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Fig. 7 | Bioelectronic Medicine

Fig. 7

From: Spinal cord stimulation in chronic pain: evidence and theory for mechanisms of action

Fig. 7

Neurophysiological testing. Somatosensory evoked potentials (SSEP) waveforms are measured by applying an electrical stimuli to the tibial nerve. SSEP waveforms recorded with scalp electrodes at (CPz-Fz) are modulated with SCS. Panel a: During SCS ON P39-N50-P60 representative SSEP waveform decreases in amplitude. Flexor reflexes (RIII) are obtained with noxious electrical stimuli are applied to the sural nerve. The RIII waveform is recorded from the ipsilateral biceps femoris. Panel b: During SCS ON there is decrease the amplitude of the RIII waveform (adapted from (Sankarasubramanian et al., 2018b)). Quantitative sensory testing (QST) applies different sensory stimuli, such as vibratory, tactile or thermal stimuli to the subject extremity. Panels c, d: SCS results in variable effects on QST sensory thresholds and may increase increases pain threshold and tolerance. Advanced QST measures including temporal summation (TS) and conditioned pain modulation (CPM) can provide further insight into P-SCS, PF-SCS and DRG-S analgesic mechanisms

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