Awareness In Disorders Of Consciousness Research Articles

Precise detection of awareness in disorders of consciousness using deep learning framework

Diagnosis of disorders of consciousness (DOC) remains a formidable challenge. Deep learning methods have been widely applied in general neurological and psychiatry disorders, while limited in DOC domain. Considering the successful use of resting-state functional MRI (rs-fMRI) for evaluating patients with DOC, this study seeks to explore the conjunction of deep learning techniques and rs-fMRI in precisely detecting awareness in DOC. We initiated our research with a benchmark dataset comprising 140 participants, including 76 unresponsive wakefulness syndrome (UWS), 25 minimally conscious state (MCS), and 39 Controls, from three independent sites. We developed a cascade 3D EfficientNet-B3-based deep learning framework tailored for discriminating MCS from UWS patients, referred to as “DeepDOC”, and compared its performance against five state-of-the-art machine learning models. We also included an independent dataset consists of 11 DOC patients to test whether our model could identify patients with cognitive motor dissociation (CMD), in which DOC patients were behaviorally diagnosed unconscious but could be detected conscious by brain computer interface (BCI) method. Our results demonstrate that DeepDOC outperforms the five machine learning models, achieving an area under curve (AUC) value of 0.927 and accuracy of 0.861 for distinguishing MCS from UWS patients. More importantly, DeepDOC excels in CMD identification, achieving an AUC of 1 and accuracy of 0.909. Using gradient-weighted class activation mapping algorithm, we found that the posterior cortex, encompassing the visual cortex, posterior middle temporal gyrus, posterior cingulate cortex, precuneus, and cerebellum, as making a more substantial contribution to classification compared to other brain regions. This research offers a convenient and accurate method for detecting covert awareness in patients with MCS and CMD using rs-fMRI data.

Diagnosing awareness in disorders of consciousness with gamma-band auditory responses.

The prolonged disorders of consciousness (pDOC) describe a group of neurological conditions characterized by severe impairment of consciousness resulting from the injury of the central nervous system. As the behavioral diagnosis of pDOC remains challenging, the methods based on observing brain activity appear as promising alternatives. One of these methods is electroencephalography, which allows for noninvasive assessment of brain function. In this study, we evaluated evoked auditory responses to the chirp-modulated auditory stimulation as a potential biomarker of awareness in pDOC. Chirp-modulated stimulation is based on the repetitive presentation of auditory stimuli with a changing frequency over time. Two protocols were tested: amplitude-modulated narrow-band chirps (frequency range 25-55 Hz) and click-based wide-band chirps (30-100 Hz). The studied pDOC patient group included 62 patients (19 females and 43 males, mean age 40.72 years) diagnosed with Coma Recovery Scale-Revised. Envelope-following responses to stimulation were examined using the intertrial phase clustering coefficient. For both types of stimulation, the strength of the response in the low-gamma range (around 40 Hz) was related to the diagnosis of pDOC. Patients diagnosed with unresponsive wakefulness syndrome exhibited diminished responses, while more favorable diagnoses, suggesting awareness (minimally conscious state or emergence from the minimally conscious state), showed elevated responses. The variations in the integrity of the auditory pathway and the etiology of brain injury altered the observed response strength. Narrow-band stimulation yielded a more systematic relationship between low-gamma response and pDOC diagnosis. The results suggest the potential role of low gamma-band responses to chirp-modulated stimulation as the supportive diagnostic tool to detect awareness in the pDOC patient group.

