Assessment of command-following in minimally conscious brain injured patients

Special Considerations in Behavioral Assessments for Disorders of Consciousness

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

Emergence from Disorders of Consciousness: Optimizing Self-Agency Through Communication

Language and communication deficits are intrinsic to disorders of consciousness. This article will provide an overview of language and communication deficits that can significantly confound the accuracy of diagnostic assessment in these patients. Authors will also discuss interventions to promote early communication using assistive technology and augmentative communication rehabilitation strategies. Finally, this article will discuss the importance of family education as well as ethical considerations connected to the recovery of communication and adaptive strategies to support patient autonomy and enhance self-agency.

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.

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.

Neuropsychological assessment through Coma Recovery Scale-Revised and Coma/Near Coma Scale in a sample of pediatric patients with disorder of consciousness

BACKGROUND

The Coma Recovery Scale-Revised (CRS-R) has become a standard tool in assessing Disorders of consciousness (DoC) in adults. However, its measurement validity in pediatrics has only been ascertained in healthy cases. Increasing use of CRS-R in children with DoC imposes appropriate comparison against previously validated tools. The aims of the study were to describe the emergence to a conscious state (eMCS) in pediatric acquired brain injury (ABI); to explore the agreement between the CRS-R and Coma Near Coma Scale (CNCS) and to discuss the advantage of administering the CRS-R in pediatric age.

MATERIALS AND METHODS

In this observational prospective study, 40 patients were recruited. Inclusion criteria were age 5 to 18 years, Glasgow Coma Scale (GCS) score ≤ 8 at the insult, and unresponsive wakefulness syndrome (UWS) or minimally conscious state (MCS) at admission. Patients were assessed with CRS-R, and CNCS was used as standard.

RESULTS

The agreement between scales was moderate (r = - 0.71). The analysis of the CRS-R domain scores also confirmed that decreasing CNCS levels (from a coma to eMCS) corresponded to concurrent increas of CRS-R scores in all domains. Moreover, CRS-R better defined patients' status in the emergency phase from MCS. Conversely, CRS-R had lower DoC scoring ability in the presence of severe motor impairment.

CONCLUSION

We show that CRS-R can track changes in DoC in children as young as 5 years old, and we provide evidence that the agreement with CNCS scores is good.

The role of the Neuropsychologist across the stages of recovery from acquired brain injury: a summary from the pediatric rehabilitation Neuropsychology collaborative

Neuropsychologists working in a pediatric neurorehabilitation setting provide care for children and adolescents with acquired brain injuries (ABI) and play a vital role on the interdisciplinary treatment team. This role draws on influences from the field of clinical neuropsychology and its pediatric subspecialty, as well as rehabilitation psychology. This combination of specialties is uniquely suited for working with ABI across the continuum of recovery. ABI recovery often involves a changing picture that spans across stages of recovery (e.g., disorders of consciousness, confusional state, acute cognitive impairment), where each stage presents with distinctive characteristics that warrant a specific evidence-based approach. Assessment and intervention are used reciprocally to inform diagnostics, treatment, and academic planning, and to support patient and family adjustment. Neuropsychologists work with the interdisciplinary teams to collect and integrate data related to brain injury recovery and use this data for treatment planning and clinical decision making. These approaches must often be adapted and adjusted in real time as patients recover, demanding a dynamic expertise that is currently not supported through formal training curriculum or practice guidelines. This paper outlines the roles and responsibilities of pediatric rehabilitation neuropsychologists across the stages of ABI recovery with the goal of increasing awareness in order to continue to develop and formalize this role.

Enhancing management of agitation after traumatic brain injury: Psychiatric perspectives and quantitative assessments

BACKGROUND

Post-traumatic agitation is a common and problematic complication after traumatic brain injury. It may present with features consistent with psychiatric disorders, which may provide clues as to management.

OBJECTIVE

This is a narrative review of pertinent literature and a description of a collaborative clinical approach utilizing psychiatric and brain injury rehabilitation strategies to optimize outcomes in the management of post-traumatic agitation.

METHODS

Describe and provide evidence for a transdisciplinary clinical approach supported by existing literature and clinical experience.

RESULTS

Given the heterogeneity of the problem and limitations in the current literature there is no standardized approach to manage post-traumatic agitation; nevertheless, a strategy is proposed that clinicians may utilize to guide treatment and assess efficacy of the chosen intervention(s).

CONCLUSION

A clinical approach that uses quantitative assessment of targeted behavior to objectively evaluate pharmacological interventions that are generated by a collaborative approach may yield improved outcomes for managing post-traumatic agitation.

