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Carrasco M, Spering M. Perception-action Dissociations as a Window into Consciousness. J Cogn Neurosci 2024; 36:1557-1566. [PMID: 38865201 DOI: 10.1162/jocn_a_02122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Understanding the neural correlates of unconscious perception stands as a primary goal of experimental research in cognitive psychology and neuroscience. In this Perspectives paper, we explain why experimental protocols probing qualitative dissociations between perception and action provide valuable insights into conscious and unconscious processing, along with their corresponding neural correlates. We present research that utilizes human eye movements as a sensitive indicator of unconscious visual processing. Given the increasing reliance on oculomotor and pupillary responses in consciousness research, these dissociations also provide a cautionary tale about inferring conscious perception solely based on no-report protocols.
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2
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Lo CCH, Woo PYM, Cheung VCK. Task-based EEG and fMRI paradigms in a multimodal clinical diagnostic framework for disorders of consciousness. Rev Neurosci 2024; 0:revneuro-2023-0159. [PMID: 38804042 DOI: 10.1515/revneuro-2023-0159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 05/09/2024] [Indexed: 05/29/2024]
Abstract
Disorders of consciousness (DoC) are generally diagnosed by clinical assessment, which is a predominantly motor-driven process and accounts for up to 40 % of non-communication being misdiagnosed as unresponsive wakefulness syndrome (UWS) (previously known as prolonged/persistent vegetative state). Given the consequences of misdiagnosis, a more reliable and objective multimodal protocol to diagnosing DoC is needed, but has not been produced due to concerns regarding their interpretation and reliability. Of the techniques commonly used to detect consciousness in DoC, task-based paradigms (active paradigms) produce the most unequivocal result when findings are positive. It is well-established that command following (CF) reliably reflects preserved consciousness. Task-based electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can detect motor-independent CF and reveal preserved covert consciousness in up to 14 % of UWS patients. Accordingly, to improve the diagnostic accuracy of DoC, we propose a practical multimodal clinical decision framework centered on task-based EEG and fMRI, and complemented by measures like transcranial magnetic stimulation (TMS-EEG).
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Affiliation(s)
- Chris Chun Hei Lo
- School of Biomedical Sciences, and Gerald Choa Neuroscience Institute, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Peter Yat Ming Woo
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Vincent C K Cheung
- School of Biomedical Sciences, and Gerald Choa Neuroscience Institute, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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3
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Șerban CA, Barborică A, Roceanu AM, Mîndruță IR, Ciurea J, Stancu M, Pâslaru AC, Zăgrean AM, Zăgrean L, Moldovan M. Towards an electroencephalographic measure of awareness based on the reactivity of oscillatory macrostates to hearing a subject's own name. Eur J Neurosci 2024; 59:771-785. [PMID: 37675619 DOI: 10.1111/ejn.16138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 08/09/2023] [Accepted: 08/16/2023] [Indexed: 09/08/2023]
Abstract
We proposed that the brain's electrical activity is composed of a sequence of alternating states with repeating topographic spectral distributions on scalp electroencephalogram (EEG), referred to as oscillatory macrostates. The macrostate showing the largest decrease in the probability of occurrence, measured as a percentage (reactivity), during sensory stimulation was labelled as the default EEG macrostate (DEM). This study aimed to assess the influence of awareness on DEM reactivity (DER). We included 11 middle cerebral artery ischaemic stroke patients with impaired awareness having a median Glasgow Coma Scale (GCS) of 6/15 and a group of 11 matched healthy controls. EEG recordings were carried out during auditory 1 min stimulation epochs repeating either the subject's own name (SON) or the SON in reverse (rSON). The DEM was identified across three SON epochs alternating with three rSON epochs. Compared with the patients, the DEM of controls contained more posterior theta activity reflecting source dipoles that could be mapped in the posterior cingulate cortex. The DER was measured from the 1 min quiet baseline preceding each stimulation epoch. The difference in mean DER between the SON and rSON epochs was measured by the salient EEG reactivity (SER) theoretically ranging from -100% to 100%. The SER was 12.4 ± 2.7% (Mean ± standard error of the mean) in controls and only 1.3 ± 1.9% in the patient group (P < 0.01). The patient SER decreased with the Glasgow Coma Scale. Our data suggest that awareness increases DER to SON as measured by SER.
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Affiliation(s)
- Cosmin-Andrei Șerban
- Physics Department, University of Bucharest, Bucharest, Romania
- Termobit Prod SRL, Bucharest, Romania
- FHC Inc, Bowdoin, Maine, USA
| | - Andrei Barborică
- Physics Department, University of Bucharest, Bucharest, Romania
- Termobit Prod SRL, Bucharest, Romania
- FHC Inc, Bowdoin, Maine, USA
| | | | | | - Jan Ciurea
- Department of Neurosurgery, Bagdasar-Arseni Emergency Hospital, Bucharest, Romania
| | - Mihai Stancu
- Division of Physiology and Neuroscience, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Division of Neurobiology, Faculty of Biology, Ludwig Maximilian University, Munich, Germany
| | - Alexandru C Pâslaru
- Division of Physiology and Neuroscience, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Ana-Maria Zăgrean
- Division of Physiology and Neuroscience, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Leon Zăgrean
- Division of Physiology and Neuroscience, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Mihai Moldovan
- Termobit Prod SRL, Bucharest, Romania
- Division of Physiology and Neuroscience, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Clinical Neurophysiology and Neurology, Rigshospitalet, Copenhagen, Denmark
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4
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Comanducci A, Casarotto S, Rosanova M, Derchi CC, Viganò A, Pirastru A, Blasi V, Cazzoli M, Navarro J, Edlow BL, Baglio F, Massimini M. Unconsciousness or unresponsiveness in akinetic mutism? Insights from a multimodal longitudinal exploration. Eur J Neurosci 2024; 59:860-873. [PMID: 37077023 DOI: 10.1111/ejn.15994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/02/2023] [Accepted: 04/17/2023] [Indexed: 04/21/2023]
Abstract
The clinical assessment of patients with disorders of consciousness (DoC) relies on the observation of behavioural responses to standardised sensory stimulation. However, several medical comorbidities may directly impair the production of reproducible and appropriate responses, thus reducing the sensitivity of behaviour-based diagnoses. One such comorbidity is akinetic mutism (AM), a rare neurological syndrome characterised by the inability to initiate volitional motor responses, sometimes associated with clinical presentations that overlap with those of DoC. In this paper, we describe the case of a patient with large bilateral mesial frontal lesions, showing prolonged behavioural unresponsiveness and severe disorganisation of electroencephalographic (EEG) background, compatible with a vegetative state/unresponsive wakefulness syndrome (VS/UWS). By applying an unprecedented multimodal battery of advanced imaging and electrophysiology-based techniques (AIE) encompassing spontaneous EEG, evoked potentials, event-related potentials, transcranial magnetic stimulation combined with EEG and structural and functional MRI, we provide the following: (i) a demonstration of the preservation of consciousness despite unresponsiveness in the context of AM, (ii) a plausible neurophysiological explanation for behavioural unresponsiveness and its subsequent recovery during rehabilitation stay and (iii) novel insights into the relationships between DoC, AM and parkinsonism. The present case offers proof-of-principle evidence supporting the clinical utility of a multimodal hierarchical workflow that combines AIEs to detect covert signs of consciousness in unresponsive patients.
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Affiliation(s)
| | - Silvia Casarotto
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
- Department Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Mario Rosanova
- Department Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | | | | | | | - Valeria Blasi
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
| | - Marta Cazzoli
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
| | - Jorge Navarro
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
| | - Brian L Edlow
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | | - Marcello Massimini
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
- Department Biomedical and Clinical Sciences, University of Milan, Milan, Italy
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5
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Arciniegas DB, Gurin LJ, Zhang B. Structural and Functional Neuroanatomy of Core Consciousness: A Primer for Disorders of Consciousness Clinicians. Phys Med Rehabil Clin N Am 2024; 35:35-50. [PMID: 37993192 DOI: 10.1016/j.pmr.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Understanding the structural and functional neuroanatomy of core consciousness (ie, wakefulness and awareness) is an asset to clinicians caring for persons with disorders of consciousness. This article provides a primer on the structural and functional neuroanatomy of wakefulness and awareness. The neuroanatomical structures supporting these elements of core consciousness functions are reviewed first, after which brief description of the clinically evaluable relationships between disruption of these structures and disorders of consciousness (ie, brain-behavior relationships) are outlined. Consideration of neuroanatomy at the mesoscale (ie, the mesocircuit hypothesis) as well as in relation to several large-scale neural networks is offered.
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Affiliation(s)
- David B Arciniegas
- Marcus Institute for Brain Health, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Neurology, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Psychiatry, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Psychiatry and Behavioral Sciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA.
| | - Lindsey J Gurin
- Department of Neurology, NYU Grossman School of Medicine, New York, NY 10017, USA; Department of Psychiatry, NYU Grossman School of Medicine, New York, NY 10016, USA; Department of Physical Medicine & Rehabilitation, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Bei Zhang
- Division of Physical Medicine and Rehabilitation, Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Assessing Cognitive Outcomes in Coma Survivors: A Literature Review. Brain Sci 2023; 13:brainsci13010096. [PMID: 36672078 PMCID: PMC9856711 DOI: 10.3390/brainsci13010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023] Open
Abstract
(1) Background: Although cognitive impairments in coma survivors are common, methods of measuring long-term cognitive outcomes in this population are inconsistent, precluding the development of a strong evidence-base to support clinical decision making. In this literature review, we identify and characterize the measures used to track cognitive recovery in coma survivors to data. (2) Methods: We extracted the instrument used for cognitive assessment, the cognitive domains assessed, methods administration and scoring, and timing of assessment from 134 of 996 screened records. (3) Results: A total of 133 unique cognitive tests and cognitive testing batteries were identified, with 97 cognitive instruments used in less than three articles. The instruments assessed 20 different cognitive domains, with 73 articles also using tests that assess general "cognitive ability". Cognitive instruments ranged from subjective assessments to comprehensive cognitive batteries. There were inconsistent points of reference for the timing of assessment across studies, with few studies repeating assessments at more than one time point, and arbitrary time intervals between tests. (4) Conclusions: Overall, this review illustrates the enormous disparity between studies that track cognitive outcome in coma survivors, and the need for a systematic, patient-accessible method of assessing cognitive functioning in future studies with this population.
