The Nociception Coma Scale: a new tool to assess nociception in disorders of consciousness

Pain Assessment in the Patient Unable to Self- Report: Clinical Practice Recommendations in Support of the ASPMN 2024 Position Statement

Recognizing and managing pain is especially challenging for vulnerable populations who cannot communicate their discomfort. Because there is no valid and reliable objective measure of pain, the American Society for Pain Management Nursing advocates for comprehensive assessment practices articulated in a Hierarchy of Pain Assessment. These practices must gather relevant information to infer the presence of pain and evaluate a patient's response to treatment. Nurses and other healthcare providers must be advocates for those who cannot communicate their pain experience.

Rasch Analysis of the Chinese Version of the Nociception Coma Scale-Revised in Patients with Prolonged Disorders of Consciousness

OBJECTIVES

The aim of this study was to analyze the Chinese version of the Nociception Coma Scale-Revised in patients with prolonged disorders of consciousness within the framework of Rasch modeling, including investigating the invariance of total scores across different etiologies of disorders of consciousness.

DESIGN

Prospective psychometric study.

PARTICIPANTS

Patients with prolonged disorders of consciousness from the Rehabilitation and Neurology units in hospital.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

The Nociception Coma Scale-Revised was undertaken by trained raters and the Coma Recovery Scale-Revised was used to assess patients' consciousness. The psychometric properties within the Rasch model including item-person targeting, reliability and separation, item fit, unidimensionality, and differential item functioning were assessed.

RESULTS

84 patients with prolonged disorders of consciousness (mean age 53 years; mean injury 5 months; 42 with Minimally Conscious State and 42 with Unresponsive Wakefulness Syndrome) of 252 observations were enrolled in the study. Through the procedure of repeated assessment and differential item function, a lower item bias Rasch set was purified. The Rasch model assumptions were examined and met, with item reliability and validity meeting the recommended threshold.

CONCLUSIONS

The Chinese version of the Nociception Coma Scale-Revised demonstrated unidimensionality, good reliability and separation, and good item fit, but dissatisfied person fit and item-person targeting. The verbal subscale showed a notable discrepancy between person responses and the difficulty of the items, suggesting limited clinical significance.

Nociception Coma Scale-Revised with Personalized Painful Stimulus Versus Standard Stimulation in Persons with Disorders of Consciousness: An International Multicenter Study

Background/Objectives: Persons with disorders of consciousness (DoCs) may perceive pain without being able to communicate their discomfort. The Nociception Coma Scale (NCS) and its revised form (NCS-R) have been proposed to assess nociception in persons with DoCs. The main aim of this international multicenter study was to confirm (or not) our preliminary results and compare the NCS-R scores of standard stimulus (NCS-R-SS) to scores of personalized painful stimuli (NCS-R-PS). A secondary aim of the study was to verify possible correlations between the NCS-R-PS and Coma Recovery Scale-Revised (CRS-R) and to estimate convergent validity. Methods: Sixty-one patients with prolonged DoCs (pDoCs) were enrolled from seven European post-acute rehabilitation centers. Responsiveness and pain perception were assessed by CRS-R and NCS-R with standard stimulus (NCS-R-SS) and personalized stimulation (NCS-R-PS). ClinicalTrials.gov Identifier: NCT06012357. Results: our results support our prior findings on the superiority and the validity of the personalized painful stimulus approach in assessment of pain in persons with DoCs in comparison with the standardized pain assessment methodology. Conclusions: A more in-depth and tailored assessment of pain perception in persons with a DoC may lead to better acknowledgment of its presence and by extension an objective foundation for more aggressive and appropriate pain management.

Pain anticipation is a new behavioural sign of minimally conscious state

Probing cognition and consciousness in the absence of functional communication remains an extremely challenging task. In this perspective, we imagined a basic clinical procedure to explore pain anticipation at bedside. In a series of 61 patients with a disorder of consciousness, we tested the existence of a nociceptive anticipation response by pairing a somaesthetic stimulation with a noxious stimulation. We then explored how nociceptive anticipation response correlated with (i) clinical status inferred from Coma Recovery Scale-Revised scoring, (ii) with an EEG signature of stimulus anticipation-the contingent negative variation-and (iii) how nociceptive anticipation response could predict consciousness outcome at 6 months. Proportion of nociceptive anticipation response differed significantly according to the state of consciousness: nociceptive anticipation response was present in 5 of 5 emerging from minimally conscious state patients (100%), in 10 of 11 minimally conscious state plus patients (91%), but only in 8 of 17 minimally conscious state minus patients (47%), and only in 1 of 24 vegetative state/unresponsive wakefulness syndrome patients (4%) (χ 2  P < 0.0001). Nociceptive anticipation response correlated with the presence of a contingent negative variation, suggesting that patients with nociceptive anticipation response were more prone to actively expect and anticipate auditory stimuli (Fisher's exact test P = 0.05). However, nociceptive anticipation response presence did not predict consciousness recovery. Nociceptive anticipation response appears as a new additional behavioural sign that can be used to differentiate minimally conscious state from vegetative state/unresponsive wakefulness syndrome patients. As most behavioural signs of minimally conscious state, the nociceptive anticipation response seems to reveal the existence of a cortically mediated state that does not necessarily reflect residual conscious processing.

Disorders of Consciousness

This article reviews the definition, assessment, neuroimaging, treatment, and rehabilitation for disorders of consciousness after an acquired brain injury. It also explores special considerations and new neuromodulation treatment options.

Bibliometric analysis of functional magnetic resonance imaging studies on chronic pain over the past 20 years

PURPOSE

The utilization of functional magnetic resonance imaging (fMRI) in studying the mechanisms and treatment of chronic pain has gained significant popularity. However, there is currently a dearth of literature conducting bibliometric analysis on fMRI studies focused on chronic pain.

METHODS

All the literature included in this study was obtained from the Science Citation Index Expanded of Web of Science Core Collection. We used CiteSpace and VOSviewer to analyze publications, authors, countries or regions, institutions, journals, references and keywords. Additionally, we evaluated the timeline and burst analysis of keywords, as well as the timeline and burst analysis of references. The search was conducted from 2004 to 2023 and completed within a single day on October 4th, 2023.

RESULTS

A total of 1,327 articles were retrieved. The annual publication shows an overall increasing trend. The United States has the highest number of publications and the main contributing institution is Harvard University. The journal PAIN produces the most articles. In recent years, resting-state fMRI, the prefrontal cortex, nucleus accumbens, thalamus, and migraines have been researched hotspots of fMRI studies on chronic pain.

CONCLUSIONS

This study provides an in-depth perspective on fMRI for chronic pain research, revealing key points, research hotspots and research trends, which offers valuable ideas for future research activities. It concludes with a summary of advances in clinical practice in this area, pointing out the need for critical evaluation of these findings in the light of guidelines and expert recommendations. It is anticipated that further high-quality research outputs will be generated in the future, which will facilitate the utilization of fMRI in clinical decision-making for chronic pain.

Short-term outcomes of early intensive neurorehabilitation for prolonged disorders of consciousness: A prospective cohort study

BACKGROUND

Advances in medical care have increased survival in people with severe brain injuries and with that the number of survivors with prolonged disorders of consciousness (PDOC) has increased. In the literature, early intensive neurorehabilitation (EIN) for people with PDOC is recommended to achieve the best possible outcomes.

