Researchers from the Department of Rehab Medicine at the University of Washington in Seattle evaluated the effects of a single session of four non-pharmacological pain interventions, relative to a sham procedure, on pain and electroencephalogram- (EEG-) assessed brain oscillation, in order to determine the extent to which intervention-related changes in perceived pain intensity are associated with changes in brain oscillations.

Thirty individuals with spinal cord injury and chronic pain were given an EEG and were tested for pain before and after five different procedures (hypnosis, meditation, transcranial direct current stimulation [tDCS], neurofeedback, and a control sham tDCS procedure).

Each 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.

However, very weak and mostly non-significant associations were found between changes in EEG-assessed brain activity and pain.

The investigators conclude that different non-pharmacological pain treatments have distinctive effects on brain oscillation patterns, but that changes in EEG-assessed brain oscillations are not significantly associated with changes in pain.
 
Therefore, although this study offers new findings regarding the unique effects of four non-pharmacological treatments on pain and brain activity, these shifts do not appear to be useful for explaining the benefits of these treatments.

Citation:  Jensen MP, Sherlin LH, Askew RL, Fregni F, Witkop G, Gianas A, Howe JD, Hakimian S. Effects of non-pharmacological pain treatments on brain states.  Clinical Neurophysiology. 2013 Oct;124(10):2016-24. doi: 10.1016/j.clinph.2013.04.009. Epub 2013 May 22. [email protected]