The history is that it started as NASA-funded project to prevent the astronauts from seizures. For this, it worked, but the technical gear was too cumbersome to make it available to rest of us at that time.
I worked for a doctor who used it on his daughter when nothing mainstream worked to improve her conditions. She went from a few seizures per month to a few per year. This doctor then went on to open his own practice with it. Most of his 'patients' had autism though, so it's hard to get their feedback. The parents said they notice the difference, enough that they brought their children back even though I highly doubt insurance was covering the cost of sessions.
We did have one male adult, late 40's, extremely successful businessman, former MD, come in for improved concentration. He was skeptical at first, but didn't want medication. After a few sessions he said he was amazed how well it worked for him.
I never got a chance to play with it myself.
