The influence of cephalometric parameters on resonance of speech in cleft lip and palate patients. An interdisciplinary study.

There are only few studies concerning the correlation between craniofacial morphology and resonance of speech in cleft palate patients. Moreover, these investigations show a considerable inhomogeneity in material and method, their basic approach was predominantly retrospective, and the statistical methods were restricted to univariate procedures. Thus, the aim of the present study was twofold: firstly to clarify the extent to which correlations exist between craniofacial morphology and resonance of speech in cleft palate patients, subject to a sufficiently large number of patients being available to ensure differentiation with regard to age and cleft type, and secondly, within a prospective longitudinal study in juvenile cleft palate patients, to investigate whether pubertal craniofacial growth changes result in changes of resonance. The collective comprised 137 cleft palate patients. The following investigations were performed: lateral cephalometry, nasometry, and standardized speech recording. Additionally, these investigations were repeated in 51 juvenile patients after a minimum time interval of 2 years. In order to analyze the complex relations between craniofacial morphology and degree of hypernasality, multivariate statistical procedures were applied. The results of the present study indicate complex correlations between cephalometric parameters and resonance of speech, requiring age-specific differentiation. In this regard, the ratios between the length of the soft palate and the sagittal depth of the nasopharyngeal airway were of prime importance. Beyond this, significant correlations were found between craniofacial growth changes and changes of resonance during puberty which might be influenced both by dentofacial orthopedics and by maxillofacial surgery.