When I'm writing - it's often quiet, too quiet, hard to focus and I crave a little background music. Not "Muzak" - I abhor it, and while light classical sometimes does the trick I've been trying out some of the "Binaural Beats" videos on YouTube - listening with the headphones, strange - not music, more some sort of ... I dunno, low-tones, strange, as if someone went a little overboard on their new-age kick, imagine the lightest synth played at a quarter speed - yet it seems to work, and after an hour's writing or staring at the screen you take off the headphones and feel strangely discombobulated. It's almost a mental white noise...
I'm not sure that it's all that, but the experiment is free and it definitely can't hurt ...