OBJECTIVES

To evaluate the frequency and extent of recovery of consciousness, mortality, complications, pain and discomfort, and medication during a nationwide EIN programme in people with PDOC after acquired brain injury. We hypothesized that level of consciousness would improve in half of people with PDOC.

METHODS

Prospective cohort study. People with PDOC aged 16 years and older admitted to the EIN department centralized in a single rehabilitation centre in the Netherlands (Libra Rehabilitation & Audiology) were included. The EIN delivers a subacute medical level of care and rehabilitation for a maximum duration of 14 weeks. The outcome measures were level of consciousness (CRS-R), mortality, number of complications, medication and pain/discomfort (NCS-R).

RESULTS

Of the 104 people included, 68 % emerged to a minimal conscious state with command-following or higher during EIN and 44 % regained consciousness. Mortality during EIN was 6 %, and 50 % of deaths followed a non-treatment decision or withdrawal of life-sustaining treatment. Almost all participants had at least 1 medical complication, leading to hospital readmission for 30 %. 73 % showed no pain or discomfort. During EIN, cardiovascular medication and analgesics were reduced by 15 %.

CONCLUSIONS

During the EIN programme, a large percentage of people with PDOC regained at least a minimal conscious state or even consciousness. These outcomes and the frequent medical complications in these people suggest that intensive specialized care should be offered to all people with PDOC. The outcomes of this study might help health professionals to better inform the families of people with PDOC about the short-term prognosis of PDOC.

PROTOCOL REGISTRATION NUMBER

The Dutch Trial Register, NL 8138.

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.

Assessing consciousness and cognition in disorders of consciousness

Detecting willful cognition in these patients is known to be challenging due to the patients' motor disabilities and high vigilance fluctuations but also due to the lack of expertise and use of adequate tools to assess these patients in specific settings. This review will discuss the main disorders of consciousness after severe brain injury, how to assess consciousness and cognition in these patients, as well as the challenges and tools available to overcome these challenges and reach an accurate diagnosis.

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.

Effects of simultaneous transcutaneous auricular vagus nerve stimulation and high-definition transcranial direct current stimulation on disorders of consciousness: a study protocol

Background

Non-invasive brain stimulation (NIBS) techniques are now widely used in patients with disorders of consciousness (DOC) for accelerating their recovery of consciousness, especially minimally conscious state (MCS). However, the effectiveness of single NIBS techniques for consciousness rehabilitation needs further improvement. In this regard, we propose to enhance from bottom to top the thalamic-cortical connection by using transcutaneous auricular vagus nerve stimulation (taVNS) and increase from top to bottom cortical-cortical connections using simultaneous high-definition transcranial direct current stimulation (HD-tDCS) to reproduce the network of consciousness.

Methods/design

The study will investigate the effect and safety of simultaneous joint stimulation (SJS) of taVNS and HD-tDCS for the recovery of consciousness. We will enroll 84 MCS patients and randomize them into two groups: a single stimulation group (taVNS and HD-tDCS) and a combined stimulation group (SJS and sham stimulation). All patients will undergo a 4-week treatment. The primary outcome will be assessed using the coma recovery scale-revised (CRS-R) at four time points to quantify the effect of treatment: before treatment (T0), after 1 week of treatment (T1), after 2 weeks of treatment (T2), and after 4 weeks of treatment (T3). At the same time, nociception coma scale-revised (NCS-R) and adverse effects (AEs) will be collected to verify the safety of the treatment. The secondary outcome will involve an analysis of electroencephalogram (EEG) microstates to assess the response mechanisms of dynamic brain networks to SJS. Additionally, CRS-R and AEs will continue to be obtained for a 3-month follow-up (T4) after the end of the treatment.

Discussion

This study protocol aims to innovatively develop a full-time and multi-brain region combined neuromodulation paradigm based on the mesocircuit model to steadily promote consciousness recovery by restoring thalamocortical and cortical-cortical interconnections.

Comparing indices of responsiveness for the Coma Near-Coma Scale with and without pain items: An Exploratory study

INTRODUCTION

This study aimed to establish the indices of responsiveness for the Coma/Near-Coma (CNC) scale without (8 items) and with (10 items) pain test stimuli. A secondary purpose was to examine whether the CNC 8 items and 10 items differ when detecting change in neurobehavioral function.

METHODS

We analyzed CNC data from three studies of participants with disorders of consciousness: one observational study and two intervention studies. We generated Rasch person measures using the CNC 8 items and CNC 10 items for each participant at two time points 14 ± 2 days apart using Rasch Measurement Theory. We calculated the distribution-based minimal clinically important difference (MCID) and minimal detectable change using 95% confidence intervals (MDC95 ).

RESULTS

We used the Rasch transformed equal-interval scale person measures in logits. For the CNC 8 items: Distribution-based MCID 0.33 SD = 0.41 logits and MDC95  = 1.25 logits. For the CNC 10 items: Distribution-based MCID 0.33 SD = 0.37 logits and MDC95  = 1.03 logits. Twelve and 13 participants made a change beyond measurement error (MDC95 ) using the CNC 8-item and 10-item scales, respectively.

CONCLUSION

Our preliminary evidence supports the clinical and research utility of the CNC 8-item scale for measuring the responsiveness of neurobehavioral function, and that it demonstrates comparable responsiveness to the CNC 10-item scale without administering the two pain items. The distribution-based MCID can be used to evaluate group-level changes while the MDC95 can support clinical, data-driven decisions about an individual patient.

I Feel! Therefore, I Am from Pain to Consciousness in DOC Patients

Pain assessment and management in patients with disorders of consciousness (DOC) is a challenging and important aspect of care, with implications for detecting consciousness and promoting recovery. This narrative review explores the role of pain in consciousness, the challenges of pain assessment, pharmacological treatment in DOC, and the implications of pain assessment when detecting changes in consciousness. The review discusses the Nociception Coma Scale and its revised version, which are behavioral scales used to assess pain in DOC patients, and the challenges and controversies surrounding the appropriate pharmacological treatment of pain in these patients. Moreover, we highlight recent evidence suggesting that an accurate pain assessment may predict changes in the level of consciousness in unresponsive wakefulness syndrome/vegetative state patients, underscoring the importance of ongoing pain management in these patients.

Clinical application of recommendations for neurobehavioral assessment in disorders of consciousness: an interdisciplinary approach

Accurate diagnosis, prognosis, and subsequent rehabilitation care planning for persons with Disorders of Consciousness (DoC) has historically posed a challenge for neurological care professionals. Evidence suggests rates of misdiagnosis may be as high as 40% when informal beside evaluations are used to determine level of consciousness. The presence of myriad medical, neurological, functional (motor, sensory, cognitive) and environmental confounds germane to these conditions complicates behavioral assessment. Achieving diagnostic certainty is elusive but critical to inform care planning, clinical decision making, and prognostication. Standardized neurobehavioral rating scales has been shown to improve accuracy in distinguishing between coma, unresponsive wakefulness syndrome/vegetative state and minimally consciousness state as compared to informal assessment methods. Thus, these scales are currently recommended for use as the informal "gold standard" for diagnostic assessment in DoC. The following paper will present an evidence-based approach to neurobehavioral assessment for use in clinical practice. Strategies for optimizing assessment and aiding in identification and management of confounds that can limit diagnostic accuracy will be provided. Finally, clinical application of an interdisciplinary approach to identifying and managing confounds will be discussed and how assessment results can be used to identify trends in performance and guide prognostic counseling with families.

