Study of the normal and insufficient velopharyngeal valve by the "Forced Sucking Test"

A thorough assessment of the velopharyngeal (VP) closure dynamics is important for therapeutic planning in patients with nasal speech. An additional diagnostic tool to the standard endoscopic examination of the VP valve, the "Forced Sucking Test" (FST) is presented. In this study, 110 patients with a normal VP valve and 40 patients with VP insufficiency were subjected to a comprehensive endoscopic examination. When existent, Passavant's ridge clearly appears in 80% of these cases during the FST. This is advantageous, since the ridge is often unseen during routine nasendoscopy. Passavant's ridge appears indistinguishable in shape and level during speech and FST. During FST, the bulge of the uvular ridge is clearly seen on the flat or concave nasal surface of the velum. In cases of diastasis of the velar musculature, the midline V-defect of the velum is clearly seen. The test is particularly important in children with concomitant adenoid hypertrophy. The findings are discussed in terms of their implications for the anatomy and physiology of the VP valve. FST is recommended as an additional and complementary part of the endoscopic examination of the VP valve.