목적: People with unilateral deafness (UD) typically complain of impaired ability to locate sound location. However, recent studies have suggested that paying attention to the sound could mitigate the degradation of spatial processing such that attention guides which information should be suppressed or permitted to process. To investigate cortical processing to spatially varied sounds under attentive listening, the current study examined cortical evoked responses while at the same time measured sound localization in UD individuals. 방법:20 UD patients and 32 normal-hearing (NH) controls participated. Among the NH participants, one ear of 21 people was earplugged and masked to simulate acute unilateral hearing loss (AUHL). Cortical potentials were recorded while actively detecting sound locations at different azimuth angles. N1, P2, N2, and late positive complex (LPC) were analyzed as a function of angles. 결과:UD group showed poorer localization ability than NH and AUHL groups. The AUHL groups revealed prolonged N1 latency and greater LPC amplitudes compared to NH and UD groups. P2 amplitudes in UD groups were positively correlated with sound localization accuracy. The lateralization index calculated by N2 source activity indicated the left hemispheric asymmetry for NH. In AUHL groups, stronger activity ipsilateral to the intact ear was revealed, regardless of the side of hearing loss. Unlike AUHL, UD groups showed distinct patterns of the laterality such that left-sided UD had greater activity on the hemisphere contralateral to the hearing side, whereas no hemispheric asymmetry was found for the right-sided UD. The cortical source activities in UD groups were negatively correlated with the onset of deafness in the area encompassing the right frontal cortex. 결론:Our finding suggests that AUHL can exert immediate cortical reorganization evidenced by the change of hemispheric laterality. In people with UD, patterns of cortical plasticity are different depending on the side of deafness.