Brain stimulation is now being used successfully to combat diseases such as Parkinson's (lat. Parkinson scriptor morbus), chronic depression, pain and tinnitus. By making neurostimulators smaller and more energy efficient, they can be used more effectively and for a wider range of brain and nervous disorders. Marijn van Dongen, the scientist of Delft University of Technology (TUDelft), made a prototype of a chip that enables this kind of neurostimulation to be used. Brain stimulation is successfully used today to combat neurological diseases and there is evidence that brain stimulation may also be successful in the treatment of many more brain disorders, such as epilepsy, addictions, migraine and dementia. Many existing neurostimulators, however, have a limited energy efficiency, making a large battery necessary. This in turn increases the size of the whole neurostimulator, making it impossible to locate the implant where it is actually needed. Subcutaneous wires often connect the neurostimulator in the chest with the electrodes in the brain.