Assessment and management of pain/nociception in patients with disorders of consciousness or locked-in syndrome: A narrative review

The assessment and management of pain and nociception is very challenging in patients unable to communicate functionally such as patients with disorders of consciousness (DoC) or in locked-in syndrome (LIS). In a clinical setting, the detection of signs of pain and nociception by the medical staff is therefore essential for the wellbeing and management of these patients. However, there is still a lot unknown and a lack of clear guidelines regarding the assessment, management and treatment of pain and nociception in these populations. The purpose of this narrative review is to examine the current knowledge regarding this issue by covering different topics such as: the neurophysiology of pain and nociception (in healthy subjects and patients), the source and impact of nociception and pain in DoC and LIS and, finally, the assessment and treatment of pain and nociception in these populations. In this review we will also give possible research directions that could help to improve the management of this specific population of severely brain damaged patients.

Pain assessment during physiotherapy and noxious stimuli in patients with disorders of consciousness: A preliminary study

Objectives

The primary purpose of this study is to determine whether patients with disorders of consciousness (DOC) (unresponsive wakefulness syndrome, UWS; minimally conscious state, MCS) experience pain during physiotherapy and noxious stimuli in a larger patient population.

Materials and methods

The patients’ level of consciousness was measured with the Coma Recovery Scale-Revised (CRS-R). Additionally, the Nociception Coma Scale-revised (NCS-R) was used to assess their pain response. The NCS-R total scores between UWS and MCS at baseline, physiotherapy and noxious stimulus were compared using the Mann-Whitney U test (Wilcoxon rank-sum test) and the Kruskal-Wallis H test with Bonferroni correction.

Results

The study enrolled 93 participants. There was a statistically significant difference in NCS-R total scores between the three conditions (H = 215.25, p < 0.001). At baseline, there was no statistically significant difference between MCS and UWS (U = 378, z = –1.35, p = 0.178). While there was a statistically significant difference between MCS and UWS during physiotherapy (U = 1,362, z = –3.06, p < 0.01) and under noxious stimuli (U = 5142.5, z = –11.22, p < 0.001).

Conclusion

Physiotherapy improved the activity responsiveness of DOC patients, and patients experienced less potential pain. However, some DOC patients, especially MCS patients, perceived pain under the noxious stimuli.

Disruption in structural-functional network repertoire and time-resolved subcortical fronto-temporoparietal connectivity in disorders of consciousness

Understanding recovery of consciousness and elucidating its underlying mechanism is believed to be crucial in the field of basic neuroscience and medicine. Ideas such as the global neuronal workspace (GNW) and the mesocircuit theory hypothesize that failure of recovery in conscious states coincide with loss of connectivity between subcortical and frontoparietal areas, a loss of the repertoire of functional networks states and metastable brain activation. We adopted a time-resolved functional connectivity framework to explore these ideas and assessed the repertoire of functional network states as a potential marker of consciousness and its potential ability to tell apart patients in the unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS). In addition, the prediction of these functional network states by underlying hidden spatial patterns in the anatomical network, that is so-called eigenmodes, was supplemented as potential markers. By analysing time-resolved functional connectivity from functional MRI data, we demonstrated a reduction of metastability and functional network repertoire in UWS compared to MCS patients. This was expressed in terms of diminished dwell times and loss of nonstationarity in the default mode network and subcortical fronto-temporoparietal network in UWS compared to MCS patients. We further demonstrated that these findings co-occurred with a loss of dynamic interplay between structural eigenmodes and emerging time-resolved functional connectivity in UWS. These results are, amongst others, in support of the GNW theory and the mesocircuit hypothesis, underpinning the role of time-resolved thalamo-cortical connections and metastability in the recovery of consciousness.

Behavioral Assessment of Patients with Disorders of Consciousness

Severe brain injury is associated with a period of impaired level of consciousness that can last from days to months and results in chronic impairment. Systematic assessment of level of function in patients with disorders of consciousness (DoC) is critical for diagnosis, prognostication, and evaluation of treatment efficacy. Approximately 40% of patients who are thought to be unconscious based on clinical bedside behavioral assessment demonstrate some signs of consciousness on standardized behavioral assessment. This finding, in addition to a growing body of literature demonstrating the advantages of standardized behavioral assessment of DoC, has led multiple professional societies and clinical guidelines to recommend standardized assessment over routine clinical evaluation of consciousness. Nevertheless, even standardized assessment is susceptible to biases and misdiagnosis, and examiners should consider factors, such as fluctuating arousal and aphasia, that may confound evaluation. We review approaches to behavioral assessment of consciousness, recent clinical guideline recommendations for use of specific measures to evaluate patients with DoC, and strategies for mitigating common biases that may confound the examination.

Pain in Persons with Disorders of Consciousness

Pain and suffering in persons with disorders of consciousness (DoC) remain poorly understood, frequently unaddressed or inadequately addressed, and controversial on numerous levels. This narrative literature review will address a number of critical issues germane to pain and suffering in this challenging group of patients, providing an introductory overview of the topic, perspectives on current knowledge regarding pain pathoanatomy and pathophysiology, and a review of common pain generators and factors that can lead to the chronifcation of pain. Caveats on bedside pain assessment challenges, as well as electrophysiologic and neuroimaging findings in these patients, will also be explored. Pain management techniques, including non-pharmacological and pharmacological, will be reviewed. Ethical considerations in the context of pain and suffering in persons with disorders of consciousness will round out the review prior to our concluding comments.

Evaluation of the effect of analgesic treatment on signs of nociception-related behaviors during physiotherapy in patients with disorders of consciousness: a pilot crossover randomized controlled trial

ABSTRACT

Neuro-orthopedic disorders are common in patients with disorders of consciousness (DOC) and can lead to potential pain. However, the patients' inability to communicate makes pain detection and management very challenging for clinicians. In this crossover randomized double-blind placebo-controlled study, we investigated the effects of an analgesic treatment on the presence of nociception-related behaviors. At baseline, the Nociception Coma Scale-Revised (NCS-R) was performed in 3 conditions: a non-noxious stimulation, a noxious stimulation, and during a physiotherapy session. Patients with a NCS-R total score during physiotherapy equal or above the score observed after the noxious stimulation could participate to the clinical trial, as well as patients with a score above 5. They received an analgesic treatment and a placebo on 2 consecutive days in a randomized order followed by an assessment with the NCS-R. Of the 18 patients, 15 displayed signs of potential pain during physiotherapy. Patients showed higher NCS-R scores during physiotherapy compared with the other conditions, suggesting that mobilizations were potentially painful. Of these 15 patients, 10 met the criteria to participate in the placebo-controlled trial. We did not find any effect of analgesic treatment on the NCS-R scores. This study highlights that physiotherapy may be potentially painful for patients with DOC, while analgesic treatments did not reduced NCS-R scores. Therefore, careful monitoring with appropriate assessment and treatment before and during mobilization should become a priority in clinical settings. Future studies should focus on the development of assessment tools sensitive to analgesic dosage to manage pain in DOC.

