A perceptual outcome measure of velopharyngeal function based on the Cleft Audit Protocol for Speech-Augmented (CAPS-A VPC-Sum): Validation through a speech osteotomy study.

Abstract

The status of the velopharyngeal mechanism can be inferred from perceptual ratings of specified speech parameters. Several studies have proposed the measure of an overall velopharyngeal composite score based on these perceptual ratings and have reported good validity. The Cleft Audit Protocol for Speech-Augmented (CAPS-A) is a validated and reliable perceptual framework for the assessment of cleft speech and velopharyngeal function used by all Regional Cleft Services in the UK and Ireland. An overall velopharyngeal composite summary score based on the CAPS-A would serve as an important surgical outcome measure of speech. To develop and validate a velopharyngeal composite summary score based on perceptual ratings made on the CAPS-A (CAPS-A VPC-Sum) using data from a maxillary osteotomy (MO) study. There were two surgical groups: a cleft lip and palate (CLP) (N = 20) group and a non-CLP group (N = 10), and a normal control group (N = 20). Participants in groups 1 and 2 were seen for perceptual and instrumental assessments of speech and velopharyngeal function preoperatively (T1), 3 months (T2) and 12 months (T3) postoperatively. Perceptual speech data were collected and rated by independent listeners using CAPS-A. Moderate to strong interrater reliability for perceptual data (rs = 0.503-1.000, all p < 0.01) and strong to very strong reliability for videofluoroscopic measurements (rs = 0.746-0.947) were found. Construct validity of the CAPS-A VPC-Sum was shown by an increase in postoperative scores for the CLP group only ϰ2 (2) = 9.769, p = 0.008 and significant differences between the CLP and the other two groups at T2 and T3 using independent t-tests. Convergent and divergent validity was indicated by a positive moderate correlation with related parameters (e.g., hypernasality rs = 0.869, p < 0.01) and a weak correlation with unrelated parameters (e.g., amount of forward advancement rs = 0.160, p = 0.526). Criterion validity was found by a moderate correlation between closure ratio rs = -0.541, p = 0.020 and CAPS-A VPC-Sum. A velopharyngeal composite score based on perceptually rated parameters serves as an important surgical speech outcome measure. The CAPS-A VPC-Sum is a useful, reliable and valid outcome measure of velopharyngeal function. There are added positive implications for other clinicians using geographically and language-specific adapted versions of the CAPS-A internationally. What is already known on this subject Velopharyngeal composite scores based on perceptually rated speech parameters have been shown to have both clinical and research utility, serving as a useful surgical outcome measure. However, such a composite score must be specifically validated on the perceptual speech framework upon which it is based, as there are differences in measurement methods and terminology across cleft speech perceptual frameworks internationally. What this paper adds to existing knowledge The CAPS-A is a nationally used tool in the UK and Ireland for audit and research purposes with validated and adapted international versions. This paper reports on the validation of the derived velopharyngeal composite score measure based on the CAPS-A and an English-speaking sample, providing evidence of its validity through a speech osteotomy study. What are the potential or actual clinical implications of this work? This work provides CLP teams who use CAPS-A with a validated surgical speech outcome measure of velopharyngeal function. It has positive implications also for adapted versions of the CAPS-A internationally.