Practice guideline update recommendations summary: Disorders of consciousness: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology; the American Congress of Rehabilitation Medicine; and the National Institute on Disability, Independent Living, and Rehabilitation Research

Mortality and Timing of Withdrawal of Life-Sustaining Therapies After Out-of-Hospital Cardiac Arrest: Two-Center Retrospective Pediatric Cohort Study

OBJECTIVES

Pediatric out-of-hospital cardiac arrest (OHCA) is associated with substantial morbidity and mortality. Limited data exist to guide timing and method of neurologic prognostication after pediatric OHCA, making counseling on withdrawal of life-sustaining therapies (WLSTs) challenging. This study investigates the timing and mode of death after pediatric OHCA and factors associated with mortality. Additionally, this study explores delayed recovery after comatose examination on day 3 postarrest.

DESIGN

This is a retrospective, observational study based on data collected from hospital databases and chart reviews.

SETTING

Data collection occurred in two pediatric academic hospitals between January 1, 2016, and December 31, 2020.

PATIENTS

Patients were identified from available databases and electronic medical record queries for the International Classification of Diseases , 10th Edition (ICD-10) code I46.9 (Cardiac Arrest). Patient inclusion criteria included age range greater than or equal to 48 hours to less than 18 years, OHCA within 24 hours of admission, greater than or equal to 1 min of cardiopulmonary resuscitation, and return-of-spontaneous circulation for greater than or equal to 20 min.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred thirty-five children (65% male) with a median age of 3 years (interquartile range 0.6-11.8) met inclusion criteria. Overall, 63 of 135 patients (47%) died before hospital discharge, including 34 of 63 patients (54%) after WLST. Among these, 20 of 34 patients underwent WLST less than or equal to 3 days postarrest, including 10 of 34 patients who underwent WLST within 1 day. WLST occurred because of poor perceived neurologic prognosis in all cases, although 7 of 34 also had poor perceived systemic prognosis. Delayed neurologic recovery from coma on day 3 postarrest was observed in 7 of 72 children (10%) who ultimately survived to discharge.

CONCLUSIONS

In our two centers between 2016 and 2020, more than half the deaths after pediatric OHCA occurred after WLST, and a majority of WLST occurred within 3 days postarrest. Additional research is warranted to determine optimal timing and predictors of neurologic prognosis after pediatric OHCA to better inform families during goals of care discussions.

How well do neural signatures of resting-state EEG detect consciousness? A large-scale clinical study

The assessment of consciousness states, especially distinguishing minimally conscious states (MCS) from unresponsive wakefulness states (UWS), constitutes a pivotal role in clinical therapies. Despite that numerous neural signatures of consciousness have been proposed, the effectiveness and reliability of such signatures for clinical consciousness assessment still remains an intense debate. Through a comprehensive review of the literature, inconsistent findings are observed about the effectiveness of diverse neural signatures. Notably, the majority of existing studies have evaluated neural signatures on a limited number of subjects (usually below 30), which may result in uncertain conclusions due to small data bias. This study presents a systematic evaluation of neural signatures with large-scale clinical resting-state electroencephalography (EEG) signals containing 99 UWS, 129 MCS, 36 emergence from the minimally conscious state, and 32 healthy subjects (296 total) collected over 3 years. A total of 380 EEG-based metrics for consciousness detection, including spectrum features, nonlinear measures, functional connectivity, and graph-based measures, are summarized and evaluated. To further mitigate the effect of data bias, the evaluation is performed with bootstrap sampling so that reliable measures can be obtained. The results of this study suggest that relative power in alpha and delta serve as dependable indicators of consciousness. With the MCS group, there is a notable increase in the phase lag index-related connectivity measures and enhanced functional connectivity between brain regions in comparison to the UWS group. A combination of features enables the development of an automatic detector of conscious states.

Resting-State Functional Magnetic Resonance Imaging Network Association With Mortality, Epilepsy, Cognition, and Motor Two-Year Outcomes in Suspected Severe Neonatal Acute Brain Injury

BACKGROUND AND OBJECTIVES

In acute brain injury of neonates, resting-state functional magnetic resonance imaging (MRI) (RS) showed incremental association with consciousness, mortality, cognitive and motor development, and epilepsy, with correction for multiple comparisons, at six months postgestation in neonates with suspected acute brain injury (ABI). However, there are relatively few developmental milestones at six months to benchmark against, thus, we extended this cohort study to evaluate two-year outcomes.

METHODS

In 40 consecutive neonates with ABI and RS, ordinal scores of resting-state networks; MRI, magnetic resonance spectroscopy, and electroencephalography; and up to 42-month outcomes of mortality, general and motor development, Pediatric Cerebral Performance Category Scale (PCPC), and epilepsy informed associations between tests and outcomes.

RESULTS

Mean gestational age was 37.8 weeks, 68% were male, and 60% had hypoxic-ischemic encephalopathy. Three died in-hospital, four at six to 42 months, and five were lost to follow-up. Associations included basal ganglia network with PCPC (P = 0.0003), all-mortality (P = 0.005), and motor (P = 0.0004); language/frontoparietal network with developmental delay (P = 0.009), PCPC (P = 0.006), and all-mortality (P = 0.01); default mode network with developmental delay (P = 0.003), PCPC (P = 0.004), neonatal intensive care unit mortality (P = 0.01), and motor (P = 0.009); RS seizure onset zone with epilepsy (P = 0.01); and anatomic MRI with epilepsy (P = 0.01).

CONCLUSION

For the first time, at any age, resting state functional MRI in ABI is associated with long-term epilepsy and RSNs predicted mortality in neonates. Severity of RSN abnormality was associated with incrementally worsened neurodevelopment including cognition, language, and motor function over two years.

Minimally conscious state plus versus minus: Likelihood of emergence and long-term functional independence

OBJECTIVE

Severe brain injuries can result in disorders of consciousness, such as the Minimally Conscious State (MCS), where individuals display intermittent yet discernible signs of conscious awareness. The varied levels of responsiveness and awareness observed in this state have spurred the progressive delineation of two subgroups within MCS, termed "plus" (MCS+) and "minus" (MCS-). However, the clinical validity of these classifications remains uncertain. This study aimed to investigate and compare the likelihood of emergence from MCS, as well as the functional independence after emergence, in individuals categorized as in MCS+ and MCS-.

METHODS

Demographic and behavioral data of 80 participants, admitted as either in MCS+ (n = 30) or MCS- (n = 50) to a long-term neurorehabilitation unit, were retrospectively analyzed. The neurobehavioral condition of each participant was evaluated weekly until discharge, demise, or emergence from MCS. The functional independence of those participants who emerged from MCS was assessed 6 months after emergence.

RESULTS

While only about half of the individuals classified as in MCS- (n = 24) emerged from the MCS, all those admitted as in MCS+ did, and in a shorter postinjury period. Despite these differences, all individuals who emerged from the MCS demonstrated similar high disability and low functional independence 6 months after emergence, regardless of their state at admission.

INTERPRETATION

Individuals classified as MCS+ exhibited a higher likelihood of emergence and a shorter time to emergence compared to those in MCS-. However, the level of functional independence 6 months after emergence was found to be unrelated to the initial state at admission.

Multimodal approaches supporting the diagnosis, prognosis and investigation of neural correlates of disorders of consciousness: A systematic review

The limits of the standard, behaviour-based clinical assessment of patients with disorders of consciousness (DoC) prompted the employment of functional neuroimaging, neurometabolic, neurophysiological and neurostimulation techniques, to detect brain-based covert markers of awareness. However, uni-modal approaches, consisting in employing just one of those techniques, are usually not sufficient to provide an exhaustive exploration of the neural underpinnings of residual awareness. This systematic review aimed at collecting the evidence from studies employing a multimodal approach, that is, combining more instruments to complement DoC diagnosis, prognosis and better investigating their neural correlates. Following the PRISMA guidelines, records from PubMed, EMBASE and Scopus were screened to select peer-review original articles in which a multi-modal approach was used for the assessment of adult patients with a diagnosis of DoC. Ninety-two observational studies and 32 case reports or case series met the inclusion criteria. Results highlighted a diagnostic and prognostic advantage of multi-modal approaches that involve electroencephalography-based (EEG-based) measurements together with neuroimaging or neurometabolic data or with neurostimulation. Multimodal assessment deepened the knowledge on the neural networks underlying consciousness, by showing correlations between the integrity of the default mode network and the different clinical diagnosis of DoC. However, except for studies using transcranial magnetic stimulation combined with electroencephalography, the integration of more than one technique in most of the cases occurs without an a priori-designed multi-modal diagnostic approach. Our review supports the feasibility and underlines the advantages of a multimodal approach for the diagnosis, prognosis and for the investigation of neural correlates of DoCs.

