Audiological findings in Down's children.

The authors have investigated the auditory function in 35 Down's subjects, aged between 1 month and 16 years. Clinical examination revealed the occurrence of impaired nasal breathing in 18 subjects (51.4%), while otoscopy results were bilaterally normal in 12 cases (34.3%). Behavioural pure-tone audiometry yielded reliable results in 10 children (28.6%), impedance tests in 28 (80.0%), and brainstem audiometry in 29 (82.9%). A clinical and audiological follow-up has been performed in 11 cases (31.4%). Pure-tone audiometry, which may be employed in all cases only beyond 8 years of age, revealed a conductive hearing loss in 7 cases (20.0%). Impedance tests, whose usefulness is limited by the high occurrence of external ear canal stenosis, showed bilateral type A tympanograms only in 8 cases (28.6%). Stapedial reflex data were often missing, even in presence of a type A tympanogram, due to the weakness of tubaric muscles and to the presence of ossicles abnormalities. ABR has been performed in 29 cases (82.9%) and resulted to be as effective as in the normal population. It revealed a normal configuration concerning threshold and morphology in 16 cases (55.1%). The authors conclude that middle ear pathology in the Down's population is more frequent than expected on clinical basis and that objective tests are mandatory in order to obtain a reliable evaluation. While impedance tests are very sensible in detecting mild middle ear pathologies, but are not effective in threshold definition, brainstem audiometry is the choice tool in the uncooperative child, even if it cannot allow a differential diagnosis between normality and mild low-frequency conductive hearing losses.