A novel assistive method for rigidity evaluation during deep brain stimulation surgery using acceleration sensors.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurological Surgery

Background:

• Deep brain stimulation (DBS) is widely used for Parkinson's disease (PD), but precise anatomical targeting remains challenging.
• Current intraoperative assessments of rigidity rely on subjective, semiquantitative evaluations by experts, leading to variability.
• Identifying the optimal DBS target is crucial for maximizing therapeutic effects and minimizing side effects.

Purpose of the Study:

• To evaluate an acceleration sensor as an objective tool for assessing rigidity changes during intraoperative DBS.
• To compare the accuracy and reproducibility of sensor-based rigidity assessment with traditional subjective methods.
• To determine if quantitative acceleration data can lead to more precise DBS lead placement and identify optimal stimulation targets.

Main Methods:

• An acceleration sensor was attached to the evaluator's wrist to measure passive movement speed, correlating with rigidity.
• The method was tested in 3 patients during postoperative follow-up and 9 patients during bilateral DBS operations for PD.
• Accelerometer data were analyzed to extract outcome measures, identify rigidity-suppressing amplitudes, and compare with neurologist assessments and anatomical locations.

Main Results:

• Accelerometer data provided reproducible rigidity assessments, enhancing reliability during intraoperative stimulation tests.
• The number of identified rigidity-suppressing sites increased when using accelerometer evaluations, and effective amplitudes were significantly lower (0.9 mA vs. 1.4 mA).
• Acceleration-based lead placement choices differed significantly from subjective evaluations, and Forel's fields showed comparable rigidity relief to the subthalamic nucleus with fewer side effects.

Conclusions:

• A novel assistive method using acceleration sensors for objective rigidity assessment during DBS procedures has been described and validated.
• Initial results suggest this method is a clinically useful aid for optimizing DBS lead placement in Parkinson's disease.
• The acceleration sensor offers a new tool for scientific research into the optimal DBS targets for PD and other movement disorders.