Leibniz Institute for Neurobiology, Magdeburg, Combinatorial NeuroImaging Core Facility, Germany.
Leibniz Institute for Neurobiology, Magdeburg, Combinatorial NeuroImaging Core Facility, Germany; University Hospital of the Otto von Guericke University Magdeburg, Department of Otorhinolaryngology, Germany.
Clin Neurophysiol. 2022 Aug;140:29-39. doi: 10.1016/j.clinph.2022.05.008. Epub 2022 May 20.
In binaurally deaf subjects, speech processing particularly benefits from a cochlear implant (CI) in the right ear, which is contralateral to the commonly left speech-dominant hemisphere. However, it is unclear whether such effects of implantation side also occur in speech processing in patients with single-sided deafness (SSD).
Lateralization of N1 responses was analyzed with a high-density electroencephalogram (EEG) in fourteen adults with postlingually acquired left or right SSD who received a CI in adulthood. During recording, patients performed a speech and a pure-tone discrimination task. Lateralization of N1 responses was assessed by side-specific global field power (GFP) and compared (a) between normal hearing and CI-implanted ears within subjects and (b) between implantation sides across subjects.
N1 responses were stronger in the contralateral than in the ipsilateral hemisphere during stimulation of the normal hearing ear (except for left speech stimulation), and was bilateral symmetric with CI stimulation on either side. A significant correlation between speech discrimination performance and left lateralization was found across subjects for the left CI ear.
CI stimulation altered auditory processing across hemispheres. Speech discrimination in left CI-implanted SSD patients improved with left lateralization of the N1 response.
Side-specific rehabilitation in SSD patients might improve speech processing across hemispheres.
在双耳失聪的受试者中，言语处理特别受益于对侧（即通常为左利手的优势半球的对侧）右耳中的人工耳蜗植入（CI）。然而，在单侧聋（SSD）患者的言语处理中，植入侧是否也存在这种影响尚不清楚。
在 14 名成年后天获得左或右侧 SSD 的成年人中，使用高密度脑电图（EEG）分析 N1 反应的侧化。在记录过程中，患者进行了言语和纯音辨别任务。通过特定于一侧的全局电场功率（GFP）评估 N1 反应的侧化，并在（a）受试者内比较正常听力和 CI 植入耳之间，以及（b）受试者间比较植入侧之间。
在正常听力耳刺激时，N1 反应在对侧比同侧半球更强（除了左侧言语刺激），并且在两侧的 CI 刺激时均为双侧对称。在左侧 CI 耳中，发现了受试者间言语辨别性能与左侧侧化之间的显著相关性。
CI 刺激改变了整个半球的听觉处理。左侧 SSD 患者的 CI 植入后的言语辨别能力随着 N1 反应的左侧侧化而提高。
SSD 患者的特定于侧的康复可能会改善整个半球的言语处理。
