I imagine the CIA or something already can do an analysis of someone's typing rhythm to figure out passwords. I remember somewhere reading that the sound of someone typing can be used to deduce what characters are being typed too. I don't expect either method works all that well when you get someone that never learned to touch type pecking away at the keyboard, or someone that fat-fingers part of their password, hits backspace a few times, then types in the rest. Which is a technique I sometimes use if someone is annoyingly watching me when I type in mine.
If I'm understanding the article correctly, it probably doesn't work all that well when someone is using an on-screen keyboard, such as with a tablet or phone. Either way, I don't think it's going to help you much with an already secure password that includes special characters and a mix of upper and lower-case letters, as many people that can even touch type break up their rhythm to look at the keyboard for some symbols or numbers.