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Parkinson’s disease (PD) is a neurodegenerative disorder that is caused by the death of dopamine producing neurons in the brain. Primary motor symptoms of PD include tremor, rigidity, bradykinesia (slowed movements or hesitations) and gait and balance issues. Since there is currently no cure for PD, the symptoms are treated typically with pharmaceutical interventions.

One of the more common medications prescribed for PD is L-Dopa, which is used to increase levels of dopamine in the brain. While effective, a common issue with the use of L-Dopa is that there is a fine line between the correct amount of medication and too much. Too much medication results in dyskinesias, or wild, uncontrollable movements. Also, the effectiveness of L-Dopa decreases over time.

When L-Dopa is no longer effective as a treatment for PD symptoms, patients can consider a surgical procedure called deep brain stimulation, or DBS. When patients opt to have DBS surgery, tiny electrodes are implanted in the brain through a hole in the skull which emit pulses of stimulation that aide in symptom alleviation. The location of the electrode can vary depending on the patient but the two most common are subthalamic nucleus (STN) and the globus pallidus interna (GPi). A patient can also have electrodes implanted on one side of the brain or both, depending on whether their symptoms are unilateral or bilateral. The electrode or electrodes connect to a pulse generator which is typically implanted below the skin near the collarbone. The implanted pulse generator, or IPG, controls the electrode stimulation output. Parameters such as amplitude (the power of the stimulation), frequency (how often the stimulations pulses occur) and duration (how long each pulse lasts) must be set.

During DBS surgery the patient is awake and fully aware. This is because a nurse must perform motor assessments with the patient to determine if the electrode has been placed in an optimum location and depth. This assessment includes motor tasks that the patient is asked to complete to determine the severity levels of their symptoms. This can sometimes be time consuming as the patient must complete the assessment each time the electrode is moved.

Once surgery is completed, patients will return to the clinic to have the IPG settings adjusted. Again, a nurse will administer a motor assessment and alter the amplitude, frequency and duration of the pulses until an optimum combination is found with best alleviates the patient’s symptoms. This adjustment is repeated a number of times as symptoms worsen due to the progression of the disease.

While the exact reason DBS works is still not known, the number of PD patient lives the surgery has improved is dramatic. Patients with debilitating motor symptoms that leave them nearly incapable of performing activities of daily living can have the ability to move and function as they did before their diagnosis of PD. This is not to say that DBS does not have risks. It is a major surgical operation and results are not the same for each patient. The first step to determining whether or not DBS would be appropriate for any PD patient would be to discuss their options with a certified movement disorder clinician or neurologist.

Tags: bradykinesia, Deep Brain Stimulation, Movement Disorders, movement disorders monitoring, Parkinson’s disease, tremor

This entry was posted on Wednesday, April 22nd, 2009 at 9:32 am and is filed under Movement Disorders. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.