Patient-report and caregiver-report measures of rehabilitation service use following acquired brain injury: a systematic review

OBJECTIVE

To review patient-report/caregiver-report measures of rehabilitation service use following acquired brain injury (ABI).

DATA SOURCES

Medline, APA PsycINFO, Embase and CINAHL were searched on November 2021 and November 2022. Authors were contacted if measures were not included in manuscripts/appendices.

STUDY SELECTION

Included articles were empirical research or a research protocol, available in English and described measures of patient report/caregiver report of rehabilitation service use post-ABI via quantitative or qualitative methods. Two reviewers independently screened 5290 records using DistillerSR. Discrepancies were resolved by team adjudication.

DATA EXTRACTION

Data extraction was piloted with high levels of agreement (k=.94). Data were extracted by a single member with team meetings to seek guidance as needed. Data included administration characteristics (reporter, mode of administration, recall period), psychometric evidence and dimensions assessed (types of services, setting, frequency, duration, intensity, qualitative aspects).

DATA SYNTHESIS

One hundred and fifty-two measures were identified from 85 quantitative, 56 qualitative and 3 psychometric studies. Psychometric properties were reported for four measures, all of which focused on satisfaction. Most measures inquired about the type of rehabilitation services used, with more than half assessing functional (eg, physical therapy) and behavioural health rehabilitation services, but fewer than half assessing community and academic reintegration (eg, special education, vocational rehabilitation) or cognitive (eg, neuropsychology) services. Fewer than half assessed qualitative aspects (eg, satisfaction). Recall periods ranged from 1 month to 'since the ABI event' or focused on current use. Of measures that could be accessed (n=71), many included a limited checklist of types of services used. Very few measures assessed setting, frequency, intensity or duration.

CONCLUSIONS

Despite widespread interest, the vast majority of measures have not been validated and are limited in scope. Use of gold-standard psychometric methods to develop and validate a comprehensive patient-report/caregiver-report measure of rehabilitation service use would have wide-ranging implications for improving rehabilitation research in ABI.

Covert cortical processing: a diagnosis in search of a definition

Historically, clinical evaluation of unresponsive patients following brain injury has relied principally on serial behavioral examination to search for emerging signs of consciousness and track recovery. Advances in neuroimaging and electrophysiologic techniques now enable clinicians to peer into residual brain functions even in the absence of overt behavioral signs. These advances have expanded clinicians' ability to sub-stratify behaviorally unresponsive and seemingly unaware patients following brain injury by querying and classifying covert brain activity made evident through active or passive neuroimaging or electrophysiologic techniques, including functional MRI, electroencephalography (EEG), transcranial magnetic stimulation-EEG, and positron emission tomography. Clinical research has thus reciprocally influenced clinical practice, giving rise to new diagnostic categories including cognitive-motor dissociation (i.e. 'covert consciousness') and covert cortical processing (CCP). While covert consciousness has received extensive attention and study, CCP is relatively less understood. We describe that CCP is an emerging and clinically relevant state of consciousness marked by the presence of intact association cortex responses to environmental stimuli in the absence of behavioral evidence of stimulus processing. CCP is not a monotonic state but rather encapsulates a spectrum of possible association cortex responses from rudimentary to complex and to a range of possible stimuli. In constructing a roadmap for this evolving field, we emphasize that efforts to inform clinicians, philosophers, and researchers of this condition are crucial. Along with strategies to sensitize diagnostic criteria and disorders of consciousness nosology to these vital discoveries, democratizing access to the resources necessary for clinical identification of CCP is an emerging clinical and ethical imperative.

Diagnostic value of PET imaging in clinically unresponsive patients

Rapid advancements in the critical care management of acute brain injuries have facilitated the survival of numerous patients who may have otherwise succumbed to their injuries. The probability of conscious recovery hinges on the extent of structural brain damage and the level of metabolic and functional cerebral impairment, which remain challenging to assess via laboratory, clinical, or functional tests. Current research settings and guidelines highlight the potential value of fluorodeoxyglucose-PET (FDG-PET) for diagnostic and prognostic purposes, emphasizing its capacity to consistently illustrate a metabolic reduction in cerebral glucose uptake across various disorders of consciousness. Crucially, FDG-PET might be a pivotal tool for differentiating between patients in the minimally conscious state and those in the unresponsive wakefulness syndrome, a persistent clinical challenge. In patients with disorders of consciousness, PET offers utility in evaluating the degree and spread of functional disruption, as well as identifying irreversible neural damage. Further, studies that capture responses to external stimuli can shed light on residual or revived brain functioning. Nevertheless, the validity of these findings in predicting clinical outcomes calls for additional long-term studies with larger patient cohorts suffering from consciousness impairment. Misdiagnosis of conscious illnesses during bedside clinical assessments remains a significant concern. Based on the clinical research settings, current clinical guidelines recommend PET for diagnostic and/or prognostic purposes. This review article discusses the clinical categories of conscious disorders and the diagnostic and prognostic value of PET imaging in clinically unresponsive patients, considering the known limitations of PET imaging in such contexts.

Prognostication and Trajectories of Recovery in Disorders of Consciousness

Historically, there has been a pessimistic view regarding outcomes for patients with disorders of consciousness (DoC). There is a paucity of clinical diagnostic tools and prognostic protocols. Guidelines for the care of patients with DoC require behavioral observation, time, resources, and knowledge of the population. Many nonclinical factors such as patient wishes, family perception, and personal finances can indirectly influence long-term outcomes. Prognostic expectations need to be considered but we health-care professional cannot fully appreciate the decisions and influence of those decisions on the person served or on the care providers involved.

Does amantadine improve cognitive recovery in severe disorders of consciousness after aneurysmal subarachnoid hemorrhage? A double-blind placebo-controlled study

BACKGROUND

Severe disorders of consciousness (sDoC) are a common sequela of aneurysmal subarachnoid hemorrhages (aSAH), and amantadine has been used to improve cognitive recovery after traumatic brain injury.

OBJECTIVE

This study evaluated the effect of amantadine treatment on consciousness in patients with sDoC secondary to aSAH.

METHODS

This double-center, randomized, prospective, cohort study included patients ≥ 18 years old with sDoC after aSAH from February 2020 to September 2023. Individual patient data of patients were pooled to determine the effect of amantadine, in comparison to placebo. The primary outcomes at 3 and 6 months after the ictus were evaluated using the modified Rankin scale (mRS) and Glasgow outcome scale (GOS). In addition to all-cause mortality, secondary endpoints were assessed weekly during intervention by scores on Rappaport's Disability Rating Scale (RDRS) and Coma Recovery Scale-Revised (CRSR).

RESULTS

Overall, 37 patients with sDoC and initial Glasgow Coma Scale (GCS) varying between 3 and 11 were recruited and randomized to amantadine (test group, n = 20) or placebo (control group, n = 17). The average age was 59.5 years (28 to 81 year-old), 24 (65%) were women, and the mean GCS at the beginning of intervention was 7.1. Most patients evolved to vasospasm (81%), with ischemia in 73% of them. The intervention was started between 30 to 180 days after the ictus, and administered for 6 weeks, with progressively higher doses. Neither epidemiological characteristics nor considerations regarding the treatment of the aneurysm and its complications differed between both arms. Overall mortality was 10.8% (4 deaths). During the study, four patients had potential adverse drug effects: two presented seizures, one had paralytic ileus, and another evolved with tachycardia; the medication was not suspended, only the dose was not increased. At data opening, 2 were taking amantadine and 2 placebo.

