Dr. Ivan Poupyrev is a Principle Research Scientist for Disney Research in Pittsburgh, Pennsylvania. Among other creative projects, he has developed a method for transferring audio through the human body by modulating an electric charge in the body. The audio cannot be heard unless the charged up person touches someone’s ear (or other amplification device). His creation is called Ishin-Denshin, which is a Japanese expression for communicating through an unspoken medium.
Here is a description of Ishin-denshin from Dr. Poupyrev’s web site
Ishin-Den-Shin: Transmitting Sound via Touch
This project explores the use of human body as an analogue sound transmission medium. Called “Ishin-Den-Shin,” a Japanese expression for communicating through an unspoken mutual understanding, i.e. non-verbal communication, the technology turns an audio message into an inaudible signal that is relayed by the human body. When the communicator’s finger slightly rubs an object, this physical interaction creates an ad hoc speaker that makes it possible to hear the recorded sounds.
A special case of Ishin-Den-Shin is when communicator touches another person’s ear. In this case modulated electrostatic field creates a very small vibration of the ear lobe and, both the finger and other person’s ear together form a speaker which makes the signal audible only for the person touched.
The Ishin-Den-Shin system includes a handheld microphone connected to a computer.. When someone speaks into the microphone, the computer turns the sound into a looped recording. The recording is then converted into high-voltage, low-current inaudible signal that flows into a thin wire connected to the interior of the microphone. This looped, inaudible signal creates a modulated electrostatic field produces a very small vibration of a finger touching an object, forming a speaker.
The Ishin-Den-Shin technology thus can turn everyday artifacts into interactive sound devices without the need to instrument them with any special technological apparatus. It can be used for inter-personal communication and furthemore it can be transmitted from person to person via any sort of physical contact.
Ishin-Den-Shin was exhibited at Cyber Arts 2013 Exhibition in Linz. A microphone can be used to record and store a person’s voice, and an amplification driver converts the sound loop into a high voltage, low current (~300 Vpp, ~50 mA) inaudible signal which is applied to the conductive metallic casing of the microphone via an additional connector. When holding the microphone, the visitor comes in contact with the inaudible, high voltage, low power version of the recorded sound. This creates a modulated electrostatic field around the person’s body. When touching and sliding a hand on an object this modulated electrostatic field creates a very small vibrations. As a result, both the finger and the object together form a speaker, that makes the signal audible. The human ear can also be used as an object to reproduce the sound: in this case the modulated electrostatic field creates a very small vibration of the ear lobe. This makes recorded sound audible only for the person touched. The audio recording can be transmitted by physical contact, from body to body. Secrets, messages and whispers can then be transmitted from person to person in physical contact with each others. [Visit Dr. Poupyrev’s website for more information] 
