정상 성인에서 듣기 노력과 관련된 신경 생리학적 변화

Background and Objectives Several studies have proven that listening efforts cause neuroanatomical and physiological changes in the frontal lobe in adults with hearing loss as well as in the elderly with normal hearing. However, there is still a lack in research into how brain function changes when the cognitive load is increased based on noise level. We conducted a preliminary study using functional near-infrared spectroscopy to determine differences in listening effort according to varying listening conditions. Subjects and Method Five adults with normal hearing participated in the study. Listening effort was measured in three listening environments (resting, quiet, and noise) using NIRSIT Lite (OBELAB, Seoul, Korea). The measures variables were concentration changes in oxygenated hemoglobin (ΔHbO2) and the percent correct response rate. Results As a result of ΔHbO2, channels 1 (p=0.045), 5 (p=0.042) and 7 (p=0.033) (right channels) showed significantly higher ΔHbO2 in the noise condition than in the resting condition. In addition, in channel 1, ΔHbO2 was significantly higher even in the quiet condition than in the resting condition (p=0.041). The percent correct response rate was significantly decreased in the noise condition (35.6%) as compared to the quiet condition (64.4%) (p=0.024). Conclusion We observed that a decrease in cerebral localization to compensate through the right hemisphere was presented with increased listening effort. The results of the study will be useful in situations where listening effort need to be accurarely measured.