In the early 1950s, doctors found that lesioning, or destroying, specific areas within the brain could help treat certain movement disorders. When areas of the brain involved in the disorder were lesioned, the symptoms often improved. Soon, lesioning surgeries became a standard treatment for reducing problems in motor control caused by conditions like Parkinson's disease.
Unfortunately, lesioning surgery was not an ideal solution. They weren't always effective in reducing negative symptoms, and sometimes they resulted in damaging side effects. One of the main problems with lesioning surgeries is that their effects cannot be undone; a lesioned brain structure is permanently destroyed. As a result, unwanted side effects are usually irreversible.
In the 1970s a new drug therapy for movement disorders was introduced. Treatment with the new drug, called levodopa, could be used to control some of the same types of symptoms as lesioning, but without the risky brain surgery. Levodopa therapy quickly began to replace lesioning surgeries, mainly because of the advantages it provided patients. One of the benefits was dosages that could be adjusted to suit individual needs.
After many years, however, long-term levodopa therapy was found to cause new problems. The brain eventually compensates for the effects of the drugs. The result was often serious. Patients were developing new movement control problems that were considered worse than the original symptoms.
Then, in the late 1980s, a new discovery was made. Experts found that the same effects caused by lesioning brain tissue could be achieved by stimulating the tissue with harmless pulses of electricity. This was an exciting find, because the effects of electrical stimulation are completely reversible. In fact, when the stimulation is turned off, the brain resumes its normal behavior. Similar to drug treatments, doctors could tailor the electrical stimulation to fit the exact needs of each patient. Unlike drug treatments, the electrical stimulation could be localized so that only intended parts of the brain were affected.
Treatments with deep brain stimulation (DBS) were used on an experimental basis for several years, and positive treatment results were observed. In 2002, the use of DBS for conditions such as Parkinson's disease was approved by the Food and Drug Administration (FDA). DBS remains the standard treatment for several brain disorders similar to, and including, Parkinson's.
In the next section, we'll show you what an implantable DBS device looks like and find out how each part functions.