilt ergometer) and ANOVA to compare the blood pressure and heart rate between the groups at the four time intervals (supine, at 2 minutes, at 6 minutes and end of head-up tilt). RESULTS: Separate chi-square tests performed for each experiment showed significant differences in the occurrence of near syncope or syncope based on the device used. Comparison of the two groups (tilt stepper/ tilt table) in experiment one (ANOVA) showed that blood pressure was significantly higher at the end of head-up tilt on the tilt stepper and on the tilt table there was a greater increase in heart rate (2 minutes after head-up tilt). Comparison of the two groups (tilt ergometer/tilt table) in experiment 2 (ANOVA) showed that blood pressure was significantly higher on the tilt ergometer at the end of head-up tilt and on the tilt table the increase in heart rate was significantly larger (at 6 min and end of head-up tilt). CONCLUSIONS: Stabilization of blood circulation and prevention of benign syncope can be achieved by passive leg movement during a tilt table test in healthy adults.

Journal Article↗

PubMed2004

HeiDATAProVIT-Heidelberg data archiving, tag assembling, processing and visualization tool.

The demands that have to be met by software tools for biomedical data evaluation strongly differ depending on the background of their application. In clinical routine emphasis is placed on ease of handling and application of standardized procedures, whereas in biomedical research the main focus lies on flexibility and extensibility. These contradictory requirements are reflected by the design principles of existing software solutions: programs for routine application are barely extensible or modifiable by the user and the complexity of highly flexible data processing tools for research purposes hampers the application of new methods to larger data volumes. This gap poses technical difficulties to the transfer of methods from research into clinical routine. The software we present in this paper bridges this discrepancy by incorporating two different levels of application. The lower level offers options to integrate custom written MATLAB((R)) processing routines and to add new evaluation schemes to a pool of existing procedures. The higher level allows for performing standard evaluations by accessing and applying these previously defined procedures. Four basic concepts were introduced to ensure that the program is both maximally flexible on a lower level and readily applicable on a higher level: the tag concept, the concept of modularized visualization, the dummy file concept, and the batchjob concept. These concepts are the key to flexibly assemble and apply the three universal stages of data evaluation: (1) archiving of acquired data, (2) processing the data using signal processing algorithms and (3) visualizing the results in appropriate graphical formats. The present paper illustrates the four concepts within the two levels of the software architecture. The basic functionality and usefulness of the program are demonstrated using an evaluation of gait analysis data as sample application. In summary, this software tool closely integrates a database for biomedical datasets and an extensible pool of evaluation and visualization procedures realized using MATLAB((R)). It is well suited both for data processing in clinical routine and for evaluation of measurement data in any medical research project.

Information Storage and Retrieval↗

PubMed2003

'Thought'--control of functional electrical stimulation to restore hand grasp in a patient with tetraplegia.

The aim of the present study was to demonstrate the first time the non-invasive restoration of hand grasp function in a tetraplegic patient by electroencephalogram (EEG)-recording and functional electrical stimulation (FES) using surface electrodes. The patient was able to generate bursts of beta oscillations in the EEG by imagination of foot movement. These beta bursts were analyzed and classified by a brain-computer interface (BCI) and the output signal used to control a FES device. The patient was able to grasp a cylinder with the paralyzed hand.

Adult↗

PubMed2003

Quantifying the variability of a complex motor task specifically studying the gait of dyskinetic CP children.

Lately, more and more interest has been directed towards the variability of complex motor tasks and its diagnostic value in motion disorders. However, there is no standardized way of quantifying variability of motion. In this respect, the purpose of this study is to explore the usefulness of variability computations derived from three-dimensional (3D) motion trajectories. A mathematical and computational algorithm was defined to first extract and overlay the 3D data for the trajectories. As an example for the application, the trajectories of the ankle marker representing the motion during swing were chosen. The method was used to determine the variability during swing for CP children with and without dyskinesia (n=31). A group of healthy adult normals served as control (n=8). The results were validated against the visual rating of swing variability by experienced clinical observers. The calculated values were superior to the previously used pelvic span/ankle spread ratio. The proposed method of quantifying the variability of a complex, repetitive motor task proved to be valid and useful. It has no limitation with regard to reprocessing previously collected data, or as to which equipment is used to gather the 3D coordinates during the motion.

Algorithms↗

PubMed2002

[HeiDATAProViT--a universal software tool for evaluating biomedical data].

Evaluation of large sets of biomedical data can be divided into three universal stages: 1. archiving of clinical data together with data obtained from measurements, 2. processing of numerical data using signal processing algorithms and 3. visualizing the results. In this paper a software is presented which tightly integrates a data base under MS Access and the possibilities for data processing and visualization offered by Matlab. This software tool provides an interface between a data base containing large sets of biomedical data and an extensible pool of evaluation and visualization procedures. It can serve both as an instrument for data processing in clinical routine and an important component for evaluation of measurement data in any medical research project.

Algorithms↗