A Pacemaker For Your Brain?
We’ve always heard and studied about pacemakers for the heart, but have you heard of one for the brain?
We’ve come across neurology in many of our major subjects and I honestly was always a little lost with all the tracts and nuclei and trying to make sense of how it all works. As we progressed into learning more and more every year, it started making a tad bit more sense to me. Recently, I had the 5th year neurology block, and I realized the significance of what we’ve been learning so far. During the block, I learned about how phenomenal of a difference research into treatments for neurological disorders has made in patients’ lives. One of the treatments that stood out for me was Deep Brain Stimulation (DBS).
Deep brain stimulation is the use of a neurostimulator “brain pacemaker” that sends electric impulses to specific nuclei in the brain through implanted electrodes. Mostly used for the treatment of movement disorders like Parkinson’s disease, dystonia, and essential tremor. DBS is also used and under active investigation for the treatment of resistant neurological and psychiatric disorders like obsessive-compulsive disorder, epilepsy, major depression, and Tourette syndrome.
The exact workings of DBS aren’t completely understood but are believed to regulate abnormal electric signalling in the brain. Possible mechanisms of action could be the blockade of depolarization near electrode site, synaptic inhibition to indirectly regulate the neuronal output, desynchronizing abnormal oscillatory activity of neurons.
The effects of treatment depend on the placement of electrodes and targets being stimulated. The conventionally used DBS system uses a four-contact stimulating electrode implanted in the brain and connected via subcutaneous wires to the neurostimulator, called an implantable pulse generator (IPG) placed under the collar bone or sometimes on the abdomen. The clinician can use a handheld device to wirelessly communicate with the IPG and calibrate it when needed, for instance, to control side effects.
The electrodes are implanted in specific brain nuclei depending on the indication. Targets are usually deep brain structures, some being:
• Globus pallidus internus for the treatment of primary dystonia
• Pedunculopontine nucleus, subthalamic nucleus, and globus pallidus internus for the therapy of Parkinson’s disease
• Ventral intermediate nucleus of the thalamus for treating essential tremor.
Personally, what stood out for me with DBS is how drastically it can change a patient’s quality of life. I’ve been reading up on different case studies and articles on how patients have been improving with the treatment. Some of the patients, young women, suffering from early-onset Parkinson’s disease with severe motor and psychiatric disturbances were losing out on a basic social and family life, however, when they started DBS, they had significant improvement in their symptoms. They were able to move through life easier and even have babies safely! Another positive factor of DBS is its non-systemic mechanism of action, this is especially helpful in pregnant women. When patients get pregnant, they usually have to discontinue their meds to prevent unknown teratogenic effects, which leads to the aggravation of their symptoms, and studies so far have shown that DBS can prevent this and help reduce or completely interrupt disease-specific medication during pregnancy.
To conclude, deep brain stimulation has proven to be life-changing and with more research and development it could help so many more patients dealing with complex neuropsychiatric disorders.
Alaika is a 5th year medical student at Masaryk University with a keen interest in Interventional Medicine.