Objective: To investigate the utility of a novel biomarker in predicting clinical response to subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Parkinson’s disease (PD).

Background: DBS has substantially improved motor outcomes and quality of life in PD patients. However, current devices have shortcomings due to electrode positioning errors, sub-optimal manual parameter selection and delivery of continuous ‘open-loop’ stimulation despite fluctuating patient state. Together, these limitations result in partial efficacy, adverse effects and reduced battery life. A possible solution is the development of an electrical feedback signal or “biomarker” recorded from DBS electrodes. To date, the most widely studied signal has been spontaneous local field potentials (LFPs), particularly beta band activity (13-30Hz). Here, we report a novel biomarker in the form of a large amplitude, multi-peaked DBS evoked potential. At the end of a stimulation burst, there is a characteristic oscillatory decay and hence, we have termed this signal evoked resonant neural activity (ERNA).

Methods: LFPs and DBS-evoked neural activity were recorded in 10 patients with PD (20 hemispheres) undergoing STN DBS surgery. The four contacts in each electrode array were ranked according to (1) ERNA amplitude, (2) beta power, and (3) proximity to the anatomically ideal stimulation location. Patients were recalled at least 3 months after the surgery and motor scores (UPDRS III) were evaluated off-medication during 4 conditions comprising stimulation through each of the 4 electrode contacts (delivered in randomised order).

Results: The magnitude of therapeutic response to DBS was significantly greater at electrode contacts with higher ERNA amplitude (p<0.001) (Figure 1), higher beta power (p<0.001) and increased proximity to the anatomically ideal stimulation site (p<0.001). ERNA amplitude (p = 0.003) was a stronger predictor of DBS response than beta power (p = 0.086) and anatomical location (p = 0.825).

Conclusions: ERNA is a readily recordable, large amplitude signal that accurately correlates with motor response to DBS. It holds significant promise as a robust biomarker for ideal contact selection, potentially in steering electrodes and in automated parameter selection and delivery of closed-loop DBS.

« Back to 2018 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/subthalamic-nucleus-deep-brain-stimulation-evoked-neural-activity-predicts-clinical-response-to-dbs/