Nasometry normative data for young Dutch children.

Objective: Hypernasality is a common problem in cleft care. It should be treated before the age of six, because of the impact it can have on speech sound development in young children. An objective method of nasalance evaluation is nasometry. To decide whether a nasometer test result is normal or abnormal, normative data and cut off points are needed. Normative data for children are not available for every language and age. For Dutch children two sets of Dutch speech stimuli, the Van Zundert sentences or the Moolenaar-Bijl, sentences, are often used in the diagnostic process for hypernasality. Primary goal of this study is to determine normative data and cut off points for two sets of Dutch speech stimuli for Dutch children from four to six years of age. Secondary is to compare those two sets of oral sentences.

Method: Children without clefts were recruited from schools. According to their teachers their speech was normal. They were tested with the nasometer with the two sets of speech stimuli. The set from Van Zundert has oral and oronasal sentences, the Moolenaar-Bijl set only has oral sentences.

Results: 118 children were recruited. Out of these children, 55 produced recording samples which were suitable for analysis. There were no significant differences between age groups or gender. The two different sets of speech stimuli used were significantly different, but the confidence intervals overlapped.

Conclusions: Normal nasalance scores of the tested sentences are between 3 and 19% for oral sentences and between 17 and 37% for oronasal sentences. The Moolenaar-Bijl speech sentences are preferred to evaluate hypernasality in young Dutch children, because of the shortness and intelligibility. Normative nasalance scores are applicable to the whole group of children from four to six years of age.