Misdiagnosing the vegetative state after severe brain injury: the influence of medication

Prognosis and enhancement of recovery in disorders of consciousness

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

Unexpected emergence from the vegetative state: delayed discovery rather than late recovery of consciousness

BACKGROUND

The vegetative state, also known as the unresponsive wakefulness syndrome, is one of the worst possible outcomes of acquired brain injury and confronts rehabilitation specialists with various challenges. Emergence to (minimal) consciousness is classically considered unlikely beyond 3-6 months after non-traumatic or 12 months after traumatic etiologies. A growing body of evidence suggests that these timeframes are too narrow, but evidence regarding chances of recovery is still limited.

OBJECTIVE

To identify the moment of recovery of consciousness in documented cases of late emergence from a vegetative state.

METHODS

Four cases of apparent late recovery of consciousness, identified within a prospective cohort study, were studied in-depth by analyzing medical, paramedical and nursing files and interviewing the patients' families about their account of the process of recovery.

RESULTS

All patients were found to have shown signs of consciousness well within the expected time frame (5 weeks-2 months post-ictus). These behaviors, however, went unnoticed or were misinterpreted, leading to a diagnostic delay of several months to over 5 years. Absence of appropriate diagnostics, the use of erroneous terminology, sedative medication but also patient-related factors such as hydrocephalus, language barriers and performance fluctuations are hypothesized to have contributed to the delay.

CONCLUSIONS

Delayed recognition of signs of consciousness in patients in a vegetative state may not only lead to suboptimal clinical care, but also to distorted prognostic figures. Discriminating late recovery from the delayed discovery of consciousness, therefore, is vital to both clinical practice and science.

Evidence-based position paper on Physical and Rehabilitation Medicine professional practice for Adults with Acquired Brain Injury. The European PRM position (UEMS PRM Section)

BACKGROUND

Acquired brain injury (ABI) is damage to the brain that occurs after birth caused either by a traumatic or by a nontraumatic injury. The rehabilitation process following ABI should be performed by a multi-professional team, working in an interdisciplinary way, with the aim of organizing a comprehensive and holistic approach to persons with every severity of ABI. This Evidence Based Position Paper represents the official position of the European Union through the UEMS Physical and Rehabilitation Medicine (PRM) Section and designates the professional role of PRM physicians for people with ABI. The aim was to formulate recommendations on the PRM physician's professional practice for persons with ABI in order to promote their functioning and enhance quality of life.

METHODS

This paper has been developed according to the methodology defined by the Professional Practice Committee of the UEMS-PRM Section: a systematic literature search has been performed in PubMed and Core Clinical Journals. On the basis of the selected papers, recommendations have been made as a result of five Delphi rounds.

RESULTS

The literature review as well as thirty-one recommendations are presented.

CONCLUSIONS

The expert consensus is that structured, comprehensive and holistic rehabilitation program delivered by the multi-professional team, working in an interdisciplinary way, with the leadership and coordination of the PRM physician, is likely to be effective, especially for those with severe disability after brain injury.

Neurotechnological assessment of consciousness disorders: five ethical imperatives

Disorders of consciousness (DOCs) cause great human suffering and material costs for society. Understanding of these disorders has advanced remarkably in recent years, but uncertainty remains with respect to the diagnostic criteria and standards of care. One of the most serious problems concerns misdiagnoses, their impact on medical decision-making, and on patients' well-being. Recent studies use neurotechnology to assess residual consciousness in DOC patients that traditional behavioral diagnostic criteria are unable to detect. The results show an urgent need to strengthen the development of new diagnostic tools and more refined diagnostic criteria. If residual consciousness may be inferred from robust and reproducible results from neurotechnological communication with DOC patients, this also raises ethical challenges. With reference to the moral notions of beneficence and fundamental rights, five ethical imperatives are here suggested in terms of diagnosis, communication, interpretation of subjective states, adaptation of living conditions, and care.

Will time heal? A long-term follow-up of severe disorders of consciousness

Objective

Little is known about the long-term outcome of patients with disorders of consciousness (DOCs) such as unresponsive wakefulness syndrome (UWS) or minimally conscious state (MCS). We describe the disease course of a large group of DOC patients 2–14 years after brain damage.

