Speech Acoustic Analysis in Adult Patients With Cleft Palate After Cleft Palate Repair and Speech Therapy

This study aims to evaluate the enhancement of speech functionality in adult patients with cleft palate through acoustic analysis, assessing pronunciation level improvements before and after palatopharyngoplasty and speech treatment. The findings aim to provide an objective assessment of the treatment efficacy for older patients with cleft palate.

The study involved acoustic comparisons encompassing vowel formants, voice onset time (VOT) of consonant syllables, syllable duration, and voice characteristic analysis. Speech functionality in each adult cleft palate patient was evaluated thrice: before palatopharyngoplasty, after palatopharyngoplasty, and following speech therapy, using a self-comparative analysis method to discern phonological differences.

No significant alteration in vowel formants was observed in adult cleft palate patients pre-palatopharyngoplasty and post-palatopharyngoplasty. Post-speech treatment, the F2 and F3 values for the anterior high vowel /i/ significantly improved, aligning closely with those of the normal adult group. Similarly, while consonant parameters (VOT value and syllable duration) remained unchanged post-surgery, both metrics showed significant improvement after speech therapy. Except for the prolonged syllable duration of /s/ compared with normal adults, other indicators were not significantly different. Voice parameter analysis revealed no significant change post-operation; however, both HNR and CPPS values post-speech treatment notably increased, matching those of normal adults.

Surgical intervention addresses the physical closure of the cleft palate and reconstructs the resonator's structure. Conversely, consonant improvement predominantly occurs through targeted speech therapy aimed at rectifying pronunciation habits and tutoring patients on the effective utilization of repaired articulatory organs. The combined intervention of cleft palate surgery and speech therapy plays a complementary role in speech restoration for cleft palate patients.