Principles of deep brain stimulation

Deep brain stimulation (DBS) is a minimally invasive targeted neurosurgical intervention that enables structures deep in the brain to be stimulated electrically by an implanted pacemaker. It has become the treatment of choice in Parkinson’s disease patients with either disabling medication side effects, on-off fluctuations, or tremor. Its efficacy in Parkinson’s disease has been demonstrated robustly by randomized controlled clinical trials, with numerous brain areas having been targeted in the last two decades for indications including dystonia and tremor in movement disorders; depression, obsessive-compulsive disorder, and Tourette’s syndrome in psychiatry; epilepsy, cluster headache, and chronic pain. The principles of framed stereotactic surgery enabling DBS electrode placement are reviewed here, before describing the putative mechanisms underlying DBS and its action upon individual neurons. Recent and future developments in DBS technology such as segmented, directional leads, and smart, adaptive stimulation are then discussed alongside related technological advances such as diffusion tensor imaging, robotic surgery, and molecular and cellular therapies. The role of stereotactic lesions in the era of DBS and the different modalities of lesioning are then summarized.