Spinal Cord Stimulation Frequency Influences the Hemodynamic Response in Patients with Disorders of Consciousness

Figures

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  Fig. 1. X-ray images illustrating the location of implanted SCS devices. A An SCS electrode implanted in the epidural space at C2–C4. B An implantable impulse generator arranged subcutaneously on the collarbone.

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  Fig. 2. The experimental configuration. A Experimental paradigm for SCS. B Arrangement of probes over the prefrontal and occipital areas. C Photograph of the experimental setup.

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  Fig. 3. Group-averaged hemodynamic responses of DOC patients during the SCS procedure in the prefrontal and occipital areas. The SCS duration is indicated by the space between the two vertical gray lines. The shadowed areas indicate the standard errors of the mean values across all patients.

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  Fig. 4. Peak and mean values of the HbT concentrations among the five SCS frequencies during the on-SCS period. Error bars indicate the standard errors of the mean (*P < 0.05).

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  Fig. 5. Mean HbT concentrations at the five different SCS frequencies in the pre-, on-, and post-SCS periods. Error bars indicate the standard errors of the mean (*P < 0.05).

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  Fig. 6. Effects of SCS on the functional integrity of the brain. A Group-level results of functional connectivity between the prefrontal and occipital areas for the five frequencies in the period before and after the SCS procedure. Red lines indicate positive, and blue lines negative correlation values. B Group-level functional connectivity between the periods before and after the SCS procedure for the five frequencies. White and black bars represent the means of the functional connectivity coefficients before and after the SCS procedure, respectively. Error bars indicate the standard error of the mean (*P < 0.05).