Speech Intelligibility and Perceived Listening Effort in Children With Cleft Palate: A Comparison Between Non-Syndromic and Selected Syndromic Conditions.

BACKGROUND: Children with syndromic cleft lip and/or palate (SCL/P) often experience more severe speech impairments than those with non-syndromic clefts, yet most research has focused on velopharyngeal function rather than overall communication burden. Speech intelligibility alone may not fully capture listener difficulty, making perceived listening effort (PLE) a potentially valuable complementary metric. This study compares intelligibility and PLE between children with SCL/P and NSCL/P to better understand how syndromic features impact communicative effectiveness.

AIMS: Examine the differences in speech intelligibility and PLE between children with non-syndromic cleft lip and/or palate (NSCL/P) and those with SCL/P.

METHODS AND PROCEDURES: Speech recordings of 21 speakers with cleft palate, with/without cleft lip (10 in the NSCLP group and 11 in the SCLP), aged 4-12 years, were used. Fifty-two naïve speakers of American English served as listeners to judge intelligibility and PLE ratings. Each speaker produced 10 sentences from the HINT list, and the listeners used a VAS scale to rate intelligibility and PLE. Mean intelligibility scores and PLE scores across two groups of speakers with SCLP and NSCLP were compared.

OUTCOMES AND RESULTS: The estimated correlation between the two responses, PLE and intelligibility, was -0.88 across observations. The comparison between the SCLP and NSCLP groups showed that the former was significantly higher in PLE for 21.23 units (Z = -11.07, p < 0.001) and lower in VAS for 23.95 units (Z = 12.78, p < 0.001).

CONCLUSIONS AND IMPLICATIONS: This study revealed significant differences in speech intelligibility and PLE between children with syndromic and NSCL/P. Children in the SCLP group were perceived as significantly less intelligible and required substantially greater listening effort compared to their peers in the NSCLP group. These findings underscore the need for targeted clinical approaches in considering speech intelligibility as a diagnostic marker for identifying undiagnosed syndromic cases of cleft palate, like individuals with submucous cleft palate.

WHAT THIS PAPER ADDS: What is already known about the subject Orofacial clefts often lead to speech and communication difficulties, with syndromic cases at higher risk for poor outcomes. Prior research has mainly focused on velopharyngeal function (e.g., hypernasality) rather than intelligibility. Listening effort is recognized in other disorders but has not been studied in cleft populations. What this paper adds to existing knowledge This study is the first to compare intelligibility and perceived listening effort (PLE) in syndromic versus non-syndromic cleft palate using naïve listener ratings. It shows a strong negative correlation between intelligibility and PLE and reveals that syndromic cases have significantly poorer intelligibility and higher listening effort. Age improves outcomes in both groups, but less so in syndromic cases. What are the potential or actual clinical implications of this work? Including PLE in assessments offers a more complete picture of communicative challenges than intelligibility alone. Findings support early, intensive intervention for syndromic cases and provide guidance for counselling families about prognosis. PLE may also serve as a new outcome metric for therapy and surgical decision-making.