CONCLUSION

Despite some good results associated with amantadine in the literature, this study did not find statistically significant positive effects in cognitive recovery in patients with delayed post-aSAH sDoC. Further large randomized clinical trials in patients' subgroups are needed to better define its effectiveness and clarify any therapeutic window where it can be advantageous.

Conceptualizing Consciousness: a Change in Perspective: The Elephant Still Surprises Those only Touching Its Trunk

Providers of patients with disorders of consciousness (DoC) face clinical and ethical challenges that could be lessened by becoming acquainted with the subjective and objective aspects of consciousness. A first step to improving DoC taxonomies, management, and outcomes might be to recognize the shortcomings of the medical concept of consciousness and to improve the terminology used for the clinical parameters assessed. The authors critically review the medical perspective of consciousness represented by three sub-concepts that do not necessarily correlate with one another and discuss how none of them reflects fully the personal subjective nature of consciousness.

Disorders of Consciousness in Children: Assessment, Treatment, and Prognosis

Children with acquired brain injury may experience prolonged disorders of consciousness (DoC); research on children with DoC lags behind adult literature. Rigorous evaluation of assessment tools used in children with DoC is lacking, though recent developments may contribute to improvements in care, particularly for assessment of young children and those without overt command following. Literature on prognosis continues to grow, reinforcing that early signs of consciousness suggest better long-term outcome. Although large clinical trials for children with DoC are lacking, single-site and multisite programmatic data inform standards of care and treatment options for children with DoC.

Disorders of Consciousness Programs: Components, Organization, and Implementation

Rehabilitation of patients with disorders of consciousness (DoC) presents unique challenges requiring comprehensive and specialized care. This article reviews the components, organization, and implementation of an inpatient DoC program under the framework of recent evidence-based practice guidelines and minimum competency recommendations. The evidence and clinical applications of these recommendations are elaborated upon with the goal of offering providers a reference to translate guidelines into clinical practice.

Special Considerations in Behavioral Assessments for Disorders of Consciousness

Behavioral assessment remains the cornerstone of the clinical evaluation of disorders of consciousness (DoC). Because the basic approach to these evaluations has been extensively reviewed elsewhere, this article focuses on special considerations in the behavioral assessment of patients with a DoC. All therapy disciplines (physical therapy/occupational therapy/speech language pathologist) have a significant role to play and other staff and family members should also be encouraged to share their observations. Finally, the assessment with standardized scales should be supplemented by qualitative behavioral observations as well as, when appropriate, an individualized quantitative behavioral assessment.

Cognitive Motor Dissociation: Gap Analysis and Future Directions

BACKGROUND

Patients with disorders of consciousness who are behaviorally unresponsive may demonstrate volitional brain responses to motor imagery or motor commands detectable on functional magnetic resonance imaging or electroencephalography. This state of cognitive motor dissociation (CMD) may have prognostic significance.

METHODS

The Neurocritical Care Society's Curing Coma Campaign identified an international group of experts who convened in a series of monthly online meetings between September 2021 and April 2023 to examine the science of CMD and identify key knowledge gaps and unmet needs.

RESULTS

The group identified major knowledge gaps in CMD research: (1) lack of information about patient experiences and caregiver accounts of CMD, (2) limited epidemiological data on CMD, (3) uncertainty about underlying mechanisms of CMD, (4) methodological variability that limits testing of CMD as a biomarker for prognostication and treatment trials, (5) educational gaps for health care personnel about the incidence and potential prognostic relevance of CMD, and (6) challenges related to identification of patients with CMD who may be able to communicate using brain-computer interfaces.

CONCLUSIONS

To improve the management of patients with disorders of consciousness, research efforts should address these mechanistic, epidemiological, bioengineering, and educational gaps to enable large-scale implementation of CMD assessment in clinical practice.

Disorders of Consciousness: Classification and Taxonomy

In this article, we discuss the taxonomy associated with the four major disorders of consciousness (DoC): coma, vegetative state or unresponsive wakefulness syndrome, minimally conscious state, and post-traumatic confusional state. We briefly review the history of each disorder and then provide operational definitions and diagnostic criteria for each one. We rely heavily on recently released practice guidelines and, where appropriate, identify knowledge gaps and discuss future directions to advance DoC research and practice.

Education, Training, and Support Across the Continuum of Recovery for Caregivers of Persons with Disorders of Consciousness

Evolving knowledge highlights the deleterious effects of caregiving on the emotional, psychosocial, and financial well-being of caregivers of persons with disorders of consciousness (DoC). Current practice guidelines and minimal competency recommendations emphasize the importance of identifying and addressing DoC caregiver needs. This article serves as a dissemination tool to enhance communication between providers and caregivers. Essential components of education and training are outlined for each level of care. Addressing caregiver needs may mitigate the level of perceived burden, reduce the risk of burnout, and increase care proficiency and likelihood of community discharge, thus potentially reducing long-term costs of care for this population.

Disorders of Consciousness Rehabilitation: Ethical Dimensions and Epistemic Dilemmas

Patients with disorders of consciousness who survive to discharge following severe acute brain injury may face profoundly complex medical, ethical, and psychosocial challenges during their courses of recovery and rehabilitation. Although issues encountered in caring for such patients during acute hospitalization have received substantial attention, ethical challenges that may arise in subacute and chronic phases have been underexplored. Shedding light on these issues, this article explores the landscape of normative issues in the course of treating and facilitating access to care for persons with disorders of consciousness during rehabilitation and examines potential implications for patients, clinicians, family members, and society.

Neuroimaging in Disorders of Consciousness and Recovery

There is a clinical need for more accurate diagnosis and prognostication in patients with disorders of consciousness (DoC). There are several neuroimaging modalities that enable detailed, quantitative assessment of structural and functional brain injury, with demonstrated diagnostic and prognostic value. Additionally, longitudinal neuroimaging studies have hinted at quantifiable structural and functional neuroimaging biomarkers of recovery, with potential implications for the management of DoC.

A predictive model for awakening in patients with prolonged disorders of consciousness after craniocerebral injury

This study aimed to develop and validate a nomogram to predict awakening at 1 year in patients with prolonged disorders of consciousness (pDOC). We retrospectively analyzed the data of 381 patients with pDOC at 2 centers. The data were randomly divided into training and validation sets using a ratio of 6:4. For the training set, univariate and multivariate logical regression analyses were used to identify the predictive variables. Receiver operating characteristic curves, calibration curves, and a decision curve analysis were utilized to assess the predictive accuracy, discriminative ability, and clinical utility of the model, respectively. The final model included age, Glasgow Coma Scale score, serum albumin level, and computed tomography midline shift, all of which had a significant effect on awakening after pDOC. For the 1-year awakening in the training set, the model had good discriminative power, with an area under the curve of 0.733 (95% confidence interval: 0.667-0.789). For the validation set, the area under the curve for 1-year awakening was 0.721 (95% confidence interval: 0.617-0.826). Model performance was good for both the training and validation sets according to calibration plots and decision curve analysis. We developed a precise, effective nomogram to assist clinicians in better assessing patients' outcomes, guiding clinical judgment, and personalizing the therapeutic process.

Research hotspots and frontiers of neuromodulation techniques in disorders of consciousness: a bibliometric analysis

Background

The characteristics of disorders of consciousness (DOC) are changes in arousal and/or awareness caused by severe brain injuries. To date, the management of DOC patients remains a complex and challenging task, and neuromodulation techniques offer a promising solution. However, a bibliometric analysis focusing on neuromodulation techniques in DOC is currently absent. The aim of this study is to provide a bibliometric visualization analysis to investigate the research hotspots and frontiers in the field of neuromodulation techniques in DOC from 2012 to 2022.

Methods

The publications were collected and retrieved from the Web of Science (WoS) from 2012 to 2022. CiteSpace and Microsoft Excel were utilized perform the first global bibliographic analysis of the literature related to neuromodulation techniques for DOC.

