An electrical impedance model for deep brain stimulation of Parkinson's disease

Abstract

Deep brain stimulation is an accepted technique for the treatment of Parkinson's disease. Deep brain stimulation affects the electrical functions of neurons and several explanations are available to describe this treatment modality. Such as depolarization blockade, synaptic inhibition, synaptic depression and stimulation induced modulation of pathological network activity. An electrical impedance model of the treatment area around the electrodes in the brain is determined to further increase the understanding of deep brain stimulation. This model shows the contact impedance between the electrodes and the tissue, the extra cellular resistance, the intra cellular resistance of the neurons and the effect of deep brain stimulation on the treated area in the brain, which in this case is stimulation of the sub thalamic nucleus. The generated electrical field near the electrodes is high enough to perform an electropermeabilization of the cell membranes. This is modelled as a cell membrane capacitance in series with a resistance. The resistance is the consequence of electropermeabilization of the cell membranes. Many observed parameters that occur during deep brain stimulation is reduced tremor activity, influence on speech, the same effect as a lesion, increased axon activity downstream, stimulation followed by durations of nerve silence. © Springer-Verlag 2007.