Wideband reflectance in Down syndrome

Author(s)

Jordana Costa Soares

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2013-08-13

Examining board members

Renata Mota Mamede de Carvallo; Marisa Frasson de Azevedo; Christiane Marques do Couto; Suelly Cecilia Olivan Limongi; Alessandra Giannella Samelli

• Advisor: Renata Mota Mamede de Carvallo

Abstract

INTRODUCTION: Children with Down syndrome have high incidence of disorders of the middle ear, as well as congenital abnormalities in the external, middle and inner ear. Such conditions may change the sound transmission through the ossicular chain to the cochlea and central auditory pathways, impairing the comprehension of spoken language. An recent assessment tool of the middle ear, the wideband reflectance energy, can measure the sound energy reflected or absorbed in the ear canal over a wide frequency range, faster than tympanometry. OBJECTIVE: To compare the wideband reflectance measurements between children with Down syndrome and a control group matched by age, according to the tympanometric findings. METHODS: This study evaluated four groups with Down syndrome, between 28 and 195 months: normal tympanogram (19 ears), flat tympanogram (13 ears), moderate negative pressure tympanogram (6 ears), severe negative pressure tympanogram (4 ears). All findings were compared to a control group (21 ears). The subjects underwent to tympanometry and acoustic reflex ipsilateral with a 226 Hz probe tone frequency, pure tone audiometry, speech recognition thresholds, transient otoacoustic emissions and wideband reflectance over the 200-6000 Hz range with chirp and tone stimuli. RESULTS: Results revealed that the five groups had different reflectance curves, without significant difference in some comparisons. There was a negative correlation between the volume of the external auditory meatus and the wideband reflectance with the chirp stimulus between 250 and 1600 Hz and with the tone stimulus between 258 and 1500 Hz, and between the static acoustic admittance at the tympanic membrane level and the wideband reflectance with chirp stimulus at 500 and 1000 Hz. There was no correlation between the frequency of the chirp stimulus with reflectance at 1000 and 2000 Hz and the results of the otoacoustic emissions at 1000, 2000 Hz and general response. The discriminant analysis technique used to classify participants\' data based on the values of reflectance with chirp stimulus in 1000 and 1600 Hz, achieved a correct classification rate of 60% for participants with Down syndrome. CONCLUSIONS: The findings showed the responses of the middle ear, for different tympanograms in Down syndrome through the wideband reflectance. In this study, children with Down syndrome and normal tympanogram showed wideband reflectance curve similar to the control group. A discriminant analysis with the tympanometric results and reflectance with chirp stimulus at 1600 and 1000 Hz correctly classified 60% of the data for children with Down syndrome (AU)

• FAPESP's process: 10/04000-7 - Middle ear reflectance in Down syndrome
• Grantee: Jordana Costa Soares
• Support Opportunities: Scholarships in Brazil - Doctorate