Results

The analysis included a total of 338 publications. From 2012 to 2022, a consistent yet irregular increase in the number of articles published on neuromodulation techniques in DOC was observed. Frontiers in Neurology published the highest number of papers (n = 16). Neurosciences represented the main research hotspot category (n = 170). The most prolific country, institution, and author were the USA (n = 105), the University of Liege (n = 41), and Laureys Steven (n = 38), respectively. An analysis of keywords revealed that UWS/VS, MCS, and TMS constituted the primary research trends and focal points within this domain.

Conclusion

This bibliometric study sheds light on the current progress and emerging trends of neuromodulation techniques in DOC from 2012 to 2022. The focal topics in this domain encompass the precise diagnosis of consciousness levels in patients suffering from DOC and the pursuit of efficacious neuromodulation-based evaluation and treatment protocols for such patients.

Diagnosing awareness in disorders of consciousness with gamma-band auditory responses

Introduction

The prolonged disorders of consciousness (pDOC) describe a group of neurological conditions characterized by severe impairment of consciousness resulting from the injury of the central nervous system. As the behavioral diagnosis of pDOC remains challenging, the methods based on observing brain activity appear as promising alternatives. One of these methods is electroencephalography, which allows for noninvasive assessment of brain function.

Methods

In this study, we evaluated evoked auditory responses to the chirp-modulated auditory stimulation as a potential biomarker of awareness in pDOC. Chirp-modulated stimulation is based on the repetitive presentation of auditory stimuli with a changing frequency over time. Two protocols were tested: amplitude-modulated narrow-band chirps (frequency range 25-55 Hz) and click-based wide-band chirps (30-100 Hz). The studied pDOC patient group included 62 patients (19 females and 43 males, mean age 40.72 years) diagnosed with Coma Recovery Scale-Revised. Envelope-following responses to stimulation were examined using the intertrial phase clustering coefficient.

Results

For both types of stimulation, the strength of the response in the low-gamma range (around 40 Hz) was related to the diagnosis of pDOC. Patients diagnosed with unresponsive wakefulness syndrome exhibited diminished responses, while more favorable diagnoses, suggesting awareness (minimally conscious state or emergence from the minimally conscious state), showed elevated responses. The variations in the integrity of the auditory pathway and the etiology of brain injury altered the observed response strength. Narrow-band stimulation yielded a more systematic relationship between low-gamma response and pDOC diagnosis.

Discussion

The results suggest the potential role of low gamma-band responses to chirp-modulated stimulation as the supportive diagnostic tool to detect awareness in the pDOC patient group.

Head Control Contributes to Prediction of Emergence From the Minimally Conscious State in Children Admitted to Inpatient Rehabilitation

OBJECTIVE

To examine the utility of head and trunk control, assessed using the Physical Abilities and Mobility Scale, for predicting emergence from a minimally conscious state (eMCS) among children with acquired brain injury admitted to inpatient rehabilitation in a disorder of consciousness (DoC).

DESIGN

Retrospective study.

SETTING

Pediatric inpatient rehabilitation hospital.

PARTICIPANTS

Forty patients (2-21 years-old) directly admitted from acute care to pediatric inpatient brain injury rehabilitation in a DoC (average length of stay=85 days; N=40).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

State of consciousness (eMCS vs not) at discharge from inpatient rehabilitation.

RESULTS

Forty-five percent of patients emerged from a minimally conscious state during inpatient rehabilitation. Admission state of consciousness and head control (but not trunk control) were significantly associated with eMCS and provided complementary prognostic information. Admission state of consciousness (ie, admitting in a vegetative state/unresponsive wakefulness syndrome) afforded the greatest negative predictive value (93.8%), whereas admission head control ability afforded the greatest positive predictive value (81.8% for any independent head control; 100% for maintaining head-up position for >30 seconds). Fifty percent of patients who emerged during the inpatient stay did not have independent head control at admission, highlighting the importance of exploring head control as a prognostic marker in conjunction with indicators with greater sensitivity (eg, state of consciousness at admission).

CONCLUSIONS

A brief measure of head control at admission may contribute to identification of a subgroup of patients who are likely to emerge.

Distinct Spectral Profiles of Awake Resting EEG in Disorders of Consciousness: The Role of Frequency and Topography of Oscillations

The prolonged disorders of consciousness (PDOC) pose a challenge for an accurate clinical diagnosis, mainly due to patients' scarce or ambiguous behavioral responsiveness. Measurement of brain activity can support better diagnosis, independent of motor restrictions. Methods based on spectral analysis of resting-state EEG appear as a promising path, revealing specific changes within the internal brain dynamics in PDOC patients. In this study we used a robust method of resting-state EEG power spectrum parameter extraction to identify distinct spectral properties for different types of PDOC. Sixty patients and 37 healthy volunteers participated in this study. Patient group consisted of 22 unresponsive wakefulness patients, 25 minimally conscious patients and 13 patients emerging from the minimally conscious state. Ten minutes of resting EEG was acquired during wakefulness and transformed into individual power spectra. For each patient, using the spectral decomposition algorithm, we extracted maximum peak frequency within 1-14 Hz range in the centro-parietal region, and the antero-posterior (AP) gradient of the maximal frequency peak. All patients were behaviorally diagnosed using coma recovery scale-revised (CRS-R). The maximal peak frequency in the 1-14 Hz range successfully predicted both neurobehavioral capacity of patients as indicated by CRS-R total score and PDOC diagnosis. Additionally, in patients in whom only one peak within the 1-14 Hz range was observed, the AP gradient significantly contributed to the accuracy of prediction. We have identified three distinct spectral profiles of patients, likely representing separate neurophysiological modes of thalamocortical functioning. Etiology did not have significant influence on the obtained results.

Combining HD-tDCS with music stimulation for patients with prolonged disorders of consciousness: Study protocol for an RCT trial

BACKGROUND

Patients with prolonged disorders of consciousness (pDOC) pose significant challenges to healthcare workers due to their severe motor impairments and limited interaction with the environment. Non-invasive brain stimulation such as high-definition transcranial direct current stimulation (HD-tDCS) and music stimulation show promise in awakening this population.

OBJECTIVE

In this study, we present a protocol aiming at investigating the efficacy of combined HD-tDCS and music stimulation in awakening patients with pDOC through a single-blind, randomized controlled trial.

METHODS

Ninety patients with pDOC will be randomly divided into three groups: active HD-tDCS with music stimulation, active HD-tDCS, and sham HD-tDCS. All participants will receive 20 treatment sessions over a period of 10 days and the Coma Recovery Scale-Revised, Glasgow Outcome Scale and electroencephalogram will be used as assessment measures to evaluate their level of consciousness throughout the study. Adverse events and complications will be recorded during treatment. Within-group pre-post comparisons and between-group efficacy comparisons will be conducted to identify the most effective intervention approach. Statistical analysis will be performed using SPSS software with a significance level set at P < 0.05.

CONCLUSION

The pursuit of awakening therapy for patients with pDOC remains a clinical research challenge. This study protocol is designed with the aim of introducing an innovative non-pharmacological approach which combined HD-tDCS and music stimulation to facilitate the reinstatement of consciousness in patients with pDOC.

Covert consciousness

Covert consciousness is a state of residual awareness following severe brain injury or neurological disorder that evades routine bedside behavioral detection. Patients with covert consciousness have preserved awareness but are incapable of self-expression through ordinary means of behavior or communication. Growing recognition of the limitations of bedside neurobehavioral examination in reliably detecting consciousness, along with advances in neurotechnologies capable of detecting brain states or subtle signs indicative of consciousness not discernible by routine examination, carry promise to transform approaches to classifying, diagnosing, prognosticating and treating disorders of consciousness. Here we describe and critically evaluate the evolving clinical category of covert consciousness, including approaches to its diagnosis through neuroimaging, electrophysiology, and novel behavioral tools, its prognostic relevance, and open questions pertaining to optimal clinical management of patients with covert consciousness recovering from severe brain injury.

