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.

中文翻译：

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呈现率对雷特综合征听觉处理的影响：事件相关电位研究

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、用手和说话。感知和认知功能的保留很难评估，而临床医生和护理人员指出，这些患者比一般发育中的同龄人需要更多的时间来处理信息。听觉处理的神经生理学相关性也被发现在 RS 中被扭曲，但在这些研究中声音呈现速率相对较快（刺激开始异步，SOA < 1000 ms）。由于听觉事件相关电位 (ERP) 通常会随着 SOA 的延长而增加，因此我们的目的是研究 SOA 延长是否可以补偿观察到的异常。我们对 RS 儿童（N = 24，平均年龄 = 9.0 ± 3.1）及其典型发育 (TD) 同龄人 (N = 27，平均年龄= 9.7 ± 3.4），同时记录28通道脑电图，EEG。一些 RS 参与者 (n = 10) 没有表现出明显的 ERP，因此被排除在分析之外。两组中 SOA 900 时的主要 ERP 成分（此处评估为 N1P1 和 P2N1 峰峰值）均小于较长 SOA 时的较小，这表明至少在 RS 患者中保留了听觉系统适应的基本机制具有明显的 ERP。同时，这些组件的延迟在 RS 中比在 TD 中显着延迟。此外，无论 SOA 如何，Rett 综合征中的晚期成分（P2N1 和 N2P2）都急剧减少，这表明即将到来的感觉输入与记忆的整合机制受到很大影响。此外，RS患者的听觉ERP发育停滞是其特征：没有典型的P2N1增大，并且P1和N1随着年龄的增长而缩短，至少对于最短的SOA来说是这样。我们无法找出无明显 ERP RS 参与者比例高的原因，而且我们的 RS 组的最终样本相当小。此外，我们的研究不包括对照临床组。因此，听觉 ERP 告诉我们听觉处理中的异常情况，而这些异常情况无法通过降低呈现速率来完全克服。