Validation of the Use of the Rapid Speech Transmission Index (Rasti) In Elementary School Classrooms

The aim of this study was to assess the validity of an objective method of speech intelligibility, the Rapid Speech Transmission Index (RASTI), in elementary school classrooms, The RASTI can be obtained more quickly than subjective measures of speech intelligibility and has been shown to be highly valid with adult listeners in auditoriums. In this study RASTI values were correlated with scores on a subjective test of speech intelligibility, the word intelligibility by Picture Identification (WIPI) test, for 45 students in two elementary classrooms (grades 1 through 3 and grade5). Results indicated that the RASTI value is a poor predictor of subjective speech intelligibility (WIPI) scores for these students. There was no significant difference between the correlations obtained in the two classrooms or between the correlations obtained with the average and largest of the three RASTI values and the WIPI scores. Further study needs to be done to determine the applicability of the RASTI to classroom environments