Assessment of Intelligibility in Children with Velopharyngeal Insufficiency: The Relationship between Intelligibility in Context Scale and Experimental Measures

Abstract

Purpose: The purpose of this study was to investigate the clinical application of the Intelligibility in Context Scale (ICS) instrument in children with velopharyngeal insufficiency (VPI). This study investigated the relationship between clinical speech outcomes and parental reports of speech intelligibility across various communicative partners. Methods: The ICS was completed by the parents of 20 English-speaking children aged 4–12 years diagnosed with VPI. The parents were asked to rate their children’s speech intelligibility across communication partners using a 5-point scale. Clinical metrics obtained using standard clinical transcription on the Picture-Cued SNAP-R Test were: (1) percentage of consonants correct (PCC), (2) percentage of vowels correct (PVC), and (3) percentage of phonemes correct (PPC). Nasalance from nasometer data was included as an indirect measure of nasality. Intelligibility scores obtained from naive listener’s transcriptions and speech-language pathologists’ (SLP) ratings were compared with the ICS results. Result: Greater PCC, PPC, PVC, and transcription-based intelligibility values were significantly associated with higher ICS values, respectively (r[20] = 0.84, 0.82, 0.51, and 0.70, respectively; p < 0.05 in all cases). There was a negative and significant correlation between ICS mean scores and SLP ratings of intelligibility (r = –0.74; p < 0.001). There was no significant correlation between ICS values and nasalance scores (r[20] = –0.28; p = 0.22). Conclusion: The high correlations obtained between the ICS with PCC and PPC measures indicate that articulation accuracy has had a great impact on parents’ decision-making regarding intelligibility in this population. Significant agreement among ICS scores with naive listener transcriptions and clinical ratings supports use of the ICS in practice.