One hundred and forty-four years ago, Parkinson1 described a few cases of a chronic, disabling disease characterized by tremor, rigidity, and abnormal gait, for which a fully satisfactory treatment has not yet been found. Although many drugs have been tried, and some were temporarily effective, little progress has been made on the development of a pharmaceutical agent which permanently alleviates the symptoms.
The most active workers in this field today are the neurosurgeons. They have conducted extensive laboratory research and have operated on patients at various levels of the central nervous system from the cerebral cortex on down to the upper areas of the spinal cord. Their surgical work in recent years has been directed in large part toward the basal ganglia. This is a difficult approach. The basal ganglia are deep within the brain and their exact location with respect to the surrounding brain tissue and skull varies