Etiology of deafness in Afyon school for the deaf in Turkey.

OBJECTIVE

Otolaryngologists play an important role in the evaluation of children with a hearing impairment. The group of unknown cause still has a high incidence. The purposes of this study were to determine the etiology of deafness in Afyon School for the Deaf in Turkey and to compare the results with the other studies from Turkey and other countries.

METHODS

This study was a retrospective analysis of 130 deaf students, aged 5-16 years. Medical and family histories of the children were obtained. Clinical and laboratory examinations were carried out.

RESULTS

Etiological groups showed the following distribution: febril convulsion, 26.9%; cause unknown, 26.1%; hereditary group, 23.8%; meningitis, 10%; measles, 6.1%; and miscellaneous, 6.6%. A total of 90.3% of the students with hereditary deafness were from consanguineous families. A marital consanguinity was noted in the parents of 64 (49.2%) of all children in the school and this rate was higher than the average in Turkey (P<0.05). Neither syndromic deafness nor maternal rubella was identified. A total of 27.6% of the cases were diagnosed after the age of 30 months.

CONCLUSION

Febril convulsions and hereditary factors were the major causes of hearing loss in the present study. The high incidence of consanguineous marriage among the parents of the children with hereditary deafness seemed a strong evidence of genetic origin, indicating a close relationship between them. Congenital rubella syndrome did not appear as a significant etiology of deafness in Turkey.