Publications by authors named "Stefanie Blain-Moraes"

26 Publications

  • Page 1 of 1

Neural Correlates of the Shamanic State of Consciousness.

Front Hum Neurosci 2021 18;15:610466. Epub 2021 Mar 18.

Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.

Psychedelics have been recognized as model interventions for studying altered states of consciousness. However, few empirical studies of the shamanic state of consciousness, which is anecdotally similar to the psychedelic state, exist. We investigated the neural correlates of shamanic trance using high-density electroencephalography (EEG) in 24 shamanic practitioners and 24 healthy controls during rest, shamanic drumming, and classical music listening, followed by an assessment of altered states of consciousness. EEG data were used to assess changes in absolute power, connectivity, signal diversity, and criticality, which were correlated with assessment measures. We also compared assessment scores to those of individuals in a previous study under the influence of psychedelics. Shamanic practitioners were significantly different from controls in several domains of altered states of consciousness, with scores comparable to or exceeding that of healthy volunteers under the influence of psychedelics. Practitioners also displayed increased gamma power during drumming that positively correlated with elementary visual alterations. Furthermore, shamanic practitioners had decreased low alpha and increased low beta connectivity during drumming and classical music and decreased neural signal diversity in the gamma band during drumming that inversely correlated with insightfulness. Finally, criticality in practitioners was increased during drumming in the low and high beta and gamma bands, with increases in the low beta band correlating with complex imagery and elementary visual alterations. These findings suggest that psychedelic drug-induced and non-pharmacologic alterations in consciousness have overlapping phenomenal traits but are distinct states of consciousness, as reflected by the unique brain-related changes during shamanic trance compared to previous literature investigating the psychedelic state.
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http://dx.doi.org/10.3389/fnhum.2021.610466DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012721PMC
March 2021

"You're Part of Us and We're Happy to Have You Here": Practices of Social Inclusion for Persons with Dementia.

Clin Gerontol 2021 Mar 4:1-12. Epub 2021 Mar 4.

School of Physical & Occupational Therapy, McGill University, Montreal, Canada.

: Practices of social inclusion are important for maintaining the relationships of persons with dementia and are associated with positive clinical outcomes. The objective of this study was to explore the in-action practices of social inclusion in the activity center of a community-based organization. This study applies an ethnographic approach - including participant observation, informal and semi-structured interviews with persons with dementia (n = 31) and organization staff members (n = 9) to explore the in-action practices of social inclusion. Seven in-action practices of inclusion were identified: ensuring time for individual relationships, building schedules centered around flexibility, empowering decision-making, normalizing dementia-related behaviors, involving family members, soliciting and integrating persons with dementia's feedback, and supporting persons with dementia to practice social inclusion. Care providers of individuals with dementia can effectively facilitate active connections with them by continually soliciting and incorporating their feedback, and by supporting persons with dementia to practice inclusion and care for others.: Community-based organizations can be effective at supporting the active connection of individuals with dementia with others and should be promoted for individuals with mild to moderate dementia.
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http://dx.doi.org/10.1080/07317115.2021.1891170DOI Listing
March 2021

Enacting agency: movement, dementia, and interaction.

Arts Health 2021 Mar 2:1-16. Epub 2021 Mar 2.

School of Physical & Occupational Therapy, Faculty of Medicine, McGill University, Montreal, Quebec.

Arts-based programs can counter the dominant narrative of loss associated with dementia, in part through fostering expressions of agency. This study uses social science theories of interaction between structure and agency to examine how an arts-based movement program, entitled Mouvement de passage, supports agency among individuals with dementia. Ethnographic methods were used to trace how participants enact agency within the structure of the movement program. The program's sessions were video recorded and iteratively analyzed. Participants expressed their agency in three ways: 1) transforming the exercise's structure according to individual interests and desires; 2) resisting the exercise's structure; and 3) improvising movements collectively. The movements of individuals with dementia were shaped by both program structure and individual/collective expressions of agency. The design of Mouvement de passage, based on open-ended structures and voluntary participation, provides a template for developing interventions that foster agency among these persons.
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http://dx.doi.org/10.1080/17533015.2021.1894464DOI Listing
March 2021

Brain network motifs are markers of loss and recovery of consciousness.

Sci Rep 2021 Feb 16;11(1):3892. Epub 2021 Feb 16.

School of Physical and Occupational Therapy, McGill University, Montreal, Canada.