[Diagnostic criteria for prolonged and chronic disturbances of consciousness after aneurysmal subarachnoid hemorrhages]

BACKGROUND

In recent years, prolonged states of impaired consciousness became widespread among patients with aneurysmal subarachnoid hemorrhage. Treatment and maintenance of vital functions in such patients represent a complex medical, economic and social problem. In this regard, searching for the causes of prolonged states of impaired consciousness and predicting the outcomes are important.

OBJECTIVE

To analyze available literature data on prevention and treatment of prolonged states of impaired consciousness after aneurysmal subarachnoid hemorrhage.

RESULTS

We reviewed the PubMed database using the keywords «unresponsive wakefulness syndrome», «persistent vegetative state2, «minimal consciousness state» and «outcome of subarachnoid hemorrhage». Only 4 reports devoted to the causes and treatment outcomes in patients with prolonged impairment of consciousness after aneurysmal subarachnoid hemorrhage were found. At the same time, patients with aneurysmal subarachnoid hemorrhage comprise up to 11% among all cases of prolonged states of impaired consciousness. Examination, management and treatment of patients with prolonged impairment of consciousness after aneurysmal subarachnoid hemorrhage are carried out according to general principles without taking into account specific etiological and pathogenetic factors.

CONCLUSION

Increased number of patients with prolonged impairment of consciousness after aneurysmal subarachnoid hemorrhage necessitates analysis of etiopathogenesis and outcomes of these disorders based on modern clinical, instrumental and laboratory assessment of the brain.

Pediatric disorders of consciousness: Considerations, controversies, and caveats

Pediatric disorders of consciousness (PedDOC) encompass conditions that may occur following very severe traumatic or other forms of acquired brain injury sustained during childhood. As in adults, PedDOC is described as a disturbance of awareness and/or responsiveness. PedDOC is a complex condition that requires specialized care, infrastructures, and technologies. PedDOC poses many challenges to healthcare providers and caregivers during recovery and throughout development. In this commentary, we intend to highlight some considerations, controversies, and caveats on the diagnosis, prognosis and treatment of PedDOC.

Ethical issues of nosology in disorders of consciousness

The current classification scheme for severe disorders of consciousness (DoC) has several shortcomings. First, there is no consensus on how to incorporate patients with covert consciousness. Second, there is a mismatch between the definitions of severe DoC, based on consciousness, and the diagnosis of these same DoC, which is based on observable motoric responsiveness. Third, current categories are grouped into large heterogeneous syndromes which share phenotype, but do not incorporate underlying pathophysiology. Here we discuss several ethical issues pertaining to the current nosology of severe DoC. We conclude by proposing a revised nosology which addresses these shortcomings.

Medical comorbidities in patients with prolonged disorder of consciousness: A narrative review

BACKGROUND

A few studies specifically addressed medical comorbidities (MCs) in patients with severe acquired traumatic or non-traumatic brain injury and prolonged disorders of consciousness (pDoC; i.e., patients in vegetative state/unresponsive wakefulness syndrome, VS/UWS, or in minimally conscious state, MCS).

OBJECTIVE

To provide an overview on incidence of MCs in patients with pDoC.

METHODS

Narrative review on most impacting MCs in patients with pDoC, both those directly related to brain damage (epilepsy, neurosurgical complications, spasticity, paroxysmal sympathetic hyperactivity, PSH), and those related to severe disability and prolonged immobility (respiratory comorbidities, endocrine disorders, metabolic abnormalities, heterotopic ossifications).

RESULTS

Patients with pDoC are at high risk to develop at least one MC. Moderate or severe respiratory and musculoskeletal comorbidities are the most common MCs. Epilepsy and PSH seem to be more frequent in patients in VS/UWS compared to patients in MCS, likely because of higher severity in the brain damage in VS. Endocrine metabolic, PSH and respiratory complications are less frequent in traumatic etiology, whereas neurogenic heterotopic ossifications are more frequent in traumatic etiology. Spasticity did not significantly differ between VS/UWS and MCS and in the three etiologies. MCs are associated with higher mortality rates, worse clinical improvement and can impact accuracy in the clinical diagnosis.

CONCLUSIONS

The frequent occurrence of several MCs requires a specialized rehabilitative setting with high level of multidisciplinary medical expertise to prevent, appropriately recognize and treat them. Comprehensive rehabilitation could avoid possible progression to more serious complications that can negatively impact clinical outcomes.

Medicolegal issues and disorders of consciousness

BACKGROUND

The tasks and responsibilities that come with clinician involvement in medicolegal proceedings can be daunting and particularly so in challenging areas such as provision of medicolegal opinions in cases involving disorders of consciousness (DoC).

OBJECTIVE

The aim of this narrative review was to provide education and advice to healthcare practitioners who by choice or circumstance are asked and/or required to provide medicolegal opinions in cases involving patients with DoC.

METHODS

A literature search was conducted using PubMed Central and MedlinePlus for articles dealing with clinician involvement in medicolegal cases involving persons with DoC. The information provided also integrates the authors' nearly 40 years of clinical experience, brain injury medicine practice and "trials and tribulations" associated with medicolegal involvement in such cases.

RESULTS

The literature was found to be replete with articles on brain death and withdrawal/withholding of care (which are not the focus of this review). The extant medical literature in brain injury medicine on the other hand is currently lacking in practical information for clinicians working "in the trenches" regarding the challenges and caveats of medicolegal involvement in such cases.

CONCLUSION

This review provides the reader with a big picture overview of the most pertinent medicolegal topics inherent in clinical work with patients with DOC including pertinent nomenclature, caveats regarding forensic consultation including independent medical examinations, testimony tips, discussion of life expectancy/median survival concepts, prognostication in a medicolegal context, documentation and record keeping as well as some of the specific challenges pertinent to these types of brain injury cases that are not per se relevant in less severe injuries.

[Recovery of consciousness under therapy with benzodiazepines. A case report and literature review]

BACKGROUND

Treatment of patients with prolonged and permanent disturbance of consciousness is still an extremely difficult problem. Nowadays, management is based on pathophysiological and molecular mechanisms of impaired consciousness. Several electrophysiological and pharmacological methods were proposed to restore consciousness in appropriate patients.

OBJECTIVE

We present recovery of clear consciousness under therapy with phenazepam and literature review devoted to therapy of these disorders.

RESULTS AND CONCLUSION

This case confirms available data on drug neuromodulation in complex treatment of patients with prolonged impairment of consciousness and substantiates the need for individual multimodal assessment of structural and functional disorders in prolonged and chronic impairment of consciousness for adequate therapy.

The accuracy of different mismatch negativity amplitude representations in predicting the levels of consciousness in patients with disorders of consciousness

Introduction

The mismatch negativity (MMN) index has been used to evaluate consciousness levels in patients with disorders of consciousness (DoC). Indeed, MMN has been validated for the diagnosis of vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state (MCS). In this study, we evaluated the accuracy of different MMN amplitude representations in predicting levels of consciousness.

Methods

Task-state electroencephalography (EEG) data were obtained from 67 patients with DoC (35 VS and 32 MCS). We performed a microstate analysis of the task-state EEG and used four different representations (the peak amplitude of MMN at electrode Fz (Peak), the average amplitude within a time window -25- 25 ms entered on the latency of peak MMN component (Avg for peak ± 25 ms), the average amplitude of averaged difference wave for 100-250 ms (Avg for 100-250 ms), and the average amplitude difference between the standard stimulus ("S") and the deviant stimulus ("D") at the time corresponding to Microstate 1 (MS1) (Avg for MS1) of the MMN amplitude to predict the levels of consciousness.

Results

The results showed that among the four microstates clustered, MS1 showed statistical significance in terms of time proportion during the 100-250 ms period. Our results confirmed the activation patterns of MMN through functional connectivity analysis. Among the four MMN amplitude representations, the microstate-based representation showed the highest accuracy in distinguishing different levels of consciousness in patients with DoC (AUC = 0.89).

Conclusion

We discovered a prediction model based on microstate calculation of MMN amplitude can accurately distinguish between MCS and VS states. And the functional connection of the MS1 is consistent with the activation mode of MMN.

