A display device that transmits crude images to the tongue has been adapted to alert people suffering from sensory loss that they may have remained seated in one position for too long.
The system, developed by medical physicists at the Institut d’Informatique et Mathématiques Appliquées in Grenoble, France, includes a Tongue Display Unit (TDU) and a pressure sensitive pad placed under the buttocks. The TDU is a square array of 36 electrodes that can apply patterns of low voltage signals to the tongue.
The continuous pressure on one portion of the body that occurs when someone lies or sits still for long periods can lead to dangerous pressure ulcers, commonly called bedsores. The TDU in combination with the sensor pad is an attempt at sensory replacement – substituting one sensory signal for another – to reduce the incidence of pressure ulcers in people who are partially paralyzed or have lost sensory responses below the waist.
Although the system has only been tested in healthy subjects thus far, the researchers report a 92% success rate among 10 people asked to interpret TDU signals representing the front, back, left, or right portions of their buttocks. The ribbon cable attached to the TDU is unwieldy, but wireless versions currently in development could make the device more clandestine.
The research group is also developing TDU-based devices that may eventually guide the hands of surgeons. Other researchers have studied using TDUs as alternative to Braille, or to replace sight altogether
The article describing the TDU/buttock monitor was published July 12, 2006 in the French medical journal L’escarre.
An English language press release is available on the group’s website