Spectroscopy Probe Could Improve Safety and Effectiveness of Deep Brain Simulation Treatment for Parkinson’s Disease

Deep brain simulation (DBS) is an increasingly common treatment for patients with advanced Parkinson’s disease. However, the procedure carries significant risks.

Recently, researchers have developed a new probe that could make DBS safer and more effective for patients with advanced Parkinson’s disease (1). As an operation, DBS is a two-part procedure that involves a surgery to place electrodes in specific parts of the brain and a second surgery to implant a battery pack that delivers electrical current to the electrodes. Doctors typically rely on pre-surgery magnetic resonance imaging scans to plan where they will insert electrodes. However, this can sometimes lead to inaccurate placement because the brain can shift by up to 2 mm during the process of drilling an access hole through the skull. As a result, placing electrodes in the wrong spot can lead to psychological disorders and reduce the effectiveness of the treatment.

This new spectroscopy probe can conduct two types of spectroscopies, which is designed to assist doctors in navigating instruments inside the brain more accurately. The desired effect is that this probe would improve success rates.

Led by Mireille Quémener from the CERVO Brain Research Center at Université Laval in Québec, the research team identified white and grey matter using principal component analysis (PCA), proving that spectroscopic measurements could be suitable for neuronavigation.

To test the new probe, researchers created a DBS electrode that is enhanced with an optical probe to perform coherent anti-Stokes Raman spectroscopy (CARS) and diffuse reflectance spectroscopy (DRS) on brain tissues during the insertion process. The probe fits within the DBS electrode and contains two fibers for illumination and a third fiber for collecting signals. Once the electrode reaches the target position, the optical probe can be removed while the electrode stays in place.

To confirm the accuracy of the probe, a neurosurgeon used it to implant electrodes in six regions of the brain of a human cadaver. CARS and DRS measurements were collected along a total length of 50 mm in each of the brain’s two hemispheres. After the procedure, researchers extracted the brain and visually identified the white and grey matter through which the probe had passed. Comparing the readouts from the CARS and DRS measurements to the visual record of brain structures, the researchers found the methods identified brain tissue with great accuracy.

The researchers plan to study whether the approach could be used to collect even more detailed spectroscopic information, such as to measure neurotransmitters that provide a chemical signature of brain activity. They are currently working on adapting the optical probe to use in clinical trials for patients who will receive a DBS surgery. Quémener said the team is convinced that optical methods have enormous potential.

“Our team is currently working on adapting the optical probe to use it in clinical trials for patients who will receive a DBS surgery. We are convinced that optical methods have enormous potential for surgical guidance, and hope that our technology will emerge in the clinic to assist surgeons in various brain procedures,” said Quémener.

In summary, Mireille Quémener from the CERVO Brain Research Center at Université Laval in Québec and the research team developed an optical spectroscopy probe that could improve the effectives of DBS treatment for those patients afflicted with Parkinson’s disease. Currently, most doctors rely on pre-surgery magnetic resonance imaging scans to plan where they will insert the electrodes in the brain, but this technique can lead to inaccuracies. The newly developed spectroscopy probe is designed to aid in electrode placement, and that could result in higher accuracy and effectiveness at treating patients for Parkinson’s disease.

Reference

(1) Optica, Spectroscopy probe could enhance deep brain stimulation procedure for Parkinson’s. https://www.optica.org/en-us/about/newsroom/news_releases/2023/march/spectroscopy_probe_could_enhance_deep_brain_stimul/ (accessed 04-05-2023).