the children is summarized in Table 1.
Blood bilirubin levels at birth for each child
were determined according to the medical
record. In the inclusion criteria, a history of
phototherapy or exchange transfusion,
negative family history of hearing loss, no
history of respiratory distress, no history of
head trauma, epilepsy and ototoxic
medications and negative history of other
diseases or syndromes affecting the auditory
system were met. The selected children were
originated from the children's audiology
rehabilitation center as well as the Children's
Hospital in Tehran. This study was approved
by the ethical committee of Tehran
University of Medical Sciences.
At the initiation, a case history was
obtained for each child. Subsequently,
following ensuring of normal middle ear
function using a calibrated Interacoustics
AZ26 tympanometer, behavioral air
conduction hearing thresholds at frequencies
of 500, 1000, 2000 and 4000 Hz were
recorded using a calibrated Interacoustics
AC40 audiometer. Threshold acquisition
procedure was different according to the age
of the child. In children aged less than 5
years, the conditioned play audiometry
(CPA) was used and in children of 5 to 11
years, conventional adult’s audiometry was