Association of Subthalamic Beta Frequency Sub-bands to Symptom Severity in Patients with Parkinson’s Disease: A Systematic Review (P5-11.014)

Abstract

<h3>Objective:</h3> To synthesize existing literature regarding the association of beta sub-band local field potential (LFP) characteristics to clinical ratings of motor symptoms in patients with Parkinson’s disease (PD). <h3>Background:</h3> Beta (13–30 Hz) frequency measures have been found to be associated with motor dysfunction in patients with PD undergoing deep brain stimulation (DBS). Low-beta may be more responsive to medication states and express stronger association to motor dysfunction in PD compared to High-beta. However, a consensus on beta sub-band relationships to clinical state has yet to be determined. <h3>Design/Methods:</h3> A systematic search of existing literature was completed using EMBASE. Articles which collected subthalamic nucleus (STN) LFPs using macroelectrodes in patients with PD, analyzed low- (13–20 Hz) and high-beta (21–35 Hz) bands, collected UPDRS-III measures, and reported correlational strength or predictive capacity of LFPs to UPDRS-III scores. Articles were screened by title and abstract prior to undergoing full-text review for inclusion and data extraction. <h3>Results:</h3> The initial search yielded 233 articles. After screening and full-text review, 10 articles, with a total of 300 patients, were included. Beta measures included power spectral density, peak characteristics, and burst characteristics. Eight (80%) articles found low-beta and six (60%) found high-beta to be significantly correlated with, or predictive of, UPDRS-III scores or response to therapy. Four (40%) articles found both low- and high-beta to be associated with, or predictive of, UPDRS-III sub-scores or response to therapy. However, only one of the four found that high-beta had a stronger association to symptom severity compared to low-beta. <h3>Conclusions:</h3> This systematic review suggests that low-beta measures represent a biomarker of Parkinsonian symptom severity in patients with STN-DBS to a greater capacity than high-beta measures. Interestingly, these associations were found across multiple LFP measures, suggesting multiple analytical approaches using LFP signals can still yield clinically meaningful biomarkers of patient clinical state. <b>Disclosure:</b> Rebekah Summers has received personal compensation for serving as an employee of Medtronic. Rebekah Summers has received research support from National Institute of Health. Dr. Morelli has received personal compensation for serving as an employee of Medtronic.