Motifs are patterns of inter-connections between nodes of a network, and have been investigated as building blocks of directed networks. This study explored the re-organization of 3-node motifs during loss and recovery of consciousness. Nine healthy subjects underwent a 3-h anesthetic protocol while 128-channel electroencephalography (EEG) was recorded. In the alpha (8-13 Hz) band, 5-min epochs of EEG were extracted for: Baseline; Induction; Unconscious; 30-, 10- and 5-min pre-recovery of responsiveness; 30- and 180-min post-recovery of responsiveness. We constructed a functional brain network using the weighted and directed phase lag index, on which we calculated the frequency and topology of 3-node motifs. Three motifs (motifs 1, 2 and 5) were significantly present across participants and epochs, when compared to random networks (p < 0.05). The topology of motifs 1 and 5 changed significantly between responsive and unresponsive epochs (p-values < 0.01; Kendall's W = 0.664 (motif 1) and 0.529 (motif 5)). Motif 1 was constituted of long-range chain-like connections, while motif 5 was constituted of short-range, loop-like connections. Our results suggest that anesthetic-induced unconsciousness is associated with a topological re-organization of network motifs. As motif topological re-organization may precede (motif 5) or accompany (motif 1) the return of responsiveness, motifs could contribute to the understanding of the neural correlates of consciousness.
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http://dx.doi.org/10.1038/s41598-021-83482-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887248PMC
February 2021

Brain network motif topography may predict emergence from disorders of consciousness: a case series.

Neurosci Conscious 2020 16;2020(1):niaa017. Epub 2020 Aug 16.

Montreal General Hospital, McGill University Health Center Research Institute, Montreal, QC, Canada.

Neuroimaging methods have improved the accuracy of diagnosis in patients with disorders of consciousness (DOC), but novel, clinically translatable methods for prognosticating this population are still needed. In this case series, we explored the association between topographic and global brain network properties and prognosis in patients with DOC. We recorded high-density electroencephalograms in three patients with acute or chronic DOC, two of whom also underwent an anesthetic protocol. In these two cases, we compared functional network motifs, network hubs and power topography (i.e. topographic network properties), as well as relative power and graph theoretical measures (i.e. global network properties), at baseline, during exposure to anesthesia and after recovery from anesthesia. We also compared these properties to a group of healthy, conscious controls. At baseline, the topographic distribution of nodes participating in alpha motifs resembled conscious controls in patients who later recovered consciousness and high relative power in the delta band was associated with a negative outcome. Strikingly, the reorganization of network motifs, network hubs and power topography under anesthesia followed by their return to a baseline patterns upon recovery from anesthesia, was associated with recovery of consciousness. Our findings suggest that topographic network properties measured at the single-electrode level might provide more prognostic information than global network properties that are averaged across the brain network. In addition, we propose that the brain network's capacity to reorganize in response to a perturbation is a precursor to the recovery of consciousness in DOC patients.
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http://dx.doi.org/10.1093/nc/niaa017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7751128PMC
August 2020

Protocol for the Prognostication of Consciousness Recovery Following a Brain Injury.

Front Hum Neurosci 2020 12;14:582125. Epub 2020 Nov 12.

School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.

Individuals who have suffered a severe brain injury typically require extensive hospitalization in intensive care units (ICUs), where critical treatment decisions are made to maximize their likelihood of recovering consciousness and cognitive function. These treatment decisions can be difficult when the neurological assessment of the patient is limited by unreliable behavioral responses. Reliable objective and quantifiable markers are lacking and there is both (1) a poor understanding of the mechanisms underlying the brain's ability to reconstitute consciousness and cognition after an injury and (2) the absence of a reliable and clinically feasible method of tracking cognitive recovery in ICU survivors. Our goal is to develop and validate a clinically relevant EEG paradigm that can inform the prognosis of unresponsive, brain-injured patients in the ICU. This protocol describes a study to develop a point-of-care system intended to accurately predict outcomes of unresponsive, brain-injured patients in the ICU. We will recruit 200 continuously-sedated brain-injured patients across five ICUs. Between 24 h and 7 days post-ICU admission, high-density EEG will be recorded from behaviorally unresponsive patients before, during and after a brief cessation of pharmacological sedation. Once patients have reached the waking stage, they will be asked to complete an abridged Cambridge Brain Sciences battery, a web-based series of neurocognitive tests. The test series will be repeated every day during acute admission (ICU, ward), or as often as possible given the constraints of ICU and ward care. Following discharge, patients will continue to complete the same test series on weekly, and then monthly basis, for up to 12 months following injury. Functional outcomes will also be assessed up to 12 months post-injury. We anticipate our findings will lead to an increased ability to identify patients, as soon as possible after their brain injury, who are most likely to survive, and to make accurate predictions about their long-term cognitive and functional outcome. In addition to providing critically needed support for clinical decision-making, this study has the potential to transform our understanding of key functional EEG networks associated with consciousness and cognition.
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http://dx.doi.org/10.3389/fnhum.2020.582125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690215PMC
November 2020

Wearable Technology for Detecting Significant Moments in Individuals with Dementia.

Biomed Res Int 2019 25;2019:6515813. Epub 2019 Sep 25.

Biosignal Interaction and Personhood Technology Lab, McGill University, Montreal, Quebec H3G 1A4, Canada.

