Types of Deep Brain Stimulation (DBS)
- Subthalamic DBS is most effective in terms of the range of symptoms that respond and the ability of patients to reduce medication. Subthalamic DBS is effective for gait and balance problems. Problems associated with subthalamic DBS include diplopia (double vision), nausea and dizziness, paresthesias (tingling skin) and muscle contraction. Patients who undergo subthalamic DBS sometime experience changes in mood, including both depression and hypomania.
- Globus pallidus DBS is effective for many of the symptoms of Parkinson's disease, with the possible exception of gait and balance. It is especially effective at suppressing dyskinesia (involuntary movements or tics) as occur in dystonia, Tourette’s syndrome and as a consequence of medication therapy for Parkinson’s disease. Globus pallidus DBS is not as potent as subthalamic DBS in terms of the range of symptoms improved, the degree of improvement and the ability to reduce medications.
- Thalamic DBS is limited in use because it is only effective for patients exhibiting tremors and possibly rigidity. Thalamic DBS also poses higher risks of voice, speech and swallowing complications.
- Pedunculopontine nucleus DBS is a newer technique that has great promise to help gait and balance problems for patients with Parkinson’s disease.
Choosing a Stimulation Method
Stimulation is generally considered safer and more effective than ablative techniques (where tissue is removed) because complications can be mitigated by adjusting the stimulator.
As with any surgical treatment the skill and experience of the neurosurgeon is critically important. In addition, the safest and most effective DBS treatments are provided by a comprehensive team consisting of movement disorder neurologist specialists, intraoperative neurophysiologists for target identification and specially-trained nurses.
Accurate placement of the DBS electrodes is critically important to the safety and effectiveness of treatment. While neurosurgeons use sophisticated neuroimaging techniques such as MRI scans, these are insufficient alone.
Intraoperative neurophysiologists use electrical recording techniques to precisely locate the best target. In the case of DBS, this involves the use of microelectrode recordings that allow "eavesdropping" on the electrical conversation among the neurons to determine the exact location.