Validation of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness With the Coma Recovery Scale-Revised

ObjectiveTo examine (1) the concurrent validity of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) with the criterion standard Coma Recovery Scale-Revised (CRS-R) for outcomes of awareness in patients with prolonged disorders of consciousness (PDoC), (2) the relationship between MATADOC items and CRS-R function subscales in similar domains, and (3) determine if items/function subscales measure different constructs. DesignA prospective multicentric blinded study with repeated concurrent measures. SettingThree inpatient rehabilitation units. ParticipantsConvenience sample of 74 adults with PDoC (N=74). Main Outcome MeasuresThe MATADOC protocol elicits behavioral responsiveness using live music in 5 tasks. A total score ranges 0-10 scoring behaviors across 14-items. The CRS-R uses a language-based protocol and scores observed responses ranging from 0-23 in 6 function subscales. Both measures were delivered at 4 concurrent time points over 2 weeks. ResultsFair (κ=0.238, P=.006) ranging to moderate (κ=0.419, P<.001) significant agreement was found between CRS-R and MATADOC diagnostic outcomes. Fair-borderline moderate significant agreement was found for overall diagnostic outcomes across all diagnostic categories (κ=0.397, P=.001). There was moderate significant agreement between measures for motor scores (0.551≤κ≤0.571, P<.001) and visual outcomes (0.192≤κ≤0.415, .001≤P<.005) but no agreement for item/function subscale outcomes assessing auditory responsiveness. Exploratory factor analysis of all items showed 2 factors, suggesting that MATADOC and CRS-R measure the same underlying latent variable (awareness) in different ways and could complement each other for diagnosis and intervention purposes. This was supported by scale analysis, which showed increased reliability when the 2 scales are used together rather than separately. ConclusionsUnlike the CRS-R, the music-based MATADOC scores auditory localization for complexity of response and categorizes these behaviors as conscious rather than reflexive. The MATADOC may supplement the CRS-R, having a particular role in interdisciplinary programming for providing a more robust assessment of auditory responsiveness because of using nonverbal musical stimuli.

Machine learning and network analysis for diagnosis and prediction in disorders of consciousness

BackgroundProlonged Disorders of Consciousness (PDOC) resulting from severe acquired brain injury can lead to complex disabilities that make diagnosis challenging. The role of machine learning (ML) in diagnosing PDOC states and identifying intervention strategies is relatively under-explored, having focused on predicting mortality and poor outcome. This study aims to: (a) apply ML techniques to predict PDOC diagnostic states from variables obtained from two non-invasive neurobehavior assessment tools; and (b) apply network analysis for guiding possible intervention strategies.MethodsThe Coma Recovery Scale-Revised (CRS-R) is a well-established tool for assessing patients with PDOC. More recently, music has been found to be a useful medium for assessment of coma patients, leading to the standardization of a music-based assessment of awareness: Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC). CRS-R and MATADOC data were collected from 74 PDOC patients aged 16–70 years at three specialist centers in the USA, UK and Ireland. The data were analyzed by three ML techniques (neural networks, decision trees and cluster analysis) as well as modelled through system-level network analysis.ResultsPDOC diagnostic state can be predicted to a relatively high level of accuracy that sets a benchmark for future ML analysis using neurobehavioral data only. The outcomes of this study may also have implications for understanding the role of music therapy in interdisciplinary rehabilitation to help patients move from one coma state to another.ConclusionsThis study has shown how ML can derive rules for diagnosis of PDOC with data from two neurobehavioral tools without the need to harvest large clinical and imaging datasets. Network analysis using the measures obtained from these two non-invasive tools provides novel, system-level ways of interpreting possible transitions between PDOC states, leading to possible use in novel, next-generation decision-support systems for PDOC.

