I don't know what the difference is. I left a message since people rarely answer phones. I think when I tried to get DD into the neuropsych that DS went to, they told me they would only see DS, but recommended this other place for DD (the one that charges $1000). It specializes in ADHD and learning disablities. I'll look for clinical trials but you'd think the neuropsych that is seeing DS would have known about that.