The Deep Brain Stimulation (DBS) is an invasive therapy that alleviates the symptoms of several neurological disorders by electrically stimulating specific regions of the brain, generally within the basal ganglia. Until now Medtronic DBS system is the only approved by the Food and Drug Administration, nevertheless European and Australian countries  have recently approved St. Jude DBS systems to treat Parkinson’s disease and related movement disorders.

     Traditionally, voltage-controlled stimulation (the type of systems provided by Medtronic) has been used and clinicians are familiar with its settings; however the knowledge about systems based in current-controlled stimulation (St. Jude systems) is rather scarce. One of the key factors for a successful therapy is the optimal selection of the electrical parameters for stimulation. Due to the critical zone where the surgery is performed, modeling and simulations of DBS systems have been extensively used to observe how the electric field is distributed in the brain tissue and ultimately to help the clinicians to select the best parameters.

     In this thesis two finite element models of the DBS systems mentioned above have been developed; five examinations were designed, based on the physical and electrical differences between the systems, to observe and quantitatively compare the electric field distribution.

    The aim of this thesis was to investigate the differences between two representative models of each company but moreover to contribute with information regarding current-controlled stimulation.

The results obtained are expected to be useful for further investigations where the magnitude and distribution of the electric field generated by this type of electrodes are needed.