Do Adult Naïve Listeners Perceive Differences in Speech Before and After Therapy for Cleft Palate Speech Disorders? A Reliability Study of Perceptual Speech Ratings

Abstract

Purpose: This study compared the interrater reliability of adult naïve listeners' perceptual assessments of different speech variables in children with a cleft palate with or without a cleft lip (CP ± L). In addition, the study investigated whether the listeners were able to perceive differences in these speech variables before and after speech therapy for cleft palate speech disorders. Method: Thirty-four speech samples of 14 children with a CP ± L (14 samples collected immediately before 10 hr of speech intervention, 14 samples collected immediately after speech intervention, and six randomly selected samples that were duplicated to assess intrarater reliability) were perceptually assessed by 26 adult naïve listeners. The listening panel consisted of nine men and 17 women (age range: 18–51 years). The speech variables included speech understandability, speech acceptability, hypernasality, hyponasality, nasal airflow, and articulation, which were assessed on a visual analog scale. Furthermore, the need for speech therapy was assessed. Results: Good to very good interrater reliability was observed for the naïve listeners' ratings of all speech variables. A significant time effect was found for the pre- and postevolution of the speech variables “speech understandability,” “speech acceptability,” “nasal airflow,” and “articulation.” This time effect indicates an improvement of these variables postintervention. According to the naïve listeners, children were less in need of additional speech therapy after the 10-hr intervention period compared to assessments before this intervention period. Conclusions: Adult naïve listeners perceptually identified an improvement in different speech variables after 10 hr of cleft palate speech therapy. These findings confirm previous assessments of expert speech-language pathologists and suggest that speech improvements after cleft palate speech therapy can also be perceived by communication partners outside the therapy room. Perceptual ratings of naïve listeners can, thus, be used to add life-situation significance to the assessments of experts. Future research could include both expert raters and caregivers or relatives of children with a CP ± L in listening panels, as previous knowledge on craniofacial anomalies may lead to different results.