Subcortical atrophy correlates with the perturbational complexity index in patients with disorders of consciousness

BackgroundThe complexity of neurophysiological brain responses to direct cortical stimulation, referred to as the perturbational complexity index (PCI), has been shown able to discriminate between consciousness and unconsciousness in patients surviving severe brain injury as well as several other conditions (e.g., wake, dreamless sleep, sleep and ketamine dreaming, anesthesia).ObjectiveThis study asks whether, in patients with a disorder of consciousness (DOC), the complexity of the neurophysiological response to cortical stimulation is preferentially associated with atrophy within specific brain structures.MethodsWe perform a retrospective analysis of 40 DOC patients and correlate their maximal PCI to MR-based measurements of cortical thinning and subcortical atrophy.ResultsPCI was systematically and inversely associated with the degree of local atrophy within the globus pallidus, a region previously linked to electrocortical and behavioral arousal. Conversely, we fail to detect any association between variance in cortical ribbon thickness and PCI.ConclusionThese findings corroborate the previously reported association between pallidal atrophy and low behavioral arousal and suggest that this region’s role in maintaining the overall balance of excitation and inhibition may critically affect the emergence of complex cortical interactions in chronic disorders of consciousness. This finding thus also suggests a target for potential neuromodulatory intervention in DOC patients.     

The vigilance scale: An analysis of elicited behavioral responses

Summary The Vigilance Scale (VS) is a 12-step additive scale (Guttman scale) that allows assessment of the behavioral deficit in the unconscious state and the state of clouding of consciousness. Despite restrictions on its applicability, which are discussed in detail, the VS seems to be a useful measuring device that indicates the level of brain function a patient with a disturbance of consciousness can actually attain. There are two categories of scale errors to be found, the first being caused by various instrumental disorders, i.e., severe motor deficits, the second resulting from the probabilistic approach of the VS to a Guttman scale.     

Alterations in the contents of consciousness in partial epileptic seizures

Epilepsy research suffers from a deficiency of systematic studies concerning the phenomenology of the contents of consciousness during seizures, partially because of the lack of suitable research methods. The Phenomenology of Consciousness Inventory (PCI), a standardized, valid, and reliable questionnaire, was used here to study which dimensions of the contents of consciousness are distorted during partial epileptic seizures compared with baseline. Further, the similarity of the altered pattern of subjective experiences across recurring seizures was also explored. Our results indicate that patients with epilepsy report alterations on most dimensions of the contents of consciousness in conjunction with seizures, but individual seizure experiences remain similar from one seizure to another. The PCI was found suitable for the assessment of subjective experiences during epileptic seizures and could be a valuable tool in providing new information about phenomenal consciousness in epilepsy in both the research and clinical settings.     

Infectious diseases and impaired consciousness

Any of a number of neuroinfectious diseases can cause a disorder of consciousness. The priority in the care of the patient is to identify an infectious disease that is treatable. This article examines disorders of consciousness that may be caused by a septic encephalopathy, bacterial meningoencephalitis, viral encephalitis, tick-borne bacterial disease, fungal meningitis, tuberculous meningitis, a focal infectious mass lesion, such as a brain abscess, or an autoimmune-mediated disorder as a complication of infection.     

脑干意识中枢损伤的实验研究

目的：本研究旨在探索脑干意识中枢损伤对意识状态的影响及其形态学特征，为脑干意识中枢肿瘤的手术与术后治疗提供依据。方法：建立猫脑干意识中枢电凝损毁的动物模型，用意识水平与神经系统功能缺失记分进行神经行为学评价，用Ｅｖａｎｓ蓝和ＨＥ染色做脑干损伤的大体与光镜下观察，用透射电镜和扫描电镜观察脑干损伤的超微结构表现。结果：电凝损毁脑干各部位网状结构可引起不同程度的意识障碍和神经系统功能缺失，其神经系统功能缺失记分均高于假手术组。形态学研究发现，电凝损毁的中心部位以坏死为主，周围则坏死与凋亡并存，周围的微小血管异常是重要的继发性损伤。结论：电凝损毁脑干网状结构可引起意识障碍、神经系统功能缺失、形态学上的广泛异常和迟发性神经元与胶质细胞的死亡。     

The rise of machine consciousness: Studying consciousness with computational models

