The role of current audiological tests in the early diagnosis of hearing impairment in children

[Cochlear implantation at the Ear, Nose and Throat Clinic of the Clinical Center of Vojvodina]

INTRODUCTION

A cochlear implant is a small electronic device that can provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. Cochlear implants bypass the damaged hearing systems and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound. Hearing through a cochlear implant differs from normal hearing and takes time to learn or relearn. Cochlear implantations have been performed at the ENT Clinic in Novi Sad since 2002. The aim of this retrospective investigation was to evaluate performance of cochlear implanted patients in regard to the age of hearing loss identification, age at implantation, as well as complications.

MATERIAL AND METHODS

During a 5-year period (2002-2007), 45 patients underwent cochlear implantation (46 implants) at the ENT Clinic in Novi Sad. Only four patients were postlingually deaf adults. Forty-one implanted patients were children with a mean age at implantation of 42.2 months (range: 2 to 8 years). Out of these patients, 28 (68.2%) had congenital deafness of unknown cause. The commonest known cause was meningitis, found in 4 (9.7%) patients, followed by use of ototoxic drugs and hereditary deafness. Etiological factors included: postnatal hypoxia, intracranial hemorrhage, pre term birth, cytomegalovirus infection during pregnancy, middle ear cholesteatoma, as well as sudden bilateral deafness. The time span between diagnosis of hearing loss and implantation was 34.6 months in 2002 and only 10 months in 2007.

RESULTS

6 (13%) patients presented with complications. There were 4 major, and two minor complications. The following complications were noted: ossified cochlea which required reoperation, unsuccessful operation in a patient with Down syndrome, facial tics, temporary facial weakness and ataxia. Five out of six complications were successfully resolved

CONCLUSION

New, more sophisticated audiological evaluation is essential to shorten the time for diagnosing hearing impairment. The results of the investigation performed at the Cochlear Implantation Center of the ENT Clinic in Novi Sad show that cochlear implantation is an effective procedure which should be continued.