Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools <s> New stimulation systems <s> Background Over the last two decades, deep brain stimulation (DBS) has become a recognized and effective clinical therapy for numerous neurologic conditions. Since its inception, clinical DBS technology has progressed at a relatively slow rate; however, numerous advances in neural engineering research have the potential to improve DBS systems. One such advance is the concept of current steering, or the use of multiple stimulation sources to direct current flow through targeted regions of brain tissue. The goals of this study were to develop a theoretical understanding of the effects of current steering in the context of DBS, and use that information to evaluate the potential use of current steering during stimulation of the subthalamic nucleus. Methods We used finite element electric field models, coupled to multicompartment cable axon models, to predict the volume of tissue activated (VTA) by DBS as a function of the stimulation parameter settings. Results Balancing current flow through adjacent cathodes can increase the VTA magnitude, relative to monopolar stimulation, and current steering can be an effective technique to sculpt the shape of the VTA to fit a given anatomic target. Conclusions These results provide motivation for the integration of current steering technology into clinical DBS systems, thereby expanding opportunities to customize DBS to individual patients, and potentially enhancing therapeutic efficacy. <s> BIB001 </s> Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools <s> New stimulation systems <s> In the past decade deep brain stimulation (DBS)-the application of electrical stimulation to specific target structures via implanted depth electrodes-has become the standard treatment for medically refractory Parkinson's disease and essential tremor. These diseases are characterized by pathological synchronized neuronal activity in particular brain areas. We present an external trial DBS device capable of administering effectively desynchronizing stimulation techniques developed with methods from nonlinear dynamics and statistical physics according to a model-based approach. These techniques exploit either stochastic phase resetting principles or complex delayed-feedback mechanisms. We explain how these methods are implemented into a safe and user-friendly device. <s> BIB002
For the last 20 years, the market has been dominated by the Medtronic DBS-system  . At the moment, several companies and research groups show strong interest in development and improvement of neurostimulation devices  . Among these, St. Jude Medical has received the European CE mark approval of the Libra Ò and LibraXP Further development of established electrode techniques are also expected and suggested improvements include: miniaturised cranial implantable neurostimulators which would allow the entire surgical procedure to be done as one incision procedure; material and leads that make MR imaging safer and reduces the risk of RF-induced heating; and field steering  . Steering of the electric field towards a target area of interest has also been simulated. Å ström et al.  used patient-specific models and simulations of the electric field to visualise a multi-contact asymmetrical voltage steering technique beneficial for reduction of DBSinduced speech deficits, and Butson and McIntyre BIB001 evaluated the use of current steering for better control of the activated tissue volume during STN-DBS. Other suggestions to improve the stimulation effect include alteration of the stimulation pulses by desynchronisation BIB002 .