Pupil Light Reflex for the Assessment of Analgesia in Critically Ill Sedated Patients With Traumatic Brain Injury: A Preliminary Study

ABSTRACT

BACKGROUND: Analgesia monitoring is essential to preserve comfort in critically ill sedated patients with traumatic brain injury (TBI). Although pupil dilation (PD) and pain behaviors can be used to assess analgesia, these indicators require application of noxious stimulations for elicitation. Recently, the pupillary light reflex (PLR) has emerged as a nonnoxious parameter that may be used to predict analgesia requirements in non-brain-injured patients. Here, we explored whether PLR can be used for the purpose of analgesia monitoring in critically ill sedated TBI patients. METHODS: Fifteen mechanically ventilated TBI patients (11 men; 54 ± 20 years) under continuous analgesia and sedation infusions were assessed at predefined time within 72 hours of intensive care unit admission. Data collection was performed using video-pupillometry and the Behavioral Pain Scale. At each assessment, pupil size and PLR at rest were recorded followed immediately by the documentation of PD and pain behaviors elicited by a calibrated noxious stimulus. Blood concentrations of analgesics/sedatives were monitored. RESULTS: One hundred three assessments were completed. PLR resulted in an average decrease of 19% in pupil diameter, and PD resulted in an average increase of 10% in pupil diameter. Variations in PLR and PD were more pronounced in subjects who showed a Behavioral Pain Scale score greater than 3 (a recognized sign of subanalgesia) compared with those with no behavioral reaction. Multiple regression analyses suggest a significant overlap between fluctuations in pupillary reflexes and blood levels of fentanyl, not propofol. CONCLUSION: In our sample, percentages of variation in PLR and PD were found to be directly representative of TBI patients' fentanyl blood concentration. Considering information about blood drug concentration is generally not available at bedside, PLR could be used as a proxy to assess analgesia requirements before a nociceptive procedure in critically ill sedated TBI patients who are vulnerable to stress.

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 prolonged disorders of consciousness associated with coronavirus disease 2019 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 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 people 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.

Nociceptive Response Is a Possible Marker of Evolution in the Level of Consciousness in Unresponsive Wakefulness Syndrome Patients

The Nociception Coma Scale (NCS) and its revised version (NCS-R) were used to evaluate behavioral responses to pain in non-communicative patients. We hypothesized that if patients demonstrate changes to their NCS(-R) scores over time, their evolving behavioral abilities could indicate a forthcoming diagnostic improvement with the Coma Recovery Scale-Revised (CRS-R). Forty-three Vegetative State/Unresponsive Wakefulness Syndrome (VS/UWS) patients were enrolled in the study. The patients were assessed weekly using the CRS-R and NCS(-R) for four consecutive weeks. The first assessment was within 10 days after hospitalization. The assessments were performed between 09:30 and 11:30 AM in a room with constant levels of humidity, light and temperature, as well as an absence of transient noise. Noxious stimuli were administered using a Newton-meter, with pressure applied to the fingernail bed for a maximum of 5 s unless interrupted by a behavioral response from subjects. Seventeen patients demonstrated improvements in their level of consciousness, 13 of whom showed significant behavioral changes through the NCS(-R) before being diagnosed with a Minimally Conscious State (MCS) according to the CRS-R. The behavioral changes observed using the NCS(-R) corresponded to a high probability of observing an improvement from VS/UWS to MCS. To characterize the increased likelihood of this transition, our results present threshold scores of ≥5 for the NCS (accuracy 86%, sensitivity 87%, and specificity 86%) and ≥3 for the NCS-R (accuracy 77%, sensitivity 89%, and specificity 73%). In conclusion, a careful evaluation of responses to nociceptive stimuli in DOC patients could constitute an effective procedure in assessing their evolving conscious state.

Comparison of Feature Extraction Methods for Physiological Signals for Heat-Based Pain Recognition

While even the most common definition of pain is under debate, pain assessment has remained the same for decades. But the paramount importance of precise pain management for successful healthcare has encouraged initiatives to improve the way pain is assessed. Recent approaches have proposed automatic pain evaluation systems using machine learning models trained with data coming from behavioural or physiological sensors. Although yielding promising results, machine learning studies for sensor-based pain recognition remain scattered and not necessarily easy to compare to each other. In particular, the important process of extracting features is usually optimised towards specific datasets. We thus introduce a comparison of feature extraction methods for pain recognition based on physiological sensors in this paper. In addition, the PainMonit Database (PMDB), a new dataset including both objective and subjective annotations for heat-induced pain in 52 subjects, is introduced. In total, five different approaches including techniques based on feature engineering and feature learning with deep learning are evaluated on the BioVid and PMDB datasets. Our studies highlight the following insights: (1) Simple feature engineering approaches can still compete with deep learning approaches in terms of performance. (2) More complex deep learning architectures do not yield better performance compared to simpler ones. (3) Subjective self-reports by subjects can be used instead of objective temperature-based annotations to build a robust pain recognition system.

Preservation of Brain Activity in Unresponsive Patients Identifies MCS Star

Objective

Brain‐injured patients who are unresponsive at the bedside (ie, vegetative state/unresponsive wakefulness syndrome – VS/UWS) may present brain activity similar to patients in minimally conscious state (MCS). This peculiar condition has been termed “non‐behavioural MCS” or “MCS*”. In the present study we aimed to investigate the proportion and underlying brain characteristics of patients in MCS*.

Methods

Brain ¹⁸F‐fluorodeoxyglucose Positron Emission Tomography (FDG‐PET) was acquired on 135 brain‐injured patients diagnosed in prolonged VS/UWS (n = 48) or MCS (n = 87). From an existing database, relative metabolic preservation in the fronto‐parietal network (measured with standardized uptake value) was visually inspected by three experts. Patients with hypometabolism of the fronto‐parietal network were labelled “VS/UWS”, while its (partial) preservation either confirmed the behavioural diagnosis of “MCS” or, in absence of behavioural signs of consciousness, suggested a diagnosis of “MCS*”. Clinical outcome at 1‐year follow‐up, functional connectivity, grey matter atrophy, and regional brain metabolic patterns were investigated in the three groups (VS/UWS, MCS* and MCS).

Results

67% of behavioural VS/UWS presented a partial preservation of brain metabolism (ie, MCS*). Compared to VS/UWS patients, MCS* patients demonstrated a better outcome, global functional connectivity and grey matter preservation more compatible with the diagnosis of MCS. MCS* patients presented lower brain metabolism mostly in the posterior brain regions compared to MCS patients.

