Acoustic signal of silent tracheal aspiration in children with oropharyngeal dysphagia.

Objetive: The aim of this study was to characterize the acoustic signal of silent tracheal aspiration in children with oropharyngeal dysphagia (OPD). METHOD: Thirty-two children with OPD were examined with combined digital cervical auscultation (DCA) and videofluoroscopic swallow study (VFSS). Power spectral density (PSD, in 1/√Hz) of the acoustic signal from a sequential series of five liquid swallows was used for comparisons between children who silently aspirated and children who did not aspirate on VFSS. Fourteen children were excluded due to either DCA/VFSS artifact or non-silent aspiration (cough, choking). RESULTS: The remaining 18 participants (median age 6 years, range 2-12.8) were classified based on VFSS as aspirators (n = 8) and non-aspirators (n = 10). The PSD curve of aspirators presented an ascending pattern (1st vs. 5th deglutition: 695.2 vs. 4421.9 1/√Hz), while the curve of non-aspirators was flat (1st vs. 5th deglutition: 509 vs. 463.4 1/√Hz), with marked differences being observed from the 3rd measure onwards (p < .001). In this study, DCA was able to identify silent tracheal aspiration in children with OPD. CONCLUSION: This non-invasive technique identified aspiration by an increase in the PSD curve in aspiration sounds.

Assessment of swallowing sounds by digital cervical auscultation in children.

OBJECTIVES: There is a lack of studies regarding swallowing sounds in children 3 to 11 years of age. This study aimed to assess swallowing sounds by digital cervical auscultation in children of this age group without symptoms of oropharyngeal dysphagia. METHODS: Digital cervical auscultation was performed in 118 subjects by use of a piezoelectric microphone. The children swallowed 5 mL of liquid and yogurt. The components of perceptual acoustic analysis were discrete initial signal (DIS), main signal of swallowing sound (MS), discrete final signal (DFS), and expiratory return (ER). Duration in seconds was the objective parameter of the swallowing sound signal analyzed. RESULTS: Fifty-six boys and 62 girls were evaluated at a mean (+/- SD) age of 6.9 +/- 2.03 years. A complete DIS-MS-DFS-ER swallowing sequence was found in 60% of the children. There was no significant difference in swallowing sound duration between both food consistencies (p = .189) or between genders either for liquid (p = .327) or yogurt (p = .792). There was no correlation between age and duration of the swallowing sound for liquid or yogurt. CONCLUSIONS: We concluded that digital cervical auscultation was able to provide objective information about the swallowing process that could contribute to methodological standardization in children.