December 15, 2021
Neurofeedback, also known as electroencephalogram (EEG) biofeedback, aims to help persons with ADHD train themselves to self-regulate patterns of brain activity associated with the disorder.
An example is theta-beta ratio frequency (TBR) training. Beta waves, with a frequency of 18 to 25 Hz, are associated with electrical activity when the brain is conscious or alert. Theta waves, with a frequency of 4 to 7 Hz, are associated with meditative, daydreaming, or drowsy states. In youths with ADHD, the theta to beta ratio tends to be elevated. TBR training seeks to reduce it.
Neurofeedback is often described as a promising emerging alternative or complement to pharmaceutical treatment. Previous meta-analyses have found neurofeedback can reduce symptoms of ADHD.
But what effect does it have on executive functions? A Thai research team based at Chiang Mai University conducted a comprehensive search of the peer-reviewed journal literature and identified ten studies with results suitable for meta-analysis.
A meta-analysis of all ten studies with a combined total, of 378 participants found no improvement whatsoever in response inhibition.
A second meta-analysis, of nine studies with a combined total of 349 participants, found no improvement in sustained attention.
Finally, a meta-analysis of three studies with a total of 121 participants likewise found no improvement in working memory.
In all three cases, there was no evidence of publication bias.
The authors concluded, "Results did not show the benefits of neurofeedback on executive functions assessed by neuropsychological tests."
OrawanLouthrenoo, NonglakBoonchooduang, NaruepornLikhitweerawong, KittipatCharoenkwan, and ManitSrisurapanont, "The Effects of Neurofeedback Executive Functioning in Children With ADHD: A Meta-Analysis," Journal of Attention Disorders(2021), published online,https://doi.org/10.1177/10870547211045738.