Methods

In 102 patients (59 UWS, 43 MCS), clinical and demographic variables from disorder onset were related to the patients' outcomes 2–14 years after discharge. Etiology, age at event, time since onset, gender, and home care versus institutional care were assessed as predictors and similarities and differences between UWS and MCS determined.

Results

Seventy-one percent of the patients had passed away or showed no improvement in condition. Twenty-nine percent regained consciousness and developed some communicative capacities. The time a syndrome persisted did not predict clinical outcome in either condition. Six patients regained consciousness after more than 3 years. Of these, five had been UWS (42% of recovered UWS, three traumatic origins, one tumor, one hypoxia) and one MCS (5% of recovered MCS, traumatic origin). In UWS, younger patients, those cared for at home, and in tendency those with traumatic origins, were more likely to recover. In MCS, no reliable outcome predictors were found.

Interpretation

Current predictors are too vague for single patient predictions. This study identifies a subgroup of late-recovering patients, casting doubt on the 12-month boundary, after which UWS is stated to be permanent. Routine reexamination, use of more reliable outcome predictors and research determining optimal care settings are needed to inform the crucial decisions made for these patients.

N400 predicts recovery from disorders of consciousness

OBJECTIVE

Patients with the unresponsive wakefulness syndrome (UWS; formerly vegetative state) or in a minimally conscious state (MCS) open their eyes spontaneously but show no (UWS) or only marginal (MCS) signs of awareness. Because these states can become permanent, residual information processing capacities need to be determined, and reliable outcome predictors need to be found. We assessed higher-order cortical information processing in UWS or MCS in a large group of patients using electroencephalographic event-related potentials (ERPs) and determined their long-term prognostic value for recovery.

METHODS

Cognitive ERPs elicited by sound (P300) and speech (N400) were used to assess information processing in 92 behaviorally unresponsive patients diagnosed as in the state of either UWS (n=53) or MCS (n=39). ERPs were assessed with a clinical standard evaluation method and a computerized method, the t-continuous wavelet transform. The patients' clinical outcome was followed up between 2 and 14 years after discharge from the rehabilitation center.

RESULTS

Within the first year of the disease, many patients showed an intact P300 and several also an N400, indicating considerable residual information processing. At clinical follow-up, about 25% of the patients recovered and regained communicative capabilities. A highly significant relationship between N400, but not P300, presence and subsequent recovery was found.

INTERPRETATION

Results specify cognitive capabilities in disorders of consciousness, and determine their prognostic value. Specifically the N400 ERP is suggested as an important tool to assess information-processing capacities that can predict the likelihood of recovery of patients in UWS or MCS.

Increased levels of serum MAP-2 at 6-months correlate with improved outcome in survivors of severe traumatic brain injury

OBJECTIVE

To evaluate microtubule-associated proteins (MAP-2), a dendritic marker of both acute damage and chronic neuronal regeneration after injury, in serum of survivors after severe TBI and examine the association with long-term outcome.

METHODS

Serum concentrations of MAP-2 were evaluated in 16 patients with severe TBI (Glasgow Coma Scale score [GCS] ≤ 8) 6 months post-injury and in 16 controls. Physical and cognitive outcomes were assessed, using the Glasgow Outcome Scale Extended (GOSE) and Levels of Cognitive Functioning Scale (LCFS), respectively.

RESULTS

Severe TBI patients had significantly higher serum MAP-2 concentrations than normal controls with no history of TBI (p = 0.008) at 6 months post-injury. MAP-2 levels correlated with the GOSE (r = 0.58, p = 0.02) and LCFS (r = 0.65, p = 0.007) at month 6. Significantly lower serum levels of MAP-2 were observed in patients in a vegetative state (VS) compared to non-VS patients (p < 0.05). A trend tracking the level of consciousness was observed.

CONCLUSIONS

Severe TBI results in a chronic release of MAP-2 into the peripheral circulation in patients with higher levels of consciousness, suggesting that remodelling of synaptic junctions and neuroplasticity processes occur several months after injury. The data indicate MAP-2 as a potential marker for emergence to higher levels of cognitive function.

