EEG Measures of Auditory and Tactile Stimulations in Computer Vision Based Sensory Substitution System for Visually Impaired Users

Any kind of a sensory substitution device designed as an assistive technology for a particular group of users must address a very important question: what senses should be utilized as well as how to design and optimize the stimulation patterns? Various measures can be applied in order to estimate the quality of the proposed solution: one can measure the length of the training process, scores and navigation times in various use case scenarios, evaluate the cognitive load of the system, design surveys and questionnaires for the users, etc. Unfortunately, as the human brain and sensory substitution problem are both very complex, there is no single, true quantitative and qualitative method that can be used to compare different solutions. In the studies presented in this article, isolated responses to external auditory and tactile sensory stimulation events, their parameters and features are measured in a series of cognitive experiments and confronted with individual preferences of the visually impaired (VIP) and normally sighted (NSP) users.