Time to Follow Commands in Severe Traumatic Brain Injury Survivors With Favorable Recovery at 2 Years

BACKGROUND

The recovery of severe traumatic brain injury (TBI) survivors with long-term favorable outlook is understudied. Time to follow commands varies widely in this patient population but has important clinical implications.

OBJECTIVE

To (1) evaluate time to follow commands in severe patients with TBI with favorable outcomes, (2) characterize their trajectory of recovery, and (3) identify predictors associated with delayed cognitive improvement.

METHODS

Participants were recruited prospectively at a Level I trauma center through the Brain Trauma Research Center from 2003 to 2018. Inclusion criteria were age 16 to 80 years, Glasgow Coma Scale score ≤8 and motor score <6, and Glasgow Outcome Scale-Extended measure ≥4 at 2 years postinjury.

RESULTS

In 580 patients, there were 229 (39.5%) deaths and 140 (24.1%) patients had favorable outcomes at 2 years. The mean age was 33.7 ± 14.5 years, median Glasgow Coma Scale was 7 (IQR 6-7), and median Injury Severity Score was 30 (IQR 26-38). The mean time to follow commands was 12.7 ± 11.8 days. On multivariable linear regression, the presence of diffuse axonal injury (B = 9.2 days [4.8, 13.7], P < .0001) or intraventricular hemorrhage (B = 6.4 days [0.5, 12.3], P < .035) was associated with longer time before following commands and patients who developed nosocomial infections (B = 6.5 days [1.6-11.4], P < .01).

CONCLUSION

In severe TBI survivors with favorable outcomes, time to follow commands varied widely. Most patients began to follow commands within 2 weeks. Evidence of diffuse axonal injury, intraventricular hemorrhage, and infections can delay cognitive improvement in the acute period. Patients make considerable recovery up to 2 years after their injury.

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.

Language Assessment in Patients with Disorders of Consciousness

The assessment of residual language abilities in patients with disorders of consciousness (DoC) after severe brain injury is particularly challenging due to their limited behavioral repertoire. Moreover, associated language impairment such as receptive aphasia may lead to an underestimation of actual consciousness levels. In this review, we examine past research on the assessment of residual language processing in DoC patients, and we discuss currently available tools for identifying language-specific abilities and their prognostic value. We first highlight the need for validated and sensitive bedside behavioral assessment tools for residual language abilities in DoC patients. As regards neuroimaging and electrophysiological methods, the tasks involving higher level linguistic commands appear to be the most informative about level of consciousness and have the best prognostic value. Neuroimaging methods should be combined with the most appropriate behavioral tools in multimodal assessment protocols to assess receptive language abilities in DoC patients in the most complete and sensitive manner.

Behavioral Assessment of Patients With Disorders of Consciousness

SUMMARY

Brain injury resulting in coma may evolve into a prolonged disorder of consciousness, including the vegetative and minimally conscious states. Early detection of emerging consciousness has positive prognostic significance, and improvement in consciousness at any point may indicate the potential for meaningful communication and environmental control. Despite the importance of accurate assessment of consciousness, research indicates that as many as 40% of patients with a disorder of consciousness may be assessed incorrectly. Assessment of consciousness is challenging for many reasons, including the fact that consciousness cannot be measured directly but must be inferred from patterns of behavioral activity, that many patients have confounding deficits and treatments that may mask consciousness, and that patient performance may be highly variable over time. In this manuscript, we discuss strategies for optimizing patient status during assessment and review a number of structured assessment approaches that can be used. The available assessment techniques vary in their length and cost, and the expertise required to use them. Which of these approaches is most applicable to a given acute or subacute setting will vary with the volume of patients with a disorder of consciousness and the available resources. Importantly, lack of consciousness in the acute setting should not be used to justify the withdrawal of care or denial of rehabilitation services.

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.

Minimum Competency Recommendations for Programs That Provide Rehabilitation Services for Persons With Disorders of Consciousness: A Position Statement of the American Congress of Rehabilitation Medicine and the National Institute on Disability, Independent Living and Rehabilitation Research Traumatic Brain Injury Model Systems

