These were used in a series of concert performances in 2003 DECONcert: Music For Cyborgs
James Fung, Ariel Garten, and Steve Mann (~2003) have created a wide variety of underwater biophone systems that use physiological signals to control different musical variables in an intericate way, as well as to actually generate sounds, including underwater ECG and EEG concerts
The electrocardiophone is a quintephone in the sense that it creates sound from the "5th classical element" (i.e. from beyond the world of matter).
In addition to sound-production, regenerative brainwave musical performances use brainwave interfaces to modify or manipulate or play along with sounds of other instruments in a live performance context.