What is the most common cause of velopharyngeal insufficiency?

Velopharyngeal insufficiency (VPI) occurs when the velopharyngeal mechanism fails to close completely during speech, which can result in nasal speech and other complications. The most common cause of VPI is a cleft palate, which is a congenital disorder that affects the structure of the oral and facial area.

In individuals with a cleft palate, there is a structural gap that can impair the ability of the palate to elevate and close off the nasal cavity from the oral cavity during speech. This dysfunction in the closure leads to the characteristic speech impediments associated with VPI, making it the predominant cause in affected individuals.

Other conditions, such as submucous cleft palate and neuromuscular disorders, can also lead to VPI, but they are not as prevalent as cleft palate. Allergic rhinitis may cause temporary nasal obstruction but does not lead to anatomical defects that would structurally impair the velopharyngeal closure mechanism like a cleft palate does.