Adaptive vs conventional deep-brain stimulation offers advantages for Parkinson’s disease

A small open-label study supports the safety and motor performance effectiveness of closed-loop adaptive deep-brain stimulation (aDBS) compared with conventional daily deep-brain stimulation (cDBS) sessions in Parkinson’s disease (PD) patients.

DBS uses subthalamic nucleus (STN) implanted electrodes to deliver electrical stimulation to specific brain targets to treat movement disorders, such as tremor, rigidity and bradykinesia associated with PD as well as other conditions. cDBS uses an 8-hour daily stimulation protocol, while the aDBS approach is based on a simple feedback model in which biopotential recordings from the STN are used to drive changes in DBS parameters, depending on patients’ clinical state.

Eight newly implanted DBS patients were assessed during normal daily activities in two 8-hour stimulation sessions (first day, cDBS; second day, aDBS), whilst maintaining their regular levodopa intake. The primary outcome was motor improvement with aDBS vs cDBS, in terms of both dyskenisia and motor scores, as assessed by Unified Parkinson’s Disease Rating Scale part III scores (UPDRS-III), while the secondary outcome was changes in total electrical energy delivered to the tissues per second (TEEDs). [NPJ Parkinsons Dis 2021;7:88]

The UPDRS-III scores, Rush scale for dyskinesias, and TEEDs were significantly lower in the aDBS vs cDBS session. “Equally important, the UPDRS-III scores were less variable during aDBS sessions, thus stabilizing the clinical outcome with respect to cDBS,” added the researchers.

No side effects were observed throughout the entire experiment. “aDBS avoids side effects related to cDBS, including gait and speech disturbances, reducing at the same time both motor and nonmotor fluctuations,” noted the researchers. [J Neurol Neurosurg Psychiatry 2016;87: 717-721; J Neurol Neurosurg Psychiatry 2016;87:1388-1389]

In addition, although a significant reduction in rigidity among PD patients has been attained by cDBS, aDBS improved these scores to a greater extent (rigidity subscore: aDBS, 56.0 percent; cDBS, 35.3 percent). [Brain Stimulation 2020;13:1507-1516]

“In conclusion, our work further confirms the safety and effectiveness of aDBS vs cDBS, both in terms of motor performance and of DBS side effects, in a day-long time window. Further studies and larger clinical trials comparing aDBS and cDBS are needed to confirm our results, especially in the long-term period, in freely moving PD patients,” wrote the researchers.