Platybasia in 22q11.2 Deletion Syndrome Is Not Correlated with Speech Resonance

Abstract

BackgroundAn abnormally obtuse cranial base angle, also known as platybasia, is a common finding in patients with 22q11.2 deletion syndrome (22q11DS). Platybasia increases the depth of the velopharynx and is therefore postulated to contribute to velopharyngeal dysfunction. Our objective was to determine the clinical significance of platybasia in 22q11DS by exploring the relationship between cranial base angles and speech resonance.MethodsIn this retrospective chart review at a tertiary hospital, 24 children (age, 4.0-13.1 years) with 22q11.2DS underwent speech assessments and lateral cephalograms, which allowed for the measurement of the cranial base angles.ResultsOne patient (4%) had hyponasal resonance, 8 (33%) had normal resonance, 10 (42%) had hypernasal resonance on vowels only, and 5 (21%) had hypernasal resonance on both vowels and consonants. The mean cranial base angle was 136.5° (standard deviation, 5.3°; range, 122.3-144.8°). The Kruskal-Wallis test showed no significant relationship between the resonance ratings and cranial base angles (P=0.242). Cranial base angles and speech ratings were not correlated (Spearman correlation=0.321, P=0.126). The group with hypernasal resonance had a significantly more obtuse mean cranial base angle (138° vs. 134°, P=0.049) but did not have a greater prevalence of platybasia (73% vs. 56%, P=0.412).ConclusionsIn this retrospective chart review of patients with 22q11DS, cranial base angles were not correlated with speech resonance. The clinical significance of platybasia remains unknown.

Impact of Cranial Base Abnormalities on Cerebellar Volume and the Velopharynx in 22q11.2 Deletion Syndrome

“…Differences in the cranial base angles are visualized in Figure 2. Using an anterior cranial base angle greater than 136° to define platybasia (similar to methods used by Spruijt et al, 2014), we found that 5 of the 13 participants (38%) had platybasia. This is below the reported incidence of platybasia in individuals with 22q11DS, possibly due to the exclusion of individuals with cleft palate in the group with 22q11DS in the present study.…”

“…This is below the reported incidence of platybasia in individuals with 22q11DS, possibly due to the exclusion of individuals with cleft palate in the group with 22q11DS in the present study. Nachmani et al (2013) reported 50% of their participants presented with platybasia while Spruijt et al (2014) reported platybasia in 67% of their participants. Platybasia, although a common characteristic in 22q11DS, is not always present.…”