Take-Home Messages •This paper describes neurophysiological, psychophysical, and behavioral observations from laboratory studies involving human and animal subjects. •Absorption of a single microwave pulse impinging on the head may be perceived as an acoustic zip, click, or knocking sound. •A train of microwave pulses may be sensed as an audible buzz, chirp, or tune by humans. •Mechanistic studies show absorption of microwave pulses by soft tissues in the head launches a thermoelastic pressure wave that travels in the brain •Depending on the power of the impinging microwave pulses, the level of induced sound pressure could be considerably above the threshold of auditory perception. •The microwave auditory effects and associated pressure waves could potentially render damage to brain tissues to cause lethal or nonlethal injury.

The microwave auditory effect has been widely recognized as one of the most interesting and significant biological phenomena from microwave exposure. The hearing of pulsed microwaves is a unique exception to sound waves encountered in human auditory perception. The hearing of microwave pulses involves electromagnetic waves. This paper reviews the research in humans and animals leading to scientific documentations that absorption of a single microwave pulse impinging on the head may be perceived as an acoustic zip, click, or knocking sound. A train of microwave pulses may be sensed as buzz, chirp, or tune by humans. It describes neurophysiological, psychophysical, and behavioral observations from laboratory studies involving humans and animals. Mechanistic studies show that the microwave pulse, upon absorption by tissues in the head, launches a pressure wave that travels by bone conduction to the inner ear, where it activates the cochlear receptors via the same process involved for norm...