Swallowing Assessment in Post-Comatose Patients: A Feasibility Study on the SWADOC Tool.

Background: After a severe brain injury and a coma, patients may develop disorders of consciousness (DoC), frequently accompanied by severe dysphagia. The evaluation and therapy of swallowing are therefore essential aspects of their management. Objectives: This study aims to evaluate the SWallowing Assessment in Disorders of Consciousness (SWADOC) tool in the assessment of swallowing in post-comatose patients. Here, we validate its quantitative items, describe preliminary results and identify limitations. Methods: Fourteen post-comatose patients were repeatedly evaluated with the Simplified Evaluation of CONsciousness Disorders (SECONDs) and with the SWADOC. Results: The internal consistency of the oral and pharyngeal subscales of the SWADOC was good. The test-retest reliability showed that all items, all subscores and the total score were stable except for two items (endo-buccal secretions and bronchial congestion). A comparison to the Facial Oral Tract Therapy Swallowing Assessment of Saliva (F.O.T.T-SAS) confirmed that scoring with the SWADOC offers a greater potential for quantitative observations in assessing swallowing abilities among patients with DoC. The SECONDs scores and SWADOC total scores showed a significant positive correlation (τ = 0.78, p < 0.001). Conclusions: This study provides preliminary but encouraging results on the psychometric properties of the SWADOC tool. It shows that this tool is relevant and feasible as a bedside assessment of dysphagia in patients with DoC.

Swallowing dysfunctions in patients with disorders of consciousness: Evidence from neuroimaging data, assessment, and management.

Following severe brain injuries, a subset of patients may remain in an altered state of consciousness; most of these patients require artificial feeding. Currently, a functional oral phase and the presence of exclusive oral feeding may constitute signs of consciousness. Additionally, the presence of pharyngo-laryngeal secretions, saliva aspiration, cough reflex and tracheostomy are related to the level of consciousness. However, the link between swallowing and consciousness is yet to be fully understood. The primary aim of this review is to establish a comprehensive overview of the relationship between an individual's conscious behaviour and swallowing (reflexive and voluntary). Previous studies of brain activation during volitional and non-volitional swallowing tasks in healthy subjects are also reviewed. We demonstrate that the areas activated by voluntary swallowing tasks (primary sensorimotor, cingulate, insula, premotor, supplementary motor, cerebellum, and operculum) are not specific to deglutitive function but are shared with other motor tasks and brain networks involved in consciousness. This review also outlines suitable assessment and treatment methods for dysphagic patients with disorders of consciousness. Finally, we propose that markers of swallowing could contribute to the development of novel diagnostic guidelines for patients with disorders of consciousness.

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

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

Auditory and Somatosensory P3 Are Complementary for the Assessment of Patients with Disorders of Consciousness.

The evaluation of the level of consciousness in patients with disorders of consciousness (DOC) is primarily based on behavioural assessments. Patients with unresponsive wakefulness syndrome (UWS) do not show any sign of awareness of their environment, while minimally conscious state (MCS) patients show reproducible but fluctuating signs of awareness. Some patients, although with remaining cognitive abilities, are not able to exhibit overt voluntary responses at the bedside and may be misdiagnosed as UWS. Several studies investigated functional neuroimaging and neurophysiology as an additional tool to evaluate the level of consciousness and to detect covert command following in DOC. Most of these studies are based on auditory stimulation, neglecting patients suffering from decreased or absent hearing abilities. In the present study, we aim to assess the response to a P3-based paradigm in 40 patients with DOC and 12 healthy participants using auditory (AEP) and vibrotactile (VTP) stimulation. To this end, an EEG-based brain-computer interface was used at DOC patient's bedside. We compared the significance of the P3 performance (i.e., the interpretation of significance of the evoked P3 response) as obtained by 'direct processing' (i.e., theoretical-based significance threshold) and 'offline processing' (i.e., permutation-based single subject level threshold). We evaluated whether the P3 performances were dependent on clinical variables such as diagnosis (UWS and MCS), aetiology and time since injury. Last we tested the dependency of AEP and VTP performances at the single subject level. Direct processing tends to overestimate P3 performance. We did not find any difference in the presence of a P3 performance according to the level of consciousness (UWS vs. MCS) or the aetiology (traumatic vs. non-traumatic brain injury). The performance achieved at the AEP paradigm was independent from what was achieved at the VTP paradigm, indicating that some patients performed better on the AEP task while others performed better on the VTP task. Our results support the importance of using multimodal approaches in the assessment of DOC patients in order to optimise the evaluation of patient's abilities.