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Communicating With Unconscious Patients. Dimens Crit Care Nurs 2023; 42:3-11. [DOI: 10.1097/dcc.0000000000000561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Galiotta V, Quattrociocchi I, D'Ippolito M, Schettini F, Aricò P, Sdoia S, Formisano R, Cincotti F, Mattia D, Riccio A. EEG-based Brain-Computer Interfaces for people with Disorders of Consciousness: Features and applications. A systematic review. Front Hum Neurosci 2022; 16:1040816. [PMID: 36545350 PMCID: PMC9760911 DOI: 10.3389/fnhum.2022.1040816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/17/2022] [Indexed: 12/11/2022] Open
Abstract
Background Disorders of Consciousness (DoC) are clinical conditions following a severe acquired brain injury (ABI) characterized by absent or reduced awareness, known as coma, Vegetative State (VS)/Unresponsive Wakefulness Syndrome (VS/UWS), and Minimally Conscious State (MCS). Misdiagnosis rate between VS/UWS and MCS is attested around 40% due to the clinical and behavioral fluctuations of the patients during bedside consciousness assessments. Given the large body of evidence that some patients with DoC possess "covert" awareness, revealed by neuroimaging and neurophysiological techniques, they are candidates for intervention with brain-computer interfaces (BCIs). Objectives The aims of the present work are (i) to describe the characteristics of BCI systems based on electroencephalography (EEG) performed on DoC patients, in terms of control signals adopted to control the system, characteristics of the paradigm implemented, classification algorithms and applications (ii) to evaluate the performance of DoC patients with BCI. Methods The search was conducted on Pubmed, Web of Science, Scopus and Google Scholar. The PRISMA guidelines were followed in order to collect papers published in english, testing a BCI and including at least one DoC patient. Results Among the 527 papers identified with the first run of the search, 27 papers were included in the systematic review. Characteristics of the sample of participants, behavioral assessment, control signals employed to control the BCI, the classification algorithms, the characteristics of the paradigm, the applications and performance of BCI were the data extracted from the study. Control signals employed to operate the BCI were: P300 (N = 19), P300 and Steady-State Visual Evoked Potentials (SSVEP; hybrid system, N = 4), sensorimotor rhythms (SMRs; N = 5) and brain rhythms elicited by an emotional task (N = 1), while assessment, communication, prognosis, and rehabilitation were the possible applications of BCI in DoC patients. Conclusion Despite the BCI is a promising tool in the management of DoC patients, supporting diagnosis and prognosis evaluation, results are still preliminary, and no definitive conclusions may be drawn; even though neurophysiological methods, such as BCI, are more sensitive to covert cognition, it is suggested to adopt a multimodal approach and a repeated assessment strategy.
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Affiliation(s)
- Valentina Galiotta
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Ilaria Quattrociocchi
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,Department of Computer, Control, and Management Engineering “Antonio Ruberti”, Sapienza University of Rome, Rome, Italy
| | - Mariagrazia D'Ippolito
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,*Correspondence: Mariagrazia D'Ippolito
| | - Francesca Schettini
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,Servizio di Ausilioteca per la Riabilitazione Assistita con Tecnologia, Fondazione Santa Lucia (IRCCS), Rome, Italy
| | - Pietro Aricò
- Department of Computer, Control, and Management Engineering “Antonio Ruberti”, Sapienza University of Rome, Rome, Italy,Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy,BrainSigns srl, Rome, Italy
| | - Stefano Sdoia
- Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Rita Formisano
- Neurorehabilitation 2 and Post-Coma Unit, Fondazione Santa Lucia (IRCCS), Rome, Italy
| | - Febo Cincotti
- Department of Computer, Control, and Management Engineering “Antonio Ruberti”, Sapienza University of Rome, Rome, Italy
| | - Donatella Mattia
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,Servizio di Ausilioteca per la Riabilitazione Assistita con Tecnologia, Fondazione Santa Lucia (IRCCS), Rome, Italy
| | - Angela Riccio
- Neuroelectric Imaging and Brain-Computer Interface Laboratory, Fondazione Santa Lucia (IRCCS), Rome, Italy,Servizio di Ausilioteca per la Riabilitazione Assistita con Tecnologia, Fondazione Santa Lucia (IRCCS), Rome, Italy
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9
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Trajkovic J, Di Gregorio F, Marcantoni E, Thut G, Romei V. A TMS/EEG protocol for the causal assessment of the functions of the oscillatory brain rhythms in perceptual and cognitive processes. STAR Protoc 2022; 3:101435. [PMID: 35677610 PMCID: PMC9168164 DOI: 10.1016/j.xpro.2022.101435] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The combined use of transcranial magnetic stimulation (TMS), electroencephalogram (EEG), and behavioral performance allows investigation of causal relationships between neural markers and their functional relevance across a number of perceptual and cognitive processes. Here, we present a protocol for combining and applying these techniques on human subjects. We describe correlation approach and causal approach to disentangle the role of different oscillatory parameters, namely alpha frequency and amplitude that control for accuracy and metacognitive abilities, respectively, in a visual detection task. For complete details on the use and execution of this protocol, please refer to Di Gregorio et al. (2022). EEG-behavior correlations to frame hypotheses on how the brain shapes behavior Combined TMS-EEG-behavior to establish causal brain-behavior relationships Tune alpha frequency and amplitude to shape perceptual accuracy and metacognition
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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10
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Istace T. Empowering the voiceless. Disorders of consciousness, neuroimaging and supported decision-making. Front Psychiatry 2022; 13:923488. [PMID: 36147989 PMCID: PMC9488582 DOI: 10.3389/fpsyt.2022.923488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Patients suffering from (Prolonged) Disorder of Consciousness are deemed incompetent to give valid informed consent due to the presumed impairment of their cognitive functions and the impossibility to communicate with them. Neuroscientists have, however, discovered ways in which communication with some of these patients might be possible by using neuroimaging. This would for the first time make it possible to include them in the decision-making on their own medical treatment. In this article, I elaborate on the prospect of communicating with patients with impaired consciousness in order to obtain their informed consent. I first map the current state-of-the-art in neuroimaging research that exhibits the possibility of communicating with some of these patients. Secondly, I examine how obtaining informed consent from these patients might be possible, given that the specificities and limitations of communication via neuroimaging render the task of assessing their competence rather difficult. Thirdly, I identify some of the important ethical and legal considerations that have to be taken into account before introducing neuroimaging in clinical practice as a means to obtain informed consent. Lastly, I look into the concept of supported decision-making and how this concept relates to the use of neurotechnology to support minimally conscious patients in their abilities to decide over their own medical treatment.
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Affiliation(s)
- Timo Istace
- Department of Law, Research Group Personal Rights and Property Rights, University of Antwerp, Antwerp, Belgium.,Antwerp Health Law and Ethics Chair (AHLEC), Antwerp, Belgium
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11
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Eliciting and Recording Event Related Potentials (ERPs) in Behaviourally Unresponsive Populations: A Retrospective Commentary on Critical Factors. Brain Sci 2021; 11:brainsci11070835. [PMID: 34202435 PMCID: PMC8301772 DOI: 10.3390/brainsci11070835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/19/2021] [Accepted: 06/19/2021] [Indexed: 12/05/2022] Open
Abstract
A consistent limitation when designing event-related potential paradigms and interpreting results is a lack of consideration of the multivariate factors that affect their elicitation and detection in behaviorally unresponsive individuals. This paper provides a retrospective commentary on three factors that influence the presence and morphology of long-latency event-related potentials—the P3b and N400. We analyze event-related potentials derived from electroencephalographic (EEG) data collected from small groups of healthy youth and healthy elderly to illustrate the effect of paradigm strength and subject age; we analyze ERPs collected from an individual with severe traumatic brain injury to illustrate the effect of stimulus presentation speed. Based on these critical factors, we support that: (1) the strongest paradigms should be used to elicit event-related potentials in unresponsive populations; (2) interpretation of event-related potential results should account for participant age; and (3) speed of stimulus presentation should be slower in unresponsive individuals. The application of these practices when eliciting and recording event-related potentials in unresponsive individuals will help to minimize result interpretation ambiguity, increase confidence in conclusions, and advance the understanding of the relationship between long-latency event-related potentials and states of consciousness.
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12
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Nekrasova J, Kanarskii M, Borisov I, Pradhan P, Shunenkov D, Vorobiev A, Smirnova M, Pasko V, Petrova MV, Luginina E, Pryanikov I. One-Year Demographical and Clinical Indices of Patients with Chronic Disorders of Consciousness. Brain Sci 2021; 11:brainsci11050651. [PMID: 34065687 PMCID: PMC8156613 DOI: 10.3390/brainsci11050651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
This work aims to evaluate the prognostic value of the demographical and clinical data on long-term outcomes (up to 12 months) in patients with severe acquired brain injury with vegetative state/unresponsive wakefulness syndrome (VS/UWS/UWS) or a minimally conscious state (MCS). Patients (n = 211) with VS/UWS/UWS (n = 123) and MCS (n = 88) were admitted to the Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology after anoxic brain injury (n = 53), vascular lesions (n = 59), traumatic brain injury (n = 93), and other causes (n = 6). At the beginning of the 12-month study, younger age and a higher score by the Coma Recovery Scale-Revised (CRS-R) predicted a survival. However, no reliable markers of significant positive dynamics of consciousness were found. Based on the etiology, anoxic brain injury has the most unfavorable prognosis. For patients with vascular lesions, the first three months after injury have the most important prognostic value. No correlations were found between survival, increased consciousness, and gender. The demographic and clinical characteristics of patients with chronic DOC can be used to predict long-term mortality in patients with chronic disorders of consciousness. Further research should be devoted to finding reliable predictors of recovery of consciousness.
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Affiliation(s)
- Julia Nekrasova
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Mikhail Kanarskii
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Ilya Borisov
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Pranil Pradhan
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
- Correspondence: ; Tel.: +7-(977)-709-4468
| | - Denis Shunenkov
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Alexey Vorobiev
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Maria Smirnova
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Vera Pasko
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Marina V. Petrova
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
- Department of Anestesiology-Reanimatology, People’s Friendship University of Russia, 117198 Moscow, Russia
| | - Elena Luginina
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
| | - Igor Pryanikov
- Department for the Study of Chronic Disorder of Consciousness, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia; (J.N.); (M.K.); (I.B.); (D.S.); (A.V.); (I.P.); (M.S.); (V.P.); (M.V.P.); (E.L.)