The detection of significant moments can support the care of individuals with dementia by making visible what is most meaningful to them and maintaining a sense of interpersonal connection. We present a novel intelligent assistive technology (IAT) for the detection of significant moments based on patterns of physiological signal changes in individuals with dementia and their caregivers. The parameters of the IAT are tailored to each individual's idiosyncratic physiological response patterns through an iterative process of incorporating subjective feedback on videos extracted from candidate significant moments identified through the IAT algorithm. The IAT was tested on three dyads (individual with dementia and their primary caregiver) during an eight-week movement program. Upon completion of the program, the IAT identified distinct, personal characteristics of physiological responsiveness in each participant. Tailored algorithms could detect moments of significance experienced by either member of the dyad with an agreement with subjective reports of 70%. These moments were constituted by both physical and emotional significances (e.g., experiences of pain or anxiety) and interpersonal significance (e.g., moments of heighted connection). We provide a freely available MATLAB toolbox with the IAT software in hopes that the assistive technology community can benefit from and contribute to these tools for understanding the subjective experiences of individuals with dementia.
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http://dx.doi.org/10.1155/2019/6515813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778872PMC
March 2020

Brain-computer interfaces and personhood: interdisciplinary deliberations on neural technology.

J Neural Eng 2019 11 11;16(6):063001. Epub 2019 Nov 11.

Pragmatic Health Ethics Research Unit, Institut de recherches cliniques de Montréal, Montréal, Canada. McGill University, Montréal, Canada.

Objective: Scientists, engineers, and healthcare professionals are currently developing a variety of new devices under the category of brain-computer interfaces (BCIs). Current and future applications are both medical/assistive (e.g. for communication) and non-medical (e.g. for gaming). This array of possibilities has been met with both enthusiasm and ethical concern in various media, with no clear resolution of these conflicting sentiments.

Approach: To better understand how BCIs may either harm or help the user, and to investigate whether ethical guidance is required, a meeting entitled 'BCIs and Personhood: A Deliberative Workshop' was held in May 2018.

Main Results: We argue that the hopes and fears associated with BCIs can be productively understood in terms of personhood, specifically the impact of BCIs on what it means to be a person and to be recognized as such by others.

Significance: Our findings suggest that the development of neural technologies raises important questions about the concept of personhood and its role in society. Accordingly, we propose recommendations for BCI development and governance.
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http://dx.doi.org/10.1088/1741-2552/ab39cdDOI Listing
November 2019

Development of a point of care system for automated coma prognosis: a prospective cohort study protocol.

BMJ Open 2019 07 17;9(7):e029621. Epub 2019 Jul 17.

School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.

Introduction: Coma is a deep state of unconsciousness that can be caused by a variety of clinical conditions. Traditional tests for coma outcome prediction are based mainly on a set of clinical observations. Recently, certain event-related potentials (ERPs), which are transient electroencephalogram (EEG) responses to auditory, visual or tactile stimuli, have been introduced as useful predictors of a positive coma outcome (ie, emergence). However, such tests require the skills of clinical neurophysiologists, who are not commonly available in many clinical settings. Additionally, none of the current standard clinical approaches have sufficient predictive accuracies to provide definitive prognoses.

Objective: The objective of this study is to develop improved machine learning procedures based on EEG/ERP for determining emergence from coma.

Methods And Analysis: Data will be collected from 50 participants in coma. EEG/ERP data will be recorded for 24 consecutive hours at a maximum of five time points spanning 30 days from the date of recruitment to track participants' progression. The study employs paradigms designed to elicit brainstem potentials, middle-latency responses, N100, mismatch negativity, P300 and N400. In the case of patient emergence, data are recorded on that occasion to form an additional basis for comparison. A relevant data set will be developed from the testing of 20 healthy controls, each spanning a 15-hour recording period in order to formulate a baseline. Collected data will be used to develop an automated procedure for analysis and detection of various ERP components that are salient to prognosis. Salient features extracted from the ERP and resting-state EEG will be identified and combined to give an accurate indicator of prognosis.

Ethics And Dissemination: This study is approved by the Hamilton Integrated Research Ethics Board (project number 4840). Results will be disseminated through peer-reviewed journal articles and presentations at scientific conferences.

Trial Registration Number: NCT03826407.
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http://dx.doi.org/10.1136/bmjopen-2019-029621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661548PMC
July 2019

Consciousness and Personhood in Medical Care.

Front Hum Neurosci 2018 2;12:306. Epub 2018 Aug 2.

Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI, United States.

Current paradigms in Western medicine often fail to differentiate clearly between consciousness, responsiveness and personhood. The growing number of individuals who exist with sustainable cardiopulmonary systems but who are behaviorally unresponsive has prompted a cultural reconsideration of the relationship between the presence of consciousness and what it means to be a person. This article presents relevant clinical situations that exemplify the different modes in which personhood and consciousness can be associated and dissociated: disorders of consciousness, emergence from anesthesia, and neocortical death. We draw from these examples to call for a reflection on and possible revision of the dominant approach towards unresponsive persons to one in which care providers may work from the default assumption of the existence of an individual's personhood as part of their therapeutic intervention. Behavior consistent with this assumption aligns with the principle of respect for persons in the face of the uncertainty created by the high rate of misdiagnosis of unconsciousness in unresponsive patients and is most consistent with a therapeutic approach to care considering evidence suggesting that attributing personhood may in fact evoke consciousness in these patients.
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http://dx.doi.org/10.3389/fnhum.2018.00306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6082939PMC
August 2018

Long-range temporal correlations in the brain distinguish conscious wakefulness from induced unconsciousness.

