Objective: The purpose of this study was to determine the etiology of bilateral sensorineural hearing disorders in children and to evaluate the performed hearing tests by comparison of the results of the objective and subjective tests.
Methods: The medical history and the hearing tests (behavioral observation audiometry, acoustic evoked potentials and pure tone audiometry) of 106 bilaterally hearing impaired children were analyzed in a retrospective follow-up study.
Results: The total group included 52 males and 54 females. The ages at first diagnosis ranged from 4 months to 11 years with a mean age of 42 months and a median of 33 months. The degree of hearing loss for the better hearing ear was mild in one child, moderate in 28 children, severe in 29 children, profound in 32 children and total in 16 children. The delay between the first examination and diagnosis ranged from 0 to 597 days with a mean of 83 days and a median of 28 days. In 47 children (44%) no cause of hearing impairment could be determined. Nineteen children (18%) had a history of familial hearing loss, 40 (38%) suffered from acquired hearing loss (seven children had prenatal causes, 21 perinatal and 12 postnatal). A comparison between behavioral observation audiometry and brainstem evoked response audiometry revealed a statistically good agreement. Twenty-nine children (32%) showed progressive hearing loss, which was defined as a threshold shift of +10 dB or more in the pure tone average in at least one ear.
Conclusions: In a significant number of children with early hearing impairments the etiology still remains uncertain. Further research in the field of genetic disorders will diminish this number. Evaluation of hearing tests showed that behavioral observation audiometry still is an excellent tool in the hands of an experienced examiner. The age at identification of hearing disorders in industrialized countries still is unacceptably high. To obtain ideal care of hearing impaired children, universal neonatal hearing screening programs are mandatory.