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13
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Picolas C. Is the “Minimally Conscious State” Patient Minimally Self-Aware? Front Psychol 2020; 11:539665. [PMID: 33281657 PMCID: PMC7689014 DOI: 10.3389/fpsyg.2020.539665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022] Open
Abstract
Patients in a Minimally Conscious State (MCS) constitute a subgroup of awareness impaired patients who show minimal signs of awareness as opposed to patients in a Vegetative State who do not exhibit any such signs. While the empirical literature is rich in studies investigating either overt or covert signs of awareness in such patients the question of self-awareness has only scarcely been addressed. Even in the occasion where self-awareness is concerned, it is only higher-order or reflective self-awareness that is the target of such investigations. In the first part of this paper, I briefly review the relevant clinical neuroscience literature to demonstrate that the conception of self-awareness at play in such studies is indeed that of reflective self-awareness. In the second part, I present the philosophical notion of pre-reflective (or minimal) self-awareness. This is shown to primarily refer to the implicit awareness of our embodied subjectivity which essentially permeates all our experiences. As discussed, this minimal self-awareness is not specifically addressed when clinically or experimentally assessing patients in MCS. My suggestion is that neuroimaging studies targeting minimal self-awareness as in First-Person Perspective-taking paradigms could be used with MCS patients to shed light on the question of whether those individuals are minimally self-aware even in the case where they lack self-reflective abilities. Empirical evidence of this kind could have important theoretical implications for the discussion about the notion of self-awareness but also potential medical and social/legal implications for awareness impaired patients’ management.
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Affiliation(s)
- Constantinos Picolas
- Department of Philosophy, University of Patras, Patras, Greece
- Department of Neurosurgery, Nicosia General Hospital, Strovolos, Cyprus
- *Correspondence: Constantinos Picolas,
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14
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Franceschiello B, Di Sopra L, Minier A, Ionta S, Zeugin D, Notter MP, Bastiaansen JAM, Jorge J, Yerly J, Stuber M, Murray MM. 3-Dimensional magnetic resonance imaging of the freely moving human eye. Prog Neurobiol 2020; 194:101885. [PMID: 32653462 DOI: 10.1016/j.pneurobio.2020.101885] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/21/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022]
Abstract
Eye motion is a major confound for magnetic resonance imaging (MRI) in neuroscience or ophthalmology. Currently, solutions toward eye stabilisation include participants fixating or administration of paralytics/anaesthetics. We developed a novel MRI protocol for acquiring 3-dimensional images while the eye freely moves. Eye motion serves as the basis for image reconstruction, rather than an impediment. We fully reconstruct videos of the moving eye and head. We quantitatively validate data quality with millimetre resolution in two ways for individual participants. First, eye position based on reconstructed images correlated with simultaneous eye-tracking. Second, the reconstructed images preserve anatomical properties; the eye's axial length measured from MRI images matched that obtained with ocular biometry. The technique operates on a standard clinical setup, without necessitating specialized hardware, facilitating wide deployment. In clinical practice, we anticipate that this may help reduce burdens on both patients and infrastructure, by integrating multiple varieties of assessments into a single comprehensive session. More generally, our protocol is a harbinger for removing the necessity of fixation, thereby opening new opportunities for ethologically-valid, naturalistic paradigms, the inclusion of populations typically unable to stably fixate, and increased translational research such as in awake animals whose eye movements constitute an accessible behavioural readout.
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Affiliation(s)
- Benedetta Franceschiello
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland.
| | - Lorenzo Di Sopra
- Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Astrid Minier
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Silvio Ionta
- Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - David Zeugin
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland
| | - Michael P Notter
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Jessica A M Bastiaansen
- Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - João Jorge
- École Polytechnique Fédérale de Lausanne (EPFL) Lausanne, Switzerland
| | - Jérôme Yerly
- Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
| | - Matthias Stuber
- Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
| | - Micah M Murray
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des aveugles, Lausanne, Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland; Department of Hearing and Speech Sciences, Vanderbilt University Nashville, TN, USA.
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15
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Blundon EG, Gallagher RE, Ward LM. Electrophysiological evidence of preserved hearing at the end of life. Sci Rep 2020; 10:10336. [PMID: 32587364 PMCID: PMC7316981 DOI: 10.1038/s41598-020-67234-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 06/04/2020] [Indexed: 11/17/2022] Open
Abstract
This study attempts to answer the question: “Is hearing the last to go?” We present evidence of hearing among unresponsive actively dying hospice patients. Individual ERP (MMN, P3a, and P3b) responses to deviations in auditory patterns are reported for conscious young, healthy control participants, as well as for hospice patients, both when the latter were conscious, and again when they became unresponsive to their environment. Whereas the MMN (and perhaps too the P3a) is considered an automatic response to auditory irregularities, the P3b is associated with conscious detection of oddball targets. All control participants, and most responsive hospice patients, evidenced a “local” effect (either a MMN, a P3a, or both) and some a “global” effect (P3b) to deviations in tone, or deviations in auditory pattern. Importantly, most unresponsive patients showed evidence of MMN responses to tone changes, and some showed a P3a or P3b response to either tone or pattern changes. Thus, their auditory systems were responding similarly to those of young, healthy controls just hours from end of life. Hearing may indeed be one of the last senses to lose function as humans die.
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Affiliation(s)
| | - Romayne E Gallagher
- Department of Family Medicine, Vancouver, Canada.,Department of Family and Community Medicine, Providence Health Care, Vancouver, Canada
| | - Lawrence M Ward
- Department of Psychology, Vancouver, Canada. .,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.
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16
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Binder M, Górska U, Pipinis E, Voicikas A, Griskova-Bulanova I. Auditory steady-state response to chirp-modulated tones: A pilot study in patients with disorders of consciousness. NEUROIMAGE-CLINICAL 2020; 27:102261. [PMID: 32388346 PMCID: PMC7215243 DOI: 10.1016/j.nicl.2020.102261] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/23/2020] [Accepted: 03/29/2020] [Indexed: 12/17/2022]
Abstract
Chirp-evoked responses were evaluated in patients with disorders of consciousness. PLI estimates in 38–42 Hz window positively correlated with the CRS-R total score. Gamma-range evoked activity may indicate the integrity of thalamocortical networks.
Objective Due to the problems with behavioral diagnosis of patients with prolonged DOC (disorders of consciousness), complementary approaches based on objective measurement of neural function are necessary. In this pilot study, we assessed the sensitivity of auditory chirp-evoked responses to the state of patients with severe brain injury as measured with CRS-R (Coma Recovery Scale - Revised). Methods A convenience sample of fifteen DOC patients was included in the study. Auditory stimuli, chirp-modulated at 1–120 Hz were used to evoke auditory steady-state response (ASSR). Phase-locking index (PLI) estimates within low gamma and high gamma windows were evaluated. Results The PLI estimates within a narrow low gamma 38–42 Hz window positively correlated with the CRS-R total score and with the scores of the Auditory and Visual Function subscales. In the same low gamma window, significant difference in the PLIs was found between minimally conscious (MCS) and vegetative state (VS) patients. We did not observe any between-group differences nor any significant correlations with CRS-R scores in the high gamma window (80–110 Hz). Conclusions Our results support the notion that the activity around 40 Hz may serve as a possible marker of the integrity of thalamocortical networks in prolonged DOC patients. Significance Auditory steady-state responses at gamma-band frequencies highlight the role of upper parts of auditory system in evaluation of the level of consciousness in DOC patients.
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Affiliation(s)
- Marek Binder
- Institute of Psychology, Jagiellonian University, ul. Ingardena 6, 30-060 Krakow, Poland.
| | - Urszula Górska
- Institute of Psychology, Jagiellonian University, ul. Ingardena 6, 30-060 Krakow, Poland
| | - Evaldas Pipinis
- Department of Neurobiology and Biophysics, Vilnius University, Sauletekio ave 7, LT-10257 Vilnius, Lithuania
| | - Aleksandras Voicikas
- Department of Neurobiology and Biophysics, Vilnius University, Sauletekio ave 7, LT-10257 Vilnius, Lithuania
| | - Inga Griskova-Bulanova
- Department of Neurobiology and Biophysics, Vilnius University, Sauletekio ave 7, LT-10257 Vilnius, Lithuania
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17
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Minnis H, Posserud MB, Thompson L, Gillberg C. Hypothesis: The highly folded brain surface might be structured and located so as to facilitate inter-brain synchronization. RESEARCH IDEAS AND OUTCOMES 2020. [DOI: 10.3897/rio.6.e48887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We integrate recent findings from neuro-anatomy, electroencephalography, quantum biology and social/neurodevelopment to propose that the brain surface might be specialised for communication with other brains.
Ground breaking, but still small-scale, research has demonstrated that human brains can act in synchrony and detect the brain activity of other human brains. Group aggregation, in all species, maximises community support and safety but does not depend on verbal or visual interaction. The morphology of the brain’s outermost layers, across a wide range of species, exhibits a highly folded fractal structure that is likely to maximise exchange at the surface: in humans, a reduced brain surface area is associated with disorders of social communication. The brain sits in a vulnerable exposed location where it is prone to damage, rather than being housed in a central location such as within the ribcage.
These observations have led us to the hypothesis that the brain surface might be specialised for interacting with other brains at its surface, allowing synchronous non-verbal interaction. To our knowledge, this has not previously been proposed or investigated.
