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Othman MH, Olsen MH, Hansen KIT, Amiri M, Jensen HR, Nyholm B, Møller K, Kjaergaard J, Kondziella D. Covert Consciousness in Acute Brain Injury Revealed by Automated Pupillometry and Cognitive Paradigms. Neurocrit Care 2024:10.1007/s12028-024-01983-7. [PMID: 38605221 DOI: 10.1007/s12028-024-01983-7] [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: 02/02/2024] [Accepted: 03/12/2024] [Indexed: 04/13/2024]
Abstract
BACKGROUND Identifying covert consciousness in intensive care unit (ICU) patients with coma and other disorders of consciousness (DoC) is crucial for treatment decisions, but sensitive low-cost bedside markers are missing. We investigated whether automated pupillometry combined with passive and active cognitive paradigms can detect residual consciousness in ICU patients with DoC. METHODS We prospectively enrolled clinically low-response or unresponsive patients with traumatic or nontraumatic DoC from ICUs of a tertiary referral center. Age-matched and sex-matched healthy volunteers served as controls. Patients were categorized into clinically unresponsive (coma or unresponsive wakefulness syndrome) or clinically low-responsive (minimally conscious state or better). Using automated pupillometry, we recorded pupillary dilation to passive (visual and auditory stimuli) and active (mental arithmetic) cognitive paradigms, with task-specific success criteria (e.g., ≥ 3 of 5 pupillary dilations on five consecutive mental arithmetic tasks). RESULTS We obtained 699 pupillometry recordings at 178 time points from 91 ICU patients with brain injury (mean age 60 ± 13.8 years, 31% women, and 49.5% nontraumatic brain injuries). Recordings were also obtained from 26 matched controls (59 ± 14.8 years, 38% women). Passive paradigms yielded limited distinctions between patients and controls. However, active paradigms enabled discrimination between different states of consciousness. With mental arithmetic of moderate complexity, ≥ 3 pupillary dilations were seen in 17.8% of clinically unresponsive patients and 50.0% of clinically low-responsive patients (odds ratio 4.56, 95% confidence interval 2.09-10.10; p < 0.001). In comparison, 76.9% healthy controls responded with ≥ 3 pupillary dilations (p = 0.028). Results remained consistent across sensitivity analyses using different thresholds for success. Spearman's rank analysis underscored the robust association between pupillary dilations during mental arithmetic and consciousness levels (rho = 1, p = 0.017). Notably, one behaviorally unresponsive patient demonstrated persistent command-following behavior 2 weeks before overt signs of awareness, suggesting prolonged cognitive motor dissociation. CONCLUSIONS Automated pupillometry combined with mental arithmetic can identify cognitive efforts, and hence covert consciousness, in ICU patients with acute DoC.
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Affiliation(s)
- Marwan H Othman
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Markus Harboe Olsen
- Department of Neuroanesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Karen Irgens Tanderup Hansen
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
- Faculty of Health Science, University of Southern Denmark, Odense, Denmark
| | - Moshgan Amiri
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Helene Ravnholt Jensen
- Department of Neuroanesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Benjamin Nyholm
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kirsten Møller
- Department of Neuroanesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Kjaergaard
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
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Ledesma-Ramírez CI, Hernández-Gloria JJ, Bojorges-Valdez E, Yanez-Suarez O, Piña-Ramírez O. Recurrence quantification analysis during a mental calculation task. CHAOS (WOODBURY, N.Y.) 2023; 33:063154. [PMID: 37368040 DOI: 10.1063/5.0147321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023]
Abstract
The identification of brain dynamical changes under different cognitive conditions with noninvasive techniques such as electroencephalography (EEG) is relevant for the understanding of their underlying neural mechanisms. The comprehension of these mechanisms has applications in the early diagnosis of neurological disorders and asynchronous brain computer interfaces. In both cases, there are no reported features that could describe intersubject and intra subject dynamics behavior accurately enough to be applied on a daily basis. The present work proposes the use of three nonlinear features (recurrence rate, determinism, and recurrence times) extracted from recurrence quantification analysis (RQA) to describe central and parietal EEG power series complexity in continuous alternating episodes of mental calculation and rest state. Our results demonstrate a consistent mean directional change of determinism, recurrence rate, and recurrence times between conditions. Increasing values of determinism and recurrence rate were present from the rest state to mental calculation, whereas recurrence times showed the opposite pattern. The analyzed features in the present study showed statistically significant changes between rest and mental calculation states in both individual and population analysis. In general, our study described mental calculation EEG power series as less complex systems in comparison to the rest state. Moreover, ANOVA showed stability of RQA features along time.
