Daily impedance audiometric screening of children in a day-care institution.

Fifty-seven children in a fairly new day-care institution were examined daily by impedance audiometry for 4 weeks. A Madsen Electronics ZS 330 tympanoscope was used. The tympanometric curves were divided into types A, C1, C2, and B. Completely flat curves and cases in which the compliance was less than 0.25 ml, combined with an absent ipsilateral stapedial reflex, were also interpreted as type B. The object was to ascertain how quickly the types changed and how stable the B curves were. A total of 43 episodes of B curves occurred. Of them, 16 lasted for only 1 day and thereafter 9 became quite flat. Only a few lasted for 8-23 days and 8 continued for 26 days or longer.