Perceiving Space and Optical Cues via a Visuo-Tactile Sensory Substitution System: A Methodological Approach for Training of Blind Subjects for Navigation

Abstract

A methodological approach to perceptual learning was used to allow both early blind subjects (experimental group) and blindfolded sighted subjects (control group) to experience optical information and spatial phenomena, on the basis of visuo-tactile information transmitted by a 64-taxel pneumatic sensory substitution device. The learning process allowed the subjects to develop abilities in spatial localisation, shape recognition (with generalisation to different points of view), and monocular depth cue interpretation. During the training phase, early blind people initially experienced more difficulties than blindfolded sighted subjects (having previous perceptual experience of perspective) with interpreting and using monocular depth cues. The amelioration of the performance for all blind subjects during training sessions and the quite similar level of performance reached by two groups in the final navigation tasks suggested that early blind people were able to develop and apply cognitive understanding of depth cues. Both groups showed generalisation of the learning from the initial phases to cue identification in the maze, and subjectively experienced shapes facing them. Subjects' performance depended not only on their perceptual experience but also on their previous spatial competencies.

Other ways of seeing: From behavior to neural mechanisms in the online “visual” control of action with sensory substitution

“…This knowledge is crucial for the task because the acquisition of object identity through haptics is size invariant because any object that can be touched is perceived as its three-dimensional size. This knowledge has also been reported in studies of visual-to-tactile sensory substitution ( Segond, Weiss, Kawalec, & Sampaio, 2013 ). Early or congenitally blind participants still have more difficulty using this knowledge than those who had visual experience previously.…”

Navigation Using Sensory Substitution in Real and Virtual Mazes

“…When using SSDs the congenitally blind have better visuo-tactile acuity [ 35 ], and visuo-auditory acuity [ 36 ] than their blindfolded counterparts. They can use SSDs to recognize routes [ 60 ], detect and avoid obstacles [ 37 – 40 , 43 ], recognize objects and shapes [ 33 – 36 ], and perceive depth [ 40 , 43 , 62 , 63 ]. Despite these achievements SSD use for navigation outside laboratory settings remains extremely limited [ 39 , 64 ].…”

Designing sensory-substitution devices: Principles, pitfalls and potential1

“…Van Erp et al (2005) used a haptic belt, coding distance with vibration rhythm while direction was translated into vibration location. While cueing direction by location worked well, conveying distance in this way was not successful (for other implementations see Cosgun, Sisbot & Christensen, 2014 ; Johnson & Higgins, 2006 ; Segond et al, 2013 ).…”