Nasalance scores of Thai cleft palate children using the Thai Simplified Nasometric Assessment Procedures Test (Thai SNAP Test)
Authors:   Department of Communication Sciences and Disorders, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, Lertsirivorakul Rujira , Makarabhirom Kalyanee ,   Department of Communication Sciences and Disorders, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, Numthavaj Pawin ,   Department of Clinical Epidemiology and Biostatistics Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Published: December 2022

Background: Nasometry in children with cleft lip and/ or palate (CLP) aged 4-6 years is necessary for diagnosis and planning treatments to promote decreasing velopharyngeal insufficiency (VPI) or resonance disorders that affect good speech intelligibility, prevent compensatory errors and other speech and language problems. Most Thai nasometric speech stimuli are passages suitable for literate patients. Using nasometric passages in young children who cannot read takes a long time to complete and gives unreliable nasalance scores. Due to the limitations, The Thai Simplified Nasometric Assessment Procedures Test (the Thai SNAP Test) was developed and assessed for validity and reliability, revealing that the Thai SNAP Test is proper for evaluating the speech resonance of illiterate patients. However, there is no study on nasometry in children with repaired cleft lip and/ or palate (RCLP) using the Thai SNAP Test. Objectives: To study nasalance scores between the control (non-cleft) group and the RCLP group assessed by the Thai SNAP Test and to describe the influential factors that affected nasalance scores. Materials and methods: The subjects were Thai children aged 4-7. The two groups of children were the RCLP and the control groups, and 36 children in each group. Nasalance scores were measured by a Nasometer II (model 6450). The child was asked to repeat 25 speech stimuli from the Thai SNAP Test, and then the scores were computed using a t-test or Mann-Whitney U test, depend on data distribution. The mean difference in nasalance scores between the two groups and the 95% Confident Interval (95% CI) were analyzed by the two-sample t-test with equal variances and the bootstrap confidence interval method, respectively. Results: The nasalance scores of the RCLP group were significantly higher than the control group (p<0.05) when using high-pressure oral speech stimuli. However, using nasal speech stimuli, the RCLP group’s nasalance scores were significantly lower than the control group (p<0.05), except for nasal syllable repetition (/na/ and /ni/), which did not find a significant difference (p≥0.05). This study emphasized that influential factors for the difference in the nasalance scores between the two groups were abnormal structures and functions articulators, especially the velopharyngeal port that was affected by the CLP, which caused resonance disorders, misarticulations, voice disorders, obstruction in the vocal tract, and hearing impairment. However, the phonological features used in the speech stimulus caused the difference in the mean nasalance scores of the same group. Conclusion: The trends in nasalance scores suggested that the Thai SNAP Test could identify speech resonance disorders in Thai children aged 4-7. The speech and language pathologist (SLP) or evaluator should consider factors influencing the nasalance scores. For accurately diagnosing or evaluating the progression of treatments, nasalance scores from Nasometer should be applied together with other information from various methods or instruments.