Disorders of Consciousness in China

Perception of diagnosis by family caregivers in severe brain injury patients in China

OBJECTIVES

Surrogate decision-making by family caregivers for patients with severe brain injury is influenced by the availability and understanding of relevant information and expectations for future rehabilitation. We aimed to compare the consistency of family caregivers' perceptions with clinical diagnoses and to inform their expectation of prognosis in the future.

METHODS

The Coma Recovery Scale-Revised was used to assess the diagnosis of inpatients with severe brain injury between February 2019 and February 2020. A main family caregiver was included per patient. The family caregiver's perception of the patient's consciousness and expectations of future recovery were collected through questionnaires and compared consistently with the clinical diagnosis.

RESULTS

The final sample included 101 main family caregivers of patients (57 UWS, unresponsive wakefulness syndrome, 37 MCS, minimally conscious state, 7 EMCS, emergence from MCS) with severe brain injury. Only 57 family caregivers correctly assessed the level of consciousness as indicated by the CRS-R, showing weak consistency (Kappa = 0.217, P = 0.002). Family caregivers' demographic characteristics and CRS-R diagnosis influenced the consistency between perception and clinical diagnosis. Family caregivers who provided hands-on care to patients showed higher levels of consistent perception (AOR = 12.24, 95% CI = 2.06-73.00, P = 0.006). Compared to UWS, the family caregivers of MCS patients were more likely to have a correct perception (OR = 7.68, 95% CI = 1.34-44.06). Family caregivers had positive expectations for patients' recovery in terms of both communication and returning to normal life.

CONCLUSION

Nearly half of family caregivers have inadequate understanding of their relative's level of consciousness, and most of them report overly optimistic expectations that do not align with clinical diagnosis. Providing more medical information to family caregivers to support their surrogate decision-making process is essential.

Current status and prospect of transcutaneous auricular vagus nerve stimulation for disorders of consciousness

Disordered Consciousness (DOC) is among neurological disorders for which there is currently no admitted treatment. The pathogenesis of DOC is still unclear, covering a variety of indistinguishable types of diseases, high misdiagnosis rate and poor prognosis. Most treatments remain to be clarified in the future to provide adequate evidence for clinical guidance. Neuromodulation technology aims to regulate neural circuits to promote awakening more directly. At present, it is confirmed that the potential of transcutaneous auricular vagus nerve stimulation (taVNS) as a therapeutic tool is worth exploring in the context of consciousness disorders, as previously proposed for invasive forms of VNS, in which the means of stimulating the vagus nerve to change the brain areas related to cosciousness have also received widespread attention. In this paper, we review the literature on taVNS and DOC to better understand the current status and development prospect of taVNS treament as a non-invasive neuromodulation method with sensitivity and/or specificity at the single subject.

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.

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.

Transauricular vagus nerve stimulation for patients with disorders of consciousness: A randomized controlled clinical trial

Introduction

Disorders of consciousness (DoCs) are a frequent complication of brain injury disease, and effective treatments are currently lacking. Transauricular vagus nerve stimulation (tVNS) has been proposed as a promising therapeutic method for neurological disorders such as epilepsy and depression. In our previous study, we demonstrated that vagus nerve stimulation promoted recovery in rats with DoCs caused by traumatic brain injury. However, the clinical effect of vagus nerve stimulation on consciousness disorders is unclear. We aimed to investigate the therapeutic efficacy and safety of tVNS in patients with DoCs.

Methods

We conducted a randomized, double-blinded, sham-controlled trial. Patients (N = 60) with DoCs, including minimally conscious state (MCS) and vegetative state/unresponsive wakefulness syndrome, were enrolled and randomized to groups receiving either active or sham tVNS. A frequency of 20 Hz and pulse wave of 200 us was used in the active-tVNS protocol, which was performed in the auricular branch of the vagus nerve in the left outer ear. The sham-tVNS protocol was the same as the active-tVNS protocol although without current input. Both groups of patients also received conventional treatments. Consciousness was evaluated according to the Coma Recovery Scale-Revised before and after the 4-week intervention. We also recorded the type and number of behavioral responses. Safety was primarily assessed according to the incidence of treatment-emergent adverse events. Each patient's heart rate and blood pressure were monitored during all treatment sessions.