Validation of Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) with CRS-R

<h3>Research Objectives</h3> To examine the concurrent validity of the MATADOC with the criterion standard Coma Recovery Scale (CRS-R) for diagnostic outcomes of awareness To explore the function of comparable MATADOC items and CRS-R function scales across similar domains (e.g. auditory, visual). <h3>Design</h3> Prospective multisite cohort study collected concurrent MATADOC and CRS-R data using repeated measures with patients with disorders of consciousness (DOC). Raters were blinded. <h3>Setting</h3> Three specialist inpatient rehabilitation units for DOC (US, UK, Ireland). <h3>Participants</h3> 74 adults with prolonged DOC stemming from acquired brain injury recruited using convenience sampling. <h3>Interventions</h3> The MATADOC protocol elicits behavioral responsiveness using live music in five tasks during four clinical contacts of 15-30 minutes duration (60-120 mins total). Observed behavioral responses are rated across motor, communication, arousal, visual and auditory domains using a 14-item measure. Pre and post observation period records spontaneous behaviors. The CRS-R protocol delivers tasks in the motor, visual, auditory and communication domains in clinical contacts of 15-30 minutes duration (60 – 120 minutes in total for 4 contacts). Observed responses are rated in six function scales. <h3>Main Outcome Measures</h3> Two measures of awareness: MATADOC and CRS-R. <h3>Results</h3> Fair (Cohen's kappa or "k"=0.238, p=.006) ranging to moderate (k=0.419, p<.001) significant agreement found between CRS-R and MATADOC diagnostic outcomes for each contact, with significant correlations between scores (mean Pearson = 0.721, p<.001). Agreement increased over repeated contacts. Moderate agreement found for overall diagnostic outcomes ranging across VS, MCS and EMCS (k=0.397, p<.001). Moderate significant agreement found between measures for motor scores (k=.556, p<.001) and visual outcomes (mean k=0.326). No agreement was found for item outcomes assessing auditory responsiveness. <h3>Conclusions</h3> The MATADOC complements the CRS-R in treatment planning for DOC. MATADOC measures of auditory responsiveness suggest musical stimuli may elicit more complex behaviors than non-music protocols. The MATADOC rates complexity of auditory localization as MCS in line with recent recommendations which may explain diagnostic outcome differences with CRS-R outcomes. <h3>Author(s) Disclosures</h3> None.

Exploring the Clinical Utility of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) with People with End-Stage Dementia.

Dementia is a major health concern globally and cross-culturally with progressive decline in cognition, mobility and communication. There are few interventions for end-stage dementia (ESD) although music interventions have been observed to be accessible for people with mid to late-stage dementia. The lack of protocols and measures suited to ESD has limited research into the effects of music therapy. Measure sensitivity to minimal responsiveness is one limitation to the use of existing music intervention measures with ESD. This exploratory study examined the clinical utility of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) for use with people with end-stage dementia, including preliminary reliability and validity. The MATADOC is a standardized assessment for minimally responsive patients with disorders of consciousness and may be useful for ESD. Using repeated measures with blinded MATADOC-trained raters, MATADOC data were collected with a small convenience sample of people with ESD in a residential care setting. Clinical utility data were collected from the raters and evaluated using a multidimensional model. To explore its functionality, MATADOC outcomes were compared to another measure for music interventions in dementia. The MATADOC may be useful for assessing functioning and responsiveness to music interventions for people with ESD without the risk of floor effects. Modifying the MATADOC protocol and assessment documentation prior to testing with a larger sample will enhance its sensitivity specific to ESD and age-related needs, providing a new music-based ESD assessment.

Exploring the effectiveness of music therapy intervention as part of interdisciplinary assessment and treatment for patients with prolonged disorders of consciousness

A four - year study took place at a Rehabilitation hospital in Ireland where two music therapists worked as an integral part of a Prolonged Disorders of Consciousness (PDOC) interdisciplinary team (IDT). The study aimed to explore the impact of music therapy as part of IDT assessment and treatment for patients with PDOC and their families. PDOC is defined as diminished or absent responsiveness and awareness persisting for more than four weeks following a catastrophic brain injury. A mixed method approach incorporating a case study series, the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC), questionnaires from patient’s families and IDT and video analysis was undertaken. Three research questions were explored:Does the inclusion of music therapy within an IDT enhance the service offered to PDOC patients? How does music therapy impact on the experience of family members? Can a music therapy assessment and treatment pathway be developed for this patient population?Three case studies taken from the case study series are outlined to illustrate aspects of the clinical work and address the research questions. Findings suggest that music therapy can enhance an IDT and have a positive impact on family members.

Examining the Functionality of the MATADOC With the CRS-R: A Pilot Study.