Persons who have disorders of consciousness (DoC) require care from multidisciplinary teams with specialized training and expertise in management of the complex needs of this clinical population. The recent promulgation of practice guidelines for patients with prolonged DoC by the American Academy of Neurology, American Congress of Rehabilitation Medicine (ACRM), and National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) represents a major advance in the development of care standards in this area of brain injury rehabilitation. Implementation of these practice guidelines requires explication of the minimum competencies of clinical programs providing services to persons who have DoC. The Brain Injury Interdisciplinary Special Interest Group of the ACRM, in collaboration with the Disorders of Consciousness Special Interest Group of the NIDILRR-Traumatic Brain Injury Model Systems convened a multidisciplinary panel of experts to address this need through the present position statement. Content area-specific workgroups reviewed relevant peer-reviewed literature and drafted recommendations which were then evaluated by the expert panel using a modified Delphi voting process. The process yielded 21 recommendations on the structure and process of essential services required for effective DoC-focused rehabilitation, organized into 4 categories: diagnostic and prognostic assessment (4 recommendations), treatment (11 recommendations), transitioning care/long-term care needs (5 recommendations), and management of ethical issues (1 recommendation). With few exceptions, these recommendations focus on infrastructure requirements and operating procedures for the provision of DoC-focused neurorehabilitation services across subacute and postacute settings.

Which behaviours are first to emerge during recovery of consciousness after severe brain injury?

BACKGROUND

Early detection of consciousness after severe brain injury is critical for establishing an accurate prognosis and planning appropriate treatment.

OBJECTIVES

To determine which behavioural signs of consciousness emerge first and to estimate the time course to recovery of consciousness in patients with severe acquired brain injury.

METHODS

Retrospective observational study using the Coma Recovery Scale-Revised and days to recovery of consciousness in 79 patients (51 males; 34 with traumatic brain injury; median [IQR] age 48 [26-61] years; median time since injury 26 [20-36] days) who transitioned from coma or unresponsive wakefulness syndrome (UWS)/vegetative state (VS) to the minimally conscious state (MCS) or emerged from MCS during inpatient rehabilitation.

RESULTS

Visual pursuit was the most common initial sign of MCS (41% of patients; 95% CI [30-52]), followed by reproducible command-following (25% [16-35]) and automatic movements (24% [15-33]). Ten other behaviours emerged first in less than 16% of cases. Median [IQR] time to recovery of consciousness was 44 [33-59] days. Etiology did not significantly affect time to recovered consciousness.

CONCLUSION

Recovery of consciousness after severe brain injury is most often signalled by reemergence of visual pursuit, reproducible command-following and automatic movements. Clinicians should use assessment measures that are sensitive to these behaviours because early detection of consciousness is critical for accurate prognostication and treatment planning.

Challenges and demand for modeling disorders of consciousness following traumatic brain injury

Following severe traumatic brain injury (TBI), many patients experience coma - an unresponsive state lacking wakefulness or awareness. Coma rarely lasts more than two weeks, and emergence involves passing through a state of wakefulness without awareness of self or environment. Patients that linger in these Disorders of Consciousness (DoC) undergo clinical assessments of awareness for diagnosis into Unresponsive Wakefulness Syndrome (no awareness, also called vegetative state) or Minimally Conscious State (periodic increases in awareness). These diagnoses are notoriously inaccurate, offering little prognostic value. Recovery of awareness is unpredictable, returning within weeks, years, or never. This leaves patients' families with difficult decisions and little information on which to base them. Clinical studies have made significant advancements, but remain encumbered by high variability, limited data output, and a lack of necessary controls. Herein we discuss the clear and present need to establish a preclinical model of TBI-induced DoC, the significant challenges involved, and how such a model can be applied to support DoC research.

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

OBJECTIVE

To update the 1995 American Academy of Neurology (AAN) practice parameter on persistent vegetative state and the 2002 case definition on minimally conscious state (MCS) and provide care recommendations for patients with prolonged disorders of consciousness (DoC).

METHODS

Recommendations were based on systematic review evidence, related evidence, care principles, and inferences using a modified Delphi consensus process according to the AAN 2011 process manual, as amended.

RECOMMENDATIONS

Clinicians should identify and treat confounding conditions, optimize arousal, and perform serial standardized assessments to improve diagnostic accuracy in adults and children with prolonged DoC (Level B). Clinicians should counsel families that for adults, MCS (vs vegetative state [VS]/unresponsive wakefulness syndrome [UWS]) and traumatic (vs nontraumatic) etiology are associated with more favorable outcomes (Level B). When prognosis is poor, long-term care must be discussed (Level A), acknowledging that prognosis is not universally poor (Level B). Structural MRI, SPECT, and the Coma Recovery Scale-Revised can assist prognostication in adults (Level B); no tests are shown to improve prognostic accuracy in children. Pain always should be assessed and treated (Level B) and evidence supporting treatment approaches discussed (Level B). Clinicians should prescribe amantadine (100-200 mg bid) for adults with traumatic VS/UWS or MCS (4-16 weeks post injury) to hasten functional recovery and reduce disability early in recovery (Level B). Family counseling concerning children should acknowledge that natural history of recovery, prognosis, and treatment are not established (Level B). Recent evidence indicates that the term chronic VS/UWS should replace permanent VS, with duration specified (Level B). Additional recommendations are included.

