Clinical Specialties : Movement Disorders

Parkinson’s Disease

Between 1-1 ½ million Americans are affected by Parkinson’s disease, a disorder of the central nervous system. “Parkinson’s” disease usually affects people age 50 years or older but about 10-20% of people with Parkinson’s are diagnosed before the age of 50. There is no definitive laboratory test and the diagnosis relies on a Neurologists examination of the patient.

What causes this disease?

People with Parkinson’s disease have a shortage of a chemical called Dopamine. Dopamine creates synchrony is the deep structures of the brain thereby producing normal movement. This happens because the cells that make dopamine in an area called the substantia nigra are no longer present. We do not know exactly how these changes happen. Many theories include accelerated aging and cell death, a genetic susceptibility, environmental factors, among others. It is probable that the disease is caused by a combination of the above.

Symptoms

  • Rigidity of the limbs
  • Tremors at rest
  • Slow movement (bradykinesia)
  • Postural instability (which is perceived as a loss of balance and unsteadiness sometimes associated with falls)

Treatment

Medication
Standard treatment of Parkinson’s disease is with medications. These medications attempt to either directly replace dopamine (Sinemet, Stalevo, etc.) or improve the function of areas of the brain that dopamine affects (Parlodel®, Permax®, Mirapex®, Requip®). Yet still newer drugs are under development.

Surgical
Historic techniques for treating Parkinson’s disease include thalamotomy and pallidotomy, which irreversibly destroy cells in the brain using an electrode. If side effects occur they are permanent.

The University of Miami offers a pioneering technique called Deep Brain Stimulation. With better understanding of the neurocircuitry causing abnormal movements and the advent of state of the art imaging in conjunction with more precise methods to target these areas Deep Brain Stimulation has become a reality. This surgical technique allows for attenuation of tremor, stiffness of muscles, and slowness of movement in a safe, effective, and reversible manner. From the patients perspective, there is no damage done to the brain that is irreversible. Through the use of high frequency stimulation, the cells causing abnormal movements are blocked. These devices are very versatile and allow for quick and easy adjustments to optimize benefit as the symptoms progress.

Unlike previous surgeries for Parkinson’s disease DBS does not damage healthy brain tissue by destroying nerve cells. Thus, if newer, more promising treatments develop in the future, the fine DBS electrodes can be removed without resulting injury to the brain.

Do I need medicines after DBS surgery for Parkinson’s disease?

Although most patients still need to take medication after undergoing DBS, many patients experience considerable reduction of their Parkinson’s disease symptoms and some patients are able to reduce the dose of medications by 20-50%. The reduction in dose of medication leads to a significant improvement in side effects such as dyskinesias (involuntary movements caused by long-term use of levodopa). In some cases, the stimulation itself can suppress dyskinesias without a reduction in medication.