Decreasing dots on curve - Brush?

Hi

I would like to create a simple and reusable way of putting dots on a curve that steadily decrease in size.

I was hoping to use the pattern brush feature but I don't seem to be able to steadily decrease the circles.

I can do i manually but I want to use it on lots of different curves.

Blend didn't seem to do it either without a lot of messing about.

Attached might help explain what I want.