A comparative study of musical navigation methods for visually impaired users of GUI systems

Graphical user interface (GUI) systems were considered as obstructions for the visually impaired users since it relied too much on visual channel. Thus, various auditory stimuli combined with speech served as complementary communicating methods in these systems. The purpose of this study was to compare the performance of musical stimuli (called earcons) with different constructions for transmitting positional information of auditory cursors to visually impaired users. Four different types of earcons including sequence of notes (SE), regrouped sequence of notes (R-SE), quadrant (QU), and decimal digit (DE) were studied. Twenty subjects participated in navigation of abstract coordinate locations within a graphical interface divided into 40 rows and 40 columns. At most six timbres and voices were used in construction of earcons to avoid ambiguity and confusion. Both objective and subjective criteria were adopted in the evaluation of the four types of earcons. The results of ANOVA indicated that: 1) compared with SE and QU, R-SE and DE have lower error rates; 2) with SE method, more errors occurred in the area far from origin than the area near origin, whereas error distribution was better-proportioned in R-SE, QU and DE; 3) efficiency was much higher in QU and DE than SE and R-SE. Finally discussed in this paper are advantages and disadvantages of the four methods for navigation in GUI system for visually impaired users.