Neuroimage 2018 10 7;179:30-39. Epub 2018 Jun 7.

Psychology Department, University of Montreal, QC, Canada.

Rhythmic neuronal synchronization across large-scale networks is thought to play a key role in the regulation of conscious states. Changes in neuronal oscillation amplitude across states of consciousness have been widely reported, but little is known about possible changes in the temporal dynamics of these oscillations. The temporal structure of brain oscillations may provide novel insights into the neural mechanisms underlying consciousness. To address this question, we examined long-range temporal correlations (LRTC) of EEG oscillation amplitudes recorded during both wakefulness and anesthetic-induced unconsciousness. Importantly, the time-varying EEG oscillation envelopes were assessed over the course of a sevoflurane sedation protocol during which the participants alternated between states of consciousness and unconsciousness. Both spectral power and LRTC in oscillation amplitude were computed across multiple frequency bands. State-dependent differences in these features were assessed using non-parametric tests and supervised machine learning. We found that periods of unconsciousness were associated with increases in LRTC in beta (15-30Hz) amplitude over frontocentral channels and with a suppression of alpha (8-13Hz) amplitude over occipitoparietal electrodes. Moreover, classifiers trained to predict states of consciousness on single epochs demonstrated that the combination of beta LRTC with alpha amplitude provided the highest classification accuracy (above 80%). These results suggest that loss of consciousness is accompanied by an augmentation of temporal persistence in neuronal oscillation amplitude, which may reflect an increase in regularity and a decrease in network repertoire compared to the brain's activity during resting-state consciousness.
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http://dx.doi.org/10.1016/j.neuroimage.2018.05.069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545227PMC
October 2018

The impact of Snoezelen in pediatric complex continuing care: A pilot study.

J Pediatr Rehabil Med 2018 ;11(1):31-41

Early Childhood Studies, Ryerson University, Toronto, ON, Canada.

Purpose: Snoezelen is an environment that provides sensory stimulation to individuals in health care and rehabilitative settings. With the presentation of various instruments and materials, individuals can encounter a range of sensory experiences including visual, tactile, and auditory with the purpose of inducing relaxation and restoration. Little is known about how children and adolescents experience this form of sensory stimulation, particularly those in complex continuing care who may have limited verbal and mobility capacity.

Methods: This pilot study examined autonomic physiological responses and observational data on five children and adolescents in complex continuing care within a large rehabilitation hospital. Responses to Snoezelen and watching television were compared against baseline data collected during pre-intervention phases.

Results: Using a single-subject design, this preliminary study found that individual participant responses varied considerably. Four of the five participants exhibited significant changes between sessions on one or two distinct physiological measures. The authors call on additional studies that apply unique and multiple methods capable of accessing the preferences of children and adolescent in rehabilitative care.

Conclusions: As an outcome, contributions to evidence-based practice can be made while supporting children's participation rights in health care decision making.
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http://dx.doi.org/10.3233/PRM-150373DOI Listing
October 2019

Network Efficiency and Posterior Alpha Patterns Are Markers of Recovery from General Anesthesia: A High-Density Electroencephalography Study in Healthy Volunteers.

Front Hum Neurosci 2017 28;11:328. Epub 2017 Jun 28.

Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, United States.

Recent studies have investigated local oscillations, long-range connectivity, and global network patterns to identify neural changes associated with anesthetic-induced unconsciousness. These studies typically employ anesthetic protocols that either just cross the threshold of unconsciousness, or induce deep unconsciousness for a brief period of time-neither of which models general anesthesia for major surgery. To study neural patterns of unconsciousness and recovery in a clinically-relevant context, we used a realistic anesthetic regimen to induce and maintain unconsciousness in eight healthy participants for 3 h. High-density electroencephalogram (EEG) was acquired throughout and for another 3 h after emergence. Seven epochs of 5-min eyes-closed resting states were extracted from the data at baseline as well as 30, 60, 90, 120, 150, and 180-min post-emergence. Additionally, 5-min epochs were extracted during induction, unconsciousness, and immediately prior to recovery of consciousness, for a total of 10 analysis epochs. The EEG data in each epoch were analyzed using source-localized spectral analysis, phase-lag index, and graph theoretical techniques. Posterior alpha power was significantly depressed during unconsciousness, and gradually approached baseline levels over the 3 h recovery period. Phase-lag index did not distinguish between states of consciousness or stages of recovery. Network efficiency was significantly depressed and network clustering coefficient was significantly increased during unconsciousness; these graph theoretical measures returned to baseline during the 3 h recovery period. Posterior alpha power may be a potential biomarker for normal recovery of functional brain networks after general anesthesia.
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http://dx.doi.org/10.3389/fnhum.2017.00328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487412PMC
June 2017

Protocol for the Reconstructing Consciousness and Cognition (ReCCognition) Study.