Results

Ultimately, 57 patients completed the study: 28 patients underwent active tVNS and 29 patients underwent sham tVNS. No significant differences were observed in Coma Recovery Scale-Revised scores between the active- and sham-tVNS groups before the tVNS sessions. Compared with patients in the sham-tVNS group (9.28 ± 4.38), patients with DoCs treated with active tVNS showed improved consciousness (10.93 ± 4.99), although not statistically significant. Further analysis revealed obvious differences between patients with MCS receiving active and sham tVNS, but no significant difference in patients with vegetative state/unresponsive wakefulness syndrome in both groups. All side effects were considered common medical conditions with no obvious correlation to tVNS.

Conclusion

These preliminary data provide early evidence that tVNS may be an effective and safe approach for promoting the recovery of consciousness, especially in patients with MCS.

Clinical trial registration

https://www.chictr.org.cn/edit.aspx?pid=175938&htm=4, identifier: ChiCTR2200066629.

Functional Connectivity Increases in Response to High-Definition Transcranial Direct Current Stimulation in Patients with Chronic Disorder of Consciousness

Highlights

Functional connectivity induced by HD-tDCS in DLPFC has different trends in CRS-R score improvers and non-improvers.

An increase in theta PLV in the left frontal–parietooccipital region was significantly associated with CRS-R changes.

DOC patients with increased PLV of the alpha band in the intra-bifrontal region have a better prognosis than those without.

Abstract

High-definition transcranial direct current stimulation (HD-tDCS) has been shown to play an important role in improving consciousness in patients with disorders of consciousness (DOCs), but its neuroelectrophysiological evidence is still lacking. To better explain the electrophysiological mechanisms of the effects of HD-tDCS on patients with DOCs, 22 DOC patients underwent 10 anodal HD-tDCS sessions of the left dorsolateral prefrontal cortex (DLPFC). This study used the Coma Recovery Scale-Revised (CRS-R) to assess the level of consciousness in DOC patients. According to whether the CRS-R score increased before and after stimulation, DOC patients were divided into a responsive group and a non-responsive group. By comparing the differences in resting-state EEG functional connectivity between different frequency bands and brain regions, as well as the relationship between functional connectivity values and clinical scores, the electrophysiological mechanism of the clinical effects of HD-tDCS was further explored. The change of the phase locking value (PLV) on the theta frequency band in the left frontal–parietooccipital region was positively correlated with the change in the CRS-R scores. As the number of interventions increased, we observed that in the responsive group, the change in PLV showed an upward trend, and the increase in the PLV appeared in the left frontal–parietooccipital region at 4–8 Hz and in the intra-bifrontal region at 8–13 Hz. In the non-responsive group, although the CRS-R scores did not change after stimulation, the PLV showed a downward trend, and the decrease in the PLV appeared in the intra-bifrontal region at 8–13 Hz. In addition, at the three-month follow-up, patients with increased PLV in the intra-bifrontal region at 8–13 Hz after repeated HD-tDCS stimulation had better outcomes than those without. Repeated anodal stimulation of the left DLPFC with HD-tDCS resulted in improved consciousness in some patients with DOCs. The increase in functional connectivity in the brain regions may be associated with the improvement of related awareness after HD-tDCS and may be a predictor of better long-term outcomes.

Neurorehabilitation for people with disorders of consciousness: an international survey of health-care structures and access to treatment, (Part 1)

AIMS

The provision of rehabilitation services for people with disorders of consciousness (DoC) may vary due to geographical, financial, and political factors. The extent of this variability and the implementation of treatment standards across countries is unknown. This study explored international neurorehabilitation systems for people with DoC.

METHODS

An online survey (SurveyMonkey®) was disseminated to all members of the International Brain Injury Association (IBIA) DoC Special Interest Group (SIG) examining existing rehabilitation systems and access to them.

RESULTS

Respondents (n = 35) were from 14 countries. Specialized neurorehabilitation was available with varying degrees of access and duration. Commencement of specialized neurorehabilitation averaged 3-4 weeks for traumatic brain injury (TBI) and 5-8 weeks for non-traumatic brain injury (nTBI) etiologies. Length of stay in inpatient rehabilitation was 1-3 months for TBI and 4-6 months for nTBI. There were major differences in access to services and funding across countries. The majority of respondents felt there were not enough resources in place to provide appropriate neurorehabilitation.

CONCLUSIONS

There exists inter-country differences for DoC neurorehabilitation after severe acquired brain injury. Further work is needed to implement DoC treatment standards at an international level.

