Comparative analysis of velopharyngeal activity assessed by acoustic rhinometry and rhinomanometry

ABSTRACT

Purpose:

To analyze the velopharyngeal (VP) activity of subjects with velopharyngeal dysfunction (VPD) by acoustic rhinometry, as compared to rhinomanometry.

Methods:

This was a prospective clinical study conducted in 41 adults, both genders, with repaired cleft palate, with or without a previously repaired cleft lip, and residual VPD on clinical assessment, without compensatory articulations for [p], [t], and [k]. The outcome measures were as follows: (1) on acoustic rhinometry, nasopharyngeal volumetric change (ΔV) during [p], [t], and [k], relatively to rest condition (decreases by <3 cm³ considered as absence of VP activity); (2) on modified anterior rhinomanometry, VP orifice area (areas ≥0.05 cm² considered as inadequate closure). The plosive [p] was used when comparing the techniques (n=24).

Results:

(1) A mean ΔV decrease of 18% was observed during [k], which was significantly lower (p<0.05) than the decrease reported for individuals without VPD (30%). ΔV values suggesting VPD were observed in 59% subjects. Similar results were obtained for [p] and [t], which shall be used as stimulus, given that they do not involve the use of the tongue to lift the velum during VP closure, differently from the velar plosive [k]. (2) Inadequate closure was seen in 85% subjects. No correlation was observed between ∆V and VP orifice area. Agreement between techniques was observed in 51% cases.

Conclusion:

Acoustic rhinometry had low accuracy as a diagnostic method of VPD when compared to the gold standard method. Nevertheless, the technique shows potential as a method for monitoring the outcomes of clinical and surgical treatment of VPD aimed at increasing velar and pharyngeal activity.

Keywords:
Speech; Cleft Palate; Velopharyngeal Insufficiency; Acoustic Rhinometry; Rhinomanometry