Speculations about a "4th application" of the EEG are old. Immediately after Hans Berger's invention, the EEG's potential in diagnosis and research became evident. The EEG was also used, from time to time, as a therapeutic tool in the treatment of epilepsy. But from early on, people also speculated about using it to decipher thoughts. This gave room for a remarkable history of paranoia, but it also led to serious speculations about using the EEG to communicate or, indeed, control devices. In 1977, novelist Craig Thomas let his hero control an aeroplane by thought, but the idea is probably older.
The question was: Can the EEG be used as a language? Scientists for a long time doubted it. And the large number of neurons that led to the EEG signals with a resulting poor resolution, limited information processing capabilities in the early years of computing, and a lack in robot technology to produce interesting output devices did their part to keep enthusiasm low. But things have changed: Today, we know a variety of EEG-signals that can indeed be used for communication purposes.