Sixty‐hertz stimulation improves bradykinesia and amplifies subthalamic low‐frequency oscillations

ABSTRACT Background The objective of this study was to investigate the hypothesis that attenuation of subthalamic nucleus (STN) alpha‐/beta‐band oscillations is causal to improvement in bradykinesia. Methods STN local field potentials from a sensing neurostimulator (Activa ® PC+S; Medtronic, Inc.) and kinematics from wearable sensors were recorded simultaneously during 60‐ and 140‐Hz deep brain stimulation (DBS) in 9 freely moving PD subjects (15 STNs) performing repetitive wrist flexion‐extension. Kinematics were recorded during 20‐Hz DBS in a subgroup. Results Both 60‐ and 140‐Hz DBS improved the angular velocity and frequency of movement ( P = 0.002 and P = 0.029, respectively, for 60 Hz; P < 0.001 and P < 0.001, respectively, for 140 Hz), but 60‐Hz DBS did not attenuate beta‐band power (13‐30 Hz). In fact, 60‐Hz DBS amplified alpha/low‐beta (11‐15 Hz, P = 0.007) and attenuated high‐beta power (19‐27 Hz, P < 0.001), whereas 140‐Hz DBS broadly attenuated beta power (15‐30 Hz, P < 0.001). Only 60‐Hz DBS improved the regularity of angular range ( P = 0.046) and 20‐Hz DBS did not worsen bradykinesia. There was no correlation between beta‐power modulation and bradykinesia. Conclusions These novel results obtained from freely moving PD subjects demonstrated that both 140‐ and 60‐Hz DBS improved bradykinesia and attenuated high beta oscillations; however, 60‐Hz DBS amplified a subband of alpha/low‐beta oscillations, and DBS at a beta‐band frequency did not worsen bradykinesia. Based on recent literature, we suggest that both 140‐ and 60‐Hz DBS decouple the cortico‐STN hyperdirect pathway, whereas 60‐Hz DBS increases coupling within striato‐STN circuitry. These results inform future algorithms for closed‐loop DBS in PD. © 2016 International Parkinson and Movement Disorder Society