Front Hum Neurosci 2017 7;11:284. Epub 2017 Jun 7.

Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States.

Important scientific and clinical questions persist about general anesthesia despite the ubiquitous clinical use of anesthetic drugs in humans since their discovery. For example, it is not known how the brain reconstitutes consciousness and cognition after the profound functional perturbation of the anesthetized state, nor has a specific pattern of functional recovery been characterized. To date, there has been a lack of detailed investigation into rates of recovery and the potential orderly return of attention, sensorimotor function, memory, reasoning and logic, abstract thinking, and processing speed. Moreover, whether such neurobehavioral functions display an invariant sequence of return across individuals is similarly unknown. To address these questions, we designed a study of healthy volunteers undergoing general anesthesia with electroencephalography and serial testing of cognitive functions (NCT01911195). The aims of this study are to characterize the temporal patterns of neurobehavioral recovery over the first several hours following termination of a deep inhaled isoflurane general anesthetic and to identify common patterns of cognitive function recovery. Additionally, we will conduct spectral analysis and reconstruct functional networks from electroencephalographic data to identify any neural correlates (e.g., connectivity patterns, graph-theoretical variables) of cognitive recovery after the perturbation of general anesthesia. To accomplish these objectives, we will enroll a total of 60 consenting adults aged 20-40 across the three participating sites. Half of the study subjects will receive general anesthesia slowly titrated to loss of consciousness (LOC) with an intravenous infusion of propofol and thereafter be maintained for 3 h with 1.3 age adjusted minimum alveolar concentration of isoflurane, while the other half of subjects serves as awake controls to gauge effects of repeated neurobehavioral testing, spontaneous fatigue and endogenous rest-activity patterns.
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http://dx.doi.org/10.3389/fnhum.2017.00284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5461274PMC
June 2017

Normal Brain Response to Propofol in Advance of Recovery from Unresponsive Wakefulness Syndrome.

Front Hum Neurosci 2016 2;10:248. Epub 2016 Jun 2.

Department of Anesthesiology, University of Michigan Ann Arbor, MI, USA.

Up to 40% of individuals with unresponsive wakefulness syndrome (UWS) actually might be conscious. Recent attempts to detect covert consciousness in behaviorally unresponsive patients via neurophysiological patterns are limited by the need to compare data from brain-injured patients to healthy controls. In this report, we pilot an alternative within-subject approach by using propofol to perturb the brain state of a patient diagnosed with UWS. An auditory stimulation series was presented to the patient before, during, and after exposure to propofol while high-density electroencephalograph (EEG) was recorded. Baseline analysis revealed residual markers in the continuous EEG and event-related potentials (ERPs) that have been associated with conscious processing. However, these markers were significantly distorted by the patient's pathology, challenging the interpretation of their functional significance. Upon exposure to propofol, changes in EEG characteristics were similar to what is seen in healthy individuals and ERPs associated with conscious processing disappeared. At the 1-month follow up, the patient had regained consciousness. We offer three alternative explanations for these results: (1) the patient was covertly consciousness, and was anesthetized by propofol administration; (2) the patient was unconscious, and the observed EEG changes were a propofol-specific phenomenon; and (3) the patient was unconscious, but his brain networks responded normally in a way that heralded the possibility of recovery. These alternatives will be tested in a larger study, and raise the intriguing possibility of using a general anesthetic as a probe of brain states in behaviorally unresponsive patients.
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http://dx.doi.org/10.3389/fnhum.2016.00248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4889589PMC
June 2016

Functional and Topological Conditions for Explosive Synchronization Develop in Human Brain Networks with the Onset of Anesthetic-Induced Unconsciousness.

Front Comput Neurosci 2016 21;10. Epub 2016 Jan 21.

Department of Anesthesiology, University of Michigan Medical SchoolAnn Arbor, MI, USA; Center for Consciousness Science, University of Michigan Medical SchoolAnn Arbor, MI, USA.

Sleep, anesthesia, and coma share a number of neural features but the recovery profiles are radically different. To understand the mechanisms of reversibility of unconsciousness at the network level, we studied the conditions for gradual and abrupt transitions in conscious and anesthetized states. We hypothesized that the conditions for explosive synchronization (ES) in human brain networks would be present in the anesthetized brain just over the threshold of unconsciousness. To test this hypothesis, functional brain networks were constructed from multi-channel electroencephalogram (EEG) recordings in seven healthy subjects across conscious, unconscious, and recovery states. We analyzed four variables that are involved in facilitating ES in generic, non-biological networks: (1) correlation between node degree and frequency, (2) disassortativity (i.e., the tendency of highly-connected nodes to link with less-connected nodes, or vice versa), (3) frequency difference of coupled nodes, and (4) an inequality relationship between local and global network properties, which is referred to as the suppressive rule. We observed that the four network conditions for ES were satisfied in the unconscious state. Conditions for ES in the human brain suggest a potential mechanism for rapid recovery from the lightly-anesthetized state. This study demonstrates for the first time that the network conditions for ES, formerly shown in generic networks only, are present in empirically-derived functional brain networks. Further investigations with deep anesthesia, sleep, and coma could provide insight into the underlying causes of variability in recovery profiles of these unconscious states.
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http://dx.doi.org/10.3389/fncom.2016.00001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720783PMC
February 2016

General relationship of global topology, local dynamics, and directionality in large-scale brain networks.