Efforts to create computational models of consciousness have accelerated over the last two decades, creating a field that has become known as artificial consciousness. There have been two main motivations for this controversial work: to develop a better scientific understanding of the nature of human/animal consciousness and to produce machines that genuinely exhibit conscious awareness. This review begins by briefly explaining some of the concepts and terminology used by investigators working on machine consciousness, and summarizes key neurobiological correlates of human consciousness that are particularly relevant to past computational studies. Models of consciousness developed over the last twenty years are then surveyed. These models are largely found to fall into five categories based on the fundamental issue that their developers have selected as being most central to consciousness: a global workspace, information integration, an internal self-model, higher-level representations, or attention mechanisms. For each of these five categories, an overview of past work is given, a representative example is presented in some detail to illustrate the approach, and comments are provided on the contributions and limitations of the methodology. Three conclusions are offered about the state of the field based on this review: (1) computational modeling has become an effective and accepted methodology for the scientific study of consciousness, (2) existing computational models have successfully captured a number of neurobiological, cognitive, and behavioral correlates of conscious information processing as machine simulations, and (3) no existing approach to artificial consciousness has presented a compelling demonstration of phenomenal machine consciousness, or even clear evidence that artificial phenomenal consciousness will eventually be possible. The paper concludes by discussing the importance of continuing work in this area, considering the ethical issues it raises, and making predictions concerning future developments.     

Consciousness and its function

It is plain that an individual's being conscious and an individual's being conscious of various things are both crucial for successful functioning. But it is far less clear how, if at all, it is also useful for a person's psychological states to occur consciously, as against those states occurring but without being conscious. Restricting attention to cognitive and desiderative states, a number of suggestions are current about how the consciousness of those states may be useful. It has been held that such consciousness enhances processes of rational thought and planning, intentional action, executive function, and the correction of complex reasoning. I examine these and related proposals in the light of various empirical findings and theoretical considerations and conclude that the consciousness of cognitive and desiderative states is unlikely to be useful in these or related ways. This undermines a reliance on evolutionary selection pressures in explaining why such states so often occur consciously in humans. I propose an alternative explanation, on which cognitive and desiderative states come to be conscious as a result of other highly useful psychological developments, some involving language. But on this explanation the consciousness of these states itself adds no significant function to that of those other developments.     

Concentrations of sulfur-containing free amino acids in lumbar cerebrospinal fluid from patients with consciousness disturbances

The concentrations of sulfur-containing amino acids (taurine, methionine, cystine, cystathionine, homocystine) in lumbar CSF from patients with consciousness disturbances and controls were measured, and it was investigated whether there was any correlation between the sequential changes of these amino acid concentrations and of the level of consciousness. In all patients, thyrotropin-releasing hormone (TRH) was administered and the changes of levels of consciousness and amino acid concentrations were followed before and after administration. The concentrations of taurine and cystathionine from the patients were significantly lower, and methionine and cystine significantly higher than those from the controls; they returned to the control values in parallel with improvement of consciousness level. Homocystine was not detected in either patients or controls. These results suggest that the alteration in the level of consciousness is associated with distortion of sulfur-containing amino acid metabolism within the central nervous system, at least in the CSF.     

意识障碍临床诊疗的现状与进展

随着重型颅脑损伤数量的增长以及救治技术的发展,越来越多的患者从昏迷演变成意识障碍(disorders of consciousness,DOC)。近年来,随着国际国内神经科学家和临床医生对DOC研究的日益关注和共同努力,以及神经影像学和神经调控技术的发展,在DOC的诊断、预判和治疗等方面都取得了很大的进展。     

脑室线性结构变化与严重意识障碍疾病的相关性研究

目的评价脑室线性结构在意识障碍(DOC)患者诊断和分级中的应用价值。方法收集2015年1月至2015年12月就诊于中国人民解放军陆军总医院的20例DOC患者,由两名主治医师根据CRS-R评分量表将患者分为无反应觉醒综合征组(UWS)和微意识状态组(MCS)。另选10例健康志愿者作为对照组。分析患者MRI T_1图像的结果,测量数据并探索这些测量指标与CRS-R评分之间的相关性。结果 UWS组和MCS组的Huckman值和第三脑室宽度明显高于对照组(均P0.05),而PDI指数和脑室指数则低于对照组(均P0.05),除Evans值外其余各指标在UWS组和MCS组之间差别也具有统计学意义(均P0.05)。Huckman值和第三脑室宽度与CRS-R评分呈负相关,而PDI指数和脑室指数则相反。结论脑室线性结构测量可以用于DOC患者意识水平的评估。     

Animal consciousness

The cognitive states that underlie animal behavior may include conscious, subjective, mental experiences. Familiar arguments to the contrary are inconclusive. Interactive communication between social animals may well include the exchange of information about subjective feelings and thoughts. Objective data about the subjective experiences of certain animals may thus be potentially accessible through analysis of their communicative signals.     