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18
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Pharmacologically informed machine learning approach for identifying pathological states of unconsciousness via resting-state fMRI. Neuroimage 2019; 206:116316. [PMID: 31672663 DOI: 10.1016/j.neuroimage.2019.116316] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/09/2019] [Accepted: 10/26/2019] [Indexed: 01/22/2023] Open
Abstract
Determining the level of consciousness in patients with disorders of consciousness (DOC) remains challenging. To address this challenge, resting-state fMRI (rs-fMRI) has been widely used for detecting the local, regional, and network activity differences between DOC patients and healthy controls. Although substantial progress has been made towards this endeavor, the identification of robust rs-fMRI-based biomarkers for level of consciousness is still lacking. Recent developments in machine learning show promise as a tool to augment the discrimination between different states of consciousness in clinical practice. Here, we investigated whether machine learning models trained to make a binary distinction between conscious wakefulness and anesthetic-induced unconsciousness would then be capable of reliably identifying pathologically induced unconsciousness. We did so by extracting rs-fMRI-based features associated with local activity, regional homogeneity, and interregional functional activity in 44 subjects during wakefulness, light sedation, and unresponsiveness (deep sedation and general anesthesia), and subsequently using those features to train three distinct candidate machine learning classifiers: support vector machine, Extra Trees, artificial neural network. First, we show that all three classifiers achieve reliable performance within-dataset (via nested cross-validation), with a mean area under the receiver operating characteristic curve (AUC) of 0.95, 0.92, and 0.94, respectively. Additionally, we observed comparable cross-dataset performance (making predictions on the DOC data) as the anesthesia-trained classifiers demonstrated a consistent ability to discriminate between unresponsive wakefulness syndrome (UWS/VS) patients and healthy controls with mean AUC's of 0.99, 0.94, 0.98, respectively. Lastly, we explored the potential of applying the aforementioned classifiers towards discriminating intermediate states of consciousness, specifically, subjects under light anesthetic sedation and patients diagnosed as having a minimally conscious state (MCS). Our findings demonstrate that machine learning classifiers trained on rs-fMRI features derived from participants under anesthesia have potential to aid the discrimination between degrees of pathological unconsciousness in clinical patients.
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19
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Wang F, Hu N, Hu X, Jing S, Heine L, Thibaut A, Huang W, Yan Y, Wang J, Schnakers C, Laureys S, Di H. Detecting Brain Activity Following a Verbal Command in Patients With Disorders of Consciousness. Front Neurosci 2019; 13:976. [PMID: 31572121 PMCID: PMC6753948 DOI: 10.3389/fnins.2019.00976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/30/2019] [Indexed: 11/20/2022] Open
Abstract
Background The accurate assessment of patients with disorders of consciousness (DOC) is a challenge to most experienced clinicians. As a potential clinical tool, functional magnetic resonance imaging (fMRI) could detect residual awareness without the need for the patients’ actual motor responses. Methods We adopted a simple active fMRI motor paradigm (hand raising) to detect residual awareness in these patients. Twenty-nine patients were recruited. They met the diagnosis of minimally conscious state (MCS) (male = 6, female = 2; n = 8), vegetative state/unresponsive wakefulness syndrome (VS/UWS) (male = 17, female = 4; n = 21). Results We analyzed the command-following responses for robust evidence of statistically reliable markers of motor execution, similar to those found in 15 healthy controls. Of the 29 patients, four (two MCS, two VS/UWS) could adjust their brain activity to the “hand-raising” command, and they showed activation in motor-related regions (which could not be discovered in the own-name task). Conclusion Longitudinal behavioral assessments showed that, of these four patients, two in a VS/UWS recovered to MCS and one from MCS recovered to MCS+ (i.e., showed command following). In patients with no response to hand raising task, six VS/UWS and three MCS ones showed recovery in follow-up procedure. The simple active fMRI “hand-raising” task can elicit brain activation in patients with DOC, similar to those observed in healthy volunteers. Activity of the motor-related network may be taken as an indicator of high-level cognition that cannot be discerned through conventional behavioral assessment.
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Affiliation(s)
- Fuyan Wang
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China.,Department of Radiology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
| | - Nantu Hu
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China
| | - Xiaohua Hu
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China.,Department of Rehabilitation, Hangzhou Wujing Hospital, Hangzhou, China
| | - Shan Jing
- Department of Rehabilitation, Hangzhou Wujing Hospital, Hangzhou, China
| | - Lizette Heine
- INSERM, U1028, CNRS, UMR5292, Auditory Cognition and Psychoacoustics Team, Lyon Neuroscience Research Center, Lyon, France.,Coma Science Group, GIGA-Research, CHU University Hospital of Liège, Liège, Belgium
| | - Aurore Thibaut
- Coma Science Group, GIGA-Research, CHU University Hospital of Liège, Liège, Belgium
| | - Wangshan Huang
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China
| | - Yifan Yan
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China
| | - Jing Wang
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China
| | - Caroline Schnakers
- Coma Science Group, GIGA-Research, CHU University Hospital of Liège, Liège, Belgium.,Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Steven Laureys
- Coma Science Group, GIGA-Research, CHU University Hospital of Liège, Liège, Belgium
| | - Haibo Di
- International Unresponsive Wakefulness Syndrome and Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China
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20
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Górska U, Binder M. Low- and medium-rate auditory steady-state responses in patients with prolonged disorders of consciousness correlate with Coma Recovery Scale - Revised score. Int J Psychophysiol 2019; 144:56-62. [PMID: 31381936 DOI: 10.1016/j.ijpsycho.2019.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 07/30/2019] [Accepted: 08/01/2019] [Indexed: 02/02/2023]
Abstract
Diagnosis of consciousness in patients with prolonged disorders of consciousness (PDOC) remains challenging since their responsiveness is often very impaired, while their assessment depends on observable behavior. The aim of this proof-of-concept study was to evaluate whether low- and medium-rate amplitude-modulated (AM) auditory steady-state responses (ASSRs) can be sensitive to the state of PDOC patients and may thus serve as a diagnostic tool which does not explicitly depend on a patient's cooperation. EEG was recorded from nine unresponsive wakefulness syndrome/vegetative state (UWS/VS) and eight minimally conscious state (MCS)/emergence from MCS patients during stimulation with two-minute trains of simple tones, amplitude modulated (AM) by 4 Hz, 6 Hz, 8 Hz, 12 Hz, 20 Hz, 40 Hz. The obtained ASSRs were then related to the Coma Recovery Scale - Revised (CRS-R) diagnosis and its total score. We observed significant correlations between mean inter-trial phase coherence (PC) (averaged across all stimulation frequencies) and total CRS-R score, as well as between 40 Hz relative power (RP) and total CRS-R score. Moreover, both parameters significantly differed between the patient groups. Our preliminary results suggest that a passive auditory stimulation protocol consisting of low- and medium-rate ASSRs might be used as an objective estimate of the level of neural dysfunction in PDOC patients. Consequently, the integrity of the auditory system appears to be an important predictor of the actual state of consciousness in PDOC patients.
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Affiliation(s)
- Urszula Górska
- Psychophysiology Laboratory, Institute of Psychology, Jagiellonian University, Krakow, Poland; Department of Neurophysiology, Donders Centre for Neuroscience, Radboud University Nijmegen, the Netherlands
| | - Marek Binder
- Psychophysiology Laboratory, Institute of Psychology, Jagiellonian University, Krakow, Poland.
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21
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Pennartz CMA, Farisco M, Evers K. Indicators and Criteria of Consciousness in Animals and Intelligent Machines: An Inside-Out Approach. Front Syst Neurosci 2019; 13:25. [PMID: 31379521 PMCID: PMC6660257 DOI: 10.3389/fnsys.2019.00025] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/24/2019] [Indexed: 01/02/2023] Open
Abstract
In today's society, it becomes increasingly important to assess which non-human and non-verbal beings possess consciousness. This review article aims to delineate criteria for consciousness especially in animals, while also taking into account intelligent artifacts. First, we circumscribe what we mean with "consciousness" and describe key features of subjective experience: qualitative richness, situatedness, intentionality and interpretation, integration and the combination of dynamic and stabilizing properties. We argue that consciousness has a biological function, which is to present the subject with a multimodal, situational survey of the surrounding world and body, subserving complex decision-making and goal-directed behavior. This survey reflects the brain's capacity for internal modeling of external events underlying changes in sensory state. Next, we follow an inside-out approach: how can the features of conscious experience, correlating to mechanisms inside the brain, be logically coupled to externally observable ("outside") properties? Instead of proposing criteria that would each define a "hard" threshold for consciousness, we outline six indicators: (i) goal-directed behavior and model-based learning; (ii) anatomic and physiological substrates for generating integrative multimodal representations; (iii) psychometrics and meta-cognition; (iv) episodic memory; (v) susceptibility to illusions and multistable perception; and (vi) specific visuospatial behaviors. Rather than emphasizing a particular indicator as being decisive, we propose that the consistency amongst these indicators can serve to assess consciousness in particular species. The integration of scores on the various indicators yields an overall, graded criterion for consciousness, somewhat comparable to the Glasgow Coma Scale for unresponsive patients. When considering theoretically derived measures of consciousness, it is argued that their validity should not be assessed on the basis of a single quantifiable measure, but requires cross-examination across multiple pieces of evidence, including the indicators proposed here. Current intelligent machines, including deep learning neural networks (DLNNs) and agile robots, are not indicated to be conscious yet. Instead of assessing machine consciousness by a brief Turing-type of test, evidence for it may gradually accumulate when we study machines ethologically and across time, considering multiple behaviors that require flexibility, improvisation, spontaneous problem-solving and the situational conspectus typically associated with conscious experience.
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Affiliation(s)
- Cyriel M. A. Pennartz
- Department of Cognitive and Systems Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
- Research Priority Area, Brain and Cognition, University of Amsterdam, Amsterdam, Netherlands
| | - Michele Farisco
- Centre for Research Ethics and Bioethics, Uppsala University, Uppsala, Sweden
- Biogem, Biology and Molecular Genetics Institute, Ariano Irpino, Italy
| | - Kathinka Evers
- Centre for Research Ethics and Bioethics, Uppsala University, Uppsala, Sweden
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22
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Berlucchi G. Wandering thoughts about consciousness, the brain, and the commentary system of Larry Weiskrantz. Neuropsychologia 2019; 128:266-269. [DOI: 10.1016/j.neuropsychologia.2017.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/06/2017] [Accepted: 10/08/2017] [Indexed: 11/15/2022]
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23
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Berlucchi G, Marzi CA. Neuropsychology of Consciousness: Some History and a Few New Trends. Front Psychol 2019; 10:50. [PMID: 30761035 PMCID: PMC6364520 DOI: 10.3389/fpsyg.2019.00050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 01/09/2019] [Indexed: 01/24/2023] Open
Abstract
Consciousness is a global activity of the nervous system. Its physiological and pathological mechanisms have been studied in relation to the natural sleep-wake cycle and various forms of normal or morbid unconsciousness, mainly in neurophysiology and clinical neurology. Neuropsychology has been more interested in specific higher brain functions, such as perception and memory and their disorders, rather than in consciousness per se. However, neuropsychology has been at the forefront in the identification of conscious and unconscious components in the processing of sensory and mnestic information. The present review describes some historical steps in the formulation of consciousness as a global brain function with arousal and content as principal ingredients, respectively, instantiated in the subcortex and the neocortex. It then reports a few fresh developments in neuropsychology and cognitive neuroscience which emphasize the importance of the hippocampus for thinking and dreaming. Non-neocortical structures may contribute to the contents of consciousness more than previously believed.
