Fig. 5.

Control groups. A healthy control group performing the same task as the experimental group was used in 15% of the studies. Feedback from a different region, unrelated to the symptoms, was provided to a clinical control group in 19% of the studies. SHAM neurofeedback that was either yoked or artificially created was used in 7% of the studies. 11% of the studies did not provide feedback to the control groups. Multiple control groups were used in 11% of the studies. Finally, 31% of the studies did not use a control group.