Alpha and alpha-theta protocols are used most commonly to induce meditative states. With increased knowledge of gamma waves and their role in deep meditation, alpha-theta-gamma protocols are also used to induce meditative states.
Another, quite different approach, is to use neurofeedback to strengthen meditation skills, such as noting, a meditation technique associated with insight meditation. Theoretically, it should be possible to establish EEG signatures for certain processes, such as mind wandering, thinking, hearing, and so on, and signal to the meditator their presence in a matter of milliseconds, long before the meditator would normally be aware of them.
Consider the implications of this approach. The emphasis would not be on inducing a meditative state or experience. It would be on strengthening sensitivity to psycho-physical processes (i.e., guarding the six sense doors), an essential component of mindfulness meditation..