Practice Guideline Update Recommendations Summary: Disorders of Consciousness: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology; the American Congress of Rehabilitation Medicine; and the National Institute on Disability, Independent Living, and Rehabilitation Research

OBJECTIVE

To update the 1995 American Academy of Neurology (AAN) practice parameter on persistent vegetative state and the 2002 case definition on minimally conscious state (MCS) and provide care recommendations for patients with prolonged disorders of consciousness (DoC).

METHODS

Recommendations were based on systematic review evidence, related evidence, care principles, and inferences using a modified Delphi consensus process according to the AAN 2011 process manual, as amended.

RECOMMENDATIONS

Clinicians should identify and treat confounding conditions, optimize arousal, and perform serial standardized assessments to improve diagnostic accuracy in adults and children with prolonged DoC (Level B). Clinicians should counsel families that for adults, MCS (vs vegetative state [VS]/ unresponsive wakefulness syndrome [UWS]) and traumatic (vs nontraumatic) etiology are associated with more favorable outcomes (Level B). When prognosis is poor, long-term care must be discussed (Level A), acknowledging that prognosis is not universally poor (Level B). Structural MRI, SPECT, and the Coma Recovery Scale-Revised can assist prognostication in adults (Level B); no tests are shown to improve prognostic accuracy in children. Pain always should be assessed and treated (Level B) and evidence supporting treatment approaches discussed (Level B). Clinicians should prescribe amantadine (100-200 mg bid) for adults with traumatic VS/UWS or MCS (4-16 weeks post injury) to hasten functional recovery and reduce disability early in recovery (Level B). Family counseling concerning children should acknowledge that natural history of recovery, prognosis, and treatment are not established (Level B). Recent evidence indicates that the term chronic VS/UWS should replace permanent VS, with duration specified (Level B). Additional recommendations are included.

Detecting early recovery of consciousness: a comparison of methods

Early detection of the return of consciousness has important implications for prognosis and rehabilitation access. The aim of this study was to compare the Coma Recovery Scale-Revised (CRS-R) with individualised quantitative behavioural assessments (IQBA) to determine which method is capable of detecting command-following earlier and more consistently in persons with disorders of consciousness (DoC). Data from 27 patients with DoC, who underwent both assessments concurrently during inpatient rehabilitation, were retrospectively analysed. For each person, performance trajectories on the CRS-R auditory subscale item and IQBA dual command protocols were graphed together to identify earlier and more consistent evidence of consciousness; grouped data were analysed statistically. For 22 patients, IQBA more consistently documented consciousness than the CRS-R, whereas no patients showed the reverse pattern. For 14 of 20 analysable patients, IQBA provided earlier evidence of consciousness, for two patients CRS-R provided earlier evidence, and for four patients both methods provided initial evidence on the same day. These findings suggest that IQBA approaches can provide more consistent and earlier evidence of command-following than the comparable item on the CRS-R. Whether this advantage is due to the individualisation of IQBA or the greater volume of data gathered requires further research.

Evaluation of the effectiveness of transcranial direct current stimulation (tDCS) and psychosensory stimulation through DOCS scale in a minimally conscious subject

The aim of our study was to assess the effectiveness of transcranial direct current stimulation (tDCS) on alertness improvement in a patient in a minimally conscious state (MCS) by means of disorders of consciousness scale combined with psycho-sensory stimulation. The effects of tDCS on muscle hypertonia through the Ashworth scale were also examined. tDCS was performed through a two-channel intra-cephalic stimulator. After stimulation, the patient followed a psychosensory stimulation training. Results pointed out an increase in DOCunit score, as well as an increase in alertness maintenance and an improvement in muscle hypertonia, although a MCS state persisted.

Clinical management of the minimally conscious state

The minimally conscious state (MCS) was defined as a disorder of consciousness (DoC) distinct from the vegetative state more than a decade ago. While this condition has become widely recognized, there are still no guidelines to steer the approach to assessment and treatment. The development of evidence-based practice guidelines for MCS has been hampered by ambiguity around the concept of consciousness, the lack of accurate methods of assessment, and the dearth of well-designed clinical trials. This chapter provides a critical review of existing assessment procedures, critically reviews available treatment options and identifies knowledge gaps. We close with practice-based recommendations for a rational approach to clinical management of this challenging population.

