Barnes Lydia, Petit Selene, Badcock Nicholas A, Whyte Christopher J, Woolgar Alexandra
MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, United Kingdom.
Department of Cognitive Science, Macquarie University, Sydney, NSW, Australia.
Front Neurosci. 2021 Mar 3;15:602798. doi: 10.3389/fnins.2021.602798. eCollection 2021.
Measuring cognition in single subjects presents unique challenges. On the other hand, individually sensitive measurements offer extraordinary opportunities, from informing theoretical models to enabling truly individualised clinical assessment. Here, we test the robustness of fast, periodic, and visual stimulation (FPVS), an emerging method proposed to elicit detectable responses to written words in the electroencephalogram (EEG) of individual subjects. The method is non-invasive, passive, and requires only a few minutes of testing, making it a potentially powerful tool to test comprehension in those who do not speak or who struggle with long testing procedures. In an initial study, Lochy et al. (2015) used FPVS to detect word processing in eight out of 10 fluent French readers. Here, we attempted to replicate their study in a new sample of 10 fluent English readers. Participants viewed rapid streams of pseudo-words with words embedded at regular intervals, while we recorded their EEG. Based on Lochy et al. (2015) we expected that words would elicit a steady-state response at the word-presentation frequency (2 Hz) over parieto-occipital electrode sites. However, across 40 datasets (10 participants, two conditions, and two regions of interest-ROIs), only four datasets met the criteria for a unique response to words. This corresponds to a 10% detection rate. We conclude that FPVS should be developed further before it can serve as an individually-sensitive measure of written word processing.
在个体受试者中测量认知能力面临着独特的挑战。另一方面，个体敏感测量提供了非凡的机遇，从为理论模型提供信息到实现真正个性化的临床评估。在此，我们测试了快速、周期性视觉刺激（FPVS）的稳健性，这是一种新兴方法，旨在在个体受试者的脑电图（EEG）中引发对书面文字的可检测反应。该方法是非侵入性的、被动的，且仅需几分钟测试，使其成为测试那些不会说话或难以完成冗长测试程序者的理解能力的潜在有力工具。在一项初步研究中，洛希等人（2015年）使用FPVS在10名法语流利读者中的8名身上检测到了文字处理。在此，我们试图在10名英语流利读者的新样本中重复他们的研究。参与者观看以固定间隔嵌入单词的伪词快速流，同时我们记录他们的脑电图。基于洛希等人（2015年）的研究，我们预期单词会在顶枕电极部位以单词呈现频率（2赫兹）引发稳态反应。然而，在40个数据集（10名参与者、两种条件和两个感兴趣区域——ROI）中，只有4个数据集符合对单词独特反应的标准。这相当于10%的检测率。我们得出结论，在FPVS能够作为书面文字处理的个体敏感测量方法之前，应进一步对其进行开发。
