Center for Cognitive Sciences, Sirius University of Science and Technology, Olympic Ave 1, Sochi, Russia, 354340.
Laboratory of Human Higher Nervous Activity, Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia, 117485.
Mol Autism. 2023 Oct 26;14(1):40. doi: 10.1186/s13229-023-00566-1.
Rett syndrome (RS) is a rare neurodevelopmental disorder characterized by mutations in the MECP2 gene. Patients with RS have severe motor abnormalities and are often unable to walk, use hands and speak. The preservation of perceptual and cognitive functions is hard to assess, while clinicians and care-givers point out that these patients need more time to process information than typically developing peers. Neurophysiological correlates of auditory processing have been also found to be distorted in RS, but sound presentation rates were relatively quick in these studies (stimulus onset asynchrony, SOA < 1000 ms). As auditory event-related potential (ERP) is typically increased with prolongation of SOA we aim to study if SOA prolongation might compensate for observed abnormalities.
We presented a repetitive stimulus (1000 Hz) at three different SOAs of 900 ms, 1800 ms, and 3600 ms in children with RS (N = 24, Mean age = 9.0 ± 3.1) and their typical development (TD) peers (N = 27, Mean age = 9.7 ± 3.4) while recording 28-channels electroencephalogram, EEG. Some RS participants (n = 10) did not show clear ERP and were excluded from the analysis.
Major ERP components (here assessed as N1P1 and P2N1 peak-to-peak values) were smaller at SOA 900 than at longer SOAs in both groups, pointing out that the basic mechanism of adaptation in the auditory system is preserved in at least in RS patients with evident ERPs. At the same time the latencies of these components were significantly delayed in the RS than in TD. Moreover, late components (P2N1 and N2P2) were drastically reduced in Rett syndrome irrespective of the SOA, suggesting a largely affected mechanism of integration of upcoming sensory input with memory. Moreover, developmental stagnation of auditory ERP characterized patients with RS: absence of typical P2N1 enlargement and P1 and N1 shortening with age at least for shortest SOA.
We could not figure out the cause for the high percentage of no-evident ERP RS participants and our final sample of the RS group was rather small. Also, our study did not include a control clinical group.
Thus, auditory ERPs inform us about abnormalities within auditory processing that cannot be fully overcomed by slowing presentation rate.
雷特综合征（RS）是一种罕见的神经发育障碍，其特征是 MECP2 基因突变。RS 患者有严重的运动异常，通常无法行走、使用双手和说话。感知和认知功能的保留情况难以评估，而临床医生和护理人员指出，这些患者比典型发育的同龄人需要更多的时间来处理信息。RS 患者的听觉处理的神经生理相关性也被发现存在扭曲，但在这些研究中，声音呈现率相对较快（刺激起始时相差，SOA<1000 毫秒）。由于听觉事件相关电位（ERP）通常随着 SOA 的延长而增加，我们旨在研究 SOA 延长是否可以补偿观察到的异常。
我们以 900、1800 和 3600 毫秒的三个不同 SOA 向 RS 儿童（N=24，平均年龄 9.0±3.1）和他们的典型发育（TD）同龄人（N=27，平均年龄 9.7±3.4）呈现重复刺激（1000 Hz），同时记录 28 通道脑电图（EEG）。一些 RS 参与者（n=10）没有显示出清晰的 ERP，因此被排除在分析之外。
在两个组中，主要的 ERP 成分（此处评估为 N1P1 和 P2N1 峰到峰值）在 SOA900 时比在较长的 SOA 时更小，这表明听觉系统的适应基本机制在至少具有明显 ERP 的 RS 患者中得到了保留。同时，这些成分的潜伏期在 RS 中明显长于 TD。此外，无论 SOA 如何，迟发成分（P2N1 和 N2P2）在 Rett 综合征中都明显减少，这表明即将到来的感觉输入与记忆的整合机制受到了很大的影响。此外，听觉 ERP 的发育停滞特征是 RS 患者：在最短的 SOA 下，缺乏典型的 P2N1 增大以及 P1 和 N1 随年龄的缩短。
我们无法确定 RS 参与者中高比例无明显 ERP 的原因，我们的 RS 组最终样本很小。此外，我们的研究没有包括对照组。
因此，听觉 ERP 为我们提供了有关听觉处理中异常的信息，这些异常不能通过降低呈现率来完全克服。
