Stimulus Frequencies that Produce the Perception of Visual Substitutability in the Visually Impaired

We propose the utilization of a device that combines a sensor and an energizing signal　（ES） as an information device to prevent blind people from colliding with people. Depending on the difference between congenital and acquired blindness in the probability of success in differential judgment when a person approaches or leaves, there is a difference in the skin impedance change associated with the phenomenon of catatonic sweating that causes incorrect reading of the energizing signal that affects judgment. This impedance has a frequency characteristic for AC waves. The purpose of this study was to clarify the frequencies and impedances most associated with the phenomenon of sweating. In the future, we expect to improve the probability of success by devising new frequencies and impedances and by using hygroscopic electrodes. Subjects and Methods, the study design was an experimental intervention study and a randomized controlled trial. The study period was from August 2021 to December 2022. A field experiment was conducted in a local community center-like public space. Participants were 5 congenitally blind, 2 acquired blind, and 2 healthy subjects.　They were excluded if they were undergoing treatment for a neurological disease. The intervention method was to use distance data detected by an ultrasonic sensor and a low-frequency energizer connected to an iPad by BPIO using a home-made MESH program to change the signal interval of the energizer only when a person approached. This condition was used as the intervention. The placebo condition (always a weak current and only energization that did not reflect the sensor's response) was randomly selected and assigned in a blinded fashion. Results The mean impedance in the condition that resulted in about 80% success in judging human proximity by ES was significantly different, <05, in the minimum sensing potential output between congenitally blind and acquired blind subjects. Conclusions In sensory input devices and information processing for recognizing and judging the external environment by energizing signals in congenitally blind and acquired blind people, the higher the correct response rate, the lower the subjective energizing frequency tended to be, in which case all participants could become aware at 10 Hz or higher. This was considered to be one of the conditions that should be considered in the implementation of a device to support judgment of external environment information by energizing signals.