Deep Brain Stimulation And Parkinsons

Use of Deep Brain Stimulation in Treating Parkinson's Disease Symptoms

Deep brain stimulation (DBS) has become an efficient method in treating various neurological disorders, including the symptoms of Parkinson's disease (U of JH Med, 2001). The National Institute of Neurological Disorders and Stroke (NINDS) is providing support for advancements in deep brain stimulation of the subthalamic nucleus to aid in coordination of movement and the reduction of tremors of the arms and legs (NINDS, 2007). Presently deep brain stimulation is only administered to patients whose symptoms can not be controlled with medication (NINDS, 2007). This method utilizes an electrode, implanted deep in the brain, and a battery pack to send an electrical shock down a thin insulated wire to the subthalamic nucleus. The subthalamic nucleus is believed to be responsible for rate of firing and can control how strong or weak muscle contractions are (BrainInfo, 2000). Stimulation of this area causes a disturbance in the abnormal firing rate and returns firing to a normal rate. Deep brain stimulation is proving to be a growing and efficient method for controlling the symptoms of Parkinson's disease.

Erwin B. Montgomery and the department of neurology in the University of Wisconsin (2005) conducted a study to examine effects of subthalamic nucleus stimulation patterns on motor performance in Parkinson's disease. There were seven participants between the ages of 44 and 75, all diagnosed with Parkinson's disease. After administering the DBS devices in all the participants, the participants were asked to move their wrists in different angles correlating with numbered lights. For example, when the number 5 was lit, the participants wrist should have been pointed towards the number 5 LED. The numbers were arranged in a semi-circular formation on a board with two mechanical stops at the ends to reduce "bouncing back" from tremors. The participants were allowed ample time for practice until they were proficient in the test. All the participants were on their usual doses of medication as well. This was done to reduce the risk of a confounding variable as cause of their results. Different patterns of deep brain stimulations were introduced to the participants during the course of their measurements. The efficiency of how precise their angle was and the time it took them to make the angle with their wrist was measured. Montgomery tries to understand how different patterns of stimulation affect outcomes in motor behaviors.

Montgomery (2005) found in his results that irregular patterns of brain stimulation resulted in less consistent and worse motor behaviors in the participants. "Movement times were significantly shorter for constant [regular pattern] stimulation that for cycling stimulation [irregular patterns]" (Montgomery p.4). The participants showed more coordinated movements with regular patterns of stimulation and less coordinated and more sluggish movements with irregular patterns of stimulation. Montgomery's results prove that a regular pattern of stimulation