Systems for the Evaluation of the Tactile Sensibility in Pattern Recognition Using All the Hand Fingers

This paper presents methodologies for psychophysics assessment of tactile sensibility on developed pressure and vibrotactile mechanical tactile stimulation systems. On systems of mechanical stimulus, we´ve developed a Braille display that enables the average speed estimation of character recognition in Braille pattern. The person being tested must try to recognize a character during a given initial time interval and, depending on the correct identification or not of this character, this exhibition time suffers successive approximation variations, enabling the estimation of the average speed of Braille character pattern recognition. Yet no psychophysical experiments where performed with this system. As for the vibrotactile stimulation system, we used a vibrotactile stimulator, triggered by computer, to transmit a pulse between 10 Hz and 100 Hz. Initially, we´ve analyzed the sensibility of all hand fingers (indicative, medium, annular, minimum and thumb) based on the attempts of the test person that aimed to identify the target frequencies of 13, 20, 32, 50 and 79 Hz, whose values where geometric calculated and that the test person previously received training in order to recognize. The parameters used in this psychophysical evaluation are: a) number of iterations performed by the persons being tested until he signals the achievement of the target frequency and; b) the relative average error in target frequency identification