Measuring consciousness in severely damaged brains

Significant advances have been made in the behavioral assessment and clinical management of disorders of consciousness (DOC). In addition, functional neuroimaging paradigms are now available to help assess consciousness levels in this challenging patient population. The success of these neuroimaging approaches as diagnostic markers is, however, intrinsically linked to understanding the relationships between consciousness and the brain. In this context, a combined theoretical approach to neuroimaging studies is needed. The promise of such theoretically based markers is illustrated by recent findings that used a perturbational approach to assess the levels of consciousness. Further research on the contents of consciousness in DOC is also needed.

Disorders of consciousness after acquired brain injury: the state of the science

The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest.

Responsiveness of Instruments to Assess Disorders of Consciousness: A Literature Review

Objectives: To summarise available evidence for responsiveness of six key assessments used with patients with disorders of consciousness: Coma Recovery Scale – Revised (CRS-R), Disorders Of Consciousness Scale (DOCS), Sensory Modality Assessment and Rehabilitation Technique (SMART), Sensory Stimulation Assessment Measure (SSAM), Wessex Head Injury Matrix (WHIM), and the Western Neuro Sensory Stimulation Profile (WNSSP).

Method: A literature search of five electronic databases was conducted using a systematic search strategy. Relevant literature was evaluated and pertinent information extracted.

Results: Database searches using key terms initially yielded 132 articles. Following review for inclusion identified 24 articles. No studies were specifically designed to investigate responsiveness of any of the measures and therefore responsiveness data were either based on statistical significance of change post-treatment or descriptive analysis of change scores. The majority of studies identified used the CRS-R (n= 11), WHIM (n= 5) and WNSSP (n= 6) and have established responsiveness to change. There is some preliminary evidence for the responsiveness of the other measures, based on very few available studies: DOCS (n= 2), SMART (n= 1) or SSAM (n= 1).

Conclusion: Future studies should seek to include responsiveness analysis, particularly in relation to the DOCS, SMART and SSAM.

Disorders of consciousness: responding to requests for novel diagnostic and therapeutic interventions

Severe brain injury can leave patients with chronic disorders of consciousness. Because of impaired responsiveness, many of these patients have traditionally been regarded as unaware. However, findings from recent clinical studies herald a potential paradigm shift: functional imaging and neurophysiological studies have identified ways to assess awareness and have revealed astounding cases of awareness despite clinical unresponsiveness. Hence, diagnostic classifications have been rewritten, prognostic knowledge is improving, and therapeutic studies have regained momentum, showing for the first time some therapeutic effects on responsiveness. Clinicians must increasingly respond to requests by patients' families and surrogate decision makers to use novel techniques for diagnosis, prognosis, and treatment, and in doing so several ethical and social issues need to be considered. Such requests provide an opportunity for clinicians to learn about patients' values and preferences and to maintain clinical acumen for changes in patient status with the patients' best interests in mind.

Is there anybody in there? Detecting awareness in disorders of consciousness

The bedside detection of awareness in disorders of consciousness (DOC) caused by acquired brain injury is not an easy task. For this reason, differential diagnosis using neuroimaging and electrophysiological tools in search for objective markers of consciousness is being employed. However, such tools cannot be considered as diagnostic per se, but as assistants to the clinical evaluation, which, at present, remains the gold standard. Regarding therapeutic management in DOC, no evidence-based recommendations can be made in favor of a specific treatment. The present review summarizes clinical and paraclinical studies that have been conducted with neuroimaging and electrophysiological techniques in search of residual awareness in DOC. We discuss the medical, scientific and ethical implications that derive from these studies and we argue that, in the future, the role of neuroimaging and electrophysiology will be important not only for the diagnosis and prognosis of DOC but also in establishing communication with these challenging patients.

Natural history of recovery from brain injury after prolonged disorders of consciousness: outcome of patients admitted to inpatient rehabilitation with 1-4 year follow-up

The natural history of recovery from brain injury typically consists of a period of impaired consciousness, a subsequent period of confusion and amnesia, followed by a period of post-confusional recovery of function. Patients with more severe injuries may have more prolonged episodes of unconsciousness or minimal consciousness and may not fully evolve through this continuum of recovery. There is limited information on the course of recovery and long-term outcome of patients with prolonged unconsciousness, particularly those with extended periods in the minimally conscious state. Further, patients with impaired consciousness are frequently denied access to hospital-based rehabilitation services because of uncertain prognosis and a perceived lack of benefit from rehabilitative interventions.

