What is Deep Brain Stimulation?

Deep Brain Stimulation
Procedure and follow-up
History of Deep Brain Stimulation
What does the stimulation feel like?
Does Deep Brain Stimulation Control Therapy cure Parkinson's disease?
The Deep Brain Stimulation system is made of several components

Deep Brain Stimulation works by electrically stimulating targeted structures in the brain - the subthalamic nucleus (STN) or globus pallidus interna (GPi) - that control movement and muscle function. A lead with tiny electrodes is surgically implanted in the brain and connected by an extension that lies under the skin to a neurostimulator implanted near the collarbone. The electrical stimulation can be non-invasively adjusted to meet each patient's individual needs.

The Activa System is implanted by a functional stereotactic neurosurgeon, using a stereotactic head frame and imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) scanning to map the brain and localise the target within the brain. The lead is inserted through a burr hole in the skull and implanted in the targeted site within the brain.

Before the lead implant procedure, the patient's scalp is anaesthetized. The burr hole is made and a test stimulation electrode is passed to the target in the brain. The patient remains awake and alert so the neurosurgeon and a movement disorder neurologist can test the stimulation to maximise symptom suppression and minimise side effects before placement of the chronic stimulation lead.

Once the chronic stimulation lead is properly placed, the patient is put under general anaesthesia. Then, an extension is passed under the skin of the scalp, neck, and shoulder to connect the lead to the neurostimulator. Finally, a small incision is made near the clavicle, and the neurostimulator is implanted subcutaneously.

Procedure and follow-up
Implanting one system usually takes about 4 hours for a functional stereotactic neurosurgeon experienced with Deep Brain Stimulation.

After recovery from the surgery, the patient returns to the physician for reprogramming of the stimulation parameters to optimise symptom control and minimise a side effect. The clinician will then schedule routine follow-up appointments.

The neurologists or other clinicians may adjust the stimulation using a portable programmer that controls and monitors the neurostimulator functions. This is done noninvasively in an outpatient setting.

Battery longevity varies, depending on the parameter settings and number of hours the neurostimulator is turned on each day. At typical therapeutic settings, the battery lasts an average of three to five years, but it could be less than three years depending on individual patient requirements. A simple surgical procedure is used to replace the neurostimulator; the extension and lead are typically not replaced.

History of Deep Brain Stimulation
Neurologists and neurosurgeons have used electrical stimulation since the 1960s as a way to locate and distinguish specific sites in the brain. During the process, they discovered that stimulation of certain brain structures suppresses the symptoms of neurological disorders such as essential tremor and Parkinson's disease. Medtronic developed Deep Brain Stimulation technology in the 1980s in conjunction with leading physician researchers. In 1987, professors Alim-Louis Benabid and Pierre Pollak of the University of Grenoble in France published the results of the first application of chronic Deep Brain Stimulation for the treatment of movement disorders.

• Parkinson's Control Therapy, which has been approved in Canada, Europe and Australia since 1998 and in the United States since January 2002 , extends the use of Medtronic's Deep Brain Stimulation technology to benefit patients with advanced, levodopa-responsive Parkinson's disease. Parkinson's Control Therapy targets the subthalamic nucleus (STN) or the globus pallidus interna (GPi) to suppress some of the disabling symptoms of Parkinson's disease.
• Tremor Control Therapy, which has been approved in Canada, Europe and Australia since 1995 and in the United States since 1997, targets the ventral intermediate nucleus (ViM) of the thalamus to suppress tremor associated with essential tremor or Parkinson's disease.

What does the stimulation feel like?
Most people with Deep Brain Stimulation Control Therapy will not feel the stimulation at all, but will feel the effects of stimulation when it reduces some of the symptoms of Parkinson's disease. However, some people may feel a brief tingling sensation when the therapy is first turned on.

Does Deep Brain Stimulation Control Therapy cure Parkinson's disease?
Deep Brain Stimulation does not cure Parkinson's disease. There is no cure for Parkinson's disease at this time. Deep Brain Stimulation can treat some of the symptoms of Parkinson's disease and improve function, but does not cure the underlying condition. If the therapy is discontinued, the patient's symptoms will return.

The Deep Brain Stimulation system is made of several components:

Implantable Components
	Neurostimulator This neurostimulator provides power and electrical pulses for stimulation. It is a small sealed device similar to a cardiac pacemaker. The neurostimulator is implanted beneath the skin in the chest. Only one neurostimulator is required for bilateral therapy reducing surgical time and patient trauma.
Lead The lead is a thin insulated wire with four electrodes at the tip that is implanted in the brain.
	Extension The lead is connected to an extension, a thin, insulated wire that runs under the skin from the head, down the neck and into the upper chest and connected to the neurostimulator.

Patient Component
	Patient controller The patient controller enables patients to adjust their therapy maximising effectiveness within physician set limits.

Physician Components
	The Neurological Test Stimulator is used during the operation to test the effectiveness of the Deep Brain Stimulation Therapy before the system is implanted.
Physician Programmer The physician programmer enables trouble-free remote programming of the neurostimulators. It is a completely portable, lightweight,hand-held device that can be used anywhere, any time.