The misdiagnosis of prolonged disorders of consciousness by a clinical consensus compared with repeated coma-recovery scale-revised assessment.

BACKGROUND: Previous studies have shown that a single Coma-Recovery Scale-Revision (CRS-R) assessment can identify high rates of misdiagnosis by clinical consensus. The aim of this study was to investigate the proportion of misdiagnosis by clinical consensus compared to repeated behavior-scale assessments in patients with prolonged disorders of consciousness (DOC). METHODS: Patients with prolonged DOC during hospitalization were screened by clinicians, and the clinicians formed a clinical-consensus diagnosis. Trained professionals used the CRS-R to evaluate the consciousness levels of the enrolled patients repeatedly (≥5 times) within a week. Based on the repeated evaluation results, the enrolled patients with prolonged DOC were divided into unresponsive wakefulness syndrome (UWS), minimally conscious state (MCS), and emergence from MCS (EMCS). Finally, the relationship between the results of the CRS-R and the clinical consensus were analyzed. RESULTS: In this study, 137 patients with a clinical-consensus diagnosis of prolonged DOC were enrolled. It was found that 24.7% of patients with clinical UWS were actually in MCS after a single CRS-R behavior evaluation, while the repeated CRS-R evaluation results showed that the proportion of misdiagnosis of MCS was 38.2%. A total of 16.7% of EMCS patients were misdiagnosed with clinical MCS, and 1.1% of EMCS patients were misdiagnosed with clinical UWS. CONCLUSIONS: The rate of the misdiagnosis by clinical consensus is still relatively high. Therefore, clinicians should be aware of the importance of the bedside CRS-R behavior assessment and should apply the CRS-R tool in daily procedures. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04139239 ; Registered 24 October 2019 - Retrospectively registered.

Brain-computer interfaces for consciousness assessment and communication in severely brain-injured patients.

Patients with disorders of consciousness (DOC) suffer from awareness deficits. Comorbidities such as motor disabilities or visual problems hamper clinical assessments, which can lead to misdiagnosis of the level of consciousness and render the patient unable to communicate. Objective measures of consciousness can reduce the risk of misdiagnosis and could enable patients to communicate by voluntarily modulating their brain activity. This chapter gives an overview of the literature regarding brain-computer interface (BCI) research in DOC patients. Different auditory, visual, and motor imagery paradigms are discussed, alongside their corresponding advantages and disadvantages. At this point, the use of BCIs for DOC patients in clinical applications is still preliminary. However, perspectives on the improvements in BCIs for DOC patients seem positive, and implementation during rehabilitation shows promise.

Should we include monitors to improve assessment of awareness and pain in unconscious palliatively sedated patients? A case report.

BACKGROUND: Awareness and pain during palliative sedation is typically assessed by observational scales, but the use of such scales has been put into question. CASE PRESENTATION: A woman in her mid-80s was admitted to a palliative care unit, presenting with chronic lymphatic leukemia, depression, and a cerebrovascular accident, with right-sided hemiplegia and aphasia. The patient was unable to eat and was suffering from nausea and vomiting. Before admission, the patient had expressed her desire to discontinue treatment on several occasions. CASE MANAGEMENT: The decision was made to initiate palliative sedation. The patient consented to take part in a study to assess level of comfort and pain using two monitoring devices (NeuroSense monitor and Analgesia Nociception Index monitor). CASE OUTCOME: The patient died 90 h after initiation of palliative sedation. Titration of the medication was challenging and sedation was not deep enough during the first 2 days. Thirteen assessments made with the Ramsay Sedation Scale showed that the patient was considered to be in a deep sleep, while in fact the NeuroSense monitor indicated otherwise. CONCLUSION: This case demonstrates the feasibility and potential advantages of using monitoring devices to objectify assessments of pain and discomfort in palliatively sedated patients.

