The importance of instrumental assessment in disorders of consciousness: a comparison between American, European, and UK International recommendations

The autonomic response following taVNS predicts changes in level of consciousness in DoC patients

Advancements in emergency medicine and critical care have significantly improved survival rates for patients with severe acquired brain injuries(sABI), subsequently increasing the prevalence of disorders of consciousness (DoC) such as Unresponsive Wakefulness Syndrome (UWS) and Minimally Conscious State (MCS). However, the assessment of conscious states relies on the observation of behavioral responses, the interpretation of which may vary from evaluator to evaluator, as well as the high rate of misdiagnosis, which together pose significant challenges for clinical diagnosis. The study investigates the utility of transcutaneous auricular vagus nerve stimulation (taVNS) in modulating autonomic responses, as evidenced through heart rate variability (HRV), for distinguishing between healthy individuals and DoC patients and for prognosticating patient outcomes. A prospective randomized clinical trial was conducted from Februry 9, 2022, to February 4, 2024, at Hangzhou Armed Police Hospital in China. Healthy controls (HC) and DoC patients were enrolled in this study. The taVNS was administered to each subject for ten minutes. There electrocardiogram (ECG) signals were recorded for the analysis of HRV both during the stimulation and the ten minutes of rest that preceded and followed the stimulation. Subsequent investigations utilized Support Vector Machine (SVM) modeling, enhanced by a Radial Basis Function (RBF) kernel, to explore potential predictors of patient outcomes. This approach aimed to differentiate HC from DoC and MCS from UWS patients. 26 HC and 36 patients diagnosed with DoC were included in the analysis,. The DoC group consisted of 17 patients with a diagnosis of MCS and 19 with diagnosis of UWS/VS. Significant modulations in HRV parameters (HF, VLF, SampEn) were observed, indicating variations in autonomic response between the control group and DoC patients. Using the VLF, LF, and SampEn features in SVM model, DoC and HC were correctly classified with an accuracy of 86%. Similarly, MCS and UWS were classified with an accuracy of 78%. The SVM modeling achieved an 86% accuracy rate in predicting outcomes three months post-intervention, with a 71% confirmation rate at six months.The results highlight taVNS's potential as a therapeutic modality in managing DoC by demonstrating its impact on autonomic regulation and suggesting pathways for enhancing recovery, which accentuates the significance of exploring brain-heart dynamics in DoC, presenting a novel approach to therapeutic strategies. Trial Registration Information: URL: chictr.org.cn; Unique identifier: ChiCTR2100045161. Date of the first registration: 9th/ April/ 2021.

Making Healthcare Decisions on Behalf of People in a Disorder of Consciousness. A "Risk-Making" Theory of Decisional Practices

Healthcare decisions evaluate treatment risks and benefits, using a shared decision-making process between patient and clinician. Healthcare workers (HCWs) offer treatments based on condition specific evidence and expert knowledge. The patient evaluates treatment choices from their individual perception of how helpful or harmful treatment might be. This is a "risk-taking" decision. Those in a disorder of consciousness (DOC) have unreliable or absent awareness. They cannot participate in the risk-taking decisional process outlined above. Instead, family members and HCWs evaluate the options and determine how much risk is acceptable. We propose this is a distinctly different decisional process called "risk-making," and that for those in a DOC it is influenced by multiple poorly understood factors. The different ways that decisions are made on their behalf may be negatively impacting their healthcare and creating a distributive justice need. A "risk-making" theory of DOC healthcare decision-making was developed via narrative literature review. It aims to explicate the realities of DOC decision-making practices, and surface rarely discussed assumptions and social factors possibly impacting DOC healthcare for discussion and future exploration.

Prognosis and enhancement of recovery in disorders of consciousness

Disorders of consciousness after severe brain injury encompass conditions of coma, vegetative state/unresponsive wakefulness syndrome, and minimally conscious state. DoC clinical presentation pose perplexing challenges to medical professionals, researchers, and families alike. The outcome is uncertain in the first weeks to months after a brain injury, with families and medical providers often making important decisions that require certainty. Prognostication for individuals with these conditions has been the subject of intense scientific investigation that continues to strive for valid prognostic indicators and algorithms for predicting recovery of consciousness. This manuscript aims to provide an overview of the current clinical landscape surrounding prognosis and optimizing recovery in DoC and the current and future research that could improve prognostic accuracy after severe brain injury. Improved understanding of these factors will aid healthcare professionals in providing optimal care, fostering hope, and advocating for ethical practices in the management of individuals with 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.

International variability in the diagnosis and management of disorders of consciousness

This manuscript explores the international variability in the diagnosis and management of disorders of consciousness (DoC). The identification, evaluation, intervention, exploration, prognostication and limitation of therapy for patients with DoC is reviewed through an international lens. The myriad factors that impact the diagnosis and management of DoC including 1) financial, 2) legal and regulatory, 3) cultural, 4) religious and 5) psychosocial considerations are discussed. As data comparing patients with DoC internationally are limited, findings from the general critical care or neurocritical care literature are described when information specific to patients with DoC is unavailable. There is a need for improvements in clinical care, education, advocacy and research related to patients with DoC worldwide. It is imperative to standardize methodology to evaluate consciousness and prognosticate outcome. Further, education is needed to 1) generate awareness of the impact of the aforementioned considerations on patients with DoC and 2) develop techniques to optimize communication about DoC with families. It is necessary to promote equity in access to expertise and resources for patients with DoC to enhance the care of patients with DoC worldwide. Improving understanding and management of patients with DoC requires harmonization of existing datasets, development of registries where none exist and establishment of international clinical trial networks that include patients in all phases along the spectrum of care. The work of international organizations like the Curing Coma Campaign can hopefully minimize international variability in the diagnosis and management of DoC and optimize care.

Disorder of consciousness: Structural integrity of brain networks for the clinical assessment

AIM

When studying brain networks in patients with Disorders of Consciousness (DoC), it is important to evaluate the structural integrity of networks in addition to their functional activity. Here, we investigated whether structural MRI, together with clinical variables, can be useful for diagnostic purposes and whether a quantitative analysis is feasible in a group of chronic DoC patients.

METHODS

We studied 109 chronic patients with DoC and emerged from DoC with structural MRI: 65 in vegetative state/unresponsive wakefulness state (VS/UWS), 34 in minimally conscious state (MCS), and 10 with severe disability. MRI data were analyzed through qualitative and quantitative approaches.

RESULTS

The qualitative MRI analysis outperformed the quantitative one, which resulted to be hardly feasible in chronic DoC patients. The results of the qualitative approach showed that the structural integrity of HighOrder networks, altogether, had better diagnostic accuracy than LowOrder networks, particularly when the model included clinical variables (AUC = 0.83). Diagnostic differences between VS/UWS and MCS were stronger in anoxic etiology than vascular and traumatic etiology. MRI data of all LowOrder and HighOrder networks correlated with the clinical score. The integrity of the left hemisphere was associated with a better clinical status.

CONCLUSIONS

Structural integrity of brain networks is sensitive to clinical severity. When patients are chronic, the qualitative analysis of MRI data is indicated.