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Affiliation(s)
- Giovanni Berlucchi
- Department of Neurosciences, Biomedicine and Movement, University of Verona, Verona, Italy
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24
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Huang Z, Vlisides PE, Tarnal VC, Janke EL, Keefe KM, Collins MM, McKinney AM, Picton P, Harris RE, Mashour GA, Hudetz AG. Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol. Sci Rep 2018; 8:13195. [PMID: 30181567 PMCID: PMC6123455 DOI: 10.1038/s41598-018-31436-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/17/2018] [Indexed: 12/11/2022] Open
Abstract
Detecting covert consciousness in behaviorally unresponsive patients by brain imaging is of great interest, but a reproducible model and evidence from independent sources is still lacking. Here we demonstrate the possibility of using general anesthetics in a within-subjects study design to test methods or statistical paradigms of assessing covert consciousness. Using noninvasive neuroimaging in healthy volunteers, we identified a healthy study participant who was able to exhibit the specific fMRI signatures of volitional mental imagery while behaviorally unresponsive due to sedation with propofol. Our findings reveal a novel model that may accelerate the development of new approaches to reproducibly detect covert consciousness, which is difficult to achieve in patients with heterogeneous and sometimes clinically unstable neuropathology.
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Affiliation(s)
- Zirui Huang
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA.
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Phillip E Vlisides
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Vijaykumar C Tarnal
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ellen L Janke
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kelley M Keefe
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Margaret M Collins
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Amy M McKinney
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Paul Picton
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Richard E Harris
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Anthony G Hudetz
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA.
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, USA.
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA.
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25
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Xie Q, Ni X, Yu R, Li Y, Huang R. Chronic disorders of consciousness. Exp Ther Med 2017; 14:1277-1283. [PMID: 28810588 DOI: 10.3892/etm.2017.4639] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 02/17/2017] [Indexed: 01/19/2023] Open
Abstract
Over the last 20 years, studies have provided greater insight into disorders of consciousness (DOC), also known as altered state of consciousness. Increased brain residual functions have been identified in patients with DOC due to the successful application of novel next-generation imaging technologies. Many unconscious patients have now been confirmed to retain considerable cognitive functions. It is hoped that greater insight regarding the psychological state of patients may be achieved through the use of functional magnetic resonance imaging and brain-computer interfaces. However, issues surrounding the research and treatment of DOC remain problematic. These include differing opinions on the definition of consciousness, difficulties in diagnosis, assessment, prognosis and/or treatment, and newly emerging ethical, legal and social issues. To overcome these, appropriate care must be offered to patients with DOC by clinicians and families, as DOC patients may now be considered to live in more than just a vegetative state. The present article reviews the controversy surrounding the definition of consciousness and the reliability of novel technologies, prognostic prediction, communication with DOC patients and treatment methods. The ethical and social issues surrounding the treatment of DOC and future perspectives are also considered.
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Affiliation(s)
- Qiuyou Xie
- Coma Research Group, Center for Hyperbaric Oxygen and Neurorehabilitation, Neuroscience Institute, Guangzhou General Hospital of Guangzhou Command, Guangzhou, Guangdong 510010, P.R. China
| | - Xiaoxiao Ni
- Coma Research Group, Center for Hyperbaric Oxygen and Neurorehabilitation, Neuroscience Institute, Guangzhou General Hospital of Guangzhou Command, Guangzhou, Guangdong 510010, P.R. China
| | - Ronghao Yu
- Coma Research Group, Center for Hyperbaric Oxygen and Neurorehabilitation, Neuroscience Institute, Guangzhou General Hospital of Guangzhou Command, Guangzhou, Guangdong 510010, P.R. China
| | - Yuanqing Li
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, Guangdong 510641, P.R. China
| | - Ruiwang Huang
- Centre for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, South China Normal University, Guangzhou, Guangdong 510631, P.R. China
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No-report Paradigmatic Ascription of the Minimally Conscious State: Neural Signals as a Communicative Means for Operational Diagnostic Criteria. Minds Mach (Dordr) 2017. [DOI: 10.1007/s11023-017-9433-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Weng L, Xie Q, Zhao L, Zhang R, Ma Q, Wang J, Jiang W, He Y, Chen Y, Li C, Ni X, Xu Q, Yu R, Huang R. Abnormal structural connectivity between the basal ganglia, thalamus, and frontal cortex in patients with disorders of consciousness. Cortex 2017; 90:71-87. [PMID: 28365490 DOI: 10.1016/j.cortex.2017.02.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/28/2016] [Accepted: 02/20/2017] [Indexed: 12/17/2022]
Abstract
Consciousness loss in patients with severe brain injuries is associated with reduced functional connectivity of the default mode network (DMN), fronto-parietal network, and thalamo-cortical network. However, it is still unclear if the brain white matter connectivity between the above mentioned networks is changed in patients with disorders of consciousness (DOC). In this study, we collected diffusion tensor imaging (DTI) data from 13 patients and 17 healthy controls, constructed whole-brain white matter (WM) structural networks with probabilistic tractography. Afterward, we estimated and compared topological properties, and revealed an altered structural organization in the patients. We found a disturbance in the normal balance between segregation and integration in brain structural networks and detected significantly decreased nodal centralities primarily in the basal ganglia and thalamus in the patients. A network-based statistical analysis detected a subnetwork with uniformly significantly decreased structural connections between the basal ganglia, thalamus, and frontal cortex in the patients. Further analysis indicated that along the WM fiber tracts linking the basal ganglia, thalamus, and frontal cortex, the fractional anisotropy was decreased and the radial diffusivity was increased in the patients compared to the controls. Finally, using the receiver operating characteristic method, we found that the structural connections within the NBS-derived component that showed differences between the groups demonstrated high sensitivity and specificity (>90%). Our results suggested that major consciousness deficits in DOC patients may be related to the altered WM connections between the basal ganglia, thalamus, and frontal cortex.
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Affiliation(s)
- Ling Weng
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Qiuyou Xie
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Ling Zhao
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ruibin Zhang
- Department of Psychology, The University of Hong Kong, Hong Kong, PR China
| | - Qing Ma
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Junjing Wang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Wenjie Jiang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Yanbin He
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Yan Chen
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Changhong Li
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Xiaoxiao Ni
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Qin Xu
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ronghao Yu
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China.
| | - Ruiwang Huang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China.
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40Hz auditory steady-state responses in patients with disorders of consciousness: Correlation between phase-locking index and Coma Recovery Scale-Revised score. Clin Neurophysiol 2017; 128:799-806. [PMID: 28319881 DOI: 10.1016/j.clinph.2017.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 01/23/2017] [Accepted: 02/16/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE We aimed to elucidate whether 40Hz auditory steady-state response (ASSR) could be sensitive to the state of patients with disorders of consciousness (DOC) as estimated with Coma Recovery Scale-Revised (CRS-R) diagnostic tool. METHODS Fifteen DOC patients and 24 healthy controls took part in the study. The 40Hz click trains were used to evoke ASSRs. Mean evoked amplitude (EA) and phase-locking index (PLI) within 38-42Hz window were calculated for 100ms bins, starting from -200 to 700ms relative to stimulus onset. RESULTS The PLI values from the patient group in the period of 200-500ms after the stimulus onset positively correlated with the CRS-R total score and with the scores of the Auditory and Visual subscales. CONCLUSIONS The phase-locking index of 40Hz auditory steady-state responses can be an indicator of the level of dysfunction of the central nervous system in DOC. SIGNIFICANCE Our results emphasize the role of central auditory system integrity in determining the level of functioning of DOC patients and suggest the possibility to use the ASSR protocol as an objective diagnostic method in DOC patients.
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Dykstra AR, Cariani PA, Gutschalk A. A roadmap for the study of conscious audition and its neural basis. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160103. [PMID: 28044014 PMCID: PMC5206271 DOI: 10.1098/rstb.2016.0103] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2016] [Indexed: 12/16/2022] Open
Abstract
How and which aspects of neural activity give rise to subjective perceptual experience-i.e. conscious perception-is a fundamental question of neuroscience. To date, the vast majority of work concerning this question has come from vision, raising the issue of generalizability of prominent resulting theories. However, recent work has begun to shed light on the neural processes subserving conscious perception in other modalities, particularly audition. Here, we outline a roadmap for the future study of conscious auditory perception and its neural basis, paying particular attention to how conscious perception emerges (and of which elements or groups of elements) in complex auditory scenes. We begin by discussing the functional role of the auditory system, particularly as it pertains to conscious perception. Next, we ask: what are the phenomena that need to be explained by a theory of conscious auditory perception? After surveying the available literature for candidate neural correlates, we end by considering the implications that such results have for a general theory of conscious perception as well as prominent outstanding questions and what approaches/techniques can best be used to address them.This article is part of the themed issue 'Auditory and visual scene analysis'.
