현대 사회에서는 의사소통을 어렵게 만드는 다양한 소음에 노출되기가 쉽고, 소음 상황에서 상대방의 말을 이해하기 위해서는 소음이 없는 상황에 비해 더 많은 노력이 요구 되어진다.8) 이러한 청각 능력은 언어인지력 감소와도 연관이 있으며 난청성인들은 일반적으로 건청성인들과 비교하여 다 양한 배경 소음 환경에서 화자의 말소리를 이해하는데 어려움을 호소하고,14) 소음 환경에서는 어음인지력의 감소와 더불어 공간 내 신호 인지 및 위치 변별 능력도 저하되는 것으로 보고되어지고 있다. 난청인들이 소음 환경에서 어음을 인지하는데 영향을 미치는 환경적인 요소는 다양하다. 먼저, 신호대잡음비는 배경 소음 대비 어느 정도 강도의 신호가 주어졌을 때 그 신호를 인지할 수 있는지 예측할 수 있는 단서가 될 수 있는 수치로써 신호를 지각할 수 있는 소리 강도와 그 때 주어진 소음 간의 차로 정의된다. 건청인의 경우 신호대잡음비가 +10~+15
One of the common complaints with hearing loss was difficulty in understanding speech in noisy environments. Effects of noise bands on monosyllabic word recognition were investigated in normal and hearing-impaired adult subjects under various signal to ratios and source directions. Normal hearing group contained 15 subjects (6 males and 9 females with the mean age of 25.5 years) while sensorineural hearing loss group had 10 subjects (6 males and 4 females with the mean age of 67.7 years). Subjects with sensorineural hearing loss were wearing hearing aids unilaterally for at least more than three months. Signals consisted of monosyllabic words which were fixed at 60 dB HL on various signal to noise ratios from –20 dB to +20 dB with a step size of 10 dB. They were presented through a loudspeaker at a distance of one meter in front of the subjects under different conditions (S0N0, S0N90, S90N0). Monosyllabic recognition scores were collected in response to white noise, low pass filtered noise, and high pass filtered noise with a cutoff frequency of 1,500 Hz. Response interaction components were defined and computed as the difference between sum of responses (recognition scores) to two filtered noise bands and the individual response to white noise. Results showed that significantly different interactions were noted between normal and sensorineural hearing loss groups on all conditions (P<0.05). The largest interactions resulted from the data between -20 dB of SNR (signal to noise ratios) when signal and noise were presented in front of the normal adult subjects (S0N0). In general, interaction components were significantly increased as SNRs (signal to noise ratios) were decreased. However, there were no significant differences under various source directions and SNRs (except S0N0 condition) in the hearing impaired with hearing aids group. The overall outcomes indicated that selective data from interaction components could be used to evaluate the status of hearing loss and effectiveness of rehabilitation programs. KEY WORDS：Frequency bands·Signal to noise ratio·Source location·Word recognition score·Interaction component
INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSIONS CONCLUSIONS REFERENCES
