Electroencephalography (EEG) headwear devices record the electric signals that are produced when the brain is at work and can connect them wirelessly to a computer. Their wearers can also train their minds to associate a set of EEG brain signals with a specific task.
For example, thinking about pushing a button on the computer screen produces a brainwave pattern that computer software can then recognize and associate with that task.
To make music, such thoughts are associated with notes or sounds to create a language of musical thought that's produced directly from the brain. With this established, users can simply think musical scores to life and play them via the computer.