Neural correlates of primary and reflective consciousness of spatial orienting

Using functional magnetic resonance imaging, we asked participants to perform a visual target detection task with peripheral cues. In the first part of the experiment, cues were not predictive of the side of occurrence of the incoming target. In the second part of the experiment, unbeknownst to the participants, cues became 80% predictive, thus inducing an endogenous orienting of spatial attention. Confirming previous results, in the second part response times (RTs) decreased for validly cued trials and increased for invalid trials. Half of the participants were subsequently able to correctly describe the cue-target relationships ('verbalizers'), thus demonstrating reflective consciousness of endogenous orienting. Also non-verbalizer participants showed a similar RT pattern, indicating the occurrence of endogenous orienting without reflective consciousness. Both groups of participants showed fronto-parietal activity typically observed in spatial attention tasks. Verbalizers, in addition, demonstrated stronger activity in the anterior cingulate cortex (ACC), consistent with the proposed role of this structure in purposeful behaviour and in the monitoring of its consequences. The extensive pattern of connectivity of the ACC is ideally suited to integrate the activity of the large neural assemblies necessary for reflective consciousness to emerge.     

脑机接口技术在慢性意识障碍诊疗中的应用进展

慢性意识障碍(DOC)包括植物状态(VS)或无反应觉醒综合征(UWS)和微意识状态(MCS),目前临床鉴别诊断以及治疗仍是难题。慢性意识障碍评估,目前临床使用较多的是量表,但存在误判。为了提高诊断准确率,出现一些基于神经影像学的辅助检测方法,如脑机接口(BCI)技术。BCI主要通过脑电信号的处理用人机对话的方法检测患者是否存在指令跟随,被用于意识障碍患者意识状态的检测及康复治疗的评价。本文简述BCI技术特点及在慢性意识障碍中的应用前景。     

Trauma and impaired consciousness

This article discusses brain trauma and impaired consciousness. It reviews the various states of impaired consciousness related to trauma, with an historical and current literature viewpoint. The causes and pathophysiology of impaired consciousness in concussion, diffuse axonal injury, and focal brain lesions are discussed and management options evaluated.     

重症颅脑外伤的救治与意识障碍的康复(附960例分析)

目的 探讨重症颅脑外伤的抢救和意识障碍的治疗效果。方法对960例病人的临床治疗结果进行回顾性分析。结果全组960例病人，死亡254例(26、5％)，植物生存31例(3.3％)，重残95例(9.8％)，中残107例(11．1％)，恢复良好473例(49.3％)。结论保持呼吸通畅，及时手术解除脑疝，术后尽快恢复脑水肿，治疗并发症，应用神经细胞营养剂、催醒剂、高压氧、物理康复治疗等手段进行综合救治措施能使重症颅脑外伤的存活率提高，意识障碍苏醒率增高。     

由缺血缺氧性脑病导致的意识障碍患者意识恢复的相关因素分析

目的探讨由缺血缺氧性脑病导致的意识障碍患者的临床特点及影响意识康复的相关因素。方法回顾性分析2013年10月至2018年10月在南部战区总医院神经康复一科住院的46例由缺血缺氧性脑病导致慢性意识障碍患者的临床资料,采用二元logistic回归方法对可能影响意识恢复的相关因素进行分析。结果单因素分析显示植物状态持续时间(P 0. 001)、发病至神经康复时间(P=0. 001)、(CRS-R)评分(P=0. 016)、性别(P=0. 034)、阵发性交感神经过度兴奋(P=0. 016)、体感诱发电位(P=0. 002)和脑电图(P=0. 003)与意识恢复相关,差异具有统计学意义(P 0. 05)。logistic回归分析显示,植物状态持续时间(OR=1. 077,95%CI:1. 009～1. 148,P=0. 025)、阵发性交感神经过度兴奋(OR=15. 511,95%CI:1. 210～198. 833,P=0. 035)是意识恢复的独立影响因素。结论植物状态持续时间过长、阵发性交感神经过度兴奋的出现是影响缺血缺氧性脑病慢性意识障碍患者意识恢复的临床指标。     

由缺血缺氧性脑病导致的意识障碍患者意识恢复的相关因素分析

目的 探讨由缺血缺氧性脑病导致的意识障碍患者的临床特点及影响意识康复的相关因素。方法 回顾性分析2013年10月至2018年10月在南部战区总医院神经康复一科住院的46例由缺血缺氧性脑病导致慢性意识障碍患者的临床资料,采用二元logistic回归方法对可能影响意识恢复的相关因素进行分析。结果 单因素分析显示植物状态持续时间（P<0.001）、发病至神经康复时间（P=0.001）、（CRS-R）评分（P=0.016）、性别（P=0.034）、阵发性交感神经过度兴奋（P=0.016）、体感诱发电位（P=0.002）和脑电图（P=0.003）与意识恢复相关,差异具有统计学意义（P<0.05）。logistic回归分析显示,植物状态持续时间（OR=1.077,95%CI：1.009~1.148,P=0.025）、阵发性交感神经过度兴奋（OR=15.511,95%CI：1.210~198.833,P=0.035）是意识恢复的独立影响因素。结论 植物状态持续时间过长、阵发性交感神经过度兴奋的出现是影响缺血缺氧性脑病慢性意识障碍患者意识恢复的临床指标。     