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Affiliation(s)
- Andrew R Dykstra
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | | | - Alexander Gutschalk
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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30
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Chandler JA, Sun JA, Racine E. Online public reactions to fMRI communication with patients with disorders of consciousness: Quality of life, end-of-life decision making, and concerns with misdiagnosis. AJOB Empir Bioeth 2017; 8:40-51. [PMID: 28949872 DOI: 10.1080/23294515.2016.1226199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
BACKGROUND Recently, the news media have reported on the discovery of covert awareness and the establishment of limited communication using a functional magnetic resonance imaging (fMRI) neuroimaging technique with several brain-injured patients thought to have been in a vegetative state. This discovery has raised many ethical, legal, and social questions related to quality of life, end-of-life decision making, diagnostic and prognostic accuracy in disorders of consciousness, resource allocation, and other issues. This project inquires into the public responses to these discoveries. METHODS We conducted a thematic analysis of online comments (n = 779) posted in response to 15 news articles and blog posts regarding the case of a Canadian patient diagnosed for 12 years as in a vegetative state, but who was reported in 2012 as having been able to communicate via fMRI. The online comments were coded using an iteratively refined codebook structured around 14 main themes. RESULTS Among the most frequent public reactions revealed in the online comments were discussions of the quality of life of patients with disorders of consciousness, whether life-sustaining treatment should be withdrawn (and whether the fMRI communication technique should be used to ask patients about this), and misgivings about the accuracy of diagnosis in disorders of consciousness and brain death. CONCLUSIONS These public perspectives are relevant to the obligations of clinicians, lawyers, and public policymakers to patients, families, and the public. Future work should consider how best to alleviate families' concerns as this type of research shakes their faith in diagnostic accuracy, to clarify the legal rules relating to advance directives in this context, and to address the manner in which public messaging might help to alleviate any indirect impact on confidence in the organ donation system.
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Affiliation(s)
| | | | - Eric Racine
- b Institut de Recherches Cliniques de Montreal (IRCM) , Neuroethics Research Unit
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31
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Abstract
There is a paucity of accurate and reliable biomarkers to detect traumatic brain injury, grade its severity, and model post-traumatic brain injury (TBI) recovery. This gap could be addressed via advances in brain mapping which define injury signatures and enable tracking of post-injury trajectories at the individual level. Mapping of molecular and anatomical changes and of modifications in functional activation supports the conceptual paradigm of TBI as a disorder of large-scale neural connectivity. Imaging approaches with particular relevance are magnetic resonance techniques (diffusion weighted imaging, diffusion tensor imaging, susceptibility weighted imaging, magnetic resonance spectroscopy, functional magnetic resonance imaging, and positron emission tomographic methods including molecular neuroimaging). Inferences from mapping represent unique endophenotypes which have the potential to transform classification and treatment of patients with TBI. Limitations of these methods, as well as future research directions, are highlighted.
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32
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Using facial electromyography to detect preserved emotional processing in disorders of consciousness: A proof-of-principle study. Clin Neurophysiol 2016; 127:3000-3006. [DOI: 10.1016/j.clinph.2016.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 06/07/2016] [Accepted: 06/11/2016] [Indexed: 11/21/2022]
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Gibson RM, Owen AM, Cruse D. Brain-computer interfaces for patients with disorders of consciousness. PROGRESS IN BRAIN RESEARCH 2016; 228:241-91. [PMID: 27590972 DOI: 10.1016/bs.pbr.2016.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The disorders of consciousness refer to clinical conditions that follow a severe head injury. Patients diagnosed as in a vegetative state lack awareness, while patients diagnosed as in a minimally conscious state retain fluctuating awareness. However, it is a challenge to accurately diagnose these disorders with clinical assessments of behavior. To improve diagnostic accuracy, neuroimaging-based approaches have been developed to detect the presence or absence of awareness in patients who lack overt responsiveness. For the small subset of patients who retain awareness, brain-computer interfaces could serve as tools for communication and environmental control. Here we review the existing literature concerning the sensory and cognitive abilities of patients with disorders of consciousness with respect to existing brain-computer interface designs. We highlight the challenges of device development for this special population and address some of the most promising approaches for future investigations.
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Affiliation(s)
- R M Gibson
- The Brain and Mind Institute, University of Western Ontario, London, ON, Canada; University of Western Ontario, London, ON, Canada.
| | - A M Owen
- The Brain and Mind Institute, University of Western Ontario, London, ON, Canada; University of Western Ontario, London, ON, Canada
| | - D Cruse
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
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34
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Peterson A. Consilience, clinical validation, and global disorders of consciousness. Neurosci Conscious 2016; 2016:niw011. [PMID: 30356913 PMCID: PMC6192376 DOI: 10.1093/nc/niw011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/08/2016] [Accepted: 07/09/2016] [Indexed: 11/14/2022] Open
Abstract
Behavioral diagnosis of global disorders of consciousness is difficult and errors in diagnosis occur often. Recent advances in neuroimaging may resolve this problem. However, clinical translation of neuroimaging requires clinical validation. Applying the orthodox approach of clinical validation to neuroimaging raises two critical questions: (i) What exactly is being validated? and (ii) what counts as a gold standard? I argue that confusion over these questions leads to systematic errors in the empirical literature. I propose an alternative approach to clinical validation motivated by reasoning by consilience. Consilience is a mode of reasoning that assigns a degree of plausibility to a hypothesis based on its fit with multiple pieces of evidence from independent sources. I argue that this approach resolves the questions raised by the orthodox approach and may be a useful framework for optimizing future clinical validation studies in the science of consciousness.
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Affiliation(s)
- Andrew Peterson
- Rotman Institute of Philosophy and The Brain and Mind Institute,
University of Western Ontario, London, ON, Canada
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35
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Poldrack RA, Farah MJ. Progress and challenges in probing the human brain. Nature 2015; 526:371-9. [DOI: 10.1038/nature15692] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 09/04/2015] [Indexed: 01/20/2023]
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36
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Osborne NR, Owen AM, Fernández-Espejo D. The dissociation between command following and communication in disorders of consciousness: an fMRI study in healthy subjects. Front Hum Neurosci 2015; 9:493. [PMID: 26441593 PMCID: PMC4569885 DOI: 10.3389/fnhum.2015.00493] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/24/2015] [Indexed: 01/18/2023] Open
Abstract
Neuroimaging studies have identified a subgroup of patients with a Disorder of Consciousness (DOC) who, while being behaviorally non-responsive, are nevertheless able to follow commands by modulating their brain activity in motor imagery (MI) tasks. These techniques have even allowed for binary communication in a small number of DOC patients. However, the majority of patients who can follow commands are unable to use their responses to communicate. A similar dissociation between present command following (CF) and absent communication abilities has been reported in overt behavioral assessments. However, the neural correlates of this dissociation in both overt and covert modalities are unknown. Here, we used functional magnetic resonance imaging (fMRI) to explore the neural mechanisms underlying CF and selection of responses for binary communication using either executed or imagined movements. Fifteen healthy participants executed or imagined two different types of arm movements that were either pre-determined by the experimenters (CF) or decided by them (action selection, AS). Action selection involved greater activity in high-level associative areas in frontal and parietal regions than CF. Additionally, motor execution (ME), as compared to MI, activated contralateral motor cortex, while the opposite contrast revealed activation in the ipsilateral sensorimotor cortex and the left inferior frontal gyrus. Importantly, there was no interaction between the task (CF/AS) and modality (MI/ME). Our results suggest that the neural processes involved in following a motor command or selecting between two motor actions are not dependent on how the response is expressed (via ME/MI). They also suggest a potential neural basis for the distinction in cognitive abilities seen in DOC patients.
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Affiliation(s)
- Natalie R Osborne
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada ; Department of Psychology, University of Western Ontario London, ON, Canada
| | - Adrian M Owen
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada ; Department of Psychology, University of Western Ontario London, ON, Canada
| | - Davinia Fernández-Espejo
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada ; Department of Psychology, University of Western Ontario London, ON, Canada
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37
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Perception of Value and the Minimally Conscious State. HEC Forum 2015; 27:265-86. [DOI: 10.1007/s10730-015-9281-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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38
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Graham M, Weijer C, Peterson A, Naci L, Cruse D, Fernández-Espejo D, Gonzalez-Lara L, Owen AM. Acknowledging awareness: informing families of individual research results for patients in the vegetative state. JOURNAL OF MEDICAL ETHICS 2015; 41:534-8. [PMID: 25079068 PMCID: PMC4515978 DOI: 10.1136/medethics-2014-102078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 07/03/2014] [Accepted: 07/15/2014] [Indexed: 05/25/2023]
Abstract
Recent findings in cognitive neuroscience have revealed that some patients previously diagnosed as being in a vegetative state may retain some degree of covert awareness. However, it is unclear whether such findings should be disclosed to the families of these patients. Concerns about the preservation of scientific validity, reliability of results and potential harms associated with disclosure suggest that individual research results should be disclosed only under certain conditions. In the following paper, we offer four criteria for the disclosure of individual research results. Because the results of functional neuroimaging studies to detect covert awareness in vegetative patients are scientifically valid, informative and reasonably reliable and have considerable potential benefit for the patient, researchers have an obligation to disclose such results to family members. Further work is needed to develop educational materials for families and to systematically study the impact of disclosure on the families themselves.
