Connecting Cortical and Subcortical Oscillatory Activity in Patients with Parkinson’s Disease and Dystonia
Archita Amudhan1, Abigail Alpers2, Richard Barbano3, Caleb Obregon4, David Sell3, Angela Hewitt3
1School of Arts and Sciences, 2Neuroscience, 3Neurology, 4School of Medicine and Dentistry, University of Rochester Medical Center
Objective:
To determine correlations between subcortical and cortical oscillatory activity and dystonia or Parkinson’s Disease (PD) severity in patients undergoing Globus Pallidus internus (GPi) Deep Brain Stimulation (DBS) therapy.
Background:
The cortico-basal ganglia-thalamic-cortico (CBGTC) motor circuit is likely implicated in both dystonia and PD. DBS targeting the GPi is a surgical treatment for both conditions. Previous studies demonstrate that GPi Local Field Potentials (LFPs) recorded from patients showed beta (20-30 Hz) oscillatory activity desynchronized prior to movement and then re-emerged. However, oscillatory activity has not been evaluated over time or correlated with symptom severity.
Design/Methods:
GPi LFPs were recorded using the PerceptTM PC DBS device along with EEG across 3-5 research visits for 10 subjects (mean age= 56.7 years) with dystonia and/or PD. Subjects performed 3 one-minute trials each of rest, right finger taps, or left finger taps. Custom MATLAB code used a Fast Fourier Transform to calculate power spectral density (PSD) plots. The area under the curve for selected frequencies was determined for the right/left GPi and sensorimotor cortex, then compared with symptom severity scores.
Results:
Beta power differed between movement and rest trials. At baseline, beta power decreased with movement compared to rest in 80% of participants. GPi and sensorimotor cortex beta activity strongly correlated at baseline (left hemisphere r(10)=0.8, p=0.3). With subsequent visits, GPi beta power progressively decreased in 5/10 participants, particularly for subjects with dystonia secondary to PD. Similarly, cortical theta activity progressively decreased with DBS therapy. While PD severity had a positive trend with beta oscillatory activity across visits, only baseline visits demonstrated significant correlation with dystonia severity.
Conclusions:
Differences in beta power during movement and rest correlate with dystonia and Parkinson’s disease symptoms during DBS therapy. The correlation between GPi and sensorimotor cortex beta oscillatory activity suggests measurable downstream effects of GPi DBS in the CBGTC motor circuit.
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