The visual stimulation in disorders of consciousness

Severe brain damage usually leads to disorders of consciousness (DOC), which include coma, unresponsive wakefulness syndrome (UWS) and a minimally conscious state (MCS). Visual stimulation is widely used, especially in the diagnosis and treatment and treatment of DOC. Researchers have indicated that tests based on visual stimulation including visual pursuit, when used in conjunction with the Coma Recovery Scale-Revised, are able to differentiate between UWS from an MCS. Recently, targeting patients' circadian rhythms has been proposed to be a possible treatment target for DOC. Indeed, light therapy has been applied in some other fields, including treating seasonal affective disorder, sleep problems, and Parkinson's disease. However, at present, although visual stimulation and light therapy are frequently used in DOC, there is still no international unified standard. Therefore, we recommend the development of an international consensus in regard to the definitions, operational criteria and assessment procedures of visual stimulation and light therapy. This review combines visual stimulation, circadian rhythm recovery, and light therapy in DOC patients and presents the mechanisms and current advances in applications related to light therapy and visual stimulation in an attempt to provide additional ideas for future research and treatment of DOC.

The efficacy and safety of transcutaneous auricular vagus nerve stimulation for patients with minimally conscious state: a sham-controlled randomized double-blind clinical trial

Background

Transcutaneous auricular vagus nerve stimulation (taVNS) has emerged as a potentially effective neuromodulation technique for addressing neurological disorders, including disorders of consciousness. Expanding upon our prior clinical study, which demonstrated the superior effectiveness of a 4-week taVNS treatment in patients with minimally conscious state (MCS) compared to those in a vegetative state/unresponsive wakefulness state, the aim of this investigation was to evaluate the safety and therapeutic efficacy of taVNS in individuals with MCS through a sham-controlled randomized double-blind clinical trial.

Methods

A cohort of 50 adult patients (male = 33, female = 17) diagnosed with a MCS were randomly assigned to either the active taVNS (N = 25) or sham taVNS (N = 25) groups. The treatment period lasted for 4 weeks, followed by an 8-week follow-up period. The Coma Recovery Scale-Revised (CRS-R) and Glasgow Coma Scale (GCS) were administered at baseline and weekly during the initial 4 weeks. Additionally, the Disability Rating Scale (DRS) was used to assess the patients' functional abilities via telephone at week 12. Furthermore, various neurophysiological measures, including electroencephalogram (EEG), upper-limb somatosensory evoked potentials (USEP), brainstem auditory evoked potentials (BAEP), and P300 event-related potentials (P300), were employed to monitor changes in brain activity and neural conduction pathways.

Results

The scores for the active taVNS group in the CRS-R and GCS showed greater improvement over time compared to the sham taVNS group (CRS-R: 1-week, Z = -1.248, p = 0.212; 2-week, Z = -1.090, p = 0.276; 3-week, Z = -2.017, p = 0.044; 4-week, Z = -2.267, p = 0.023. GCS: 1-week, Z = -1.325, p = 0.185; 2-week, Z = -1.245, p = 0.213; 3-week, Z = -1.848, p = 0.065; 4-week, Z = -1.990, p = 0.047). Additionally, the EEG, USEP, BAEP, and P300 also demonstrated significant improvement in the active taVNS group compared to the sham taVNS group at week 4 (EEG, Z = -2.086, p = 0.037; USEP, Z = -2.014, p = 0.044; BAEP, Z = -2.298, p = 0.022; P300 amplitude, Z = -1.974, p = 0.049; P300 latency, t = 2.275, p = 0.027). Subgroup analysis revealed that patients with MCS derived greater benefits from receiving taVNS treatment earlier (CRS-R, Disease duration ≤ 1-month, mean difference = 8.50, 95% CI = [2.22, 14.78], p = 0.027; GCS, Disease duration ≤ 1-month, mean difference = 3.58, 95% CI = [0.14, 7.03], p = 0.044). By week 12, the active taVNS group exhibited lower Disability Rating Scale (DRS) scores compared to the sham taVNS group (Z = -2.105, p = 0.035), indicating a more favorable prognosis for MCS patients who underwent taVNS. Furthermore, no significant adverse events related to taVNS were observed during treatment.

Conclusion

The findings of this study suggest that taVNS may serve as a potentially effective and safe intervention for facilitating the restoration of consciousness in individuals diagnosed with MCS. This therapeutic approach appears to enhance cerebral functioning and optimize neural conduction pathways.

Clinical trial registration

http://www.chictr.org.cn, Identifier ChiCTR2200066629.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Neuroimaging

BACKGROUND

Over the past 5 decades, advances in neuroimaging have yielded insights into the pathophysiologic mechanisms that cause disorders of consciousness (DoC) in patients with severe brain injuries. Structural, functional, metabolic, and perfusion imaging studies have revealed specific neuroanatomic regions, such as the brainstem tegmentum, thalamus, posterior cingulate cortex, medial prefrontal cortex, and occipital cortex, where lesions correlate with the current or future state of consciousness. Advanced imaging modalities, such as diffusion tensor imaging, resting-state functional magnetic resonance imaging (fMRI), and task-based fMRI, have been used to improve the accuracy of diagnosis and long-term prognosis, culminating in the endorsement of fMRI for the clinical evaluation of patients with DoC in the 2018 US (task-based fMRI) and 2020 European (task-based and resting-state fMRI) guidelines. As diverse neuroimaging techniques are increasingly used for patients with DoC in research and clinical settings, the need for a standardized approach to reporting results is clear. The success of future multicenter collaborations and international trials fundamentally depends on the implementation of a shared nomenclature and infrastructure.

METHODS

To address this need, the Neurocritical Care Society's Curing Coma Campaign convened an international panel of DoC neuroimaging experts to propose common data elements (CDEs) for data collection and reporting in this field.

RESULTS

We report the recommendations of this CDE development panel and disseminate CDEs to be used in neuroimaging studies of patients with DoC.

CONCLUSIONS

These CDEs will support progress in the field of DoC neuroimaging and facilitate international collaboration.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Hospital Course, Confounders, and Medications

The convergence of an interdisciplinary team of neurocritical care specialists to organize the Curing Coma Campaign is the first effort of its kind to coordinate national and international research efforts aimed at a deeper understanding of disorders of consciousness (DoC). This process of understanding includes translational research from bench to bedside, descriptions of systems of care delivery, diagnosis, treatment, rehabilitation, and ethical frameworks. The description and measurement of varying confounding factors related to hospital care was thought to be critical in furthering meaningful research in patients with DoC. Interdisciplinary hospital care is inherently varied across geographical areas as well as community and academic medical centers. Access to monitoring technologies, specialist consultation (medical, nursing, pharmacy, respiratory, and rehabilitation), staffing resources, specialty intensive and acute care units, specialty medications and specific surgical, diagnostic and interventional procedures, and imaging is variable, and the impact on patient outcome in terms of DoC is largely unknown. The heterogeneity of causes in DoC is the source of some expected variability in care and treatment of patients, which necessitated the development of a common nomenclature and set of data elements for meaningful measurement across studies. Guideline adherence in hemorrhagic stroke and severe traumatic brain injury may also be variable due to moderate or low levels of evidence for many recommendations. This article outlines the process of the development of common data elements for hospital course, confounders, and medications to streamline definitions and variables to collect for clinical studies of DoC.

Ethics Along the Continuum of Research Involving Persons with Disorders of Consciousness

Interest in disorders of consciousness (DoC) has grown substantially over the past decade and has illuminated the importance of improving understanding of DoC biology; care needs (use of monitoring, performance of interventions, and provision of emotional support); treatment options to promote recovery; and outcome prediction. Exploration of these topics requires awareness of numerous ethics considerations related to rights and resources. The Curing Coma Campaign Ethics Working Group used its expertise in neurocritical care, neuropalliative care, neuroethics, neuroscience, philosophy, and research to formulate an informal review of ethics considerations along the continuum of research involving persons with DoC related to the following: (1) study design; (2) comparison of risks versus benefits; (3) selection of inclusion and exclusion criteria; (4) screening, recruitment, and enrollment; (5) consent; (6) data protection; (7) disclosure of results to surrogates and/or legally authorized representatives; (8) translation of research into practice; (9) identification and management of conflicts of interest; (10) equity and resource availability; and (11) inclusion of minors with DoC in research. Awareness of these ethics considerations when planning and performing research involving persons with DoC will ensure that the participant rights are respected while maximizing the impact and meaningfulness of the research, interpretation of outcomes, and communication of results.

