A Ph.D. ABPN who does this kind of testing. The doctor visited with me, then I had to complete a 100 questionaire rated 1-5 highest being most of the time, 1 being not at all...then he also had my daughter complete one too (her opinion of how I do daily) and then I completed a four-hour testing of mutiple tests for memory, concentration, focus, thought processing etc. It took 3 months for them to get the results completed so a determination could be made. I believe it is very thorough.