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What is neuromodulation?
Neuromodulation is the alteration of nerve activity at targeted sites in the body by electrical or chemical means with the goal of normalizing nerve function. Presently, electrical stimulation is the primary means of neuromodulation in medicine, but the Neural Engineering and Precision Surgery Lab also is investigating many other treatment modalities, such as magnetic fields, intrathecal drug delivery and light-based activation of genetically engineered neurons, called optogenetics.
What is deep brain stimulation?
Deep brain stimulation (DBS) is a neuromodulation technique that the U.S. Food and Drug Administration has approved to treat Parkinson's disease, essential tremor, dystonia and medically refractory obsessive-compulsive disorder. DBS also is used experimentally to treat chronic pain, post-traumatic stress disorder, Tourette syndrome and psychiatric affective disorders such as major depression. When used to alleviate the symptoms of these disorders, DBS can drastically improve the quality of life for a patient, but the procedure does not actually treat the underlying condition.
A DBS system consists of an implanted pulse generator (IPG), typically placed below the clavicle, that generates electrical pulses via lead extensions that run from the IPG, up the neck, and to the skull, where they connect with a lead that is implanted deep in the brain. The lead targets varying structures in the brain depending on the desired effects of the surgery.
Ideally, the IPG generates an electrical current that normalizes neural function and reduces disease symptoms. The IPG is programmed during surgery to best treat the patient's symptoms and is occasionally reprogrammed during clinical follow-up visits. The battery pack must be replaced every few years as well.
What are the major research questions in the field of neural engineering?
- Why does DBS work? Although the clinical effectiveness of DBS is well established, researchers remain uncertain of exactly how DBS works. As a matter of basic science, this remains the biggest unanswered question.
- How can scientists create a closed-loop neuromodulation system? Presently, an implanted DBS stimulator must be intermittently adjusted and reprogrammed to optimize stimulation settings because a patient's physiology and disease symptoms are not static over the lifetime of the implant. The practical result is that the effectiveness of the fixed stimulation parameters tends to decrease over time, thus the requirement for reprogramming.
What is the laboratory doing to answer these questions?
The Neural Engineering and Precision Surgery Lab has four separate project teams, as well as an administration and operations team, that support all the project teams and the leadership team. The lab's primary research focus is developing a chronically implantable closed-loop DBS system for human therapy. Each project team orients around a particular aspect of moving the current technology toward this end.