Chronic consciousness disorders

Although philosophers and cognitive neuroscientists have struggled to define human consciousness, physicians can identify and assess its two clinical dimensions: wakefulness and awareness. A comatose patient has neither wakefulness nor awareness; a patient in a vegetative state has wakefulness without awareness; and a minimally conscious patient has both, but awareness is impaired. Syndromes of unconsciousness have established diagnostic criteria, but they encompass a spectrum of severity of brain damage and have indistinct boundaries. Functional neuroimaging using PET and fMRI have provided a new and complementary way to assess consciousness. Several recent provocative studies suggest that fMRI in unresponsive patients may detect evidence of conscious awareness when a careful neurological examination cannot. If these findings are verified by future studies, functional neuroimaging technologies will alter clinical practices concerning the diagnosis, classification, and prognosis of unconscious patients, and will lead to a greater understanding of the biology of human consciousness.

Guidelines for Quality Management of Apallic Syndrome / Vegetative State

INTRODUCTION

Epidemiology in Europe shows constantly increasing figures for the apallic syndrome (AS)/vegetative state (VS) as a consequence of advanced rescue, emergency services, intensive care treatment after acute brain damage and high-standard activating home nursing for completely dependent end-stage cases secondary to progressive neurological disease. Management of patients in irreversible permanent AS/VS has been the subject of sustained scientific and moral-legal debate over the past decade.

METHODS

A task force on guidelines for quality management of AS/VS was set up under the auspices of the Scientific Panel Neurotraumatology of the European Federation of Neurological Societies to address key issues relating to AS/VS prevalence and quality management. Collection and analysis of scientific data on class II (III) evidence from the literature and recommendations based on the best practice as resulting from the task force members' expertise are in accordance with EFNS Guidance regulations.

FINDINGS

The overall incidence of new AS/VS full stage cases all etiology is 0.5-2/100.000 population per year. About one third are traumatic and two thirds non traumatic cases. Increasing figures for hypoxic brain damage and progressive neurological disease have been noticed. The main conceptual criticism is based on the assessment and diagnosis of all different AS/VS stages based solely on behavioural findings without knowing the exact or uniform pathogenesis or neuropathological findings and the uncertainty of clinical assessment due to varying inclusion criteria. No special diagnostics, no specific medical management can be recommended for class II or III AS treatment and rehabilitation. This is why sine qua non diagnostics of the clinical features and appropriate treatment of AS/VS patients of "AS full, remission, defect and end stages" require further professional training and expertise for doctors and rehabilitation personnel.

INTERPRETATION

Management of AS aims at the social reintegration of patients or has to guarantee humanistic active nursing if treatment fails. Outcome depends on the cause and duration of AS/VS as well as patient's age. There is no single AS/VS specific laboratory investigation, no specific regimen or stimulating intervention to be recommended for improving higher cerebral functioning. Quality management requires at least 3 years of advanced training and permanent education to gain approval of qualification for AS/VS treatment and expertise. Sine qua non areas covering AS/VS institutions for early and long-term rehabilitation are required on a population base (prevalence of 2/100.000/year) to quicken functional restoration and to prevent or treat complications. Caring homes are needed for respectful humane nursing including basal sensor-motor stimulating techniques. Passive euthanasia is considered an act of mercy by physicians in terms of withholding treatment; however, ethical and legal issues with regard to withdrawal of nutrition and hydration and end of life discussions raise deep concerns. The aim of the guideline is to provide management guidance (on the best medical evidence class II and III or task force expertise) for neurologists, neurosurgeons, other physicians working with AS/VS patients, neurorehabilitation personnel, patients, next-of-kin, and health authorities.

Neurorehabilitation issues in states of disordered consciousness following traumatic brain injury

The assessment and care of persons with disorders of consciousness (DOC) following catastrophic traumatic brain injury is often difficult and filled with both challenges and potential controversies. Rates of misdiagnosis of low-level neurological state (LLNS) patients with signs of awareness as being vegetative have been noted to be unacceptably high and call for better education and training regarding the assessment methodologies of individuals with DOC. Clinician knowledge regarding prognostication and neural recovery from LLNSs following traumatic brain injury is often lacking, as is awareness of the neurorehabilitative interventions that can potentially facilitate recovery, as well as minimize morbidity and mortality in this unique population of neurological patients.

