Effects of non-pharmacological pain treatments on brain states

• This is the first study to examine, in the same sample, the effects of hypnosis, meditation, transcranial direct current stimulation (tDCS), and neurofeedback on pain and brain oscillations, relative to a control procedure.
• Each procedure resulted in oscillation changes that differed from the control procedure and from each other, suggesting different modes of action on brain activity.
• Changes in pain intensity associated with the procedures were not, however, significantly associated with changes in brain oscillations, suggesting that brain activity measures used in this study do not reflect pain intensity.

ObjectiveTo (1) evaluate the effects of a single session of four non-pharmacological pain interventions, relative to a sham tDCS procedure, on pain and electroencephalogram- (EEG-) assessed brain oscillations, and (2) determine the extent to which procedure-related changes in pain intensity are associated with changes in brain oscillations.Methods30 individuals with spinal cord injury and chronic pain were given an EEG and administered measures of pain before and after five procedures (hypnosis, meditation, transcranial direct current stimulation [tDCS], neurofeedback, and a control sham tDCS procedure).ResultsEach procedure was associated with a different pattern of changes in brain activity, and all active procedures were significantly different from the control procedure in at least three bandwidths. Very weak and mostly non-significant associations were found between changes in EEG-assessed brain activity and pain.ConclusionsDifferent non-pharmacological pain treatments have distinctive effects on brain oscillation patterns. However, changes in EEG-assessed brain oscillations are not significantly associated with changes in pain, and therefore such changes do not appear useful for explaining the benefits of these treatments.SignificanceThe results provide new findings regarding the unique effects of four non-pharmacological treatments on pain and brain activity.