The site is in Japanese, but the scoring is in numbers
Just look at the displayed numbers while they flash up, then click on the circles in correct number order.
http://flashfabrica.com/f_learning/brain/brain.html
And no, it's not one of those zombie face scary things. Although I admit I was halfway expecting it to be one...
I think I got up to seven numbers, and it said my brain is 22 years old. I guess that explains the juvenile humor things lately...
So... how old are you, and what's your peak number count?