Prolonged disorders of consciousness (PDOC) following acquired brain injury affect a person's awareness of self and the environment. Motor, communication, sensory, and cognitive deficits challenge assessment. Rigorously tested behavioral assessments, sensitive to detecting awareness, are critical for discerning a prognosis for recovery and access to treatment. The Coma Recovery Scale-Revised (CRS-R) is considered the gold standard in PDOC diagnostic assessments. This study explored preliminary concurrent validity of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) with the CRS-R. The MATADOC and CRS-R were administered concurrently to 8 participants utilizing a repeated measures design. Correlations for diagnosis and item functionality were explored between and within the 2 measures. There was an adequate level of agreement between the 2 measures for overall diagnosis. Significant positive correlations were found between measures for all domains utilizing the MATADOC repeated administrations design. Within-measure relationships were significant for each of the auditory and communication domains with diagnosis for both measures, and additionally for each of the visual and arousal domains with diagnosis on the MATADOC. Both measures yielded significant inter-item relationships for auditory-visual domains, communication-visual domains, arousal-auditory domains, and arousal-visual domains. The MATADOC yielded an additional significant correlation for the auditory-communication domains. The findings have positive implications for the MATADOC as a diagnostic measure and companion assessment in cases of questionable diagnosis. Research with a larger sample is warranted. Generally, higher arousal scores on the MATADOC support music as effective in eliciting arousal, giving patients the opportunity to perform at their optimal level of function.

Music Therapy Assessment Tool for Awareness in Disorders of Consciousness: Assessment of Awareness in DOC

To investigate the psychometric properties of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC).

A Comparison of Diagnostic Outcomes Between the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (Matadoc) and Crs-R

The purpose of this study was to explore preliminary external validation of a standardized music therapy assessment tool used in the detection of awareness with the DOC patient population with an external reference standard.

Somatosensory attention identifies both overt and covert awareness in disorders of consciousness.

Some patients diagnosed with disorders of consciousness retain sensory and cognitive abilities beyond those apparent from their overt behavior. Characterizing these covert abilities is crucial for diagnosis, prognosis, and medical ethics. This multimodal study investigates the relationship between electroencephalographic evidence for perceptual/cognitive preservation and both overt and covert markers of awareness. Fourteen patients with severe brain injuries were evaluated with an electroencephalographic vibrotactile attention task designed to identify a hierarchy of residual somatosensory and cognitive abilities: (1) somatosensory steady-state evoked responses, (2) bottom-up attention orienting (P3a event-related potential), and (3) top-down attention (P3b event-related potential). Each patient was also assessed with a clinical behavioral scale and 2 functional magnetic resonance imaging assessments of covert command following. Six patients produced only sensory responses, with no evidence of cognitive event-related potentials. A further 8 patients demonstrated reliable bottom-up attention-orienting responses (P3a). No patient showed evidence of top-down attention (P3b). Only those patients who followed commands, whether overtly with behavior or covertly with functional neuroimaging, also demonstrated event-related potential evidence of attentional orienting. Somatosensory attention-orienting event-related potentials differentiated patients who could follow commands from those who could not. Crucially, this differentiation was irrespective of whether command following was evident through overt external behavior, or through covert functional neuroimaging methods. Bedside electroencephalographic methods may corroborate more expensive and challenging methods such as functional neuroimaging, and thereby assist in the accurate diagnosis of awareness. Ann Neurol 2016;80:412-423.

Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC): Reliability and Validity of a Measure to Assess Awareness in Patients with Disorders of Consciousness

