URMC testing new device for Parkinson's

Feb 14 2008

The University of Rochester Medical Center (URMC) is one of a handful of sites nationwide testing a new device for patients with Parkinson's disease and essential tremor, a neurological movement disorder.

The study will help determine whether a new Deep Brain Stimulation (DBS) technology is effective in providing relief for patients who are unable to adequately control symptoms of their disease with medication.

URMC is one of 12 locations nationwide participating in the study of the new Libra DBS system. The trial is being funded by the device's manufacturer, Advanced Neuromodulation Systems (ANS), a division of St. Jude Medical Company.

The DBS system is a surgically implanted medical device that delivers an electrical stimulation to areas of the brain that control movement. The system consists of a neurostimulator – a pocket-watch-sized device that is implanted under the collarbone – and wires, or leads, which run from the neurostimulator under the skin and into the brain through an opening in the skull. The leads are surgically guided to one of two areas in the brain depending upon the patient and the condition being treated. The system then functions in a manner similar to a heart pacemaker by delivering mild electrical pulses that disrupt or block the irregular nerve signals responsible for symptoms of Parkinson's disease and essential tremor.

“In these diseases, we think that there is abnormal firing in circuits in the brain important for controlling movement,” said neurosurgeon Jason Schwalb, M.D., co-investigator of the study. “When these circuits do not work or abnormal signals resonate within these circuits, people can develop tremor, rigidity, difficulty initiating movement and increased tone in opposing muscles that can even be painful. It is believed that DBS disrupts abnormal firing patterns present in movement disorders at discrete points in this circuitry and replaces them with more regular patterns of firing.”

Parkinson's disease is a progressive neurological disorder that erodes a person's control over their movements and speech. Over time, Parkinson's patients may experience stiffness or rigidity of the arms and legs, slowness or lack of movement, and walking difficulties, in addition to tremor of their hands, arms, legs, jaw or face. Essential tremor is a neurological disorder characterized by involuntary shaking of hands and, less frequently, other parts of the body. In both conditions, these symptoms can make simple, everyday tasks like getting dressed, shaving, eating with utensils and drinking from a glass almost impossible.

In most patients, the problems associated with these diseases can be managed with medication. However, in some instances these medications are not effective or, in patients with an advanced stage of the disease, the medications slowly lose their potency.

“Many Parkinson's patients experience a wearing off between doses as their medications lose effectiveness over time,” said URMC neurologist Frederick Marshall, M.D., co-investigator in the study. “While adjusting the timing of the dose or changing medications can sometimes help, there comes a point when, as a neurologist, I reach the end of my medical rope in terms of what I am able to really achieve for the patient. With the right patients, surgical intervention like DBS then becomes a more effective option.”