Hypernasality and the nasopharyngeal space. A cephalometric study.

In the present study cephalometric measurements reflecting the nasopharyngeal space were traced on lateral cephalometric X-rays in 59 young adults with an isolated cleft palate. The distribution of the measurements AD1-PNS, AD2-PNS, AD1-BA, AD2-SO and PNS-BA and the magnitude of the hypernasality were analyzed with the ANOVA procedure and Duncan's multiple range test. The degree of hypernasality was assessed in terms of the hypernasality index. The results showed that AD1-PNS and AD2-PNS measurements were significantly related to the hypernasality index at the risk level of 0.03 and 0.05 per cent, respectively. The patients with the shortest sagittal depth of the nasopharynx had normal resonance in their speech, while the patients with the longest measurements demonstrated hypernasality. The thickness of the posterior pharyngeal wall in terms of AD2-SO was not clearly significant for speech, although the patients with the longest measurements tended to speak without hypernasal resonance. The other cephalometric measurements, i.e. AD1-BA and PNS-BA were not significantly related to the occurrence of hypernasality. It was concluded that the cephalometric measurements reflecting nasopharyngeal space are correlated with the occurrence of hypernasality, but the relationship is by no means simple and linear, and therefore it requires further study.