Interpretation

MCS* is a frequent phenomenon that is associated with better outcome and better brain preservation than the diagnosis of VS/UWS. Complementary exams should be provided to all unresponsive patients before taking medical decisions. ANN NEUROL 2021;90:89–100

Pain Perception in Disorder of Consciousness: A Scoping Review on Current Knowledge, Clinical Applications, and Future Perspective

Pain perception in individuals with prolonged disorders of consciousness (PDOC) is still a matter of debate. Advanced neuroimaging studies suggest some cortical activations even in patients with unresponsive wakefulness syndrome (UWS) compared to those with a minimally conscious state (MCS). Therefore, pain perception has to be considered even in individuals with UWS. However, advanced neuroimaging assessment can be challenging to conduct, and its findings are sometimes difficult to be interpreted. Conversely, multichannel electroencephalography (EEG) and laser-evoked potentials (LEPs) can be carried out quickly and are more adaptable to the clinical needs. In this scoping review, we dealt with the neurophysiological basis underpinning pain in PDOC, pointing out how pain perception assessment in these individuals might help in reducing the misdiagnosis rate. The available literature data suggest that patients with UWS show a more severe functional connectivity breakdown among the pain-related brain areas compared to individuals in MCS, pointing out that pain perception increases with the level of consciousness. However, there are noteworthy exceptions, because some UWS patients show pain-related cortical activations that partially overlap those observed in MCS individuals. This suggests that some patients with UWS may have residual brain functional connectivity supporting the somatosensory, affective, and cognitive aspects of pain processing (i.e., a conscious experience of the unpleasantness of pain), rather than only being able to show autonomic responses to potentially harmful stimuli. Therefore, the significance of the neurophysiological approach to pain perception in PDOC seems to be clear, and despite some methodological caveats (including intensity of stimulation, multimodal paradigms, and active vs. passive stimulation protocols), remain to be solved. To summarize, an accurate clinical and neurophysiological assessment should always be performed for a better understanding of pain perception neurophysiological underpinnings, a more precise differential diagnosis at the level of individual cases as well as group comparisons, and patient-tailored management.

Validation of the Critical-Care Pain Observation Tool-Neuro in brain-injured adults in the intensive care unit: a prospective cohort study

Background

Pain assessment in brain-injured patients in the intensive care unit (ICU) is challenging and existing scales may not be representative of behavioral reactions expressed by this specific group. This study aimed to validate the French-Canadian and English revised versions of the Critical-Care Pain Observation Tool (CPOT-Neuro) for brain-injured ICU patients.

Methods

A prospective cohort study was conducted in three Canadian and one American sites. Patients with a traumatic or a non-traumatic brain injury were assessed with the CPOT-Neuro by trained raters (i.e., research staff and ICU nurses) before, during, and after nociceptive procedures (i.e., turning and other) and non-nociceptive procedures (i.e., non-invasive blood pressure, soft touch). Patients who were conscious and delirium-free were asked to provide their self-report of pain intensity (0–10). A first data set was completed for all participants (n = 226), and a second data set (n = 87) was obtained when a change in the level of consciousness (LOC) was observed after study enrollment. Three LOC groups were included: (a) unconscious (Glasgow Coma Scale or GCS 4–8); (b) altered LOC (GCS 9–12); and (c) conscious (GCS 13–15).

Results

Higher CPOT-Neuro scores were found during nociceptive procedures compared to rest and non-nociceptive procedures in both data sets (p < 0.001). CPOT-Neuro scores were not different across LOC groups. Moderate correlations between CPOT-Neuro and self-reported pain intensity scores were found at rest and during nociceptive procedures (Spearman rho > 0.40 and > 0.60, respectively). CPOT-Neuro cut-off scores ≥ 2 and ≥ 3 were found to adequately classify mild to severe self-reported pain ≥ 1 and moderate to severe self-reported pain ≥ 5, respectively. Interrater reliability of raters’ CPOT-Neuro scores was supported with intraclass correlation coefficients > 0.69.

Conclusions

The CPOT-Neuro was found to be valid in this multi-site sample of brain-injured ICU patients at various LOC. Implementation studies are necessary to evaluate the tool’s performance in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03561-1.

Telemonitoring of Patients With Chronic Traumatic Brain Injury: A Pilot Study

Telehealth systems have shown success in the remote management of several neurological disorders, but there is a paucity of evidence in disorders of consciousness (DOC). In this study, we explore the effectiveness of a new telemonitoring system, for monitoring Vegetative State (VS) and Minimally Conscious State (MCS) patients. This was a prospective, mono-center randomized controlled study. We included only traumatic brain injury (TBI) patients who required long-term motor/cognitive assistance having a stable clinical condition. We examined their clinical evolution over ~4 years of the follow-up period. Twenty-two TBI patients were enrolled and equally divided into two groups: one telemonitored at home with our service and the second admitted to a standard long-stay hospitalization (LSH) program. Patients enrolled in the telehealth service (age: 49.9 ± 20.4; 45% female; diagnosis: 36% VS/64% MCS) were demographically and clinically-matched with those admitted to the LSH program (age: 55.1 ± 15; 18% female; diagnosis: 54% VS/46% MCS). Thirty-six percent of patients in the LSH program died before completing follow up evaluation with respect to 18% of death in the group of TBI patients telemonitored at home. At follow-up, patients in LSH and telemonitoring groups showed similar clinical progression, as measured by CRS-r, NCS, WHIM, and LCF scales, as well as by the number of medical complications (i.e., bedsores, infections). Finally, we estimated the total daily cost per patient. Severe TBI patients enrolled in the conventional LSH program cost 262€ every single day, whereas the cost per patient in the telehealth service resulted to be less expensive (93€). Here, we highlight that our telehealth monitoring service is as efficacious as in-person usual care to manage a severe neurological disorder such as TBI in a cost-effective way.

Addressing Pain for a Proper Rehabilitation Process in Patients With Severe Disorders of Consciousness

Consciousness constitutes a fundamental prerequisite in the individual appraisal and experience of pain. In the same way, a person needs to be able to report on pain perception. Patients who suffered a severe brain injury with disorders of consciousness (DOC) represent a spectrum of pathologies affecting patients' capacity to interact with the external world. In these patients, the most relevant aspects in response to pain are physiologic and behavioral. The treatments and management of pain are challenging issues in these patients, arising serious ethical concerns and bringing emotional load among medical staff, caregivers, and relatives. In this review, we report the importance of having a correct pain management in DOC patients, to individuate the best pharmacological treatment that can make the difference in detecting a behavioral response, indicative of a change in the level of consciousness, and in planning a more effective rehabilitative approach.

Outcome registry of early intensive neurorehabilitation in patients with disorders of consciousness: study protocol of a prospective cohort study

BACKGROUND

Prolonged disorders of consciousness (PDOC) may occur after severe brain injury. Two diagnostic entities are distinguished within PDOC: unresponsive wakefulness syndrome (UWS, previously known as vegetative state) and minimally conscious state (MCS). Patients with PDOC may benefit from early intensive neurorehabilitation (EIN). In the Netherlands, the EIN programme is provided by one designated expert rehabilitation centre and forms the starting point of a dedicated chain of specialised rehabilitation and care for this group. This study project, called DOCTOR: Disorders of Consciousness; Treatment and Outcomes Registry, sets up a registry and systematically investigates multiple short- and long-term outcomes of patients with PDOC who receive EIN.

METHODS

Single-centre prospective cohort study with a 2-year follow-up period. Patients with PDOC due to acute brain injury who receive EIN, aged 16 years and older are included. Measurements will take place at start EIN, in week 5, 10, and at discharge from the EIN programme (duration = max 14 weeks) and at week 28, 40, 52, and 104 after admission to the EIN programme, following patients through the health-care chain. Outcome measures are the changes over time in level of consciousness, using the Coma Recovery Scale-Revised; the frequency and type of medical complications; the mortality rate; level of disability, including the level of motor, cognitive, behavioural and emotional functioning; participation; and quality of life. Secondary outcomes include self-efficacy of caregivers, caregivers' strain and cost-effectiveness of the programme.

