METHODS: AEPs were recorded to simple 100 Hz tones from 18 RTT and 27 age-matched controls (Ages: 6-22 years). We applied standard AEP averaging, as well as measures of neuronal reliability at the single-trial level (i.e. SNR, ITV, ITPC). To separate signal-carrying components from non-neural noise sources, we also applied a denoising source separation (DSS) algorithm and then repeated the reliability measures.
RESULTS: Substantially increased ITV, lower SNRs, and reduced ITPC were observed in auditory responses of RTT participants, supporting a \"neural unreliability\" account. Application of the DSS technique made it clear that non-neural noise sources contribute to overestimation of the extent of processing deficits in RTT. Post-DSS, ITV measures were substantially reduced, so much so that pre-DSS ITV differences between RTT and TD populations were no longer detected. In the case of SNR and ITPC, DSS substantially improved these estimates in the RTT population, but robust differences between RTT and TD were still fully evident.
CONCLUSIONS: To accurately represent the degree of neural dysfunction in RTT using the ERP technique, a consideration of response reliability at the single-trial level is highly advised. Non-neural sources of noise lead to overestimation of the degree of pathological processing in RTT, and denoising source separation techniques during signal processing substantially ameliorate this issue.
方法:从18个RTT和27个年龄匹配的对照(年龄:6-22岁)将AEP记录到简单的100Hz音调。我们采用标准AEP平均,以及单次试验水平的神经元可靠性度量(即SNR,ITV,ITPC)。为了将携带信号的分量与非神经噪声源分开,我们还应用了去噪源分离(DSS)算法,然后重复了可靠性措施。
结果:ITV大幅增加,较低的SNR,在RTT参与者的听觉反应中观察到ITPC降低,支持“神经不可靠”账户。DSS技术的应用清楚地表明,非神经噪声源有助于高估RTT中处理缺陷的程度。后DSS,ITV措施大幅减少,如此之多,以至于不再检测到RTT和TD人群之间的DSS前ITV差异。在SNR和ITPC的情况下,DSS大大改善了RTT群体中的这些估计,但RTT和TD之间的强劲差异仍然非常明显。
结论:为了使用ERP技术准确表示RTT中的神经功能障碍程度,强烈建议在单次试验水平上考虑响应可靠性。非神经性噪声源导致对RTT中病理处理程度的高估,信号处理过程中的去噪源分离技术大大改善了这个问题。