Assessment of Nociception and Pain in Participants in an Unresponsive or Minimally Conscious State After Acquired Brain Injury: The Relation Between the Coma Recovery Scale-Revised and the Nociception Coma Scale-Revised.

OBJECTIVES: To investigate the relation between consciousness and nociceptive responsiveness (ie, Nociception Coma Scale-Revised [NCS-R]), to examine the suitability of the NCS-R for assessing nociception in participants with disorders of consciousness (DOC), and to replicate previous findings on psychometric properties of the scale. DESIGN: Specialized DOC program. SETTING: Specialized DOC program and university hospitals. PARTICIPANTS: Participants (N=85) diagnosed with DOC. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We prospectively assessed consciousness with the Coma Recovery Scale-Revised (CRS-R). Responses during baseline, non-noxious, and noxious stimulations were scored with the NCS-R and CRS-R oromotor and motor subscales. RESULTS: CRS-R total scores correlated with NCS-R total scores and subscores. CRS-R motor subscores correlated with NCS-R total scores and motor subscores, and CRS-R oromotor subscores correlated with NCS-R total scores as well as verbal and facial expression subscores. There was a difference between unresponsive wakefulness syndrome and minimally conscious state in the proportion of grimacing and/or crying participants during noxious conditions. We replicated previous findings on psychometric properties of the scale but found a different score as the best threshold for nociception. CONCLUSIONS: We report a strong relation between the responsiveness to nociception and the level of consciousness. The NCS-R seems to be a valuable tool for assessing nociception in an efficient manner, but additional studies are needed to allow recommendations for clinical assessment of subjective pain experience.

Personalized objects can optimize the diagnosis of EMCS in the assessment of functional object use in the CRS-R: a double blind, randomized clinical trial.

BACKGROUND: Behavioral assessment has been acted as the gold standard for the diagnosis of disorders of consciousness (DOC) patients. The item "Functional Object Use" in the motor function sub-scale in the Coma Recovery Scale-Revised (CRS-R) is a key item in differentiating between minimally conscious state (MCS) and emergence from MCS (EMCS). However, previous studies suggested that certain specific stimuli, especially something self-relevant can affect DOC patients' scores of behavioral assessment scale. So, we attempted to find out if personalized objects can improve the diagnosis of EMCS in the assessment of Functional Object Use by comparing the use of patients' favorite objects and other common objects in MCS patients. METHODS: Twenty-one post-comatose patients diagnosed as MCS were prospectively included. The item "Functional Object Use" was assessed by using personalized objects (e.g., cigarette, paper) and non-personalized objects, which were presented in a random order. The rest assessments were performed following the standard protocol of the CRS-R. The differences between functional uses of the two types of objects were analyzed by the McNemar test. RESULTS: The incidence of Functional Object Use was significantly higher using personalized objects than non-personalized objects in the CRS-R. Five out of the 21 MCS studied patients, who were assessed with non-personalized objects, were re-diagnosed as EMCS with personalized objects (χ2 = 5, df = 1, p < 0.05). CONCLUSIONS: Personalized objects employed here seem to be more effective to elicit patients' responses as compared to non-personalized objects during the assessment of Functional Object Use in DOC patients. TRIAL REGISTRATION: Clinical Trials.gov: NCT02988206 ; Date of registration: 2016/12/12.

Mirror efficiency in the assessment of visual pursuit in patients in minimally conscious state.

OBJECTIVE: Visual pursuit should be tested with a mirror in patients with disorders of consciousness. This stimulus was indeed more efficient than a person or an object, and the auto-referential aspect was supposed to be the key feature. The present study tested the hypothesis that the mirror was more efficient because of its self-aspect. METHODS: The mirror was compared (1) to the patient's picture and to the picture of a famous face, in 22 patients in minimally conscious state and (2) to the patient's picture and a fake mirror, which had dynamical and bright aspects of the mirror, without reflecting the face, in 26 other patients in minimally conscious state. RESULTS: The mirror was more efficient than the patient's picture, which was not statistically different from the famous face. The second part of the study confirmed the statistical difference between the mirror and the picture. However, the fake mirror was neither statistically different from the mirror nor from the picture. CONCLUSIONS: Although our results suggest that the hypothesis proposed by previous studies was partly wrong, they confirm that the mirror is the best stimulus to use when assessing visual pursuit.

