BACKGROUND: respiratory dynamics measurements are frequently used in the speech-language pathology practice, but few are the scientific data for children. AIM: to study the respiratory dynamics in children with nasal breathing. METHOD: the study was performed with a stratified random sample of 106 nasal breathing children, male and female, from schools of the city of Marília-SP, with ages between four and ten years. The following measurements were obtained: vital capacity (VC) in both standing and sitting positions, with and without nasal occlusion; maximum phonation time (MPT) of sustained vowels and consonants and also of speech when counting numbers. RESULTS: the mean values for VC in the standing position with and without nasal occlusion were of 1515.56ml and 1538.67ml respectively and for the sitting position of 1524ml and 1539.15ml respectively. MPT of vowels in seconds were: /a/ = 8.32, /i/ = 8.61 and /u/ = 8.42; of consonants: /s/ = 6.64 and /z/ = 7.65; and when counting numbers: 7.76. It was observed that the mean values of these measurements progressively increased according to age. There was a statistically significant difference (p<0.05) not only for the MPT of vowels but also for the MPT of consonants in older children, i.e. between 4 and 10 year olds, 4 and 9 year olds and 4 and 8 year olds. There was no significant statistical difference for the VC values in consecutive age groups. There was a strong association between VC and the child's physical development. CONCLUSION: this study presented respiratory dynamics measurements in children that can be used for the speech-language diagnosis and therapy. Other studies should be developed in order to bring additional information on the subject.
Vital Capacity; Phonation; Respiration