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Affiliation(s)
- Mackenzie Graham
- Department of Philosophy, Rotman Institute of Philosophy, Western University, London, Ontario, Canada
| | - Charles Weijer
- Department of Philosophy, Rotman Institute of Philosophy, Western University, London, Ontario, Canada
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Andrew Peterson
- Department of Philosophy, Rotman Institute of Philosophy, Western University, London, Ontario, Canada
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Lorina Naci
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Damian Cruse
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Davinia Fernández-Espejo
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Laura Gonzalez-Lara
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
| | - Adrian M Owen
- Department of Philosophy, Rotman Institute of Philosophy, Western University, London, Ontario, Canada
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada
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39
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Fabbro F, Aglioti SM, Bergamasco M, Clarici A, Panksepp J. Evolutionary aspects of self- and world consciousness in vertebrates. Front Hum Neurosci 2015; 9:157. [PMID: 25859205 PMCID: PMC4374625 DOI: 10.3389/fnhum.2015.00157] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 03/07/2015] [Indexed: 12/16/2022] Open
Abstract
Although most aspects of world and self-consciousness are inherently subjective, neuroscience studies in humans and non-human animals provide correlational and causative indices of specific links between brain activity and representation of the self and the world. In this article we review neuroanatomic, neurophysiological and neuropsychological data supporting the hypothesis that different levels of self and world representation in vertebrates rely upon (i) a “basal” subcortical system that includes brainstem, hypothalamus and central thalamic nuclei and that may underpin the primary (or anoetic) consciousness likely present in all vertebrates; and (ii) a forebrain system that include the medial and lateral structures of the cerebral hemispheres and may sustain the most sophisticated forms of consciousness [e.g., noetic (knowledge based) and autonoetic, reflective knowledge]. We posit a mutual, bidirectional functional influence between these two major brain circuits. We conclude that basic aspects of consciousness like primary self and core self (based on anoetic and noetic consciousness) are present in many species of vertebrates and that, even self-consciousness (autonoetic consciousness) does not seem to be a prerogative of humans and of some non-human primates but may, to a certain extent, be present in some other mammals and birds
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Affiliation(s)
- Franco Fabbro
- Department of Human Sciences, University of Udine Udine, Italy ; Perceptual Robotics Laboratory, Scuola Superiore Sant'Anna Pisa, Italy
| | - Salvatore M Aglioti
- Department of Psychology, Sapienza University of Rome Rome, Italy ; Fondazione Santa Lucia, IRCCS Rome, Italy
| | | | - Andrea Clarici
- Psychiatric Unit, Department of Medical, Surgical and Health Sciences, University of Trieste Trieste, Italy
| | - Jaak Panksepp
- Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University Pullman, WA, USA
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40
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Abstract
Acute loss of consciousness poses a fascinating scenario for theoretical and clinical research. This chapter introduces a simple yet powerful framework to investigate altered states of consciousness. We then explore the different disorders of consciousness that result from acute brain injury, and techniques used in the acute phase to predict clinical outcome in different patient populations in light of models of acute loss of consciousness. We further delve into post-traumatic amnesia as a model for predicting cognitive sequels following acute loss of consciousness. We approach the study of acute loss of consciousness from a theoretical and clinical perspective to conclude that clinicians in acute care centers must incorporate new measurements and techniques besides the classic coma scales in order to assess their patients with loss of consciousness.
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41
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Peterson A, Cruse D, Naci L, Weijer C, Owen AM. Risk, diagnostic error, and the clinical science of consciousness. Neuroimage Clin 2015; 7:588-97. [PMID: 25844313 PMCID: PMC4375779 DOI: 10.1016/j.nicl.2015.02.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 01/14/2015] [Accepted: 02/18/2015] [Indexed: 11/27/2022]
Abstract
In recent years, a number of new neuroimaging techniques have detected covert awareness in some patients previously thought to be in a vegetative state/unresponsive wakefulness syndrome. This raises worries for patients, families, and physicians, as it indicates that the existing diagnostic error rate in this patient group is higher than assumed. Recent research on a subset of these techniques, called active paradigms, suggests that false positive and false negative findings may result from applying different statistical methods to patient data. Due to the nature of this research, these errors may be unavoidable, and may draw into question the use of active paradigms in the clinical setting. We argue that false positive and false negative findings carry particular moral risks, which may bear on investigators' decisions to use certain methods when independent means for estimating their clinical utility are absent. We review and critically analyze this methodological problem as it relates to both fMRI and EEG active paradigms. We conclude by drawing attention to three common clinical scenarios where the risk of diagnostic error may be most pronounced in this patient group.
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Affiliation(s)
- Andrew Peterson
- Brain and Mind Institute, Western University, Natural Sciences Centre, London, Ontario N6A 5B7, Canada ; Rotman Institute of Philosophy, Western University, Stevenson Hall, London, Ontario N6A 5B7, Canada
| | - Damian Cruse
- Brain and Mind Institute, Western University, Natural Sciences Centre, London, Ontario N6A 5B7, Canada
| | - Lorina Naci
- Brain and Mind Institute, Western University, Natural Sciences Centre, London, Ontario N6A 5B7, Canada
| | - Charles Weijer
- Brain and Mind Institute, Western University, Natural Sciences Centre, London, Ontario N6A 5B7, Canada ; Rotman Institute of Philosophy, Western University, Stevenson Hall, London, Ontario N6A 5B7, Canada ; Department of Epidemiology and Biostatistics, Western University, Kresge Building, London, Ontario N6A 5B7, Canada
| | - Adrian M Owen
- Brain and Mind Institute, Western University, Natural Sciences Centre, London, Ontario N6A 5B7, Canada ; Rotman Institute of Philosophy, Western University, Stevenson Hall, London, Ontario N6A 5B7, Canada
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42
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Owen AM. Using functional magnetic resonance imaging and electroencephalography to detect consciousness after severe brain injury. HANDBOOK OF CLINICAL NEUROLOGY 2015; 127:277-93. [PMID: 25702223 DOI: 10.1016/b978-0-444-52892-6.00018-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In recent years, rapid technological developments in the field of neuroimaging have provided new methods for revealing thoughts, actions, and intentions based solely on the pattern of activity that is observed in the brain. In specialized centres, these methods are now being employed routinely in the assessment of patients diagnosed with so-called "disorders of consciousness," mapping patterns of residual function and dysfunction and helping to reduce diagnostic errors between related conditions such as the vegetative and minimally conscious states. Both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) have now been shown to be effective tools for detecting covert awareness in behaviorally nonresponsive patients when standard clinical approaches have been unable to provide that information. Indeed, in some patients, communication with the outside world via simple "yes" and "no" questions has been achieved, even in cases where no possibility for behavioral interaction exists. These studies have profound implications for clinical care, diagnosis, prognosis and medical-legal decision making relating to the prolongation, or otherwise, of life after severe brain injury. Moreover, the results suggest an urgent need for a re-evaluation of the existing diagnostic guidelines for behaviorally nonresponsive patients to include information derived from functional neuroimaging.
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Affiliation(s)
- Adrian M Owen
- Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Ontario, Canada.
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Gibson RM, Fernández-Espejo D, Gonzalez-Lara LE, Kwan BY, Lee DH, Owen AM, Cruse D. Multiple tasks and neuroimaging modalities increase the likelihood of detecting covert awareness in patients with disorders of consciousness. Front Hum Neurosci 2014; 8:950. [PMID: 25505400 PMCID: PMC4244609 DOI: 10.3389/fnhum.2014.00950] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/07/2014] [Indexed: 01/14/2023] Open
Abstract
Minimal or inconsistent behavioral responses to command make it challenging to accurately diagnose the level of awareness of a patient with a Disorder of consciousness (DOC). By identifying markers of mental imagery being covertly performed to command, functional neuroimaging (fMRI), electroencephalography (EEG) has shown that some of these patients are aware despite their lack of behavioral responsiveness. We report the findings of behavioral, fMRI, and EEG approaches to detecting command-following in a group of patients with DOC. From an initial sample of 14 patients, complete data across all tasks was obtained in six cases. Behavioral evaluations were performed with the Coma Recovery Scale—Revised. Both fMRI and EEG evaluations involved the completion of previously validated mental imagery tasks—i.e., motor imagery (EEG and fMRI) and spatial navigation imagery (fMRI). One patient exhibited statistically significant evidence of motor imagery in both the fMRI and EEG tasks, despite being unable to follow commands behaviorally. Two behaviorally non-responsive patients produced appropriate activation during the spatial navigation fMRI task. However, neither of these patients successfully completed the motor imagery tasks, likely due to specific motor area damage in at least one of these cases. A further patient demonstrated command following only in the EEG motor imagery task, and two patients did not demonstrate command following in any of the behavioral, EEG, or fMRI assessments. Due to the heterogeneity of etiology and pathology in this group, DOC patients vary in terms of their suitability for some forms of neuroimaging, the preservation of specific neural structures, and the cognitive resources that may be available to them. Assessments of a range of cognitive abilities supported by spatially-distinct brain regions and indexed by multiple neural signatures are therefore required in order to accurately characterize a patient's level of residual cognition and awareness.
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Affiliation(s)
- Raechelle M Gibson
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada ; Department of Psychology, University of Western Ontario London, ON, Canada
| | | | | | - Benjamin Y Kwan
- Department of Medical Imaging, University of Western Ontario London, ON, Canada
| | - Donald H Lee
- Department of Medical Imaging, University of Western Ontario London, ON, Canada ; Department of Radiology, London Health Sciences Centre London, ON, Canada
| | - Adrian M Owen
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada ; Department of Psychology, University of Western Ontario London, ON, Canada
| | - Damian Cruse
- The Brain and Mind Institute, University of Western Ontario London, ON, Canada
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44
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Affiliation(s)
- Jamie Sleigh
- Department of Anaesthesia, University of Auckland, Waikato Hospital, Hamilton 3240, New Zealand.
| | - Catherine E Warnaby
- Oxford Centre for Functional MRI of the Brain, University of Oxford, John Radcliffe Hospital, Oxford, UK
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45
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Ting WKC, Perez Velazquez JL, Cusimano MD. Eye movement measurement in diagnostic assessment of disorders of consciousness. Front Neurol 2014; 5:137. [PMID: 25120529 PMCID: PMC4114324 DOI: 10.3389/fneur.2014.00137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/11/2014] [Indexed: 12/16/2022] Open
Abstract
We review the literature to appraise the evidence supporting or disputing the use of eye movement measurement in disorders of consciousness (DOC) with low levels of arousal or awareness, such as minimally conscious state (MCS), vegetative state (VS), and coma for diagnostic and prognostic purposes. We will focus on the effectiveness of each technique in the diagnostic classification of these patients and the gradual trend in research from manual to computerized tracking methods. New tools have become available at clinicians' disposal to assess eye movements with high spatial and temporal fidelity. The close relationship between eye movement generation and organic dysfunction in the brain allows these tools to be applied to the assessment of severe DOC as a unique supplementary toolset. We posit that eye tracking can improve clinical diagnostic precision for DOC, a key component of assessment that often dictates the course of clinical care in DOC patients. We see the emergence of long-term eye-tracking studies with seamless integration of technology in the future to improve the performance of clinical assessment in DOC.
