Discriminating the Validity of Speech Mechanism Screening Test for Children for Children with Speech Sound Disorders: A ROC Curve Analysis

Abstract

Objectives: The purpose of the study was to examine whether the Speech Mechanism Screening Test for Children (SMST-C) can discriminate between children with speech sound disorders (SSD) and children with typical development (TD). Methods: Twenty-four children with SSD and 20 with TD from 3 to 6 years of age participated. Each group included 13 boys and 7 girls (mean age, 4.75 years). They were assessed using the SMST-C, which consists of a total score derived from structure/function, phonation/voice/articulation, and diadochokinesis (DDK) scores and DDK rates. DDK rates are alternative motion rates (AMRs) of /p h ʌ/, /t h ʌ/, /k h ʌ/, /lʌ/, and /kʌŋ/ and sequential motion rates (SMR) of /p h ʌt h ʌk h ʌ/. These variables were compared between the two groups. The cutoff value of each variable to discriminate between two groups was determined by receiver operating characteristic (ROC) analyses. Results: The SMST-C scores of the SSD group were significantly lower in total, articulation, and DDK when compared with children with the TD. DDK rates of /p h ʌ/, /k h ʌ/, /kʌŋ/, and /p h ʌt h ʌk h ʌ/ were significantly slower in the SSD group. However, no differences were found in structure/function and voice scores. ROC analyses showed DDK score (area under curve [AUC]= .879), phonation/voice/articulation score (AUC= .864), and total score (AUC = .846) had higher discrimination accuracy for classifying SSD with high sensitivity and specificity. Conclusion: This study provided quantified data regarding the validity of the SMST-C in children with SSD. The SMST-C is helpful to screen the speech mechanisms of children with SSD. Therefore, the SMST-C can be used in clinics to screen children with pathological speech mechanisms.