Influence of gender and age on the Nasality Severity Index 2.0 in Dutch-speaking Flemish children and adults

This study aimed to explore the influence of gender and age on the Nasality Severity Index 2.0 (NSI 2.0), an instrumental multiparametric index to determine hypernasality. Additionally, reference values will be established for this new index. Influence of gender and age on the NSI 2.0 was explored in 80 Flemish-speaking children (4-12 years; 40 boys, 40 girls) and 60 Flemish-speaking adults (18-60 years, 30 men, 30 women) without resonance disorders by determining its incorporated acoustic parameters: nasalance of the vowel/u/and an oral text, determined by a Nasometer, and voice low tone to high tone ratio (VLHR) of the vowel/i/. The equation yields NSI 2.0=13.20-(0.0824 x nasalance/u/(%))-(0.26 x nasalance oral text (%))-(0.242 x VLHR/i/4.47*F0Hz (dB)). No effect of gender or age was found on the NSI 2.0 in children. However, significant differences were found for the NSI 2.0, nasalance of/u/and an oral text between adult men and women. Additionally, an interaction effect between gender and age was found for these parameters. Consequently, separate reference values for the NSI 2.0 in children, adult men and adult women were established. Based on these reference scores, deviation of the NSI 2.0 score in patients with resonance disorders can be defined, which can determine the need for (additional) intervention. Further research can explore the possible influence of language on the index