Objective: This study aimed to evaluate spectral dissimilarities and their correlations with clinical symptoms of intra-operative local field potentials (LFP) acquired from wide- and close-spaced contacts (i.e. LFP03 and LFP12 respectively) within the subthalamus (STN) in Parkinson’s disease (PD), before and after Levodopa administration.

Background: PD is associated with pathological synchronous oscillatory activity in the subthalamus (STN) in the β band (11–30 Hz range), considered a biomarker for controlling novel DBS approaches (“adaptive DBS”, aDBS) [1-8]. Despite βoscillations are suppressed by levodopa and correlate with movement preparation and execution whether β and other LFP spectral changes are consistent with different electrodes geometry/disposition is still a matter of debate.

Method: LFP12 and LFP03 were recorded from 20 PD patients. We evaluated oscillatory power (PSD) and correlation with motor symptoms (UPDRSIII).

Results: Before levodopa whereas the low-β (12-20Hz) band did not differ between the two pairs of contacts (LFP12 and LFP03), δ, θ and α bands had higher power in wide-spaced contacts recordings (LFP03) than in close-spaced pairs (LFP12). Moreover, the α power of both LFP03 and LFP12 inversely correlated with the pre-treatment motor UPDRSIII score. After levodopa low-β PSD decreased only in LFP12, while differences in UPDRSIII were associated to changes in LFP03 low-β and LFP12 HFO power. Hence, whereas LFP12 are more informative for β -rhythm controlled aDBS (e.g. for sensing bradykinesia), LFP03 seem more suitable for low-frequency controlled aDBS approaches (e.g. for detection of dyskinesias).

Conclusion: This study reveals differences in spectral power between LFP12 and LFP03 before and after Levodopa administration, as well as different correlations with PD motor symptoms. These results may be relevant for the implementation of better control strategies for adaptive Deep Brain Stimulation (aDBS). LFP12 can be used to detect β power (i.e. bradykinesia), while LFP03 are optimal for low frequency oscillations (dyskinesias).

References: References [1] G. Giannicola et al., “Subthalamic local field potentials after seven-year deep brain stimulation in Parkinson’s disease,” Exp Neurol, vol. 237, no. 2, pp. 312-7, Oct 2012, doi: 10.1016/j.expneurol.2012.06.012. [2] R. Levy, P. Ashby, W. D. Hutchison, A. E. Lang, A. M. Lozano, and J. O. Dostrovsky, “Dependence of subthalamic nucleus oscillations on movement and dopamine in Parkinson’s disease,” Brain, vol. 125, no. Pt 6, pp. 1196-209, Jun 2002, doi: 10.1093/brain/awf128. [3] A. Priori et al., “Rhythm-specific pharmacological modulation of subthalamic activity in Parkinson’s disease,” Exp Neurol, vol. 189, no. 2, pp. 369-79, Oct 2004, doi: 10.1016/j.expneurol.2004.06.001. [4] N. J. Ray et al., “Local field potential beta activity in the subthalamic nucleus of patients with Parkinson’s disease is associated with improvements in bradykinesia after dopamine and deep brain stimulation,” Exp Neurol, vol. 213, no. 1, pp. 108-13, Sep 2008, doi: 10.1016/j.expneurol.2008.05.008. [5] M. Arlotti et al., “Eight-hours adaptive deep brain stimulation in patients with Parkinson disease,” Neurology, vol. 90, no. 11, pp. e971-e976, Mar 13 2018, doi: 10.1212/WNL.0000000000005121. [6] M. Rosa, G. Giannicola, S. Marceglia, M. Fumagalli, S. Barbieri, and A. Priori, “Neurophysiology of deep brain stimulation,” in International review of neurobiology, vol. 107: Elsevier, 2012, pp. 23-55. [7] S. Little et al., “Adaptive deep brain stimulation in advanced Parkinson disease,” Annals of neurology, vol. 74, no. 3, pp. 449-457, 2013. [8] S. Little et al., “Bilateral adaptive deep brain stimulation is effective in Parkinson’s disease,” Journal of Neurology, Neurosurgery & Psychiatry, vol. 87, no. 7, pp. 717-721, 2016.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/inter-electrode-distance-influences-the-spectral-power-of-subthalamic-bipolar-local-field-potentials-recordings-in-parkinsons-disease/