Article
Oscillatory local field potential beta activity correlates with motor symptoms in akinetic-rigid but not tremulous subtypes of Parkinson’s disease as assessed by the Unified Parkinson Disease Rating Scale III in a large sample of patients
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Authors
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Katharina Degen
- Klinik für Neurologie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
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Wolf-Julian Neumann
- Klinik für Neurologie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
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Julius Huebl
- Klinik für Neurologie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
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Christof Brücke
- Klinik für Neurologie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
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Gert-Helge Schneider
- Klinik für Neurochirurgie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
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Andrea A. Kühn
- Klinik für Neurologie, Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin
| Published: | June 2, 2015 |
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Outline
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Objective: Intracranial recordings from the subthalamic nucleus (STN) revealed exaggerated oscillatory beta band activity in patients with idiopathic Parkinson's disease (PD) that is suppressed by dopamine in parallel with improvement of motor symptoms. However, no correlation between the amount of beta activity and the severity of clinical motor symptoms has been shown to date, as well as there hasn't been shown a difference of the LFP – activity in the different subtypes of PD.
Method: Local field potentials (LFP) were recorded bipolarly from adjacent contact pairs (01,12,23) of bilateral STN-DBS electrodes in 68 PD patients (41m/27f, age 66,7±9,4 years) at rest with (ON) and without (OFF) dopaminergic medication. Power spectra were analysed using fft based methods and normalised to 3-47 Hz and 53-97 Hz total power. Pearson correlations were calculated for PD motor scores (UPDRS-III) and averaged LFP power per patient (6 contact pairs in two hemispheres) ON and OFF medication in the theta (x-x Hz), alpha (8-12 Hz) and beta (13-30 Hz) frequency band. Additionally, the absolute change in beta power (OFF-ON) was correlated with the absolute change in the UPDRS-III (OFF-ON).
Results: Patients showed a significantly larger power OFF medication compared to ON medication in the 9-17 Hz frequency band (p<0.05). In the group of patients with akinetic-rigid PD the spectral power in the 8-30 Hz frequency band correlated with the UPDRS-III score in the OFF condition (R=0.39, p=0.004), but not in the ON condition (P>0.05). This correlation was also significant for the beta band (13-30 Hz, OFF, r=0.25; p=0.038). Furthermore, a significant correlation could be shown for the change in the UPDRS-III and the change in 8 - 30 Hz spectral power (OFF-ON; R=0.25, p<0.05) over all patients. In the subgroup of tremor-dominant PD patients a significant positive correlation of theta band power was found with the UPDRS-III OFF score (R=0.62, p=0.013).
Conclusions: In this study we show a direct correlation between 8-30 Hz STN-activity and the motor deficit during dopamine depletion in a large sample of PD patients. The results further support an antikinetic role of beta band activity in PD. Beta power could potentially be used as a biomarker for closed-loop stimulation in PD.