DISCUSSION

The DOCTOR study will provide insight in the recovery patterns and predictors of recovery for multiple outcomes in PDOC patients after following EIN. The results of the study will enable us to benchmark and improve EIN and the organisation of the health-care chain, both for patients with PDOC and for their families.

TRIAL REGISTRATION

Netherlands Trial Register, NL 8138 . Retrospectively registered 6 November 2019.

Auditory localization should be considered as a sign of minimally conscious state based on multimodal findings

Auditory localization (i.e. turning the head and/or the eyes towards an auditory stimulus) is often part of the clinical evaluation of patients recovering from coma. The objective of this study is to determine whether auditory localization could be considered as a new sign of minimally conscious state, using a multimodal approach. The presence of auditory localization and the clinical outcome at 2 years of follow-up were evaluated in 186 patients with severe brain injury, including 64 with unresponsive wakefulness syndrome, 28 in minimally conscious state minus, 71 in minimally conscious state plus and 23 who emerged from the minimally conscious state. Brain metabolism, functional connectivity and graph theory measures were investigated by means of ¹⁸F-fluorodeoxyglucose positron emission tomography, functional MRI and high-density electroencephalography in two subgroups of unresponsive patients, with and without auditory localization. These two subgroups were also compared to a subgroup of patients in minimally conscious state minus. Auditory localization was observed in 13% of unresponsive patients, 46% of patients in minimally conscious state minus, 62% of patients in minimally conscious state plus and 78% of patients who emerged from the minimally conscious state. The probability to observe an auditory localization increased along with the level of consciousness, and the presence of auditory localization could predict the level of consciousness. Patients with auditory localization had higher survival rates (at 2-year follow-up) than those without localization. Differences in brain function were found between unresponsive patients with and without auditory localization. Higher connectivity in unresponsive patients with auditory localization was measured between the fronto-parietal network and secondary visual areas, and in the alpha band electroencephalography network. Moreover, patients in minimally conscious state minus significantly differed from unresponsive patients without auditory localization in terms of brain metabolism and alpha network centrality, whereas no difference was found with unresponsive patients who presented auditory localization. Our multimodal findings suggest differences in brain function between unresponsive patients with and without auditory localization, which support our hypothesis that auditory localization should be considered as a new sign of minimally conscious state. Unresponsive patients showing auditory localization should therefore no longer be considered unresponsive but minimally conscious. This would have crucial consequences on these patients’ lives as it would directly impact the therapeutic orientation or end-of-life decisions usually taken based on the diagnosis.

Ethical and legal considerations related to disorders of consciousness

PURPOSE OF REVIEW

The purpose of this review is to describe ethical and legal issues that arise in the management of patients with disorders of consciousness ranging from the minimally conscious state to the coma state, as well as brain death.

RECENT FINDINGS

The recent literature highlights dilemmas created by diagnostic and prognostic uncertainties in patients with disorders of consciousness. The discussion also reveals the challenges experienced by the disability community, which includes individuals with severe brain injury who are classified as having a disorder of consciousness. We review current guidelines for management of patients with disorders of consciousness including discussions around diagnosis, prognosis, consideration of neuropalliation, and decisions around life sustaining medical treatment.

SUMMARY

In the setting of uncertainty, this review describes the utility of applying a disability rights perspective and shared decision-making process to approach medical decision-making for patients with disorders of consciousness. We outline approaches to identifying surrogate decision makers, standards for decision-making and decision-making processes, specifically addressing the concept of futility as a less useful framework for making decisions. We also highlight special considerations for research, innovative and controversial care, brain death, organ donation, and child abuse and neglect.

Psychometric Properties of the Coma Near-Coma Scale for Adults in Disordered States of Consciousness: A Rasch Analysis

OBJECTIVES

To examine the construct validity and measurement precision of the Coma Near-Coma scale (CNC) in measuring neurobehavioral function (NBF) in patients with disorders of consciousness receiving postacute care rehabilitation.

DESIGN

Rasch analysis of retrospective data.

PARTICIPANTS

Participants (N=48) with disordered consciousness who were admitted to postacute care rehabilitation.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

CNC.

RESULTS

Assessment with CNC repeated weekly until the participant was conscious or discharged from the postacute care facility (451 participant records). Rating scale steps were ordered for all items. Eight of the 10 CNC items evaluated in this study fit the measurement model (χ²=5332.58; df=11; P=.17); pain items formed a distinct construct. The ordering of the 8 items from most to least challenging makes clinical sense and compares favorably with other published hierarchies of NBF. Tactile items are more easily responded to. Visual and auditory items requiring higher cognitive processing were more challenging. In the full sample, the CNC achieved good measurement precision, with a person separation reliability of 0.87.

CONCLUSIONS

The items of the CNC reflect good construct validity and acceptable interrater reliability. The measurement precision achieved indicates that the CNC may be used to make decisions about groups of individuals but that these items may not be sufficiently precise for individual patient treatment decision-making.

Assessing pain in critically ill brain-injured patients: a psychometric comparison of 3 pain scales and videopupillometry

Three clinical scales (the Nociception Coma Scale adapted for Intubated patients [NCS-I], its Revised version [NCS-R-I], and the Behavioral Pain Scale [BPS]) and videopupillometry were compared for measuring pain in intubated, noncommunicating, critically ill, brain-injured patients. Pain assessment was performed before, during, just after, and 5 minutes after 3 procedures: the reference non-nociceptive procedure (assessment of the Richmond Agitation Sedation Scale) and 2 nociceptive procedures (turning and tracheal suctioning). The primary endpoint was construct validity (discriminant and criterion validation), determined by comparing pain measurements between different times/procedures. Secondary endpoints were internal consistency, inter-rater reliability, and feasibility. Fifty patients (54% women, median age 63 years [56-68]) were included 13 [7-24] days after brain injury (76% hemorrhagic or ischemic strokes). All tools increased significantly more (P < 0.001) during the nociceptive procedures vs the non-nociceptive procedure. The BPS was the only pain tool that did not increase significantly during the non-nociceptive procedure (P = 0.41), suggesting that it was the most discriminant tool. The BPS, NCS-I, and NCS-R-I were good predictors of nociception with areas under the curves ≥0.96, contrary to videopupillometry (area under the curve = 0.67). The BPS, NCS-I, and NCS-I-R had high inter-rater reliabilities (weighted kappa = 0.86, 0.82 and 0.84, respectively). Internal consistency was moderate (>0.60) for all pain scales. Factor analysis represented a majority of information on a first dimension, with motor domains represented on a second dimension. Scale feasibility was better for the NCS-I and NCS-R-I than for the BPS. In conclusion, the BPS, NCS-I, and NCS-R-I are valid, reliable, and acceptable pain scales for use in intubated critically ill, brain-injured patients, unlike videopupillometry. Future research requires tool design centered on domains of observation adapted to this very specific population.

Evaluating the validity, reliability and clinical utility of the Music therapy Sensory Instrument for Cognition, Consciousness and Awareness (MuSICCA): protocol of a validation study

INTRODUCTION

A growing number of children and young people are surviving severe acquired brain injuries due to advances in healthcare. However, many fail to emerge from coma and continue to live with disorders of consciousness (DOC). Diagnostic, clinical and ethical challenges are prominent in this group. Misdiagnosis can have severe consequences for children and their families, including inadequate care, insufficient access to rehabilitation and stimulation, reduced accessibility to services and inappropriately limited opportunities for participation. The proposed project will develop and validate a diagnostic measure that supports detailed goal-planning-the Music therapy Sensory Instrument for Cognition, Consciousness and Awareness (MuSICCA).