METHODS

A consecutive series of 36 patients with traumatic (TBI) and non-traumatic brain injury (nonTBI) in a vegetative state (VS) or minimally conscious state (MCS) on admission to a specialized, slow-to-recover brain injury program in an acute rehabilitation hospital was retrospectively reviewed to evaluate course of recovery during rehabilitation hospitalization and in follow-up, 1-4 years post-injury. Independent variables included: time to resolution of VS, MCS and confusional state/posttraumatic amnesia (CS/PTA), based on Aspen criteria, Coma Recovery Scale-Revised (CRS-R) and Galveston Orientation and Amnesia Test (GOAT) scores. Outcome measures (calculated separately for TBI, nonTBI, VS, or MCS on admission subgroups) included: proportion of patients who recover and recovery time to MCS, CS/PTA stages, household independence, and return to school or work, as well as Disability Rating Scale (DRS) scores at 1, 2, 3, and 4 years post-injury.

RESULTS

The majority emerged from MCS (72%) and CS/PTA (58%) by latest follow-up. It took significantly longer for patients admitted in VS (means: MCS, 16.43 weeks; CS/PTA, 30.1 weeks) than MCS (means: MCS, 7.36 weeks; CS/PTA, 11.5 weeks) to reach both milestones. Almost all who failed to clear CS/PTA by latest follow-up were patients with nonTBI or TBI with VS lasting over 8 weeks. Duration of MCS was a strong predictor of duration CS/PTA after emergence from MCS, accounting for 57% of the variance. Nearly half the patients followed at least 1 year achieved recovery to, at least, daytime independence at home and 22% returned to work or school, 17% at or near pre-injury levels. Discharge FIM score or duration of MCS, along with age, were best predictors of DRS in outcome models. DRS scores continued to improve after 2 and 3 years post-injury.

CONCLUSIONS

Patients in VS whose transition to MCS occurred within 8 weeks of onset are likely to continue recovering to higher levels of functioning, a substantial proportion to household independence, and productive pursuits. Patients with TBI are more likely to progress than patients with nonTBI, though significant improvement in the nonTBI group is still possible. Active, higher intensity, rehabilitation should be strongly considered for patients with severely impaired consciousness after brain injury, especially for patients with TBI who have signs of progression to the MCS.

Recent advances in behavioral assessment of individuals with disorders of consciousness

PURPOSE OF REVIEW

The burden of proof for establishing diagnosis and prognosis in patients with disorders of consciousness lies with behavioral assessment methods. The current review discusses recent advances in understanding the strengths and weaknesses of this methodology.

RECENT FINDINGS

Behavioral assessment methods remain the 'gold standard' for establishing diagnosis and prognosis in patients with disorders of consciousness, although their psychometric integrity and clinical utility remain largely unproven. While the Glasgow Coma Scale maintains its standing in the trauma setting, there are ongoing concerns regarding testing confounds and interrater reliability. The Full Outline of UnResponsiveness, an emerging alternative, is more sensitive to detection of locked-in syndrome but may fail to identify patients in the minimally conscious state. Recent studies investigating the relationship between behavioral and neurophysiologic measures of conscious awareness have revealed important dissociations between behavioral response profiles and corresponding neural activity.

SUMMARY

Further research is needed on the psychometric properties of existing behavioral assessment methods for disorders of consciousness. Although dissociations between behavioral and neurophysiologic findings caution against overreliance on behavioral metrics for detection of conscious awareness, we expect there will be increased effort toward combining these methodologies to increase diagnostic accuracy and prognostic specificity in patients with disorders of consciousness.

The effects of methylphenidate on command following and yes/no communication in persons with severe disorders of consciousness: a meta-analysis of n-of-1 studies

OBJECTIVE

To determine the effects of methylphenidate (MPH) on command following and yes/no communication in brain injured patients with severe disorders of consciousness (DOC).

DESIGN

A meta-analysis of a series of single-subject repeated crossover trials, using doses ranging from 7.5 to 25 mg (median dose: 10 mg), generally given twice a day. A Wilcoxon signed ranks test was performed, comparing mean responsiveness and accuracy by drug condition. Drug effect sizes were calculated for the full group and for participant subgroups of interest.

RESULTS

No significant effect of MPH was seen on either responsiveness or on accuracy in the whole group. None of the patient subgroups examined showed a substantial drug effect size.

CONCLUSIONS

This study did not identify a clinically meaningful effect of MPH in the doses used on responsiveness or accuracy in standardized command-following protocols in the overall study group of patients with severe DOC, or in any subgroup that was assessed. Because MPH has been shown to have some positive effects in higher-level patients with TBI, more research is needed to define the types of individuals with TBI who do and do not benefit from this drug, and/or the dose that provides optimal benefit.

Information processing in severe disorders of consciousness: Vegetative state and minimally conscious state

OBJECTIVE

To study the presence of electrophysiological indicators of remaining cortical functions in patients with persistent vegetative state (PVS) and minimally conscious state (MCS). Previous electrophysiological and PET data indicated that some PVS patients have partially intact cortical processing functions. However, it remains unclear whether the reported patients were representative for PVS population or just some exceptional cases.

