Congenital single-sided deafness (SSD) leads to an aural preference syndrome that is characterized by overrepresentation of the hearing ear in the auditory system. Cochlear implantation (CI) of the deaf ear is an effective treatment for SSD. However, the newly introduced auditory input in congenital SSD often does not reach expectations in late-implanted CI recipients with respect to binaural hearing and speech perception. In a previous study, a reduction of the interaural time difference (ITD) sensitivity has been shown in unilaterally congenitally deaf cats (uCDCs). In the present study, we focused on the interaural level difference (ILD) processing in the primary auditory cortex. The uCDC group was compared with hearing cats (HCs) and bilaterally congenitally deaf cats (CDCs). The ILD representation was reorganized, replacing the preference for the contralateral ear with a preference for the hearing ear, regardless of the cortical hemisphere. In accordance with the previous study, uCDCs were less sensitive to interaural time differences than HCs, resulting in unmodulated ITD responses, thus lacking directional information. Such incongruent ITDs and ILDs cannot be integrated for binaural sound source localization. In normal hearing, the predominant effect of each ear is excitation of the auditory cortex in the contralateral cortical hemisphere and inhibition in the ipsilateral hemisphere. In SSD, however, auditory pathways reorganized such that the hearing ear produced greater excitation in both cortical hemispheres and the deaf ear produced weaker excitation and preserved inhibition in both cortical hemispheres.

先天性单侧耳聋 (SSD) 会导致听觉偏好综合症，其特征是听觉系统中听觉耳的比例过高。耳蜗植入术（CI）是治疗SSD的有效方法。然而，先天性 SSD 中新引入的听觉输入通常无法达到晚期植入 CI 接受者在双耳听力和言语感知方面的预期。在之前的一项研究中，单侧先天性聋猫（uCDC）的耳间时间差（ITD）敏感性降低。在本研究中，我们重点关注初级听觉皮层的耳间电平差（ILD）处理。将 uCDC 组与听力猫 (HC) 和双侧先天性聋猫 (CDC) 进行比较。 ILD 表示进行了重组，将对侧耳朵的偏好替换为对听耳的偏好，而不管皮质半球如何。根据之前的研究，uCDC 对耳间时间差的敏感度低于 HC，导致 ITD 反应未调制，因此缺乏方向信息。这种不一致的 ITD 和 ILD 无法集成用于双耳声源定位。在正常听力中，每只耳朵的主要作用是兴奋对侧皮质半球的听觉皮层和抑制同侧皮质半球的听觉皮层。然而，在 SSD 中，听觉通路进行了重组，使得听耳在两个皮质半球中产生更大的兴奋，而聋耳在两个皮质半球中产生较弱的兴奋并保留抑制。