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Affiliation(s)
- Windsor Kwan-Chun Ting
- Injury Prevention Research Office, Keenan Research Centre for Biomedical Science, The Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, ON , Canada ; Institute of Medical Science, University of Toronto , Toronto, ON , Canada
| | - Jose Luis Perez Velazquez
- Institute of Medical Science, University of Toronto , Toronto, ON , Canada ; Neurosciences and Mental Health Programme, The Hospital for Sick Children , Toronto, ON , Canada ; Department of Paediatrics, University of Toronto , Toronto, ON , Canada
| | - Michael D Cusimano
- Injury Prevention Research Office, Keenan Research Centre for Biomedical Science, The Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, ON , Canada ; Institute of Medical Science, University of Toronto , Toronto, ON , Canada ; Division of Neurosurgery, Department of Surgery, St. Michael's Hospital , Toronto, ON , Canada ; Division of Neurosurgery, Department of Surgery, University of Toronto , Toronto, ON , Canada
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46
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Weijer C, Peterson A, Webster F, Graham M, Cruse D, Fernández-Espejo D, Gofton T, Gonzalez-Lara LE, Lazosky A, Naci L, Norton L, Speechley K, Young B, Owen AM. Ethics of neuroimaging after serious brain injury. BMC Med Ethics 2014; 15:41. [PMID: 24885720 PMCID: PMC4031564 DOI: 10.1186/1472-6939-15-41] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/29/2014] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Patient outcome after serious brain injury is highly variable. Following a period of coma, some patients recover while others progress into a vegetative state (unresponsive wakefulness syndrome) or minimally conscious state. In both cases, assessment is difficult and misdiagnosis may be as high as 43%. Recent advances in neuroimaging suggest a solution. Both functional magnetic resonance imaging and electroencephalography have been used to detect residual cognitive function in vegetative and minimally conscious patients. Neuroimaging may improve diagnosis and prognostication. These techniques are beginning to be applied to comatose patients soon after injury. Evidence of preserved cognitive function may predict recovery, and this information would help families and health providers. Complex ethical issues arise due to the vulnerability of patients and families, difficulties interpreting negative results, restriction of communication to "yes" or "no" answers, and cost. We seek to investigate ethical issues in the use of neuroimaging in behaviorally nonresponsive patients who have suffered serious brain injury. The objectives of this research are to: (1) create an approach to capacity assessment using neuroimaging; (2) develop an ethics of welfare framework to guide considerations of quality of life; (3) explore the impact of neuroimaging on families; and, (4) analyze the ethics of the use of neuroimaging in comatose patients. METHODS/DESIGN Our research program encompasses four projects and uses a mixed methods approach. Project 1 asks whether decision making capacity can be assessed in behaviorally nonresponsive patients. We will specify cognitive functions required for capacity and detail their assessment. Further, we will develop and pilot a series of scenarios and questions suitable for assessing capacity. Project 2 examines the ethics of welfare as a guide for neuroimaging. It grounds an obligation to explore patients' interests, and we explore conceptual issues in the development of a quality of life instrument adapted for neuroimaging. Project 3 will use grounded theory interviews to document families' understanding of the patient's condition, expectations of neuroimaging, and the impact of the results of neuroimaging. Project 4 will provide an ethical analysis of neuroimaging to investigate residual cognitive function in comatose patients within days of serious brain injury.
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Affiliation(s)
- Charles Weijer
- Rotman Institute of Philosophy, Western University, London, ON, N6A 5B8, Canada
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
- Department of Medicine, London Health Sciences Centre–University Hospital, London, ON, N6A 5A5, Canada
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5C1, Canada
| | - Andrew Peterson
- Rotman Institute of Philosophy, Western University, London, ON, N6A 5B8, Canada
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | - Fiona Webster
- Department of Family and Community Medicine, University of Toronto, Toronto, ON, M5G 1V7, Canada
| | - Mackenzie Graham
- Rotman Institute of Philosophy, Western University, London, ON, N6A 5B8, Canada
| | - Damian Cruse
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | | | - Teneille Gofton
- Department of Clinical Neurological Sciences, London Health Sciences Centre–University Hospital, London, ON, N6A 5A5, Canada
| | | | - Andrea Lazosky
- Department of Psychiatry, London Health Sciences Centre–Victoria Hospital, London, ON, N6A 5W9, Canada
| | - Lorina Naci
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | - Loretta Norton
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | - Kathy Speechley
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5C1, Canada
- Department of Pediatrics, Children’s Hospital of Western Ontario, London, ON, N6C 2V5, Canada
| | - Bryan Young
- Department of Clinical Neurological Sciences, London Health Sciences Centre–University Hospital, London, ON, N6A 5A5, Canada
| | - Adrian M Owen
- Rotman Institute of Philosophy, Western University, London, ON, N6A 5B8, Canada
- Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
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47
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Cruse D, Beukema S, Chennu S, Malins JG, Owen AM, McRae K. The reliability of the N400 in single subjects: implications for patients with disorders of consciousness. Neuroimage Clin 2014; 4:788-99. [PMID: 24936429 PMCID: PMC4055893 DOI: 10.1016/j.nicl.2014.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 04/28/2014] [Accepted: 05/04/2014] [Indexed: 01/13/2023]
Abstract
Functional neuroimaging assessments of residual cognitive capacities, including those that support language, can improve diagnostic and prognostic accuracy in patients with disorders of consciousness. Due to the portability and relative inexpensiveness of electroencephalography, the N400 event-related potential component has been proposed as a clinically valid means to identify preserved linguistic function in non-communicative patients. Across three experiments, we show that changes in both stimuli and task demands significantly influence the probability of detecting statistically significant N400 effects - that is, the difference in N400 amplitudes caused by the experimental manipulation. In terms of task demands, passively heard linguistic stimuli were significantly less likely to elicit N400 effects than task-relevant stimuli. Due to the inability of the majority of patients with disorders of consciousness to follow task commands, the insensitivity of passive listening would impede the identification of residual language abilities even when such abilities exist. In terms of stimuli, passively heard normatively associated word pairs produced the highest detection rate of N400 effects (50% of the participants), compared with semantically-similar word pairs (0%) and high-cloze sentences (17%). This result is consistent with a prediction error account of N400 magnitude, with highly predictable targets leading to smaller N400 waves, and therefore larger N400 effects. Overall, our data indicate that non-repeating normatively associated word pairs provide the highest probability of detecting single-subject N400s during passive listening, and may thereby provide a clinically viable means of assessing residual linguistic function. We also show that more liberal analyses may further increase the detection-rate, but at the potential cost of increased false alarms.
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Affiliation(s)
- Damian Cruse
- Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Steve Beukema
- Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Srivas Chennu
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Jeffrey G. Malins
- Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Adrian M. Owen
- Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Ken McRae
- Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 5B7, Canada
- Department of Psychology, University of Western Ontario, London, Ontario N6A 5B7, Canada
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48
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Fernández-Espejo D, Norton L, Owen AM. The clinical utility of fMRI for identifying covert awareness in the vegetative state: a comparison of sensitivity between 3T and 1.5T. PLoS One 2014; 9:e95082. [PMID: 24733575 PMCID: PMC3986373 DOI: 10.1371/journal.pone.0095082] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 03/21/2014] [Indexed: 11/18/2022] Open
Abstract
In the last few years, mental imagery fMRI paradigms have been used successfully to identify covert command-following and awareness in some patients who are thought to be entirely vegetative. However, to date there is only evidence supporting their use at magnetic fields of 3T, which limits their applicability in clinical settings where lower field strengths are typically used. Here, we test the 'gold standard' fMRI paradigm for detecting residual awareness in non-responsive patients by comparing its sensitivity at 1.5T and 3T in the same group of healthy volunteers. We were able to successfully detect brain activity showing command-following in most participants at both 3T and 1.5T, with similar reliability. These results demonstrate that fMRI assessment of covert awareness is clinically viable and therefore justify a broader use of these methods in standard assessments in severely brain injured patients.
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Affiliation(s)
- Davinia Fernández-Espejo
- The Brain and Mind Institute, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
| | - Loretta Norton
- The Brain and Mind Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Neurocritical Care, University of Western Ontario, London Health Sciences Centre-University Hospital, London, Ontario, Canada
| | - Adrian M. Owen
- The Brain and Mind Institute, The University of Western Ontario, London, Ontario, Canada
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49
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Consciousness and responsiveness: lessons from anaesthesia and the vegetative state. Curr Opin Anaesthesiol 2014; 26:444-9. [PMID: 23743554 DOI: 10.1097/aco.0b013e3283628b5d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW The aim of this article is to review recent behavioural and neuroimaging studies in anaesthesia and the vegetative state. RECENT FINDINGS These studies highlight possible dissociations between consciousness and responsiveness in both these states. SUMMARY We discuss future avenues of research in the field, in order to improve the detection of awareness during anaesthesia and the vegetative state using neuroimaging and neurophysiologic techniques.
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50
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Lancioni GE, Bosco A, Olivetti Belardinelli M, Singh NN, O'Reilly MF, Sigafoos J, Oliva D. Technology-based intervention programs to promote stimulation control and communication in post-coma persons with different levels of disability. Front Hum Neurosci 2014; 8:48. [PMID: 24574992 PMCID: PMC3920651 DOI: 10.3389/fnhum.2014.00048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/21/2014] [Indexed: 11/13/2022] Open
Abstract
Post-coma persons in a minimally conscious state and with extensive motor impairment or emerging/emerged from such a state, but affected by lack of speech and motor impairment, tend to be passive and isolated. A way to help them develop functional responding to control environmental events and communication involves the use of intervention programs relying on assistive technology. This paper provides an overview of technology-based intervention programs for enabling the participants to (a) access brief periods of stimulation through one or two microswitches, (b) pursue stimulation and social contact through the combination of a microswitch and a sensor connected to a speech generating device (SGD) or through two SGD-related sensors, (c) control stimulation options through computer or radio systems and a microswitch, (d) communicate through modified messaging or telephone systems operated via microswitch, and (e) control combinations of leisure and communication options through computer systems operated via microswitch. Twenty-six studies, involving a total of 52 participants, were included in this paper. The intervention programs were carried out using single-subject methodology, and their outcomes were generally considered positive from the standpoint of the participants and their context. Practical implications of the programs are discussed.
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Affiliation(s)
- Giulio E Lancioni
- Department of Neuroscience and Sense Organs, University of Bari Bari, Italy
| | - Andrea Bosco
- Department of Educational Science, Psychology, Communication, University of Bari Bari, Italy
| | | | - Nirbhay N Singh
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Georgia Regents University Augusta, GA, USA
| | - Mark F O'Reilly
- Department of Special Education, University of Texas at Austin Austin, TX, USA
| | - Jeff Sigafoos
- Department of Educational Psychology, Victoria University of Wellington Wellington, New Zealand
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