The neuroethics of disorders of consciousness: a brief history of evolving ideas

Neuroethical questions raised by recent advances in the diagnosis and treatment of disorders of consciousness are rapidly expanding, increasingly relevant, and yet underexplored. The aim of this thematic review is to provide a clinically applicable framework for understanding the current taxonomy of disorders of consciousness and to propose an approach to identifying and critically evaluating actionable neuroethical issues that are frequently encountered in research and clinical care for this vulnerable population. Increased awareness of these issues and clarity about opportunities for optimizing ethically-responsible care in this domain are especially timely given recent surges in critically ill patients with unusually prolonged disorders of consciousness associated with coronavirus disease 2019 (COVID-19) around the world. We begin with an overview of the field of neuroethics: what it is, its history and evolution in the context of biomedical ethics at large. We then explore nomenclature used in disorders of consciousness, covering categories proposed by the American Academy of Neurology, the American Congress of Rehabilitation Medicine, and the National Institute on Disability, Independent Living, and Rehabilitation Research, including definitions of terms such as coma, the vegetative state, unresponsive wakefulness syndrome, minimally conscious state, covert consciousness, and the confusional state. We discuss why these definitions matter, and why there has been such evolution in this nosology over the years, from Jennett and Plum in 1972 to the Multi-Society Task Force in 1994, the Aspen Working Group in 2002 and up until the 2018 American and 2020 European Disorders of Consciousness guidelines. We then move to a discussion of clinical aspects of disorders of consciousness, the natural history of recovery, and ethical issues that arise within the context of caring for persons with disorders of consciousness. We conclude with a discussion of key challenges associated with assessing residual consciousness in disorders of consciousness, potential solutions and future directions, including integration of crucial disability rights perspectives.

Recovery from prolonged disorders of consciousness: A dual-center prospective cohort study in China

BACKGROUND

Recent innovations in intensive care have improved the prognosis of patients with severe brain injuries and brought more patients with disorders of consciousness (DoC). Data are lacking regarding the long-term outcomes of those patients in China. It is necessary to study the long-term outcomes of patients with prolonged DoC in light of many factors likely to influence crucial decisions about their care and their life.

AIM

To present the preliminary results of a DoC cohort.

METHODS

This was a two-center prospective cohort study of inpatients with vegetative state (VS)/unresponsive wakefulness syndrome (UWS). The study outcomes were the recovery from VS/UWS to minimally conscious state (MCS) and the long-term status of patients with prolonged DoC considered in VS/UWS or MCS for up to 6 years. The patients were evaluated using the Glasgow coma scale, coma recovery scale-revised, and Glasgow outcome scale. The endpoint of follow-up was recovery of full consciousness or death. The changes in the primary clinical outcome improvement in clinical diagnosis were evaluated at 12 mo compared with baseline.

RESULTS

The study population included 93 patients (62 VS/UWS and 31 MCS). The post-injury interval range was 28-634 d. Median follow-up was 20 mo (interquartile range, 12-37 mo). At the endpoint, 33 transitioned to an emergence from MCS or full consciousness, eight had a locked-in syndrome, and there were 35 patients remaining in a VS/UWS and 11 in an MCS. Seven (including one locked-in syndrome) patients (7.5%) died within 12 mo of injury. Compared with the unresponsive group (n = 52) at 12 mo, the responsive group (n = 41) had a higher proportion of males (87.8% vs 63.5%, P = 0.008), shorter time from injury (median, 40.0 d vs 65.5 d, P = 0.006), higher frequency of vascular etiology (68.3% vs 38.5%, P = 0.007), higher Glasgow coma scale score at admission (median, 9 vs 6, P < 0.001), higher coma recovery scale-revised score at admission (median, 9 vs 2.5, P < 0.001), at 1 mo (median, 14 vs 5, P < 0.001), and at 3 mo (median, 20 vs 6, P < 0.001), lower frequency of VS/UWS (36.6% vs 90.0%, P < 0.001), and more favorable Glasgow outcome scale outcome (P < 0.001).

CONCLUSION

Patients with severe DoC, despite having strong predictors of poor prognosis, might recover consciousness after a prolonged time of rehabilitation. An accurate initial diagnosis of patients with DoC is critical for predicting outcome and a long-term regular follow-up is also important.