Chronic disorders of consciousness

The vegetative state and the minimally conscious state are disorders of consciousness that can be acute and reversible or chronic and irreversible. Diffuse lesions of the thalami, cortical neurons, or the white-matter tracts that connect them cause the vegetative state, which is wakefulness without awareness. Functional imaging with PET and functional MRI shows activation of primary cortical areas with stimulation, but not of secondary areas or distributed neural networks that would indicate awareness. Vegetative state has a poor prognosis for recovery of awareness when present for more than a year in traumatic cases and for 3 months in non-traumatic cases. Patients in minimally conscious state are poorly responsive to stimuli, but show intermittent awareness behaviours. Indeed, findings of preliminary functional imaging studies suggest that some patients could have substantially intact awareness. The outcomes of minimally conscious state are variable. Stimulation treatments have been disappointing in vegetative state but occasionally improve minimally conscious state. Treatment decisions for patients in vegetative state or minimally conscious state should follow established ethical and legal principles and accepted practice guidelines of professional medical specialty societies.

Residual cognitive function in comatose, vegetative and minimally conscious states

PURPOSE OF REVIEW

The clinical evaluation of cognition in non-communicative severely brain-damaged patients is inherently difficult. In addition to novel behavioural 'consciousness-scales', the role of para-clinical markers of consciousness, such as event related potentials and functional neuroimaging is reviewed.

RECENT FINDINGS

New behavioural scales for vegetative and minimally conscious patients have been shown to reduce diagnostic error but regrettably remain underused in clinical routine. Electrophysiological studies have confirmed their role in estimating outcome and possibly cognition. Several recent functional neuroimaging studies have shown residual cortical function in undeniably vegetative patients. This cortical activation, however, seems limited to primary 'low-level' areas and does not imply 'higher-order' integration, considered necessary for conscious perception. Minimally conscious patients show large-scale high-order cerebral activation, apparently dependent upon the emotional relevance of the stimulation.

SUMMARY

Careful clinical assessment of putative 'conscious behaviour' in vegetative and minimally conscious patients is the first requirement for their proper diagnosis and management. Complementary functional neuroimaging and electrophysiological studies will have a major impact on future clinical decision making and may guide selective therapeutic options. At present, more experimental evidence and the elucidation of methodological and ethical controversies are awaited prior to their routine clinical use.

Clinical diagnosis of prolonged states of impaired consciousness in adults

A prolonged state of impaired consciousness is a devastating consequence of severe structural brain injury but fortunately is uncommon. Patients may be diagnosed as being in a persistent vegetative state, having akinetic mutism, or being in a minimally conscious state. These conditions can be distinguished from each other by a comprehensive clinical neurologic examination. Recovery is determined by age, cause, and time in such state. For patients diagnosed as being in a permanent (irreversible) vegetative state, hope for a clinically meaningful recovery is unrealistic after 1 year. Prolonged survival is possible only with meticulous care and aggressive medical intervention to prevent and treat systemic complications.

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.

Vegetative and minimally conscious states: Serial assessment approaches in diagnosis and management

Assessment of vegetative (VS) and minimally conscious state (MCS) patients presents clinicians with inherent difficulties (Royal College of Physicians, 2003) in terms of the reliable detection of potential signs of awareness given that all current assessment tools rely on observed behaviour. Recently developed measures such as SMART (Gill-Thwaites & Munday, 1999) and WHIM (Shiel et al., 2000), employing structured operational defined behavioural observations can facilitate the serial assessment of patient awareness, progress and appropriate goal setting particularly as one-off bedside assessments are more likely to be inaccurate. The use of sensitive tailored approaches involving experienced multidisciplinary teams is strongly advocated (Royal College of Physicians and British Society of Rehabilitation Medicine, 2003), notwithstanding clinicians should carefully consider potential confounding clinical factors, which may deleteriously influence patient arousal or ability to respond. Finally, areas for future development and recommendations regarding multidisciplinary assessment approaches with VS and MCS patients are outlined.

Incidence and prevalence of the vegetative and minimally conscious states

The methodological difficulties of obtaining accurate epidemiological data for vegetative state (VS) and minimally conscious state (MCS) are considered, and prompt the conclusion that published data are of uncertain validity, partly due to variation in the criteria for diagnosis. On the basis of these data, incidence of VS continuing for at least six months arises at a rate of between 5 and 25 per million population (PMP). The prevalence of VS in adults in the US is between 40 and 168 PMP, and may be lower in the UK, but precise figures are not available. The incidence and prevalence of MCS have yet to be established.