Huntley Jonathan, Bor Daniel, Deng Feng, Mancuso Marco, Mediano Pedro A M, Naci Lorina, Owen Adrian M, Rocchi Lorenzo, Sternin Avital, Howard Robert
Division of Psychiatry, University College London, London, United Kingdom.
Department of Psychology, University of Cambridge, Cambridge, United Kingdom.
Front Hum Neurosci. 2023 Feb 1;16:1035195. doi: 10.3389/fnhum.2022.1035195. eCollection 2022.
There is an urgent need to understand the nature of awareness in people with severe Alzheimer's disease (AD) to ensure effective person-centered care. Objective biomarkers of awareness validated in other clinical groups (e.g., anesthesia, minimally conscious states) offer an opportunity to investigate awareness in people with severe AD. In this article we demonstrate the feasibility of using Transcranial magnetic stimulation (TMS) combined with EEG, event related potentials (ERPs) and fMRI to assess awareness in severe AD. TMS-EEG was performed in six healthy older controls and three people with severe AD. The perturbational complexity index (PCI) was calculated as a measure of capacity for conscious awareness. People with severe AD demonstrated a PCI around or below the threshold for consciousness, suggesting reduced capacity for consciousness. ERPs were recorded during a visual perception paradigm. In response to viewing faces, two patients with severe AD provisionally demonstrated similar visual awareness negativity to healthy controls. Using a validated fMRI movie-viewing task, independent component analysis in two healthy controls and one patient with severe AD revealed activation in auditory, visual and fronto-parietal networks. Activation patterns in fronto-parietal networks did not significantly correlate between the patient and controls, suggesting potential differences in conscious awareness and engagement with the movie. Although methodological issues remain, these results demonstrate the feasibility of using objective measures of awareness in severe AD. We raise a number of challenges and research questions that should be addressed using these biomarkers of awareness in future studies to improve understanding and care for people with severe AD.
迫切需要了解重度阿尔茨海默病（AD）患者的意识本质，以确保有效的以人为本的护理。在其他临床群体（如麻醉、最小意识状态）中得到验证的意识客观生物标志物为研究重度AD患者的意识提供了机会。在本文中，我们展示了使用经颅磁刺激（TMS）结合脑电图（EEG）、事件相关电位（ERP）和功能磁共振成像（fMRI）来评估重度AD患者意识的可行性。对6名健康老年对照者和3名重度AD患者进行了TMS-EEG检查。计算微扰复杂性指数（PCI）作为意识能力的一种度量。重度AD患者的PCI处于意识阈值附近或低于该阈值，表明意识能力下降。在视觉感知范式期间记录ERP。在观看面孔时，两名重度AD患者初步表现出与健康对照者相似的视觉意识负波。使用经过验证的fMRI电影观看任务，对两名健康对照者和一名重度AD患者进行独立成分分析，发现听觉、视觉和额顶叶网络有激活。患者与对照者之间额顶叶网络的激活模式没有显著相关性，表明在意识以及对电影的参与方面可能存在差异。尽管方法学问题仍然存在，但这些结果证明了在重度AD中使用意识客观测量方法的可行性。我们提出了一些挑战和研究问题，未来研究应使用这些意识生物标志物来解决，以增进对重度AD患者的理解并改善护理。
