Electrical stimulation of the denervated human thigh

The encouraging Viennese clinical results with paralyzed patients demonstrate that intensive years lasting training with electrical stimulation enables the restoration of muscle mass and force production even after long term complete denervation. For these cases a feasibility study based on the evaluation of a bio-mathematical model of the electrically stimulated lower limbs will show the advantages of a new technology with implanted electrodes in order to avoid the extreme stimulus strengths and poor muscle selectivity of currently used surface electrodes. In preliminary work we have developed a method for a three step approach to predict local electrically evoked muscle activation in thighs based on a simplified geometry as well as on CT or MRI patient data when stimulated with surface electrodes: i) find the 3-dimensional conductivity distribution from image interpretation, ii) calculation of potential distribution by solving Laplace equation for a given electrode configuration, iii) estimate the response of the electrical muscle fiber excitation model. The method has to be refined especially concerning the excitation model for the denervated muscle fiber and applied to existing and to new types of electrodes: On the one hand electrodes will be implanted to the muscle fascia. On the other hand already implanted plates mounted on the bone will be used as electrodes in order to be close to the muscle units. The goal is to optimize the electrode design concerning safety and selective stimulation of different muscles by analysis of the computed data.

The encouraging Viennese clinical results with paralyzed patients demonstrate that intensive years lasting training with electrical stimulation enables the restoration of muscle mass and force production even after long term complete denervation. For these cases a feasibility study based on the evaluation of a bio-mathematical model of the electrically stimulated lower limbs will show the advantages of a new technology with implanted electrodes in order to avoid the extreme stimulus strengths and poor muscle selectivity of currently used surface electrodes. In preliminary work we have developed a method for a three step approach to predict local electrically evoked muscle activation in thighs based on a simplified geometry as well as on CT or MRI patient data when stimulated with surface electrodes: 1. find the 3-dimensional conductivity distribution from image interpretation, 2. calculation of potential distribution by solving Laplace equation for a given electrode configuration, 3. estimate the response of the electrical muscle fiber excitation model. The method has to be refined especially concerning the excitation model for the denervated muscle fiber and applied to existing and to new types of electrodes: On the one hand electrodes will be implanted to the muscle fascia. On the other hand already implanted plates mounted on the bone will be used as electrodes in order to be close to the muscle units. The goal is to optimize the electrode design concerning safety and selective stimulation of different muscles by analysis of the computed data.