Saravanan Palani, Devi Neelamegarajan, Geetha Chinnaraj
Department of Audiology, Centre for Hearing Sciences (CHS), All India Institute of Speech and Hearing (AIISH), Mysuru, India.
Department of Audiology, All India Institute of Speech and Hearing (AIISH), Mysuru, India.
Front Hum Neurosci. 2024 Sep 13;18:1441854. doi: 10.3389/fnhum.2024.1441854. eCollection 2024.
Aided auditory late latency response (LLR) serves as an objective tool for evaluating auditory cortical maturation following cochlear implantation in children. While aided LLR is commonly measured using sound-field acoustic stimulation, recording electrically evoked LLR (eLLR) offer distinct advantages, such as improved stimulus control and the capability for single electrode stimulation. Hence, the study aimed to compare eLLR responses with single electrode stimulation in the apical, middle, and basal regions and to evaluate their relationship with speech perception in paediatric cochlear implant (CI) recipients.
eLLR responses with single electrode stimulation were measured in 27 paediatric unilateral CI users with an active recording electrode placed at Cz. The stimuli consisted of 36 msec biphasic pulse trains presented across three electrode sites (apical-E20, middle-E11, and basal-E03). eLLR responses were compared across these electrode sites, and the relationship between speech recognition scores in quiet and age at implantation with eLLR components was evaluated.
eLLR responses were detected in 77 out of 81 tested electrodes of all participants combined (27 for apical, 26 for middle, and 24 for basal stimulation). There were no significant differences in P1, N1 latencies and P1 amplitude across electrode site. However, significantly larger N1 and P1-N1 amplitudes were observed for apical stimulations compared to basal stimulations. No differences in N1 amplitude were found between middle and apical stimulations, and the P1-N1 amplitude was significantly larger for middle compared to basal electrode stimulation, with no difference between the apical and middle electrodes stimulation. A moderate positive correlation was present between speech recognition scores in quiet and both N1, P1-N1 amplitudes for apical stimulation. Age at implantation was negatively correlated with N1 amplitude for the apical and P1-N1 amplitude for basal stimulation.
eLLR responses could be elicited in majority of paediatric CI users across electrode sites. Variations in eLLR responses across electrode sites suggest disparities in auditory cortical maturation. The findings underscore the significance of the N1 biomarker in evaluating higher-order auditory cortical development. Therefore, utilizing eLLR with single electrode stimulation may serve as a valuable tool for assessing post-cochlear implantation maturational changes in paediatric populations.
辅助听觉晚期潜伏期反应（LLR）是评估儿童人工耳蜗植入后听觉皮层成熟度的一种客观工具。虽然辅助LLR通常使用声场声学刺激进行测量，但记录电诱发LLR（eLLR）具有明显优势，例如更好的刺激控制和单电极刺激能力。因此，本研究旨在比较单电极刺激在顶区、中区和基底区的eLLR反应，并评估其与小儿人工耳蜗（CI）接受者言语感知的关系。
对27名单侧CI的小儿使用者进行单电极刺激的eLLR反应测量，将有源记录电极置于头顶中央（Cz）。刺激由36毫秒的双相脉冲序列组成，通过三个电极部位（顶区-E20、中区-E11和基底区-E03）呈现。比较这些电极部位的eLLR反应，并评估安静环境下的言语识别分数与植入时年龄和eLLR成分之间的关系。
在所有参与者的81个测试电极中，有77个检测到了eLLR反应（顶区刺激27个，中区刺激26个，基底区刺激24个）。电极部位之间的P1、N1潜伏期和P1波幅没有显著差异。然而，与基底区刺激相比，顶区刺激观察到显著更大的N1和P1-N1波幅。中区和顶区刺激之间的N1波幅没有差异，中区刺激的P1-N1波幅显著大于基底电极刺激，顶区和中区电极刺激之间没有差异。安静环境下的言语识别分数与顶区刺激的N1、P1-N1波幅均呈中度正相关。植入时年龄与顶区刺激的N1波幅以及基底区刺激的P1-N1波幅呈负相关。
大多数小儿CI使用者在各个电极部位都能引出eLLR反应。电极部位间eLLR反应的差异表明听觉皮层成熟存在差异。这些发现强调了N1生物标志物在评估高阶听觉皮层发育中的重要性。因此，利用单电极刺激的eLLR可能是评估小儿人工耳蜗植入后成熟变化的有价值工具。