METHODS

Event-related brain responses to stimuli of different complexity levels, recorded in 98 patients with extremely severe diffuse brain injuries, 50 of which in PVS. Four main indicators of cortical functions were: (i) N1-P2 complex as an index of simple, undifferentiated cortical processing; (ii) mismatch negativity as an index of pre-attentive, probably unconscious, cortical orientation; (iii) P3 wave as an index of deep cortical analysis of physical stimuli, and (iv) brain responses to semantic stimuli.

RESULTS

Cortical responses were found in all PVS patients with a background EEG activity > 4 Hz. All responses investigated, including those to semantic stimuli that indicated comprehension of meaning, occurred significantly above chance, though less frequently than in patients with severe brain injuries who were conscious.

CONCLUSIONS

Cortical responses were lacking in most patients with severe EEG slowing (< 4 Hz). Follow-up data revealed that the presence of a mismatch negativity, a short disease duration, and the traumatic etiology were related to a better outcome.

SIGNIFICANCE

The data show that in a subpopulation of PVS patients with preserved thalamocortical feedback connections, remaining cortical information processing is a consistent finding and may even involve semantic levels of processing.

The vegetative state: Promoting greater clarity and improved treatment

The condition commonly referred to as the persistent vegetative state (PVS) or vegetative state (VS) generates tremendous confusion among health care professionals. Muddled and nihilistic views of very severe brain injury have hampered efforts to improve the diagnosis and treatment of patients thought to be in the VS. Significant obstacles to diagnostic clarity arise from multiple sources including imprecise terminology and conflation of the concepts of "behaviour" and "awareness". Failure to employ effective, uniform protocols of assessment and rehabilitation contributes to inadequate treatment of these extremely vulnerable patients. Despite diagnostic and prognostic difficulties, courts across the globe have accepted medical opinion as persuasive evidence for life-support withdrawal. A new outlook on severe brain injury is needed, with greater clarity and standardisation of assessment and care. Best practices in assessment and rehabilitation must be incorporated along with new developments in cognitive neuroscience and neuroimaging. Such a rehabilitative view will encourage intellectual curiosity towards improved quality of care for patients with severe brain injury. Attaining high levels of accuracy depends upon reaching a clearer understanding of the nature of human consciousness itself, of the condition, and of the patient's potential for full or partial recovery.

The vegetative and minimally conscious states: current knowledge and remaining questions

In the last 2 decades, the minimally conscious state has been distinguished conceptually from the vegetative state and operational criteria for these diagnoses have been published. Standardized and individualized assessment tools have been developed to assist with the diagnosis of severe disorders of consciousness and the measurement of clinical improvement. The natural course of recovery and the importance of key prognostic predictors have been elucidated. Important advances have also been made in defining the similarities and differences in the pathophysiology of these two states, and functional imaging modalities have begun to explicate the neural substrate underlying the behavioral features of these disorders. Research on the efficacy of treatments for severe disorders of consciousness lags behind, due to the practical and ethical difficulties in executing large rigorously controlled clinical trials. The past and future scientific developments in this area provide an important background for continuing discussions of the ethical controversies surrounding end-of-life decision making and resource allocation.

Predictors of outcome in prolonged posttraumatic disorders of consciousness and assessment of medication effects: A multicenter study

OBJECTIVES

To develop predictive models of recovery from the vegetative state (VS) and minimally conscious state (MCS) after traumatic brain injury (TBI) and to gather preliminary evidence on the impact of various psychotropic medications on the recovery process to support future randomized controlled trials. Design Longitudinal observational cohort design, in which demographic information, injury and acute care history, neuroimaging data, and an initial Disability Rating Scale (DRS) score were collected at the time of study enrollment. Weekly follow-up data, consisting of DRS score, current psychoactive medications, and medical complications, were gathered until discharge from inpatient rehabilitation.

SETTING

Seven acute inpatient rehabilitation facilities in the United States and Europe with specialized programs for treating patients in the VS and MCS.

PARTICIPANTS

People with TBI (N=124) who were in the VS or MCS 4 to 16 weeks after injury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

DRS score at 16 weeks after injury and time until commands were first followed (among those participants demonstrating no command following at study enrollment). Results DRS score at enrollment, time between injury and enrollment, and rate of DRS change during the first 2 weeks of poststudy observation were all highly predictive of both outcomes. No variables related to injury characteristics or lesions on neuroimaging were significant predictors. Of the psychoactive medications, amantadine hydrochloride was associated with greater recovery and dantrolene sodium was associated with less recovery, in terms of the DRS score at 16 weeks but not the time until commands were followed. More detailed analysis of the timing of functional improvement, with respect to the initiation of amantadine provided suggestive, but not definitive, evidence of the drug's causal role.

