사람들은 태어나면서부터 의사소통할 수 있는 기제를 가지 고 태어나며, 성장하면서 자연스럽게 소리를 들으며 의사소통 을 하게 된다. 그러나 청각 장애 아동들은 자신의 조음기관과 발성에 문제가 없음에도 불구하고 외이로부터 대뇌에서 소리 를 이해하기까지 청각 경로에 장애를 입어 듣기에 어려움을 보 이며, 신생아기 때부터 환경으로부터 언어 자극을 제대로 받지 못하여 정상적인 음운 발달을 이루지 못한다. 건청인과 비교해 볼 때 청각 장애 아동은 다른 말소리의 특성 을 갖는다. 청각 장애 아동은 분절적인 특성으로는 모음 산출에 서의 포만트(formant)와 자음에서 파열음의 발성 개시 시간(voice onset time, VOT)에서 건청인과 다르며(Oh, 1999), 초분절적인 특성으로는 쉰 목소리와 불규칙한 높낮이, 다소 느려 빼는 운율, 부적절한 공명 등으로 왜곡된 음성을 보인다(Moon, 2003). 현재 보청기의 사용 효과가 제한되는 청각 장애 아동들에게 청능재 활을 위한 청각 보조기구로서 인공와우가 가장 많이 사용되고 있다.
Purpose: The present study compared the Korean consonant discrimination ability and voice onset time (VOT) between children with cochlear implants (CI) and children with normal hearing to investigate the characteristics of speech in children with CI. Methods: Twenty children with CI and twenty children with normal hearing participated in the present study. Of twenty children with CI, ten subjects had the CI surgery before three years old and the other ten subjects had after three years old. One-syllable stimuli (consonant-vowel) and twosyllable stimuli (vowel-consonant -vowel) were used to test the consonant discrimination and VOT, respectively. The consonant discrimination test was analyzed by manner of articulation (stop, fricative, affricate), place of articulation (bilabial, alveolar, palatal, velar), and voicing (lax, tense, aspirated), and VOT was analyzed by voicing. Results: For consonant discrimination, children with normal hearing showed significantly better recognition than children with CI in all the consonants. For the manner of articulation, the differences were significantly highest discrimination in affricates and lowest in stops. For the place of articulation, the differences were significantly highest in palatals and lowest in bilabials. However, there was no difference based on voicing between groups. For consonant discrimination between children with CI implantation before 3-years old and children with CI implantation after 3-years old, there were significant differences in the manner and the place of articulation whereas no difference was found in VOT. No relationship was found between the wearing periods of CI whereas age at implantation was highly correlated with consonant discrimination. For VOT, there were no significant differences in all stop sounds but the lowest discrimination was observed in stops. Conclusion: The characteristics of speech in children with CI were apparent in the manner and the place of articulation but not in voicing. This was highly associated with ages of CI.
INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSIONS REFERENCES
