脳活動計測により無反応患者の意識を検出(Using brain technology, awareness is detected in unresponsive patients)

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2026-06-30 バース大学

英国のUniversity of Bathなどの国際研究チームは、重度の脳損傷により外見上は反応を示さない患者の意識を、脳活動を利用して検出できる技術の有効性を示した。研究では、脳波(EEG)や機能的MRI(fMRI)などのブレイン・コンピューター・インターフェース(BCI)技術を用い、患者に特定の課題を心の中で実行してもらうことで、外部からは反応が見られなくても意識的な脳活動を検出できることを確認した。この方法により、従来は意識がないと判断されていた一部の患者に「隠れた意識(Covert Consciousness)」が存在することが明らかになり、診断精度の向上や予後予測、治療方針の決定に役立つ可能性が示された。また、将来的には患者との意思疎通手段として応用できる可能性も期待される。一方で、すべての患者に適用できるわけではなく、測定環境や解析方法の標準化、倫理的配慮などが今後の課題として挙げられている。本研究は、意識障害患者の評価を客観化し、神経リハビリテーションや神経医療の発展につながる重要な成果である。

<関連情報>

長期にわたる意識障害における意識および認知の脳波に基づく評価の進歩 Advancing EEG-based assessment of consciousness and cognition in prolonged disorders of consciousness

Naomi du Bois,Attila Korik,Stephanie Hodge,Leah Hudson,Ainjila S. Elahi,Alain Bigirimana,Natalie Dayan,Jose M. Sanchez-Bornot,Alison McCann,Kudret Yelden,Lloyd Bradley,Krishnan P. S. Nair,Simon Judge,Damon Hoad,Emma Vines,Venu Harilal,Sheryl Parke,Paul Johnson,Jacqueline Pogue,Emma Dodds,Abayomi Salawu,Raymond Carson,Karl McCreadie,Jacqueline Stow,… Damien Coyle
Communications Medicine  Published:17 April 2026
DOI:https://doi.org/10.1038/s43856-026-01574-x

脳活動計測により無反応患者の意識を検出(Using brain technology, awareness is detected in unresponsive patients)

Abstract

Background

Accurate assessment of residual awareness in patients with Prolonged Disorders of Consciousness (PDoC) remains a major clinical challenge, as conventional behavioural tools can underestimate covert cognition. This study evaluates whether a structured, multi-phase motor imagery Brain–Computer Interface (MI-BCI) protocol provides objective electroencephalography (EEG)-based indicators of awareness that complement behavioural assessments.

Methods

Forty-four participants (N = 44) completed repeated imagined-movement tasks using wearable EEG (PDoC: Unresponsive Wakefulness Syndrome (UWS, n = 14), Minimally Conscious State (MCS, n = 17), Locked-In Syndrome (LIS, n = 11); two able-bodied participants as benchmarks; ClinicalTrials.gov: NCT03827187; 30-01-2019). The protocol assessed sensorimotor rhythm modulation, training with and without neurofeedback, and binary question answering across phases. Standard behavioural assessments (CRS-R and WHIM) were administered at each session.

Results

Significant MI-BCI decoding accuracy (DA) is achieved by 73.8% of patients, of whom 90% progress to Q&A testing and frequently exceed the 70% usability threshold, revealing marked inter-individual heterogeneity. For significant MI-BCI runs, LIS outperform MCS (p = 0.007) and UWS (p = 0.048), while UWS exceed MCS during Q&A (p = 0.049), driven by familiar-voice stimuli. Using leave-one-subject-out cross-validation, combining predictions from DA and behavioural assessments improves balanced diagnostic accuracy to 62% (from 55%), increasing sensitivity to MCS (39% to 69%), with a modest reduction in LIS sensitivity (78% to 67%). Task-related activity over sensorimotor and parietal cortices differentiate diagnostic groups.

Conclusions

The structured MI-BCI protocol demonstrates potential as a movement-independent, EEG-based tool for distinguishing UWS, MCS and LIS. Integrating DA and spatial patterns yields diagnostic information that may augment behavioural assessment and advance objective tools for evaluating awareness in PDoC.

生物工学一般
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