Long-term clinical evolution of patients with prolonged disorders of consciousness due to severe anoxic brain injury: A meta-analytic study

BACKGROUND AND PURPOSE

The prognosis of prolonged (28 days to 3 months post-onset) disorders of consciousness (pDoC) due to anoxic brain injury is uncertain. The present study aimed to evaluate the long-term outcome of post-anoxic pDoC and identify the possible predictive value of demographic and clinical information.

METHOD

This is a systematic review and meta-analysis. The rates of mortality, any improvement in clinical diagnosis, and recovery of full consciousness at least 6 months after severe anoxic brain injury were evaluated. A cross-sectional approach searched for differences in baseline demographic and clinical characteristics between survivors and non-survivors, patients improved versus not improved, and patients who recovered full consciousness versus not recovered.

RESULTS

Twenty-seven studies were identified. The pooled rates of mortality, any clinical improvement and recovery of full consciousness were 26%, 26% and 17%, respectively. Younger age, baseline diagnosis of minimally conscious state versus vegetative state/unresponsive wakefulness syndrome, higher Coma Recovery Scale Revised total score, and earlier admission to intensive rehabilitation units were associated with a significantly higher likelihood of survival and clinical improvement. These same variables, except time of admission to rehabilitation, were also associated with recovery of full consciousness.

CONCLUSIONS

Patients with anoxic pDoC might improve over time up to full recovery of consciousness and some clinical characteristics can help predict clinical improvement. These new insights could support clinicians and caregivers in the decision-making on patient management.

Review of spinal cord stimulation for disorders of consciousness

PURPOSE OF REVIEW

High-cervical spinal cord stimulation can alter cortical activity and cerebral metabolism. These effects are potentially beneficial for disorders of consciousness. A better understanding of the effects of clinical application of stimulation is needed. We aimed to evaluate the existing literature to determine the state of available knowledge. We performed a literature review of clinical studies assessing cervical spinal cord epidural stimulation for disorders of consciousness. Only peer-reviewed articles reporting preoperative and postoperative clinical status were included.

RECENT FINDINGS

Nineteen studies were included. A total of 532 cases were reported, and 255 patients were considered responsive (47.9%). Considering only studies published after the definition of minimally conscious state (MCS) as an entity, 402 individuals in unresponsive wakefulness syndrome (UWS) and 113 in MCS were reported. Responsiveness to SCS was reported in 170 UWS patients (42.3%) and in 78 MCS cases (69.0%), although the criteria for responsiveness and outcome measures varied among publications.

SUMMARY

Cervical SCS yielded encouraging results in patients with disorders of consciousness and seems to be more effective in MCS. More extensive investigation is needed to understand its potential role in clinical practice.

Conscientious Objection to Aggressive Interventions for Patients in a Vegetative State

Some physicians refuse to perform life-sustaining interventions, such as tracheostomy, on patients who are very likely to remain permanently unconscious. To explain their refusal, these clinicians often invoke the language of "futility", but this can be inaccurate and can mask problematic forms of clinical power. This paper explores whether such refusals should instead be framed as conscientious objections. We contend that the refusal to provide interventions for patients very likely to remain permanently unconscious meets widely recognized ethical standards for the exercise of conscience. We conclude that conscientious objection to tracheostomy and other life-sustaining interventions on such patients can be ethical because it does not necessarily constitute a form of invidious discrimination. Furthermore, when a physician frames their refusal as conscientious objection, it makes transparent the value-laden nature of their objection and can better facilitate patient access to the requested treatment.

Long-term psychological intervention for parents of children with prolonged disorders of consciousness: a pilot study

Background

Children with prolonged disorders of consciousness experience severe intellectual and behavioral disabilities that will last for decades or even a lifetime. Parents generally experience severe anxiety, stress, sadness, or family conflicts, which can lead to abnormal parenting behavior and can, in turn, adversely affect the cognitive, emotional, and behavioral well-being of the children. This causes a serious burden on children, families, and society. Psychological interventions targeting parents using online conversations provide an opportunity to improve the overall well-being of the parents, their children, and the family as a whole.

Methods

A total of 13 patients completed the protocol. Six were girls (46.2%), the mean age was 4.5 ± 3.0 years, and the length of time before emergent from minimally consciousness state was 244 ± 235 days. A staff member with psychological counseling qualifications implemented all psychological interventions. Regular online psychological interventions were performed annually before and after discharge. Evaluation data were collected before discharge and at 1 and 3-5 years post-discharge.

Results

With the extension of intervention time, the Strengths and Difficulties Questionnaire, the Depression Anxiety and Stress Scale-21, and the Parenting Sense of Competence Scale scores showed significant improvement (p < 0.05), while the Revised Scale for Caregiving Self-Efficacy scores did not. With the extension of intervention time, the Strengths and Difficulties Questionnaire (Total Difficulties scores, TD) scores showed significant improvement (p < 0.05), while the scores did not after 1 year compared with before intervention. The Index of Child Care Environment evaluation scores declined significantly (p < 0.05).

Conclusion

Psychological interventions aimed at the parents of children with prolonged disorders of consciousness performed at least once per year resulted in significant improvements in negative parental emotions, parental self-efficacy, and emotional and behavioral problems in their children. However, the childcare environment continued to decline.

Functional hub disruption emphasizes consciousness recovery in severe traumatic brain injury

Severe traumatic brain injury can lead to transient or even chronic disorder of consciousness. To increase diagnosis and prognosis accuracy of disorder of consciousness, functional neuroimaging is recommended 1 month post-injury. Here, we investigated brain networks remodelling on longitudinal data between 1 and 3 months post severe traumatic brain injury related to change of consciousness. Thirty-four severe traumatic brain-injured patients were included in a cross-sectional and longitudinal clinical study, and their MRI data were compared to those of 20 healthy subjects. Long duration resting-state functional MRI were acquired in minimally conscious and conscious patients at two time points after their brain injury. The first time corresponds to the exit from intensive care unit and the second one to the discharge from post-intensive care rehabilitation ward. Brain networks data were extracted using graph analysis and metrics at each node quantifying local (clustering) and global (degree) connectivity characteristics. Comparison with brain networks of healthy subjects revealed patterns of hyper- and hypo-connectivity that characterize brain networks reorganization through the hub disruption index, a value quantifying the functional disruption in each individual severe traumatic brain injury graph. At discharge from intensive care unit, 24 patients' graphs (9 minimally conscious and 15 conscious) were fully analysed and demonstrated significant network disruption. Clustering and degree nodal metrics, respectively, related to segregation and integration properties of the network, were relevant to distinguish minimally conscious and conscious groups. At discharge from post-intensive care rehabilitation unit, 15 patients' graphs (2 minimally conscious, 13 conscious) were fully analysed. The conscious group still presented a significant difference with healthy subjects. Using mixed effects models, we showed that consciousness state, rather than time, explained the hub disruption index differences between minimally conscious and conscious groups. While severe traumatic brain-injured patients recovered full consciousness, regional functional connectivity evolved towards a healthy pattern. More specifically, the restoration of a healthy brain functional segregation could be necessary for consciousness recovery after severe traumatic brain injury. For the first time, extracting the hub disruption index directly from each patient's graph, we were able to track the clinical alteration and subsequent recovery of consciousness during the first 3 months following a severe traumatic brain injury.

Prevalence of the Minimally Conscious State Among Institutionalized Patients in the Netherlands: A Nationwide Study

BACKGROUND AND OBJECTIVES

The minimally conscious state (MCS) is a prolonged disorder of consciousness (pDoC) and one of the most severe outcomes of acquired brain injury. Prevalence data are scarce. The aim of this study was to establish the nationwide point prevalence of institutionalized patients in MCS in the Netherlands.

