Neuromodulation

Neuromodulation is a rapidly-growing field for the treatment of neurological and psychiatric disorders.  It encompasses a wide spectrum of implantable as well as non-implantable advanced medical device technologies that use electrical stimulation to enhance or suppress nerve cell and brain activity.   Neuromodulation does not completely restore brain function however; it does help relieve symptoms by altering neurological function back to a more normal state. 

Deep Brain Stimulation (DBS)

One of the most prominent neuromodulation therapies is deep brain stimulation (DBS).  DBS is a complex surgical technique that involves implanting tiny electrodes into selected regions of the brain.  Implantation is guided by magnetic resonance imaging (MRI) or computed tomography (CT) scanning which identifies and locates the exact target within the brain where symptoms are generated.   Generally, either the thalamus, subthalamic nucleus, or globus pallidus are the areas of the brain targeted for implantation. 

How Deep Brain Stimulation (DBS) is Implemented

During DBS electrodes are connected via a thin set of wires, i.e. leads, to a small surgically implanted, programmable battery, similar to a cardiac pacemaker, that has been implanted under the skin beneath the collarbone. The leads carry therapy signals to the electrodes which then deliver tiny electrical signals that calm abnormal brain signals.  Stimulation of the programmable battery is easily adjustable and does not require additional surgery if the patient’s condition changes.  Each electrode has four contacts allowing fine tuning of the exact location of stimulation and stimulation parameters can be adjusted to optimize symptom control and minimize side effects.

Goals and Outcomes

The goal of DBS is to treat disabling symptoms by disrupting the abnormal patterns of brain activity.  This process restores normal brain rhythms and allows for the restoration of more normal movements - improving the patient’s quality of life.   It is commonly used to treat the debilitating symptoms of Parkinson’s disease (i.e. tremor, rigidity, stiffness, and slowed movement) and essential tremor, a common neurological movement disorder. Unlike previous surgeries for Parkinson’s disease, DBS does not damage healthy brain tissue by destroying nerve cells so when more promising treatments are developed, the procedure can be reversed. 

After having DBS surgery may patients see a reduction in their Parkinson’s disease symptoms and are able to reduce their medications.  The amount of reduction varies from patient to patient but can lead to a significant improvement in side effects such as dyskinesias which are involuntary movements caused by long-term use of levodopa.  In some cases, the stimulation itself can suppress dyskinesias without a reduction in medication.  DBS is not a cure for movement disorders and its exact mechanisms are unknown.