| Description |
Deep brain stimulation (DBS) has been used primarily for the treatment of movement disorders. The difference between successful and ineffective therapy often lies in stimulation parameter selection, which can be challenging to optimize. The focus of this dissertation is on specific advances in DBS programming and technology to guide and improve parameter selection for selective neural targeting. Computational modeling has been used throughout the DBS field to predict activation from stimulation, but the role of fiber orientation in these models has not been fully explored. We have found that fiber orientation influences activation thresholds, and different orientations can be selectively targeted by modifying the DBS waveform. Our results demonstrate that cathodic stimulation activates axon segments passing adjacent to the electrode, whereas anodic stimulation activates axons approaching or leaving the electrode. Accounting for fiber orientation in activation prediction models can be used to specifically target neural regions corresponding to clinical benefits. The large number of possible combinations of voltage, frequency, and pulse widths for the standard, quadripolar DBS lead makes it difficult to manually determine optimal settings, and the parameter space increases exponentially with more complex electrode geometries. We created an optimization algorithm using linear convex optimization and the Hessian matrix to maximize stimulation of a neural target and avoid stimulation outside the target. Such a programming algorithm for DBS may help reduce the time burden on iv programming physicians and patients. Further, it will be quite helpful in determining contact configurations for complex electrode designs, especially in optimizing novel, directional electrodes in DBS patients. Standard DBS technology does not provide fine stimulation resolution or stimulation steering capability in the targeting or avoidance of brain regions. We developed a novel, multiresolution DBS electrode with 864 microsized, individually controllable contacts. The novel lead, the μDBS, can stimulate at contact sizes orders of magnitude smaller than what is available in the clinic, which improves targeting of smaller diameter, therapeutic fibers. The programming flexibility offered by the μDBS may greatly improve stimulation selectivity for neural targeting. Taken together, this body of work represents a significant improvement in DBS programming that could directly impact patient care. |
