1962 // A. H. Frey
Human auditory system response to modulated electromagnetic energy
Journal of Applied Physiology 17(4):689–692
Summary & analysis
Frey reports lab tests where people heard short clicks or buzzes when their heads were exposed to certain pulsed microwave-type radio signals—even when there was no normal sound in the room. The paper shows the effect depends on how the pulses are timed and modulated.
Key claim
Pulsed, modulated microwave-type RF can produce audible clicks or buzzes in the head without ordinary room acoustics.
Relevance
This is the classic peer-reviewed paper for hearing something via electromagnetic waves without conventional sound. The effect was described early in the scientific literature.