METHODS

This was a descriptive cross-sectional study in which all 86 Dutch hospitals, all 5 specialized pDoC rehabilitation facilities, and all 274 nursing homes were asked whether they were treating patients with a pDoC on the point prevalence date of September 15, 2021. Each patient's legal representative provided informed consent for their inclusion. Patient level of consciousness was verified using the Coma Recovery Scale-Revised (CRS-R) in a single assessment session performed in the facility of residence by an experienced physician. Data on patient demographics, etiology, level of consciousness, facility of residence, and clinical status were collected from a questionnaire by the treating physician. The prevalence of institutionalized patients in MCS of per 100,000 members of the Dutch population was calculated, based on actual census data.

RESULTS

Seventy patients were reported to have a pDoC, of whom 6 were excluded. The level of consciousness was verified for 49 patients while for 15, it could not be verified. Of the patients verified, 38 had a pDoC, of whom 32 were in MCS (mean age 44.8 years, 68.8% male). The prevalence of institutionalized patients in MCS is 0.2-0.3 per 100,000 Dutch inhabitants. Traumatic brain injury was present in 21 of 32 patients (65.6%). Specialized pDoC rehabilitation was received by 17 of 32 patients (53%), with the rest admitted to nursing homes. The most frequent signs of consciousness on the CRS-R were visual pursuit, reproducible movement to command, and automatic motor response.

DISCUSSION

This nationwide study revealed a low prevalence of institutionalized patients in MCS in the Netherlands. These findings are now being used to organize pDoC care in this country.

Deep brain stimulation in disorders of consciousness: 10 years of a single center experience

Disorders of consciousness (DoC), namely unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), represent severe conditions with significant consequences for patients and their families. Several studies have reported the regaining of consciousness in such patients using deep brain stimulation (DBS) of subcortical structures or brainstem nuclei. Our study aims to present the 10 years' experience of a single center using DBS as a therapy on a cohort of patients with DoC. Eighty Three consecutive patients were evaluated between 2011 and 2022; entry criteria consisted of neurophysiological and neurological evaluations and neuroimaging examinations. Out of 83, 36 patients were considered candidates for DBS implantation, and 32 patients were implanted: 27 patients had UWS, and five had MCS. The stimulation target was the centromedian-parafascicular complex in the left hemisphere in hypoxic brain lesion or the one better preserved in patients with traumatic brain injury. The level of consciousness was improved in seven patients. Three out of five MCS patients emerged to full awareness, with the ability to interact and communicate. Two of them can live largely independently. Four out of 27 UWS patients showed consciousness improvement with two patients emerging to full awareness, and the other two reaching MCS. In patients with DoC lasting longer than 12 months following traumatic brain injury or 6 months following anoxic-ischemic brain lesion, spontaneous recovery is rare. Thus, DBS of certain thalamic nuclei could be recommended as a treatment option for patients who meet neurological, neurophysiological and neuroimaging criteria, especially in earlier phases, before occurrence of irreversible musculoskeletal changes. Furthermore, we emphasize the importance of cooperation between centers worldwide in studies on the potentials of DBS in treating patients with DoC.

Detecting passive and active response in patients with behaviourally diagnosed unresponsive wakefulness syndrome

The diagnosis of unresponsive wakefulness syndrome depends mostly on the motor response following verbal commands. However, there is a potential for misdiagnosis in patients who understand verbal commands (passive response) but cannot perform voluntary movements (active response). To evaluate passive and active responses in such patients, this study used an approach combining functional magnetic resonance imaging and passive listening tasks to evaluate the level of speech comprehension, with portable brain-computer interface modalities that were applied to elicit an active response to attentional modulation tasks at the bedside. We included ten patients who were clinically diagnosed as unresponsive wakefulness syndrome. Two of ten patients showed no significant activation, while limited activation in the auditory cortex was found in six patients. The remaining two patients showed significant activation in language areas, and were able to control the brain-computer interface with reliable accuracy. Using a combined passive/active approach, we identified unresponsive wakefulness syndrome patients who showed both active and passive neural responses. This suggests that some patients with unresponsive wakefulness syndrome diagnosed behaviourally are both wakeful and responsive, and the combined approach is useful for distinguishing a minimally conscious state from unresponsive wakefulness syndrome physiologically.

Feasibility and Validity of the Coma Recovery Scale-Revised for Accelerated Standardized Testing: A Practical Assessment Tool for Detecting Consciousness in the Intensive Care Unit

We developed and validated an abbreviated version of the Coma Recovery Scale-Revised (CRS-R), the CRS-R For Accelerated Standardized Testing (CRSR-FAST), to detect conscious awareness in patients with severe traumatic brain injury in the intensive care unit. In 45 consecutively enrolled patients, CRSR-FAST administration time was approximately one-third of the full-length CRS-R (mean [SD] 6.5 [3.3] vs 20.1 [7.2] minutes, p < 0.0001). Concurrent validity (simple kappa 0.68), test-retest (Mak's ρ = 0.76), and interrater (Mak's ρ = 0.91) reliability were substantial. Sensitivity, specificity, and accuracy for detecting consciousness were 81%, 89%, and 84%, respectively. The CRSR-FAST facilitates serial assessment of consciousness, which is essential for diagnostic and prognostic accuracy. ANN NEUROL 2023;94:919-924.

Making the visible seen: The interactional competence of a person in a disordered state of consciousness

We examine a 12-min video-recorded interaction among a patient (KN) in a disordered state of consciousness (DOC) and a speech language pathologist clinician (CL) that takes place in a medical rehabilitation setting. The video is a demonstration of how caregivers could use a clinical assessment to observe their loved one's behavior to communicate potential behavioral changes to healthcare professionals. The purpose of this paper is to make visible the communication practices used by participants that may not be obvious to researchers, medical rehabilitation practitioners, and clinical assessment developers. We use phenomenological, linguistic and conversation analytic approaches to analyze the interaction. We found that KN demonstrates multiple conversational competencies, some (but not all) of which are acknowledged by CL, and most of which are not directly addressed by the assessment scoring criteria. For example, KN demonstrates conversational competency by responding non-verbally to CL's prompts from the assessment protocol and following along with the unspoken rules of discourse. He does this primarily through gaze, which broadcasts the focus of his attention and actively signals his participation in the conversation. Though KN does not always respond correctly to CL's questions, he nevertheless demonstrates implicit conversational competencies during turns of talk such as returning to 'neutral' position which signals the completion of a turn of talk. KN's conversational competencies may be missed by CL and the assessment protocol but we argue that they are important in understanding KN's capacity. Our analyses show that competency is not simply a performance by one person who appropriately and correctly responds to a series of questions in a prescribed time frame. Competence is a collaborative achievement among participants, co-produced in situ, and influenced by linguistic and cultural habits of talk and epistemic norms that privilege clinical knowledge and expertise.

An evidence-based critical review of the mind-brain identity theory

In the philosophy of mind, neuroscience, and psychology, the causal relationship between phenomenal consciousness, mentation, and brain states has always been a matter of debate. On the one hand, material monism posits consciousness and mind as pure brain epiphenomena. One of its most stringent lines of reasoning relies on a 'loss-of-function lesion premise,' according to which, since brain lesions and neurochemical modifications lead to cognitive impairment and/or altered states of consciousness, there is no reason to doubt the mind-brain identity. On the other hand, dualism or idealism (in one form or another) regard consciousness and mind as something other than the sole product of cerebral activity pointing at the ineffable, undefinable, and seemingly unphysical nature of our subjective qualitative experiences and its related mental dimension. Here, several neuroscientific findings are reviewed that question the idea that posits phenomenal experience as an emergent property of brain activity, and argue that the premise of material monism is based on a logical correlation-causation fallacy. While these (mostly ignored) findings, if considered separately from each other, could, in principle, be recast into a physicalist paradigm, once viewed from an integral perspective, they substantiate equally well an ontology that posits mind and consciousness as a primal phenomenon.