Comparison of oscillatory activity in subthalamic nucleus in Parkinson's disease and dystonia - PubMed (original) (raw)
Comparative Study
Comparison of oscillatory activity in subthalamic nucleus in Parkinson's disease and dystonia
Xinyi Geng et al. Neurobiol Dis. 2017 Feb.
Abstract
Objectives: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been successfully used to treat both Parkinson's disease (PD) and dystonia. Local field potentials (LFPs) recorded from the STN of PD patients demonstrate prominent beta frequency band activity. It is unclear whether such activity occurs in the STN in dystonia, and, if not, whether dystonia has another distinctive neural population activity in the STN.
Methods: Twelve patients with PD, and eight patients with dystonia underwent DBS electrode implantation targeting the STN. Seven dystonia patients were off medication and one was on aripiprazole and clonazepam. LFPs were recorded from the DBS electrodes in PD in the on/off medication states and in dystonia. Power spectra and temporal dynamics measured by the with Lempel-Ziv complexity of the LFPs were compared among these states.
Results: Normalised power spectra and Lempel-Ziv complexity of subthalamic LFPs differed between dystonia off and PD on/off, and between PD off and on over the low frequency, beta and high gamma bands. Patients with dystonia and off medication had lower beta power but higher low frequency and high gamma power than PD. Spectral power in the low beta frequency (11-20Hz) range was attenuated in medicated PD.
Conclusion: The results suggest that dystonia and PD are characterized by different patterns of oscillatory activities even within the same nucleus, and exaggerated beta activity may relate to hypo-dopaminergic status.
Keywords: Dystonia; Oscillation; Parkinson's disease; Subthalamic nucleus.
Copyright © 2016 Elsevier Inc. All rights reserved.
Conflict of interest statement
Relevant conflicts of interests/financial disclosure
Nothing to report.
Figures
Fig. 1
Group power spectra over 0–45 Hz (left) and 60–140 Hz (right) averaged across subjects with dystonia off medication (A and B, black line) and separately for case d8 on clonazepam and aripiprazole (A and B, green line); PD off levodopa (C and D, red line) and on levodopa (C and D, blue line). Dashed lines show individual spectra of all subjects in the respective conditions. Results of serial two-sample, unpaired _t_-tests between dystonia off medication and PD groups, one-sample _t_-tests between dystonia off medication and averaged case d8 on medication and paired _t_-tests between PD off and on (E and F). LFPs were z-transformed before spectral analysis. Spectral resolution is 0.5 Hz. Note ln (P) y axis scales in E and F.
Fig. 2
Group average normalised power spectra realigned to the peak frequency over 5–10 Hz in panel A, 11–32 Hz in panel B and 60–140 Hz in panel C. Results of serial two-sample, unpaired _t_-tests between the dystonia off medication (n = 14 except n = 12 for gamma band analysis) and PD group off (n = 22) and on (n = 22) medication and paired _t_-tests between PD on/off (both n = 22) states are shown in D-F. LFPs were z-transformed before spectral analysis. The shadows in the respective colours denote ±1 standard deviations of the groups. As there were no clear gamma peaks in the selected channels of PD cases, 80 Hz was taken as the centre frequency for realignment based on previous literature where fine-tuned gamma oscillations were usually found in 60–95 Hz (Kempf et al., 2009; Jenkinson et al., 2013).
Fig. 3
Complexity analysis of bandpass filtered LFPs centred on the peak frequency in low frequency band (5–10 Hz), low beta band (11–20 Hz), high beta band (20–32 Hz) and gamma band (60–140 Hz). Significant differences were found in LZC among dystonia off, PD on and off conditions over low frequency (F(2, 55) = 21.4, p < 0.0001, ANOVA), the low beta band (F(2, 55) = 104.4, p < 0.0001, ANOVA) and the gamma band F(2, 53) = 316.3, p ≤ 0.0001, ANOVA). Note that two sides from one dystonic case (d6) were excluded for analysis in the gamma band due to artefacts. *p ≤ 0.005, **p ≤ 0.001, post-hoc _t_-tests.
References
- Aboy M, Hornero R, Abásolo D, et al. Interpretation of the Lempel-Ziv complexity measure in the context of biomedical signal analysis. IEEE Trans Biomed Eng. 2006;53:2282–2288. -PubMed
- Alonso-Frech F, Zamarbide I, Alegre M, et al. Slow oscillatory activity and levodopa-induced dyskinesias in Parkinson's disease. Brain. 2006;129:1748–1757. -PubMed
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