XWave makes a basic app that presents information on brainwaves to the user, displaying different colors based on the signals received, as shown in the teaser video below. Brain-training exercises include levitating an on-screen ball for a certain amount of time or changing a colour by relaxing the brain in a bid to maximise the brain's attention span.
(XWave teaser demonstration video)
In his 1977 novel A Scanner Darkly, Philip K. Dick makes extensive use of the cephalochromoscope, a consumer device used for relaxation:
"Your cephalochromoscope that cost you nine hundred dollars, that you always turn on and play when you get home - Ernie and Barris were babbling away about it. They tried to use it today and it wouldn't work. No colors and no ceph patterns, neither one..."
(Read more about the cephalochromoscope or cephscope)
Note that the root words for cephalo-chromo-scope literally means "brain" - "color" + "watch or see".
SF movie fans may recall the 1983 movie Brainstorm, starring Christopher Walken and Natalie Wood. In the film, a team of scientists creates "The Hat, a special helmet that is able to read sensations from one person's brain and write them to tape so that others are able to experience them.