METHODS AND ANALYSIS

Face validity will be assessed using a short questionnaire and the MuSICCA will be amended if face validity is insufficient. Once face validity is sufficient, 80 participants with suspected DOC will be recruited from multiple sites around the UK, USA and Ireland.Validity will be assessed using external reference standards (Coma Recovery Scale-Revised, Coma Near-Coma Scale and Nociception Coma Scale). Intra-rater reliability will be established using repeated ratings of video recordings from the assessment sessions. Inter-rater reliability will be assessed through video ratings by a second blinded assessor. In addition to these analyses, the clinical utility of the MuSICCA will be evaluated using a questionnaire to be completed by clinicians and relatives of the participants following the completion of the MuSICCA assessment.

ETHICS AND DISSEMINATION

Ethical approval has been obtained for this study from the Research Ethics Committee and Health Research Authority of the National Health Service of the UK (ID: 167534). Results will be presented at national and international conferences, published in scientific journals and disseminated to participant representatives, clinicians, educators and care providers.

TRIAL REGISTRATION DETAILS

This study was registered at ClinicalTrials.gov Protocol Registration and Results System on 7^th August 2019 (ID: NCT04050995); Pre-results.

A study of the reliability and validity of the Chinese version of the Nociception Coma Scale–Revised

Objective:

The aim of the study was to check on the reliability and validity of the translated version of Nociception Coma Scale–Revised.

Design:

Prospective psychometric study.

Setting:

Rehabilitation and neurology unit in hospital.

Subjects:

Patients with prolonged disorders of consciousness.

Interventions:

None.

Main measures:

The original English version of the Nociception Coma Scale–Revised was translated into Chinese. The reliability and validity were undertaken by trained raters. Intraclass correlation coefficients were used to assess inter-rater reliability and test–retest reliability. Cronbach’s alpha test was used to investigate internal consistency. Spearman’s correlation was used to calculate concurrent validity. The Coma Recovery Scale–revised was used to assess the consciousness of patients.

Results:

Eighty-four patients were enrolled in the study. Inter-rater reliability of the Chinese version of Nociception Coma Scale–Revised was high for total scores and motor and verbal subscores and good for facial subscores. Test–retest reliability was high for total score and for all subscores. Analysis revealed a moderate internal consistency for subscores. For the concurrent validity, a strong correlation was found between the Nociception Coma Scale–Revised and the Face, Legs, Activity, Cry, and Consolability behavioral scale for all patients. A moderate correlation was found between the Nociception Coma Scale–Revised and the Coma Recovery Scale–revised scores for all patients.

Conclusion:

The Chinese version of Nociception Coma Scale–Revised has good reliability and validity data for assessing responses to pain in patients with prolonged disorders of consciousness.

Update on diagnosis in disorders of consciousness

INTRODUCTION

New guidelines regarding the diagnosis of disorders of consciousness (DOC) (such as vegetative state and minimally conscious state) have recently been published by the American Academy of Neurology and the European Academy of Neurology. This follows an impressive number of prospective studies performed on DOC and recent multi-centric studies with larger sample size, which have gathered precious information on the recovery of cohort of patients through years and which now call for a better management of patients with DOC.

AREAS COVERED

This review will discuss recent updates on the clinical entities of DOC, the challenges for an accurate diagnosis and the last developments in diagnostic tools.

EXPERT OPINION

The authors will also discuss the impact of the new guidelines on their way of diagnosing patients and how diagnosis will most likely change in a near future.

A Psychometric Analysis Update of Behavioral Pain Assessment Tools for Noncommunicative, Critically Ill Adults

This is an updated, comprehensive review of the psychometric properties of behavioral pain assessment tools for use with noncommunicative, critically ill adults. Articles were searched in 5 health databases. A total of 106 articles were analyzed, including 54 recently published papers. Nine behavioral pain assessment tools developed for noncommunicative critically ill adults and 4 tools developed for other non-communicative populations were included. The scale development process, reliability, validity, feasibility, and clinical utility were analyzed using a 0 to 20 scoring system, and quality of evidence was also evaluated. The Behavioral Pain Scale, the Behavioral Pain Scale-Nonintubated, and the Critical-Care Pain Observation Tool remain the tools with the strongest psychometric properties, with validation testing having been conducted in multiple countries and various languages. Other tools may be good alternatives, but additional research on them is necessary.

The Trace Conditional Learning of the Noxious Stimulus in UWS Patients and Its Prognostic Value in a GSR and HRV Entropy Study

The assessment of the consciousness level of Unresponsive Wakefulness Syndrome (UWS) patients often depends on a subjective interpretation of the observed spontaneous and volitional behavior. To date, the misdiagnosis level is around 30%. The aim of this study was to observe the behavior of UWS patients, during the administration of noxious stimulation by a Trace Conditioning protocol, assessed by the Galvanic Skin Response (GSR) and Heart Rate Variability (HRV) entropy. We recruited 13 Healthy Control (HC) and 30 UWS patients at 31 ± 9 days from the acute event evaluated by Coma Recovery Scale–Revised (CRS-R) and Nociception Coma Scale (NCS). Two different stimuli [musical stimulus (MUS) and nociceptive stimulus (NOC)], preceded, respectively by two different tones, were administered following the sequences (A) MUS1 – NOC1 – MUS2 – MUS3 – NOC2 – MUS4 – NOC3 – NOC^*, and (B) MUS1^*, NOC1^*, NOC2^*, MUS2^*, NOC3^*, MUS3^*, NOC4^*, MUS4^*. All the (^*) indicate the only tones administration. CRS-R and NCS assessments were repeated for three consecutive weeks. MUS4, NOC3, and NOC^* were compared for GSR wave peak magnitude, time to reach the peak, and time of wave's decay by Wilcoxon's test to assess the Conditioned Response (CR). The Sample Entropy (SampEn) was recorded in baseline and both sequences. Machine Learning approach was used to identify a rule to discriminate the CR. The GSR magnitude of CR was higher comparing music stimulus (p < 0.0001) and CR extinction (p < 0.002) in nine patients and in HC. Patients with CR showed a higher SampEn in sequence A compared to patients without CR. Within the third and fourth weeks from protocol administration, eight of the nine patients (88.9%) evolved into MCS. The Machine-learning showed a high performance to differentiate presence/absence of CR (≥95%). The possibility to observe the CR to the noxious stimulus, by means of the GSR and SampEn, can represent a potential method to reduce the misdiagnosis in UWS patients.

European Academy of Neurology guideline on the diagnosis of coma and other disorders of consciousness

BACKGROUND AND PURPOSE

Patients with acquired brain injury and acute or prolonged disorders of consciousness (DoC) are challenging. Evidence to support diagnostic decisions on coma and other DoC is limited but accumulating. This guideline provides the state-of-the-art evidence regarding the diagnosis of DoC, summarizing data from bedside examination techniques, functional neuroimaging and electroencephalography (EEG).

