Normative Nasalance Scores for Native French-speaking Children

The velopharyngeal mechanism (in particular the movements of the soft palate) is frequently affected by craniofacial anomalies such as cleft lip and palate and it needs to be assessed. Indeed, the velopharyngeal sphincter has to be efficient in order to properly isolate the oral cavity from the nasal cavity. Thus, the nasal cavity is protected during swallowing (preventing food or liquids from passing through the nose). It also ensures a correct phonation and articulation of oral phonemes.

A perceptual evaluation of the velopharyngeal function is always conducted by a clinician. But it is a subjective assessment which may need to be supplemented by an objective instrumental assessment. Nasofibroscopy is frequently used in clinical care to evaluate the velopharyngeal function because it allows for direct visualization of the velopharyngeal port. However, it is an invasive procedure that could not be tolerated well by children.

Nasometry on the other hand is a non-invasive acoustic measurement technique. It is based on the relation between nasal and oral acoustic energy and determines a nasalance score. Calculated in real time during speech production, the nasalance is a measure expressed as a percentage : (nasal acoustic energy) / (sum of oral and nasal acoustic energy). The device computing the nasalance score is called a Nasometer.

Thus, in addition to the speech therapist's perceptual evaluation, nasometry can be used to objectively assess and quantify a velopharyngeal dysfunction whether it can be heard or not. However in order to determine if a patient's nasalance score is pathological or not, it must be compared to standardized norms. Yet presently, there are no normative nasalance data for French-speaking children. The main objective of this study is to establish normative nasalance scores with the KayPENTAX Nasometer (Nasometer II 6450 model) for native French-speaking children between 8 and 10 years old.