Physiological Monitoring In Deep Brain Stimulation: Toward Closed-Loop Neuromodulation Therapies

Deep brain stimulation (DBS) is a widely used, efficacious neurosurgical treatment for neurological movement disorders. For example, electrical stimulation in the ventral intermediate thalamic nucleus drastically reduces tremor in patients with essential tremor. Likewise, stimulation in the subthalamic nucleus or the internal globus pallidus significantly attenuates tremor, rigidity, bradykinesia, and gait complications of Parkinson's disease. Its application is now rapidly expanding to a wide variety of conditions including epilepsy, neuropsychiatric disorders, Tourette syndrome, Alzheimer's disease, and intractable pain. However, the exact underlying therapeutic mechanisms of action of DBS remain unclear. Despite this lack of understanding, clinical utility of DBS cannot be underappreciated, and there is a great need for studies that can elucidate patient-specific optimization of DBS parameters and targets. This chapter explores recent approaches for studying the underlying mechanisms of action of DBS. Additionally, it discusses the limitations of current open-loop approaches to DBS and accentuates the importance of developing a smart closed-loop DBS system that can optimize therapeutic parameters in real time to individual patients and symptoms.