Interesting question.
My thought are no, I doubt it. LR LM and Lmusic do move along at a fast pace but having used it with many kids I can see that it actually enhances their concentration levels over time. Many of my kids who couldn't sit through a session at the start now can focus for the entire days lesson.
Also there are so many kids on this forum who can happily sit through back to back lessons of LR LM and LMusic all in one sitting!
It's not like TV where the scenes change endlessly and often for no reason ( they don't always enhance the plot) Brillkids products only change scenes in a predictable and enhancing way. I have never known flash cards to enhance ADHD and its really just digital flash cards after all.