Olfactory sniffing signals consciousness in unresponsive patients with brain injuries
Olfactory sniffing signals consciousness in unresponsive patients with brain injuries
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DOI：
10.1038/s41586-020-2245-5
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发表时间：
2020-04-29
期刊：
影响因子：
64.8
通讯作者：
Sobel, Noam
中科院分区：
文献类型：
--
作者：
Arzi, Anat;Rozenkrantz, Liron;Sobel, Noam
在严重脑损伤后，很难确定患者的意识状态，确定患者是否没有反应或可能只有最低限度的意识(1)，并预测他们是否会康复。这些诊断和预后是至关重要的，因为它们决定了治疗策略，如疼痛管理，并可以作为临终决定的基础（2,3）。然而，在确定脑损伤患者的意识状态时，错误率高达40%（4,5）。嗅觉依赖于参与唤醒基本机制的大脑结构(6)，因此我们假设它可以作为意识的生物标志物(7)。在这里，我们使用一种非语言的、非任务依赖的测量方法，即嗅觉反应（8-11）来确定脑损伤患者的意识。通过测量气味依赖嗅探，我们获得嗅觉功能的敏感测量（10-15）。我们反复测量了严重脑损伤患者的嗅觉反应，发现嗅觉反应在组水平上明显区分无反应状态和最低意识状态。值得注意的是，在单个病人的水平上，如果一个没有反应的病人有嗅觉反应，这就保证了未来的意识恢复。此外，嗅觉反应与长期存活率有关。这些结果突出了嗅觉在人脑功能中的重要性，并为脑损伤患者的意识和恢复提供了一种可访问的工具。气味依赖的嗅觉反应预测了严重脑损伤患者的长期生存率，并区分了无反应和最低意识状态的个体。
After severe brain injury, it can be difficult to determine the state of consciousness of a patient, to determine whether the patient is unresponsive or perhaps minimally conscious(1), and to predict whether they will recover. These diagnoses and prognoses are crucial, as they determine therapeutic strategies such as pain management, and can underlie end-of-life decisions(2,3). Nevertheless, there is an error rate of up to 40% in determining the state of consciousness in patients with brain injuries(4,5). Olfaction relies on brain structures that are involved in the basic mechanisms of arousal(6), and we therefore hypothesized that it may serve as a biomarker for consciousness(7). Here we use a non-verbal non-task-dependent measure known as the sniff response(8-11) to determine consciousness in patients with brain injuries. By measuring odorant-dependent sniffing, we gain a sensitive measure of olfactory function(10-15). We measured the sniff response repeatedly over time in patients with severe brain injuries and found that sniff responses significantly discriminated between unresponsive and minimally conscious states at the group level. Notably, at the single-patient level, if an unresponsive patient had a sniff response, this assured future regaining of consciousness. In addition, olfactory sniff responses were associated with long-term survival rates. These results highlight the importance of olfaction in human brain function, and provide an accessible tool that signals consciousness and recovery in patients with brain injuries.Odorant-dependent sniff responses predicted the long-term survival rates of patients with severe brain injury, and discriminated between individuals who were unresponsive and in minimally conscious states.