PLoS Comput Biol 2015 Apr 14;11(4):e1004225. Epub 2015 Apr 14.

Department of Anesthesiology, Center for Consciousness Science and Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

The balance of global integration and functional specialization is a critical feature of efficient brain networks, but the relationship of global topology, local node dynamics and information flow across networks has yet to be identified. One critical step in elucidating this relationship is the identification of governing principles underlying the directionality of interactions between nodes. Here, we demonstrate such principles through analytical solutions based on the phase lead/lag relationships of general oscillator models in networks. We confirm analytical results with computational simulations using general model networks and anatomical brain networks, as well as high-density electroencephalography collected from humans in the conscious and anesthetized states. Analytical, computational, and empirical results demonstrate that network nodes with more connections (i.e., higher degrees) have larger amplitudes and are directional targets (phase lag) rather than sources (phase lead). The relationship of node degree and directionality therefore appears to be a fundamental property of networks, with direct applicability to brain function. These results provide a foundation for a principled understanding of information transfer across networks and also demonstrate that changes in directionality patterns across states of human consciousness are driven by alterations of brain network topology.
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http://dx.doi.org/10.1371/journal.pcbi.1004225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4397097PMC
April 2015

Assessing levels of consciousness with symbolic analysis.

Philos Trans A Math Phys Eng Sci 2015 Feb;373(2034)

Center for Consciousness Science, Department of Anesthesiology, Neuroscience Graduate Program, University of Michigan Medical School, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5048, USA.

'Covert consciousness' is a state in which consciousness is present without the capacity for behavioural response, and it can occur in patients with intraoperative awareness or unresponsive wakefulness syndrome. To detect and prevent this undesirable state, it is critical to develop a reliable neurobiological assessment of an individual's level of consciousness that is independent of behaviour. One such approach that shows potential is measuring surrogates of cortical communication in the brain using electroencephalography (EEG). EEG is practicable in clinical application, but involves many fundamental signal processing problems, including signal-to-noise ratio and high dimensional complexity. Symbolic analysis of EEG can mitigate these problems, improving the measurement of brain connectivity and the ability to successfully assess levels of consciousness. In this article, we review the problem of covert consciousness, basic neurobiological principles of consciousness, current methods of measuring brain connectivity and the advantages of symbolic processing, with a focus on symbolic transfer entropy (STE). Finally, we discuss recent advances and clinical applications of STE and other symbolic analyses to assess levels of consciousness.
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http://dx.doi.org/10.1098/rsta.2014.0117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398453PMC
February 2015

Neurophysiological correlates of sevoflurane-induced unconsciousness.

Anesthesiology 2015 Feb;122(2):307-16

From the Department of Anesthesiology (S.B.-M., V.T., G.V., A.A., D.R., B.S., E.J., G.A.M.) and Neuroscience Graduate Program (G.A.M.), Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, Michigan.

Background: Recent studies of anesthetic-induced unconsciousness in humans have focused predominantly on the intravenous drug propofol and have identified anterior dominance of alpha rhythms and frontal phase-amplitude coupling patterns as neurophysiological markers. However, it is unclear whether the correlates of propofol-induced unconsciousness are generalizable to inhaled anesthetics, which have distinct molecular targets and which are used more commonly in clinical practice.

Methods: The authors recorded 64-channel electroencephalograms in healthy human participants during consciousness, sevoflurane-induced unconsciousness, and recovery (n = 10; n = 7 suitable for analysis). Spectrograms and scalp distributions of low-frequency (1 Hz) and alpha (10 Hz) power were analyzed, and phase-amplitude modulation between these two frequencies was calculated in frontal and parietal regions. Phase lag index was used to assess phase relationships across the cortex.

Results: At concentrations sufficient for unconsciousness, sevoflurane did not result in a consistent anteriorization of alpha power; the relationship between low-frequency phase and alpha amplitude in the frontal cortex did not undergo characteristic transitions. By contrast, there was significant cross-frequency coupling in the parietal region during consciousness that was not observed after loss of consciousness. Furthermore, a reversible disruption of anterior-posterior phase relationships in the alpha bandwidth was identified as a correlate of sevoflurane-induced unconsciousness.

