Tactile identification of embossed raised lines and raised squares with variable dot elevation by persons who are blind

Abstract

We present a study on the identification accuracy of embossed tactile lines and squares in eight dot elevations and two dot densities. The results of correct and misclassified matched stimuli by ten congenitally blind participants are presented in confusion matrixes for the raised-dot lines and squares test stimuli. Moreover, the overall mean response time of the identification task is provided. Participants identify better the lower three dot elevations for both lines and squares on 20 or 10 dpi, with an exception for 20 dpi squares where the highest dot elevation is third in the order of recognition. The application of a multilevel model fitting to the data indicated significant effects for the role of the DOTs (raised dot lines versus raised dot squares) with the raised dot squares being associated with significantly elevated correct responding. © Springer International Publishing Switzerland 2016.