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Affiliation(s)
| | | | - Erik Bojorges-Valdez
- Engineering Studies for Innovation, Universidad Iberoamericana, 01219 Ciudad de México, Mexico
| | - Oscar Yanez-Suarez
- Neuroimage Research Lab, Universidad Autónoma Metropolitana, 09340 Ciudad de México, Mexico
| | - Omar Piña-Ramírez
- Bioinformatics and Statistical Analysis Department, Instituto Nacional de Perinatología, 11000 Ciudad de México, Mexico
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Ding L, Duan W, Wang Y, Lei X. Test-retest reproducibility comparison in resting and the mental task states: A sensor and source-level EEG spectral analysis. Int J Psychophysiol 2022; 173:20-28. [PMID: 35017028 DOI: 10.1016/j.ijpsycho.2022.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 01/04/2023]
Abstract
Previous test-retest analysis of EEG mostly focused on eyes open and eyes closed resting-state. However, less attention was paid to the EEG during the subject-driven mental imaginary task state. In the current study, we compared the test-retest reproducibility of EEG spectrum in three mental imaginary task states (i.e. performed mental arithmetic, recalled the events of their day, and silently sang lyrics) and two resting states (i.e. eyes open and closed) during three EEG sessions. The resting state with eyes closed has the highest reproducibility, while the resting state with eyes opened has the lowest reproducibility for the spectral features of EEG signals at the sensor level. However, the reproducibility during eyes-open ranked higher among the five states at the source level. Moreover, the mental arithmetic state has the highest reproducibility among all the three task states. And its reproducibility in certain rhythms (theta, gamma, etc) was higher than the resting states. The reproducibility of the EEG spectrum was also investigated from the perspective of large-scale brain networks. The dorsal attention network showed the highest reproducibility in a wide frequency range of the alpha and beta rhythms. Our study suggests the importance of task selection based on the target brain region and the target frequency band. This may provide some suggestions for future researchers to choose appropriate experimental paradigms and provide a guideline on EEG study for the basic and clinical applications.
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Affiliation(s)
- Lihong Ding
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing 400715, China; Key Laboratory of Cognition and Personality of Ministry of Education, Chongqing 400715, China
| | - Wei Duan
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing 400715, China; Key Laboratory of Cognition and Personality of Ministry of Education, Chongqing 400715, China
| | - Yulin Wang
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing 400715, China; Key Laboratory of Cognition and Personality of Ministry of Education, Chongqing 400715, China
| | - Xu Lei
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing 400715, China; Key Laboratory of Cognition and Personality of Ministry of Education, Chongqing 400715, China.
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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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Vassilieva A, Olsen MH, Peinkhofer C, Knudsen GM, Kondziella D. Automated pupillometry to detect command following in neurological patients: a proof-of-concept study. PeerJ 2019; 7:e6929. [PMID: 31139508 PMCID: PMC6521812 DOI: 10.7717/peerj.6929] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/09/2019] [Indexed: 01/07/2023] Open
Abstract
Background Levels of consciousness in patients with acute and chronic brain injury are notoriously underestimated. Paradigms based on electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) may detect covert consciousness in clinically unresponsive patients but are subject to logistical challenges and the need for advanced statistical analysis. Methods To assess the feasibility of automated pupillometry for the detection of command following, we enrolled 20 healthy volunteers and 48 patients with a wide range of neurological disorders, including seven patients in the intensive care unit (ICU), who were asked to engage in mental arithmetic. Results Fourteen of 20 (70%) healthy volunteers and 17 of 43 (39.5%) neurological patients, including 1 in the ICU, fulfilled prespecified criteria for command following by showing pupillary dilations during ≥4 of five arithmetic tasks. None of the five sedated and unconscious ICU patients passed this threshold. Conclusions Automated pupillometry combined with mental arithmetic appears to be a promising paradigm for the detection of covert consciousness in people with brain injury. We plan to build on this study by focusing on non-communicating ICU patients in whom the level of consciousness is unknown. If some of these patients show reproducible pupillary dilation during mental arithmetic, this would suggest that the present paradigm can reveal covert consciousness in unresponsive patients in whom standard investigations have failed to detect signs of consciousness.
