Dan Brown, in 2017, taught this approacn in the "Sacred Sundays" interview, in which he gave a comprehensive review of this approach. At this time, he was probably already in the first stages of Parkinsons that slightly affected his speech.

This link starts at the meditation, pretty much at the end. 

https://www.youtube.com/watch?v=0swudgvmBbk&t=5900s

He gives an initial sketch of concentration meditation in the beginning.