CONCLUSIONS

These findings show the feasibility of improving outcome prediction from the VS and MCS using readily available clinical variables and provide suggestive evidence for the effects of amantadine and dantrolene, but these results require confirmation through randomized controlled trials.

Psychobiology of altered states of consciousness

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.

The JFK Coma Recovery Scale-Revised: measurement characteristics and diagnostic utility

OBJECTIVE

To determine the measurement properties and diagnostic utility of the JFK Coma Recovery Scale-Revised (CRS-R).

DESIGN

Analysis of interrater and test-retest reliability, internal consistency, concurrent validity, and diagnostic accuracy.

SETTING

Acute inpatient brain injury rehabilitation hospital.

PARTICIPANTS

Convenience sample of 80 patients with severe acquired brain injury admitted to an inpatient Coma Intervention Program with a diagnosis of either vegetative state (VS) or minimally conscious state (MCS).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The CRS-R, the JFK Coma Recovery Scale (CRS), and the Disability Rating Scale (DRS).

RESULTS

Interrater and test-retest reliability were high for CRS-R total scores. Subscale analysis showed moderate to high interrater and test-retest agreement although systematic differences in scoring were noted on the visual and oromotor/verbal subscales. CRS-R total scores correlated significantly with total scores on the CRS and DRS indicating acceptable concurrent validity. The CRS-R was able to distinguish 10 patients in an MCS who were otherwise misclassified as in a VS by the DRS.

CONCLUSIONS

The CRS-R can be administered reliably by trained examiners and repeated measurements yield stable estimates of patient status. CRS-R subscale scores demonstrated good agreement across raters and ratings but should be used cautiously because some scores were underrepresented in the current study. The CRS-R appears capable of differentiating patients in an MCS from those in a VS.

The minimally conscious state: defining the borders of consciousness

There is no agreement as to where the limits of consciousness lie, or even if these putative borders exist. Problems inherent to the study of consciousness continue to confound efforts to establish a universally accepted theory of consciousness. Consequently, clinical definitions of consciousness and unconsciousness are unavoidably arbitrary. Recently, a condition of severely altered consciousness has been described, which characterizes the borderzone between the vegetative state and so-called "normal" consciousness. This condition, referred to as the minimally conscious state (MCS), is distinguished from the vegetative state by the presence of minimal but clearly discernible behavioral evidence of self or environmental awareness. This chapter reviews the diagnostic criteria, pathophysiology, prognostic relevance, neurobehavioral assessment procedures and treatment implications associated with MCS.

Behavioral evaluation of consciousness in severe brain damage

This paper reviews the current state of bedside behavioral assessment in brain-damaged patients with impaired consciousness (coma, vegetative state, minimally conscious state). As misdiagnosis in this field is unfortunately very frequent, we first discuss a number of fundamental principles of clinical evaluation that should guide the assessment of consciousness in brain-damaged patients in order to avoid confusion between vegetative state and minimally conscious state. The role of standardized behavioral assessment tools is particularly stressed. The second part of this paper reviews existing behavioral assessment techniques of consciousness, showing that there are actually a large number of these scales. After a discussion of the most widely used scale, the Glasgow Coma Scale, we present several new promising tools that show higher sensitivity and reliability for detecting subtle signs of recovery of consciousness in the post-acute setting.

Life expectancy of children in vegetative and minimally conscious states

We determined estimates of survival in children, 3-15 years of age, in the vegetative state (VS) (n = 564), immobile minimally conscious state (MCS) (n = 705), and mobile MCS (n = 3,806). Data were extracted from the annual Client Development Evaluation Reports of the California Department of Developmental Services between 1988 and 1997 using the operational definitions for these three states on the basis of 15 descriptive behavioral categories. Patients were also categorized according to the following four etiologies: acquired (traumatic and nontraumatic) brain injury; perinatal/genetic; degenerative; and unknown/undetermined. The percentage of patients surviving 8 years was 63%, 65%, and 81%, for the VS, immobile MCS, and mobile MCS, respectively. Children in the VS and MCSs with acquired brain injury had lower mortality rates and those with degenerative diseases the highest mortality rates. We observed little difference in survival between patients in the VS and immobile MCS, suggesting that the presence of consciousness is not a critical variable in determining life expectancy. Furthermore, survival was much greater for patients in the mobile MCS than for those in the immobile MCS, suggesting that mobility is more important in predicting survival than the level of consciousness.