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Affiliation(s)
- Alexandra Vassilieva
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Markus Harboe Olsen
- Department of Neuroanesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Costanza Peinkhofer
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Medical Faculty, University of Trieste, Trieste, Italy
| | - Gitte Moos Knudsen
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Faculty of Health Sciences and Medicine, University of Copenhagen, Copenhagen, Denmark.,Neurobiology Research Unit, Rigshospitalet, Copenhagen University Hospital and Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Faculty of Health Sciences and Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
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Choi SI, Han CH, Choi GY, Shin J, Song KS, Im CH, Hwang HJ. On the Feasibility of Using an Ear-EEG to Develop an Endogenous Brain-Computer Interface. SENSORS (BASEL, SWITZERLAND) 2018; 18:E2856. [PMID: 30158505 PMCID: PMC6165202 DOI: 10.3390/s18092856] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 11/27/2022]
Abstract
Brain-computer interface (BCI) studies based on electroencephalography (EEG) measured around the ears (ear-EEGs) have mostly used exogenous paradigms involving brain activity evoked by external stimuli. The objective of this study is to investigate the feasibility of ear-EEGs for development of an endogenous BCI system that uses self-modulated brain activity. We performed preliminary and main experiments where EEGs were measured on the scalp and behind the ears to check the reliability of ear-EEGs as compared to scalp-EEGs. In the preliminary and main experiments, subjects performed eyes-open and eyes-closed tasks, and they performed mental arithmetic (MA) and light cognitive (LC) tasks, respectively. For data analysis, the brain area was divided into four regions of interest (ROIs) (i.e., frontal, central, occipital, and ear area). The preliminary experiment showed that the degree of alpha activity increase of the ear area with eyes closed is comparable to those of other ROIs (occipital > ear > central > frontal). In the main experiment, similar event-related (de)synchronization (ERD/ERS) patterns were observed between the four ROIs during MA and LC, and all ROIs showed the mean classification accuracies above 70% required for effective binary communication (MA vs. LC) (occipital = ear = central = frontal). From the results, we demonstrated that ear-EEG can be used to develop an endogenous BCI system based on cognitive tasks without external stimuli, which allows the usability of ear-EEGs to be extended.
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Affiliation(s)
- Soo-In Choi
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39177, Korea.
| | - Chang-Hee Han
- Berlin Institute of Technology, Machine Learning Group, Marchstrasse 23, 10587 Berlin, Germany.
| | - Ga-Young Choi
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39177, Korea.
| | - Jaeyoung Shin
- Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea.
| | - Kwang Soup Song
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39177, Korea.
| | - Chang-Hwan Im
- Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea.
| | - Han-Jeong Hwang
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39177, Korea.
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Towards using fNIRS recordings of mental arithmetic for the detection of residual cognitive activity in patients with disorders of consciousness (DOC). Brain Cogn 2018; 125:78-87. [PMID: 29909026 DOI: 10.1016/j.bandc.2018.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/30/2018] [Accepted: 06/08/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Recently, fNIRS has been proposed as a promising approach for awareness detection, and a possible method to establish basic communication in patients with disorders of consciousness (DOC). AIM Using fNIRS, the present study evaluated the applicability of auditory presented mental-arithmetic tasks in this respect. METHODS We investigated the applicability of active attention to serial subtractions for awareness detection in ten healthy controls (HC, 21-32 y/o), by comparing the measured patterns to patterns induced by self-performance of the same task. Furthermore, we examined the suitability of ignoring the given task as additional control signal to implement a two-class brain-computer interface (BCI) paradigm. Finally, we compared our findings in HC with recordings in one DOC patient (78 y/o). RESULTS AND CONCLUSION Results of the HC revealed no differences between the self-performance and the attention condition, making the attention task suitable for awareness detection. However, there was no general difference between the ignore and attend condition, making the tasks less suitable for BCI control. Despite inconsistent correlations between the patient data and the HC group, single runs of the patient recordings revealed task-synchronous patterns - however, we cannot conclude whether the measured activation derives from instruction based task performance and thus awareness.
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