OBJECTIVETo analyze the confusing factors and clinical and audiological characteristics in infants failed in hearing screening.

METHODSBetween August 2004 and January 2006, 166 infants (315 ears) with detailed birth record and hearing screening record were reviewed in the study. The age of this series ranged from 2 to 6 months. They were born in maternal and child health hospitals (MCH) in Guangzhou city and surrounding areas, and had hearing screened by otoacoustic emissions (OAE). However, they failed in the first and second hearing screening. The birth history, high-risk factors of hearing-impaired during newborn period and pregnancy history of subjects were fully detailed. Subjects were classified according to the age: 2 to 3 months old infants were considered as group 1, while 4 to 6 months old infants were considered as group 2. Auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAE) and acoustic immittance measurement were examined. Subjects with abnormal hearing-evaluation were retested during the following one to three months (before 6-month-old). The ABR results, DPOAE results and tympanic cavity pressure and static compliance value were compared between the two tests and then diagnosis was made.

RESULTS(1) Among the 166 cases, 34 (20.5%) cases were once suffered from hypercholesterolemia of newborn, and 10 cases (6.0%) had asphyxia and hypoxia history. (2) The proportion of presenting type B tympanogram in group 2 was higher than that of group 1 (chi2 = 26.22, P < 0.01). (3) The proportion of normal ABR in group 2 (37.2%) was significantly higher than that of in group 1 (23.4%, chi2 = 0.527, P < 0.05). Fifty-six percent of infants accepted twice ABR test had improving ABR results during the second test. (4) The proportion of normal DOPAE in group 2 (39.7%) was slightly lower than that of in group 1 (42.2%, chi2 = 0.14, P > 0.05). Among the infants who accepted twice DPOAE test, 32.0% had improving results in the second test. (5) Four cases (4 ears ) were diagnosed as auditory neuropathy.

CONCLUSIONSMiddle ear function and development of auditory system in infants may be confusing factors in hearing screening. The results of hearing screening should be interpreted appropriately.