Resting-state electroencephalography and magnetoencephalography as biomarkers of chronic pain: a systematic review

Figures

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  Figure 1.. PRISMA flow diagram of study selection. CP, chronic pain; EEG, electroencephalography; PRISMA, preferred reporting items for systematic reviews and meta-analyses; RS, resting state; qM/EEG, quantitative M/EEG.

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  Figure 2.. Pain type, recording modality, and study designs of included studies. The charts show absolute numbers of studies. EEG, electroencephalography; MEG, magnetoencephalography.

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  Figure 3.. Risk of bias of included studies. M/EEG, magneto-/electroencephalography.

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  Figure 4.. Open science practices of included studies. The charts show absolute numbers of studies.

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  Figure 5.. Explanatory albatross plot based on fictional data. P values on the x-axis are displayed on a logarithmic scale (log10). n.s., not significant.

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  Figure 6.. Peak alpha frequency differences between patients and healthy participants in cross-sectional studies. P values on the x-axis are displayed on a logarithmic scale (log10). n.s., not significant.

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  Figure 7.. Power and connectivity differences between patients and healthy participants in cross-sectional studies. P values on the x-axis are displayed on a logarithmic scale (log10). n.s., not significant.

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  Figure 8.. Power changes with pain relief in longitudinal studies. On the right (“[higher]”) part of each albatross plot, studies with postinterventional power increases are displayed. On the left ([“lower”]) part of each plot, studies with postinterventional power decreases are displayed. Only studies that found a postinterventional pain relief were included. P values on the x-axis are displayed on a logarithmic scale (log10). n.s., not significant.

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  Figure 9.. Correlations of power and connectivity with pain intensity in descriptive studies. On the right (“[pos.]”) part of each albatross plot, studies with positive correlations of pain intensity and power/connectivity are displayed. On the left ([“neg.”]), part of each plot, studies with negative correlations of pain intensity and power/connectivity are displayed. P values on the x-axis are displayed on a logarithmic scale (log10). n.s., not significant.