Projects: Electrotactile shape perception on the tongue (Shapes on tongue)

In this project we demonstrated, we believe for the first time, that humans tongue are capable of perceiving geometric shapes on their tongues. We used the 7x7, or 49-electrode array originally developed for fingertip electrotactile stimulation.

Five sighted adult human subjects (3M/2F) each received 4 blocks of twelve tactile patterns, approximations of circles, squares, and vertex-up equilateral triangles, sized to 4x4, 5x5, 6x6, and 7x7 electrode arrays. Perception with electrical stimulation of the tongue is better than with fingertip electrotactile stimulation, and the tongue requires 3% (5-15 V) of the voltage. The mean current for tongue subjects was 1.612 mA. Tongue shape recognition performance across all sizes was 79.8%. The approximate dimensions of the electrotactile array and the dimensions of compartments built into dental retainers have been determined. The goal is to develop a practical, cosmetically acceptable, wireless system for blind persons, with a miniature TV camera, microelectronics and FM transmitter built into a pair of glasses, and the electrotactile array in a dental orthodontic retainer. This work is published:

Form perception with a 49-point electrotactile stimulus array on the tongue: A technical note," J. Rehab. Res. Dev., vol. 35, pp. 427-430, 1998. (570 KB)

This work was supported by:

• University of Wisconsin-Madison Robert Draper technology Innovation Fund
• University of Wisconsin-Madison Industrial & Economic Development Fund
• Charles E. Culpeper Foundation

The photos below illustrate the instrumentation, shapes, and results.