We live in an era of technology innovation when many things only seen before in science fiction come true.
Treatment of brain disease by delivering electrical pulses through an implanted device is one of those examples.
Currently its application in clinical medicine, so-called neuromodulation, is becoming more popular. Neuromodulation is a collective term meaning alteration (or modulation) of neural activity by delivering electrical or pharmaceutical agents directly to a target area.
Deep brain stimulation (DBS) is the most frequently used method of neuromodulation which corrects brain dysfunction by delivering electric pulses through a device implanted within the brain. DBS is most commonly used in treating Parkinson’s disease.
Parkinson’s disease is a neurodegeneratve disease caused by the loss of a specific kind of brain cells producing a neurotransmitter called dopamine. Dopamine deficit results in various symptoms such as tremors, rigidity and bradykinesia (slow movement). The primary treatment of Parkinson’s disease is a drug to supplement the shortage of dopamine or mimic its effect.
However, medication does not stop the progression of the disease. Over time, drugs become less effective, with fluctuation of symptoms during the day.
Additionally, the adverse effects of the medication, such as involuntary movements, are a serious problem.
Now DBS is the best available solution for these patients. And so far the effect of adequately performed surgery is very impressive.
In DBS, electrodes are placed deeply into the site of the brain related to the disease or symptom to be managed. Electrodes are connected by wires to a type of pacemaker device (called an impulse generator, or IPG) implanted under the skin of the chest, usually below the collarbone.
Therefore, all components are put inside the body. The IPG can easily be 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. Once activated, the device sends continuous electrical pulses to the target areas in the brain, blocking the impulses that cause pathological symptoms such as tremor, rigidity or bradykinesia in the case of Parkinson’s disease.
The effect is so dramatic that a patient who would have been bed-ridden most of the day can walk, run and even dance once DBS is turned on. This has the same effect as traditional surgeries that actually destroy parts of brain. Theoretically, DBS does not destroy anything.
The effect of DBS is reversible and can be adjusted for each patient. It is a restorative and personalized treatment. DBS was introduced in 1987 for treating tremors and was subsequently approved for treating Parkinson’s disease and dystonia.
Besides movement disorders, DBS has been used to treat chronic pain and recently other diseases such as obsessive compulsive disorder, severe depression, and epilepsy. Now we can not only help patients walk but also alleviate the suffering of those who have psychiatric problems.
Furthermore, recent interesting experimental and clinical trial data suggests the benefit of DBS for Alzheimer’s disease. Alzheimer’s disease is the most common form of dementia and currently there is no effective treatment proven to reverse or even slow down progression of the disease.
If DBS is helpful to patients with Alzheimer’s disease, it will be the most significant discovery in that field. It is fascinating that we can help people walk, keep smart and be in good spirits with the manipulation of electronic device. Though we don’t know exactly how far the technology will advance and influence our life in the future, it is certain that neuromodulation is opening a new era of restorative medicine.
By Lee Jung-il, M.D., Ph.D.
The author is a doctor of Department of Neurosurgery at Samsung Medical Center and professor at Sungkyunkwan University School of Medicine. -- Ed.