Conclusion: In humans, sevoflurane-induced unconsciousness is not correlated with anteriorization of alpha and related cross-frequency patterns, but rather by a disruption of phase-amplitude coupling in the parietal region and phase-phase relationships across the cortex.
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http://dx.doi.org/10.1097/ALN.0000000000000482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301983PMC
February 2015

Electroencephalographic effects of ketamine on power, cross-frequency coupling, and connectivity in the alpha bandwidth.

Front Syst Neurosci 2014 1;8:114. Epub 2014 Jul 1.

Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School Ann Arbor, MI, USA ; Neuroscience Graduate Program, University of Michigan Medical School Ann Arbor, MI, USA.

Recent studies of propofol-induced unconsciousness have identified characteristic properties of electroencephalographic alpha rhythms that may be mediated by drug activity at γ-aminobutyric acid (GABA) receptors in the thalamus. However, the effect of ketamine (a primarily non-GABAergic anesthetic drug) on alpha oscillations has not been systematically evaluated. We analyzed the electroencephalogram of 28 surgical patients during consciousness and ketamine-induced unconsciousness with a focus on frontal power, frontal cross-frequency coupling, frontal-parietal functional connectivity (measured by coherence and phase lag index), and frontal-to-parietal directional connectivity (measured by directed phase lag index) in the alpha bandwidth. Unlike past studies of propofol, ketamine-induced unconsciousness was not associated with increases in the power of frontal alpha rhythms, characteristic cross-frequency coupling patterns of frontal alpha power and slow-oscillation phase, or decreases in coherence in the alpha bandwidth. Like past studies of propofol using undirected and directed phase lag index, ketamine reduced frontal-parietal (functional) and frontal-to-parietal (directional) connectivity in the alpha bandwidth. These results suggest that directional connectivity changes in the alpha bandwidth may be state-related markers of unconsciousness induced by both GABAergic and non-GABAergic anesthetics.
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http://dx.doi.org/10.3389/fnsys.2014.00114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4076669PMC
July 2014

Towards a physiological signal-based access solution for a non-verbal adolescent with severe and multiple disabilities.

Dev Neurorehabil 2014 Aug 2;17(4):270-7. Epub 2013 Oct 2.

David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA , USA .

Objective: To find physiologically arousing stimuli and labile physiological channels in a non-verbal adolescent with severe and multiple congenital disabilities, who did not have a reliable means of communication.

Methods: The client was repeatedly presented with visual and audiovisual stimuli, representing variations of six contextual factors over three sessions in a one month period. For each stimulus, reactions were detected in the client's four peripheral autonomic nervous system signals using a rule-based classification algorithm.

Results: During the presentation of audiovisual stimuli, the number of physiological reactions significantly differed from that observed in baseline (χ(2) = 3.93, p = 0.0476). Aural stimuli articulated in an unfamiliar voice, and aural stimuli containing anticipatory patterns were also physiologically arousing. Fingertip temperature was the client's most labile physiological signal.

Conclusions: The results of this case study suggest that physiological data may complement caregiver acumen in deciphering the reactions of non-verbal clients with severe and multiple disabilities.
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http://dx.doi.org/10.3109/17518423.2013.834997DOI Listing
August 2014

Performance assessment in brain-computer interface-based augmentative and alternative communication.

Biomed Eng Online 2013 May 16;12:43. Epub 2013 May 16.

Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.

A large number of incommensurable metrics are currently used to report the performance of brain-computer interfaces (BCI) used for augmentative and alterative communication (AAC). The lack of standard metrics precludes the comparison of different BCI-based AAC systems, hindering rapid growth and development of this technology. This paper presents a review of the metrics that have been used to report performance of BCIs used for AAC from January 2005 to January 2012. We distinguish between Level 1 metrics used to report performance at the output of the BCI Control Module, which translates brain signals into logical control output, and Level 2 metrics at the Selection Enhancement Module, which translates logical control to semantic control. We recommend that: (1) the commensurate metrics Mutual Information or Information Transfer Rate (ITR) be used to report Level 1 BCI performance, as these metrics represent information throughput, which is of interest in BCIs for AAC; 2) the BCI-Utility metric be used to report Level 2 BCI performance, as it is capable of handling all current methods of improving BCI performance; (3) these metrics should be supplemented by information specific to each unique BCI configuration; and (4) studies involving Selection Enhancement Modules should report performance at both Level 1 and Level 2 in the BCI system. Following these recommendations will enable efficient comparison between both BCI Control and Selection Enhancement Modules, accelerating research and development of BCI-based AAC systems.
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http://dx.doi.org/10.1186/1475-925X-12-43DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662584PMC
May 2013

Altered cortical communication in amyotrophic lateral sclerosis.

Neurosci Lett 2013 May 6;543:172-6. Epub 2013 Apr 6.

Department of Anesthesiology, University of Michigan Medical School, 7433 Med Sci I, 1150 West Medical Center Drive, Ann Arbor, MI 48105, USA.