Prolonged Disorders of Consciousness (PDOC) describes a population where a consciousness disorder has persisted for at least four weeks post injury but is still under investigation. Complex motor, sensory, communication, and cognitive impairments cause challenges with diagnosis, assessment, and intervention planning. Developing sensitive, reliable, and valid measures is a central concern. The auditory modality is the most sensitive for identifying awareness; however, the current standardized behavioral measures fail to provide adequate screening and measurement of auditory responsiveness. The Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) is a recently standardized measure for assessment with PDOC; however, psychometric values for two of its subscales require examination. To determine the measurement characteristics and properties of the MATADOC subscales two and three. In a convenience sample of 21participants with PDOC, a prospective repeated measures study examined inter-rater reliability (IRR) and test-retest reliability (TRR) for both subscales and internal consistency of subscale two. Overall, the items from the MATADOC subscales two and three demonstrated good agreement across and within assessors, with some variability on two identified items. The MATADOC is a standardized measure for assessment of auditory responsiveness in PDOC. Psychometric limitations for the two identified items may have resulted from variations in music therapist clinical experience and training, leading to variations in the administration and interpretation of PDOC patient responses to these two MATADOC assessment items. Although its psychometric properties could be improved, the MATADOC's clinimetric properties make it a valuable assessment to guide clinical work for patients with PDOC.

Feasibility of the music therapy assessment tool for awareness in disorders of consciousness (MATADOC) for use with pediatric populations.

Measuring responsiveness to gain accurate diagnosis in populations with disorders of consciousness (DOC) is of central concern because these patients have such complex clinical presentations. Due to the uncertainty of accuracy for both behavioral and neurophysiological measures in DOC, combined assessment approaches are recommended. A number of standardized behavioral measures can be used with adults with DOC with minor to moderate reservations relating to the measures’ psychometric properties and clinical applicability. However, no measures have been standardized for use with pediatric DOC populations. When adapting adult measures for children, confounding factors include developmental considerations for language-based items included in all DOC measures. Given the lack of pediatric DOC measures, there is a pressing need for measures that are sensitive to the complex clinical presentations typical of DOC and that can accommodate the developmental levels of pediatric populations. The music therapy assessment tool for awareness in disorders of consciousness (MATADOC) is a music-based measure that has been standardized for adults with DOC. Given its emphasis on non-language based sensory stimuli, it is well-suited to pediatric populations spanning developmental stages. In a pre-pilot exploratory study, we examined the clinical utility of this measure and explored trends for test-retest and inter-rater agreement as well as its performance against external reference standards. In several cases, MATADOC items in the visual and auditory domains produced outcomes suggestive of higher level functioning when compared to outcomes provided by other DOC measures. Preliminary findings suggest that the MATADOC provides a useful protocol and measure for behavioral assessment and clinical treatment planning with pediatric DOC. Further research with a larger sample is warranted to test a version of the MATADOC that is refined to meet developmental needs of pediatric DOC populations.

Hyperactive external awareness against hypoactive internal awareness in disorders of consciousness using resting-state functional MRI: highlighting the involvement of visuo-motor modulation.

Resting-state functional MRI (fMRI) has emerged as a valuable tool to characterize the complex states encompassing disorders of consciousness (DOC). Awareness appears to comprise two coexistent, anticorrelated components named the external and internal awareness networks. The present study hypothesizes that DOC interrupts the balance between the internal and external awareness networks. To gain more understanding of this phenomenon, the present study analyzed resting-state fMRI data from 12 patients with DOC versus 12 healthy age-matched controls. The data were explored using independent component analysis and amplitude of low-frequency fluctuation (ALFF) analysis. The results indicated that DOC deactivated midline areas associated with internal awareness. In addition, external awareness was strengthened in DOC because of increased activation in the insula, lingual gyrus, paracentral and supplementary motor area. The activity patterns suggested strengthened external awareness against weakened internal awareness in DOC. In particular, increased activity found in the insula, lingual gyrus, paracentral and supplementary motor area of patients with DOC implied possible involvement of augmented visuo-motor modulation in these patients. DOC is probably related to hyperactive external awareness opposing hypoactive internal awareness. This unique pattern of brain activity may potentially be a prognostic marker for DOC.

Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC): Standardisation of the principal subscale to assess awareness in patients with disorders of consciousness

Establishing valid and reliable measures for use with patients with disorders of consciousness (DOC) following profound brain injury is challenging due to a number of factors including the complex presentation of such patients and assessor variability. The auditory modality has been demonstrated to have greater sensitivity for detecting awareness in DOC patients. However, there are no measures developed to assess auditory responsiveness specifically. The objective of this study was to examine the psychometric properties of the principal subscale of a music therapy assessment tool (MATADOC) developed for use with adult DOC patients. The subscale assesses behavioural domains essential for diagnosis of awareness. Twenty-one adult patients were recruited from a specialist rehabilitation unit. In a prospective study with repeated measures, internal consistency, inter-rater and test–retest reliability and dimensionality were examined. The five-item scale showed satisfactory internal reliability (α = .76) and a strong first principal component. Corrected item-total correlations were all > .45. Inter-rater intra-class correlations (ICCs) ranged from 0.65–1.00 and intra-rater ICCs from 0.77–0.90. Rasch analysis confirmed these impressions of a reliable, unidimensional and homogenous scale. Diagnostic outcomes had 100% agreement with a validated external reference standard. The results indicate that the MATADOC principal subscale provides a new behavioural measure that can contribute to interdisciplinary assessment of awareness with DOC patients.

The complementary role of music therapy in the detection of awareness in disorders of consciousness: An audit of concurrent SMART and MATADOC assessments

In the behavioural assessment of disorders of consciousness (DOC), best practice is for several different assessment tools to be used to encourage a variety of different responses indicative of awareness. Anecdotal evidence suggests a range of musical stimuli may be particularly effective in eliciting responses to guide the assessment process, although comparative data regarding behavioural domains is lacking. This study examined 42 concurrent records of patients assessed using the Sensory Modality Assessment and Rehabilitation Technique (SMART), and the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) to explore the relationship between diagnosis and behavioural characteristics of the cohort. Whilst the two tools produced a high level of agreement in diagnostic outcome (Spearman Rho .80), divergent diagnosis and weaker correlations between behavioural response items highlight contrasting sensitivities of the tools. Whilst MATADOC has higher sensitivity within auditory and visual domains relative to SMART, SMART has higher sensitivity in the motor domain. The significant contribution of musical response items in MATADOC, and the tactile response item in SMART, indicates both tools provide unique behavioural data predictive of awareness. Multidisciplinary assessment using SMART and MATADOC provides complementary data contributing to a fuller understanding of a patient's level of awareness.

Knowledge of Partial Awareness in Disorders of Consciousness: Implications for Ethical Evaluations?

Recent results from neuroimaging appear to indicate that some patients in a vegetative state have partially intact awareness. These results may demonstrate misdiagnosis and suggest the need not only for alternative forms of treatment, but also for the reconsideration of end-of-life decisions in cases of disorders of consciousness. This article addresses the second consequence. First, I will discuss which aspects of consciousness may be involved in neuroimaging findings. I will then consider various factors relevant to ethical end-of-life decision-making, and analyse whether and to what extent the above consequence applies to these factors. It will be shown that knowledge of the existence of partial awareness in patients with disorders of consciousness only influences end-of-life decision-making if certain background assumptions are made.

Cognitive processes in disorders of consciousness as revealed by EEG time–frequency analyses

Objective Although behavioral evaluation of awareness in disorders of consciousness is difficult it remains the clinical standard. We believe that the refinement of EEG and analyses techniques would improve our characterization of those patients. Methods We focused on cognitive processing in a sample of 12 control subjects, eight vegetative-state patients, and 13 patients in the minimally consciousness state using EEG. We used an ‘active paradigm’ which asks subjects to follow instructions, specifically to actively count own or other names as compared to passively listening to them. EEG data was then analyzed using an advanced EEG analysis technique. Results Results revealed that all groups exhibit a stronger theta-synchronization to their own names when forced to count them. We also observed a delay in theta power in response to targets relative to non-targets when participants were instructed to count their own name. Conclusion Active paradigms are able to induce a different oscillatory activity compared to passive paradigms. Differences between controls and the pathologic groups are prominent in the theta- and alpha-band. Significance Time–frequency analyses allow to focus on distinct cognitive processes in patients with disorders of consciousness and thereby contribute to a refined understanding of severely brain-injured patients.

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.