Deep brain stimulation (DBS) is a surgical procedure used to treat a variety of disabling neurological symptoms – most commonly the debilitating symptoms of Parkinson’s disease. It is a therapy for well-screened patients with specific treatment-resistant neuropsychiatric diseases. It is a minimally invasive surgery. The patients are first evaluated by a neurologist who specialises in movement disorders.
Selection of patients
Patient selection is based on clinical evaluation:
- Those who experience shorter periods of relief from symptoms though on medication
- Those without cognitive impairment of speech and balance
- Medication resistance
- Allergy to medication
The right time for DBS
It is when medicines work, but not as well as they used to:
- Need to wait longer for medicines to work
- Symptoms like tremors and stiffness last for longer each day
- Medicine dosage has to be increased
- Frequency of medicines is more often, including at night
- Some medicines are causing side effects
Deep brain stimulation is a therapy that involves 3 components:
- A surgically implanted, battery-operated medical device called a neurostimulator – like a heart pacemaker – to deliver electrical stimulation to targeted areas in the brain that control movement, blocking the abnormal nerve signals that cause tremors and Parkinson’s disease symptoms
- The medical device consists of two electrodes inserted through a small opening in the skull and is implanted in the brain to stimulate the subthalamic nucleus of the brain.
- The two electrodes are connected by wires to a pacemaker like device, called the impulse generator or IPG. The IPG is implanted under the skin of the chest, just below the collarbone. When active, the device sends continuous electrical pulses to the target area in the brain, blocking impulses that cause the tremors.
The IPG can be easily programmed using a computer that sends radio signals to the device. Patients are given special magnets or other devices so they can externally turn the IPG on or off. Depending on use, the stimulators may last five to six years. The IPG replacement procedure is relatively simple.
- Stimulation of the subthalamic nucleus has been recognised as the most effective treatment for Parkinson’s disease.
- The treatment addresses tremors, rigidity, stiffness, slowed movement, gait and walking concerns.
- It enables patients to considerably reduce their medication.
- Improvement in disease-related symptoms
DBS directly changes brain activity in a controlled manner and its effects are reversible.
What does DBS surgery involve?
The surgery involves making small holes in the skull to implant the electrodes and a small procedure to place a battery device under the skin in the chest. The device is turned on a few weeks later after appropriate settings. These may sometimes need to be changed, due to side effects.
- Wrong placement of the leads
- Migration of the leads
- Seizure or fits
- Bleeding in the brain
- Eroding of the lead wire
Side effects of switching on the device
- Temporary numbness and tingling of the face and limbs
- Speech problems
- Balance and coordination issues
- Double vision
- Confusion and concentration difficulties
- Jolting or shock sensation
- Aggression or mood changes
- Allergic reaction to the implant
- It is primarily done by a neurologist, a movement disorder specialist.
- Neurological examination is done with medications on and off.
- Brain mapping MRI is done to map the areas of the brain to implant the electrodes.
- Routine lab tests are performed.