뇌간유발반응청력검사에 의한 유소아 보청기 착용의 문제

Problems in Wearing Hearing Aid for Young Children by Brainstem Evoked Response Audiometry

본 연구는 뇌간유발반응청력검사에 의한 유소아 보청기 착용의 문제를 알아보고자 실시하였다. 뇌간유발반응청력검사에서 고도 이상의 난청으로 판명된 4세 미만의 유소아 10명을 두 집단으로 분류하여, 집단1은 뇌간유발반응청력검사 결과만으로, 집단2는 뇌간유발반응청력검사와 유희청력검사를 실시하여 주파수별 역치를 알아본 후 보청기 증폭량을 결정하여 보청기를 착용시켰다. 두 집단 모두에게 한 달 간격으로 두 번의 유희청력검사를 실시하여 보청기의 증폭이 처음부터 적절하게 적용되었는지를 비교하여 보았다. 연구결과, 뇌간유발반응청력검사 결과만으로 증폭량을 결정하여 보청기를 착용시킨 경우보다는 유희청력검사를 추가로 실시한 후 보청기의 증폭량을 결정하여 착용시킨 경우가 보다 정확하다는 것을 알 수 있었다. 유소아가 청각장애가 있음이 밝혀졌을 때 빨리 보청기를 착용시키는 것도 중요하지만, 과도한 증폭이 되지 않도록 객관적 청력검사 결과와 주관적인 검사인 유희청력검사 결과를 함께 고려하여 증폭량을 결정해야 할 것이다.

Accurate audiometry is essential when providing children with proper hearing aids . But in the case of audiometry for infant s , objective test s have been exclusively used becau se it s impossible to do a subjective test reliably . T oday in many hospitals otoadmittance audiometry and otoacoustic emissions for determining hearing los s are used. T he degree of hearing loss is determinded after the test of brain stem evoked response audiometry. But the frequency range is limited to the high frequency range from 2000 Hz to 4000 Hz. We mu st determine the frequency threshold for each frequency tested in 250- 6000 Hz for hearing aid prescription. We usually get gains by gues sing if you use only the result s of brainstem evoked respon se audiometry for fitting a hearing aid. However , when worn ahearing aid, the resrult s are the sound distortion and the reduction of residual hearing due to the over - gain . The subject s of the present study are infant s (under 4 year s ) who are considered to have severe hearing loss when tested by brain stem evoked response au - diometry. T hey were divided to two groups. The hearing aids of group 1 subject s were prescribed on the basis of the result s of brain stem evoked respon se audiometry, and the hearing aids of group 2 subject s were prescribed on the basis of the result s of play audiometry which was administered one month after the test of brain stem evoked res - ponse audiometry . After wearing the hearing aids for 2- 3 weeks , both groups hearing aids were fitted again in light of the result s of the follow- up play audiometry. The result s showed that the gain of hearing aid determined only on basis of the result s of brainstem evoked response audiometry was less valid than the gain determined on the basis of the result s of play audiometry in addition to the brainstem evoked respon se audiometry . T he implication of the study is that it seems necessary that we test the hearing impairment s by both play audiometry and an objective audiometry , particularly in the case of infant s under 4 years of age.