This is a narrative review by one author of published brain imaging, brain stimulation and neurofeedback studies in ADHD, with a search up to 20 January 2018. The studies it covered included children, adolescents and adults. It did not report formal inclusion rules, study counts or quality ratings.
Across thinking tasks such as stopping a response, paying attention, timing and working memory, people with ADHD showed lower activity in several brain networks. One pooled analysis of stopping tasks included 287 patients with ADHD. Findings for reward and emotion were less consistent.
Computer programs that sort scans into ADHD or not reached high accuracy in small studies (over 80%). In a large multi-site contest, accuracy did not go above 61%. The author says the small samples may not generalize and that replication is still needed.
For a magnetic brain stimulation method (rTMS), the author's conclusion is negative. After one positive single-session pilot in adults, larger studies found no benefit over fake (sham) stimulation. In two of the three adult studies, both the real and sham groups improved, which suggests placebo effects.
Results for a mild electrical stimulation method (tDCS) were mixed. The two larger neurofeedback studies found some gains that were no better than the control conditions. Nothing is known about the long-term effects of tDCS, and more is needed on stimulation dosage in children. Most imaging studies focused on males.
Anyone weighing these approaches should talk to a clinician about their own situation.
Source: Katya Rubia. Cognitive Neuroscience of Attention Deficit Hyperactivity Disorder (ADHD) and Its Clinical Translation. Frontiers in Human Neuroscience (2018). doi:10.3389/fnhum.2018.00100