Impact of placebo-related instruction on HEG biofeedback outcomes in children with ADHD.

Studies to date have not revealed any differences between biofeedback (BFB) methods vs. placebo treatment in reducing ADHD symptoms. The purpose of this randomized controlled study was to assess the impact of placebo expectations on gain in hemoencephalographic (HEG) BFB. The final cohort consisted of 33 children with ADHD aged 9-14. Individuals were assigned to one of two groups (with standard active training instruction vs. placebo-related instruction) and were subjected to five HEG BFB sessions. Children with standard instruction exhibited higher growth of regional cerebral blood oxygenation during the HEG BFB session as well as better results in cognitive tests (vigilance and visual search) at the end of the experiment compared to children with placebo-related instruction. The data obtained indicate the difficulty in designing studies assessing BFB efficacy. Placebo expectation may adversely affect HEG BFB outcomes in children with ADHD.