METHODS

Sixteen members of the European Academy of Neurology (EAN) Scientific Panel on Coma and Chronic Disorders of Consciousness, representing 10 European countries, reviewed the scientific evidence for the evaluation of coma and other DoC using standard bibliographic measures. Recommendations followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The guideline was endorsed by the EAN.

RESULTS

Besides a comprehensive neurological examination, the following suggestions are made: probe for voluntary eye movements using a mirror; repeat clinical assessments in the subacute and chronic setting, using the Coma Recovery Scale - Revised; use the Full Outline of Unresponsiveness score instead of the Glasgow Coma Scale in the acute setting; obtain clinical standard EEG; search for sleep patterns on EEG, particularly rapid eye movement sleep and slow-wave sleep; and, whenever feasible, consider positron emission tomography, resting state functional magnetic resonance imaging (fMRI), active fMRI or EEG paradigms and quantitative analysis of high-density EEG to complement behavioral assessment in patients without command following at the bedside.

CONCLUSIONS

Standardized clinical evaluation, EEG-based techniques and functional neuroimaging should be integrated for multimodal evaluation of patients with DoC. The state of consciousness should be classified according to the highest level revealed by any of these three approaches.

Autonomic Cardiac Reactivity to Painful Procedures Under Hypnosis in Pediatric Emergencies: A Feasibility Study

Pain sensation is characterized by abrupt changes in central nervous system activity producing autonomic reactivity. While clinical hypnosis has demonstrated its benefits for children in pain management, it is not clear whether hypnosis modulated autonomic pain response in children in clinical conditions. Here, we studied autonomic responses under hypnosis to sutures in pediatric emergencies. For that, 42 children (mean age: 6.5 years, range 1.5 to 13) were divided into two groups consecutively (hypnosis and control groups), according to their choice. Time-frequency analysis was applied on RR intervals (heart rate interbeat intervals, or RRI) to estimate parasympathetic reactivity based on high frequency power (HF) and the Analgesia Nociception Index (ANI®) and on sympathetic reactivity (low frequency power [LF]) and LF/HF ratio). We observed that RRI and LF/HF ratio varied according to suture and hypnosis (p < 0.05): RRI was higher and LF/HF ratio was lower during sutures in the hypnosis group in comparison to the control group whereas HF and ANI® increased only during hypnosis. To conclude, hypnosis in pediatric emergencies reduces sympathetic cardiac pain reactivity and could be a marker of pain relief under hypnosis, while parasympathetic activity seems to be a better marker of hypnosis.

Can the Nociception Coma Scale-Revised Be Used in Patients With a Tracheostomy?

OBJECTIVE

To investigate the influence of the presence of a tracheostomy tube to assess pain with the Nociception Coma Scale-Revised (NCS-R) in patients with disorders of consciousness (DOC).

DESIGN

A cohort study in which patients were evaluated at a single time point.

SETTING

Patients were evaluated in a tertiary care hospital.

PARTICIPANTS

Patients (N=125) (unresponsive wakefulness syndrome [UWS]: 46 patients, minimally conscious state [MCS]: 74 patients, emerging from MCS [eMCS]: 5 patients, mean age: 46±16y, time since injury: 817±1280d) in a convenience sample were evaluated with the NCS-R after noxious stimulation.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We compared the NCS-R scores of patients with and without tracheostomy with a Mann-Whitney U test. A secondary outcome was to evaluate the influence of the presence of a tracheostomy on the previously described cutoff score of 2.

RESULTS

The presence of a tracheostomy was associated with lower verbal subscores (P=.002) as well as total scores (P=.039). The cutoff score of 2 remained valid for the group of patients with tracheostomy with a high sensitivity (71.43%) and specificity (89.29%), as well as when we excluded the verbal subscore of the NCS-R (sensitivity=83.2% and specificity=92.4%).

CONCLUSION

Our study confirms the validity of the NCS-R in DOC patients with a tracheostomy. However, the presence of a nonspeaking tracheostomy should be clearly mentioned when applying the NCS-R, because it significantly lowers the verbal subscore.

Narrative review of acute post-craniotomy pain. Concept and strategies for prevention and treatment of pain

The aim of this narrative review is to confirm that acute pain after craniotomy is frequent and presents with moderate to severe intensity. We also highlight the importance of not only treating post-craniotomy pain, but also of preventing it in order to reduce the incidence of chronic pain. Physicians should be aware that conventional postoperative analgesics (non-steroidal anti-inflammatory, paracetamol, cyclooxygenase inhibitors 2, opioids) are not the only options available. Performing a scalp block prior to surgical incision or after surgery, the use of intraoperative dexmedetomidine, and the perioperative administration of pregabalin are just some alternatives that are gaining ground. The management of post-craniotomy pain should be based on perioperative multimodal analgesia in the framework of an "enhaced recovery after surgery" (ERAS) approach.

Evidence for decreased Neurologic Pain Signature activation following thoracic spinal manipulation in healthy volunteers and participants with neck pain

•

The use of brain-based models of pain were explored in two clinical studies.

•

Neurologic pain signature activation decreased following spinal manipulation.

•

Spinal manipulation altered the processing of pain-related brain activity.

•

We provide evidence for a centrally mediated therapeutic action of spinal manipulation.

•

Brain-based models have potential as objective clinical biomarkers of pain.

Background Context

Spinal manipulation (SM) is a common treatment for neck and back pain, theorized to mechanically affect the spine leading to therapeutic mechanical changes. The link between specific mechanical effects and clinical improvement is not well supported. SM's therapeutic action may instead be partially mediated within the central nervous system.

Purpose

To introduce brain-based models of pain for spinal pain and manual therapy research, characterize the distributed central mechanisms of SM, and advance the preliminary validation of brain-based models as potential clinical biomarkers of pain.

Study Design

Secondary analysis of two functional magnetic resonance imaging studies investigating the effect of thoracic SM on pain-related brain activity: A non-controlled, non-blinded study in healthy volunteers (Study 1, n = 10, 5 females, and mean age = 31.2 ± 10.0 years) and a randomized controlled study in participants with acute to subacute neck pain (Study 2, n = 24, 16 females, mean age = 38.0 ± 15.1 years).

Methods

Functional magnetic resonance imaging was performed during noxious mechanical stimulation of the right index finger cuticle pre- and post-intervention. The effect of SM on pain-related activity was studied within brain regions defined by the Neurologic Pain Signature (NPS) that are predictive of physical pain.

Results

In Study 1, evoked mechanical pain (p < 0.001) and NPS activation (p = 0.010) decreased following SM, and the changes in evoked pain and NPS activation were correlated (r_RM² = 0.418, p = 0.016). Activation within the NPS subregions of the dorsal anterior cingulate cortex (dACC, p = 0.012) and right secondary somatosensory cortex/operculum (rS2_Op, p = 0.045) also decreased following SM, and evoked pain was correlated with dACC activity (r_RM² = 0.477, p = 0.019). In Study 2, neck pain (p = 0.046) and NPS (p = 0.033) activation decreased following verum but not sham SM. Associations between evoked pain, neck pain, and NPS activation, were not significant and less clear, possibly due to inadequate power, methodological limitations, or other confounding factors.

Conclusions

The findings provide preliminary evidence that SM may alter the processing of pain-related brain activity within specific pain-related brain regions and support the use of brain-based models as clinical biomarkers of pain.