Lindenbaum Laura, Steppacher Inga, Mehlmann Alexandra, Kissler Johanna Maria
Department of Psychology, Bielefeld University, Bielefeld, Germany.
Center for Cognitive Interaction Technology (CITEC), Bielefeld University, Bielefeld, Germany.
Front Neurosci. 2025 Apr 8;19:1547167. doi: 10.3389/fnins.2025.1547167. eCollection 2025.
Pre-stimulus oscillations predispose subsequent stimulus detection, but the connection between the pre-stimulus EEG activity and post-stimulus event-related potentials (ERPs) has rarely been examined in people in a disorder of consciousness (DoC). Hence, we investigate how pre-stimulus EEG band power is related to post-stimulus ERPs in individual DoC patients.
We conducted an active auditory oddball paradigm encompassing standard, target and unexpected oddball stimuli with 14 DoC patients ( = 12 minimally conscious state [MCS], = 2 unresponsive wakefulness syndrome [UWS]). We extracted post-stimulus ERPs as well as pre-stimulus power-spectra.
P3-like differences between brain responses to auditory stimuli were found in seven patients (50%). Delta and theta bands pre-dominated in all patients' pre-stimulus frequency spectra but patients with significant post-stimulus P3 had on average more pre-stimulus beta and gamma power than those without P3 effects. Pre-stimulus power and post-stimulus ERPs correlated in five patients (36%). Several patients showed negative correlations between pre-stimulus gamma and beta power and post-stimulus ERP variables, suggesting a u-shaped relationship between pre-stimulus high-frequency activity and post-stimulus ERP. Only one patient showed a relationship between pre-stimulus alpha and ERP as previously found in healthy people.
Pre-stimulus frequencies in DoC were related to post-stimulus processing at least in some patients. The pattern of the relationship showed considerable variability underscoring substantial alterations in brain activity among patients with DoC. The comparison with somatosensory results in the same patients emphasizes the need for multi-modal assessment.
The high inter-individual variability in the connection between pre-stimulus oscillations and auditory processing in DoC necessitates extensive individual assessment to determine optimal stimulation windows for DoC patients.
刺激前振荡有助于后续刺激检测，但在意识障碍（DoC）患者中，很少有人研究刺激前脑电图（EEG）活动与刺激后事件相关电位（ERP）之间的联系。因此，我们研究了个体DoC患者中刺激前EEG频段功率与刺激后ERP之间的关系。
我们对14名DoC患者（12名处于最低意识状态[MCS]，2名处于无反应觉醒综合征[UWS]）进行了一项主动听觉oddball范式实验，实验包含标准、目标和意外oddball刺激。我们提取了刺激后的ERP以及刺激前的功率谱。
7名患者（50%）的大脑对听觉刺激的反应中发现了类似P3的差异。所有患者刺激前频谱中以δ和θ频段为主，但刺激后有显著P3的患者，其刺激前β和γ功率平均比无P3效应的患者更多。5名患者（36%）的刺激前功率与刺激后ERP相关。几名患者的刺激前γ和β功率与刺激后ERP变量呈负相关，表明刺激前高频活动与刺激后ERP之间呈U形关系。只有一名患者的刺激前α与ERP之间存在如健康人先前发现的那种关系。
至少在部分患者中，DoC患者的刺激前频率与刺激后处理相关。这种关系模式显示出相当大的变异性，突出了DoC患者大脑活动的实质性改变。与同一患者体感结果的比较强调了多模态评估的必要性。
DoC患者中刺激前振荡与听觉处理之间联系的个体差异很大，需要进行广泛的个体评估以确定DoC患者的最佳刺激窗口。
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