Revisiting the optimal cut-off value of intelligibility in context scale for Cantonese-speaking children

Abstract

This study evaluated the validity of the Intelligibility in Context Scale–Traditional Chinese (ICS-TC) as a screening measure of speech sound disorder (SSD) in a large sample of Cantonese-speaking children in Hong Kong. Parents of 789 Cantonese-speaking children aged between 2;4 (years;months) and 6;9 completed the ICS-TC and children’s speech ability was evaluated using a standardized speech assessment. Firstly, the screening accuracy of a previously proposed cut-off (4.29) for ICS-TC was appraised. Specificity and sensitivity were not satisfactory. In the follow-up analysis, as the effect of age on ICS-TC scores was found to be significant, separate cut-off scores were determined for each age group and the corresponding accuracy was appraised. The new cut-off scores yielded remarkably improved accuracy for younger groups (2;4–4;5) but little to no improvement for older groups (4;6– 6;9). The proposed cut-off scores were 3.50, 3.62, 3.79, and 3.64 for children aged 2;4 to 2;11, 3;0 to 3;5, 3;6 to 3;11 and 4;0 to 4;5 respectively. The findings provide further evidence on the validity of ICS-TC as a screening measure of SSD, in particular for children from 2;4 to 4;5. Further measures were suggested to assist parents’ judgement of children’s speech intelligibility during late preschool years.