Amyotrophic lateral sclerosis (ALS) is a disorder associated primarily with the degeneration of the motor system. More recently, functional connectivity studies have demonstrated potentially adaptive changes in ALS brain organization, but disease-related changes in cortical communication remain unknown. We recruited individuals with ALS and age-matched controls to operate a brain-computer interface while electroencephalography was recorded over three sessions. Using normalized symbolic transfer entropy, we measured directed functional connectivity from frontal to parietal (feedback connectivity) and parietal to frontal (feedforward connectivity) regions. Feedback connectivity was not significantly different between groups, but feedforward connectivity was significantly higher in individuals with ALS. This result was consistent across a broad electroencephalographic spectrum (4-35 Hz), and in theta, alpha and beta frequency bands. Feedback connectivity has been associated with conscious state and was found to be independent of ALS symptom severity in this study, which may have significant implications for the detection of consciousness in individuals with advanced ALS. We suggest that increases in feedforward connectivity represent a compensatory response to the ALS-related loss of input such that sensory stimuli have sufficient strength to cross the threshold necessary for conscious processing in the global neuronal workspace.
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http://dx.doi.org/10.1016/j.neulet.2013.03.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716378PMC
May 2013

Biomusic: a novel technology for revealing the personhood of people with profound multiple disabilities.

Augment Altern Commun 2013 Jun 14;29(2):159-73. Epub 2013 Mar 14.

Department of Physical Medicine and Rehabilitation, University of Michigan, USA.

It is often difficult for family members and caregivers to interact with persons with profound multiple disabilities (PMD) because of the severely compromised communicative repertoire of this population. The resulting communication challenges may limit the ability of others to perceive personhood in individuals with PMD. This preliminary study investigated the effects of music generated in real time from physiological signals (biomusic) on caregiver perceptions of their interactions with persons with PMD. Caregivers (n = 10; parents and clinical staff) engaged in four, 10-min interactions with a person with PMD (n = 3; diagnoses = traumatic brain injury, pervasive developmental disorder, hypoxic brain injury), whose biomusic was projected throughout. Caregivers participated in two open-ended, semi-structured interviews to explore the effect of biomusic on these interactions. Most caregiver responses to biomusic were very positive, and many reported that biomusic caused an improvement in their interaction with and perceptions of the person with PMD. By providing audible evidence of the changing physiological state of persons with PMD, biomusic may enhance the perceived personhood of these individuals and enrich interactions with their family members and caregivers.
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http://dx.doi.org/10.3109/07434618.2012.760648DOI Listing
June 2013

Challenges of developing communicative interaction in individuals with congenital profound intellectual and multiple disabilities.

J Intellect Dev Disabil 2012 Dec 25;37(4):348-59. Epub 2012 Sep 25.

Department of Physical Medicine & Rehabilitation, University of Michigan Medical School, Ann Arbor, MI 48109-5841, USA.

Background: Physiological responses have been used in individuals with acquired disability to enable communicative interaction without motor movement. This study explored four autonomic nervous system (ANS) signals-electrodermal activity, skin temperature, cardiac patterns and respiratory patterns-to enable interaction with individuals born with profound intellectual and multiple disabilities (PIMD).

Method: A series of case studies were conducted to teach a 15-year-old individual with PIMD to voluntarily control his ANS signals for the purposes of communicative interaction. Training was carried out according to an alternating treatment single-subject research design.

Results: Training was unsuccessful; however, ANS signal patterns revealed issues unique to people with PIMD: profound intrasubject variability, discrepancy between physiological responses and caregiver perspectives, and the participant's lack of contingency awareness.

Conclusions: These three priority areas unique to people with congenital PIMD must be addressed before ANS signals can be used to enable communicative interaction with this population.
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http://dx.doi.org/10.3109/13668250.2012.721879DOI Listing
December 2012

Barriers to and mediators of brain-computer interface user acceptance: focus group findings.

Ergonomics 2012 29;55(5):516-25. Epub 2012 Mar 29.

Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI, USA.

Unlabelled: Brain-computer interfaces (BCI) are designed to enable individuals with severe motor impairments such as amyotrophic lateral sclerosis (ALS) to communicate and control their environment. A focus group was conducted with individuals with ALS (n=8) and their caregivers (n=9) to determine the barriers to and mediators of BCI acceptance in this population. Two key categories emerged: personal factors and relational factors. Personal factors, which included physical, physiological and psychological concerns, were less important to participants than relational factors, which included corporeal, technological and social relations with the BCI. The importance of these relational factors was analysed with respect to published literature on actor-network theory (ANT) and disability, and concepts of voicelessness and personhood. Future directions for BCI research are recommended based on the emergent focus group themes.

Practitioner Summary: This manuscript explores human factor issues involved in designing and evaluating brain-computer interface (BCI) systems for users with severe motor disabilities. Using participatory research paradigms and qualitative methods, this work draws attention to personal and relational factors that act as barriers to, or mediators of, user acceptance of this technology.
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http://dx.doi.org/10.1080/00140139.2012.661082DOI Listing
September 2012