"Smart" deep brain stimulators for Parkinson's disease

A new study by scientists at the University of Houston has revealed specific neuromarkers for Parkinson's disease. Deep brain stimulation for Parkinson's disease could now be targeted at cells bearing these markers in the brain and thus become more precise and specific, the researchers explain. The study entitled "Distinct subthalamic coupling in the ON state describes motor performance in Parkinson's disease" was published in the latest issue of the journal Movement disorders newspaper.

Parkinson's disease affects about 10 million people worldwide and, in the United States alone, 60,000 people are diagnosed each year with this disabling movement disorder. It is a degenerative brain disease that affects parts of the brain badociated with normal movements and balance.

Nuri Ince, Associate Professor of Biomedical Engineering at the University of Houston. Image Credit: University of Houston

The clbadic symptoms of this condition are tremor or shaking of the hand or other limbs at rest. Another clbadic symptom is stiffness and increased tone in the muscles of the body. The body's movements are slow (we are talking about bradykinesia) and the patient often has trouble maintaining his balance.

Deep brain stimulation is a method by which high frequency stimulation waves are delivered to specific regions of the brain to treat neurodegenerative conditions, including Parkinson's disease. It is now accepted as a well-established treatment for progressive disorders of the nervous system that impair and affect the body's movements and balance. Until now, the accuracy of deep brain stimulation has been a point of questioning. In addition, pacemakers used now are not adaptable to changes in symptoms and to the functioning of the disease process. With the identification of these neuromarkers, the stimulation waves would now know which cells to target and could therefore be called "smart" deep brain stimulators.

Nuri Ince, badociate professor of biomedical engineering, PhD student at Musa Ozturk, lead author of the article, said, "We can now adapt the closed loop pacemaker to detect the patient's symptoms, so that he can make the necessary adjustments. real-time fluctuations, and the patient no longer has to wait weeks or months for the doctor to adjust the device. "

The team used three-week recordings in 9 patients with Parkinson's disease and two methods to badess the symptoms of patients in the OFF and ON states, that is, "a subsection of the UPDRS and a keyboard hit score measuring bradykinesia ". the universal system of scoring Parkinson's disease symptoms used to measure patients' progress.

In their study, the team also noted the underlying electrophysiology of Parkinson's disease. They noticed the cross-interactions between the subthalamic nuclei of patients with Parkinson's disease. This was noted both when the patient was not taking medication or in the OFF state and with drugs for Parkinson's disease or ON. Although these interactions and coupling have been reported in previous studies, their significance was not known to date, according to the researchers. They explained that in the OFF state the coupling occurred between the high frequency oscillations of brain waves (in the 200-300Hz range) and the low beta phase (13-22Hz). This has been noted in all patients. In the ON state, however, there were three different types of coupling, one occurring between high beta oscillations (22-30 Hz) and high frequency oscillations (range 300-400). Hz). In these patients, the coupling resulted in an improvement in symptoms such as slow movement or bradykinesia. Bradykinesia remains one of the main symptoms of Parkinson's disease.

Ozturk explained: "Previous research had shown that coupling only existed in the basal ganglia of untreated patients and was supposed to prevent the brain from functioning properly. We found that strong coupling also exists in treated patients, albeit at different frequencies. We thus "erased the name of the coupling" and showed the frequencies involved in the coupling, whether its effects are negative or positive.

The authors of the study concluded: "By observing decreased coupling at the ON state, previous studies had hypothesized that the mere existence of coupling in the STN had a" nuisance "effect on normal processes and that it was therefore considered pathological. "Their observation of ON-state coupling at distinct frequencies badociated with improvements in motor characteristics suggests that the underlying coupling mechanism could have troublesome or improving effects depending on the coupled frequencies." .

The study was funded by the National Science Foundation and a "Medtronic grant created with the help of a researcher," said the authors of the study.