慢性意识障碍合并脑积水的临床特征与疗效分析

目的探讨慢性意识障碍(DOC)合并脑积水的临床特征与治疗效果。方法回顾性分析首都医科大学三博脑科医院2014年1月—2017年12月收治的43例慢性意识障碍合并脑积水患者的临床资料。分析指标主要包括:病因、临床表现、影像学表现、意识障碍程度、发生脑积水的时间及治疗效果。结果在同期收治的120例慢性意识障碍患者中,43例患者(35.8%)被诊断为脑积水接受了分流手术治疗。本组患者中,导致脑积水的原发病因主要为颅脑创伤(18例,41.8%)和蛛网膜下腔出血(11例,25.6%);意识障碍为植物状态者11例(25.6%),最小意识状态者17例(39.5%)。脑积水患者初始症状多表现为意识下降(74.4%)、消化不良(58.1%)和肌张力增高(39.5%)。不同意识障碍程度的患者出现脑积水的时间也存在差异,严重患者(CRS-R评分<6分)脑积水主要发生在1个月内(72.8%);中度患者(CRS-R评分6~9分)和轻度患者(CRS-R评分>9分)患者多发生在4~12周,分别占60.9%和48.8%,但是不同组别差异无统计学意义(P=0.1003)。分流手术后患者症状多有不同程度的改善,其中CRS-R评分总体改善患者达77.4%,消化功能改善达75%,肌张力改善达55%。结论慢性意识障碍患者合并脑积水起病隐匿,无特殊临床表现;在影像学表现方面需与脑萎缩导致的脑室扩张鉴别。分流手术能在很大程度上改善脑积水的临床预后。     

Electroencephalography quadratic phase self-coupling correlates with consciousness states and restoration in patients with disorders of consciousness

ObjectiveThe objective of this study was to explore the role for quadratic phase coupling within electroencephalography (EEG) oscillations in the diagnosis of consciousness and consciousness restoration for disorders of consciousness (DOC).MethodsFifty-one DOC patients were enrolled in this study. For each patient, a Coma Recovery Scale-Revised (CRS-R) score and 20-min resting-state EEG were recorded. Consciousness recovery was assessed with a CRS-R score at a three-month follow-up. Twenty healthy subjects were included as controls. General harmonic wavelet transform-based bicoherence was used to quantify the quadratic phase coupling characteristics of the EEG oscillations.ResultsQuadratic phase self-coupling (QPSC) at the delta (QPSC_delta), theta (QPSC_theta) and alpha (QPSC_alpha) bands were closely correlated with patient CRS-R scores. Particularly, the QPSC_theta value could significantly differentiate between vegetative state (VS) patients, minimally conscious state (MCS) patients and healthy control subjects. As compared to VS patients, patients with MCS had a lower QPSC_theta value on the left as well as a higher QPSC_alpha value in right frontal regions. The frontal QPSC_theta value showed significant differences between recovered and unrecovered patients.ConclusionQPSC characteristics could differentiate between consciousness states and show a predictive ability for the recovery of consciousness in DOC patients.SignificanceChanges in QPSC accompany consciousness injury and restoration in DOC patients. A QPSC assessment is helpful in the diagnosis and prognosis of DOC patients.     

Detecting early recovery of consciousness: a comparison of methods

ABSTRACT

Early detection of the return of consciousness has important implications for prognosis and rehabilitation access. The aim of this study was to compare the Coma Recovery Scale–Revised (CRS-R) with individualised quantitative behavioural assessments (IQBA) to determine which method is capable of detecting command-following earlier and more consistently in persons with disorders of consciousness (DoC). Data from 27 patients with DoC, who underwent both assessments concurrently during inpatient rehabilitation, were retrospectively analysed. For each person, performance trajectories on the CRS-R auditory subscale item and IQBA dual command protocols were graphed together to identify earlier and more consistent evidence of consciousness; grouped data were analysed statistically. For 22 patients, IQBA more consistently documented consciousness than the CRS-R, whereas no patients showed the reverse pattern. For 14 of 20 analysable patients, IQBA provided earlier evidence of consciousness, for two patients CRS-R provided earlier evidence, and for four patients both methods provided initial evidence on the same day. These findings suggest that IQBA approaches can provide more consistent and earlier evidence of command-following than the comparable item on the CRS-R. Whether this advantage is due to the individualisation of IQBA or the greater volume of data gathered requires further research.