Assessment of needs, psychological impact and quality of life in families of patients with locked-in syndrome.

OBJECTIVE: Family needs of patients with acquired brain injuries have been studied for about three decades. In this study, we assessed the needs, the quality of life and the psychological state of relatives of patients with locked-in syndrome (LIS). DESIGN: A survey was carried out using the family needs' questionnaire (FNQ). SUBJECTS AND METHODS: Thirty relatives of patients with LIS fully completed the FNQ. RESULTS: The most important need reported by families corresponded to the need for medical information. The highest percentage of satisfaction (66%) was also observed for this need. Among the needs for information, specifically, the most important for LIS' relatives was to know that the patient's needs and wishes were respected by the professional staff, which were fulfilled in 93% of the sample. The need for emotional support was the least important and had the lowest percentage of satisfaction (55%). The number of met/unmet needs correlated with the quality of life of the families. Most of the relatives reported anxiety feelings and depressive thoughts. CONCLUSIONS: Receiving accurate medical information is the most important need for family of patients with LIS and their quality of life is correlated with the fulfilment of their needs.

Objective assessment of visual pursuit in patients with disorders of consciousness: an exploratory study.

Visual pursuit is a key marker of residual consciousness in patients with disorders of consciousness (DOC). Currently, its assessment relies on subjective clinical decisions. In this study, we explore the variability of such clinical assessments, and present an easy-to-use device composed of cameras and video processing algorithms that could help the clinician to improve the detection of visual pursuit in a clinical context. Visual pursuit was assessed by an experienced research neuropsychologist on 31 patients with DOC and on 23 healthy subjects, while the device was used to simultaneously record videos of both one eye and the mirror. These videos were then scored by three researchers: the experienced research neuropsychologist who did the clinical assessment, another experienced research neuropsychologist, and a neurologist. For each video, a consensus was decided between the three persons, and used as the gold standard of the presence or absence of visual pursuit. Almost 10% of the patients were misclassified at the bedside according to their consensus. An automatic classifier analyzed eye and mirror trajectories, and was able to identify patients and healthy subjects with visual pursuit, in total agreement with the consensus on video. In conclusion, our device can be used easily in patients with DOC while respecting the current guidelines of visual pursuit assessment. Our results suggest that our material and our classification method can identify patients with visual pursuit, as well as the three researchers based on video recordings can.

Impact of aphasia on consciousness assessment: a cross-sectional study.

BACKGROUND: Previous findings suggest that language disorders may occur in severely brain-injured patients and could interfere with behavioral assessments of consciousness. However, no study investigated to what extent language impairment could affect patients' behavioral responses. Objective. To estimate the impact of receptive and/or productive language impairments on consciousness assessment. METHODS: Twenty-four acute and subacute stroke patients with different types of aphasia (global, n = 11; Broca, n = 4; Wernicke, n = 3; anomic, n = 4; mixed, n = 2) were recruited in neurology and neurosurgery units as well as in rehabilitation centers. The Coma Recovery Scale-Revised (CRS-R) was administered. RESULTS: We observed that 25% (6 out of 24) of stroke patients with a diagnosis of aphasia and 54% (6 out of 11) of patients with a diagnosis of global aphasia did not reach the maximal CRS-R total score of 23. An underestimation of the consciousness level was observed in 3 patients with global aphasia who could have been misdiagnosed as being in a minimally conscious state, even in the absence of any documented period of coma. More precisely, lower subscores were observed on the communication, motor, oromotor, and arousal subscales. CONCLUSION: Consciousness assessment may be complicated by the co-occurrence of severe language deficits. This stresses the importance of developing new tools or identifying items in existing scales, which may allow the detection of language impairment in severely brain-injured patients.

Technology-based assessment in patients with disorders of consciousness.

INTRODUCTION: A number of studies highlight the difficulty in forming a diagnosis for patients with disorders of consciousness when this is established merely on behavioral assessments. BACKGROUND: Positron emission tomography (PET), functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and electroencephalography combined with transcranial magnetic stimulation (TMS-EEG) techniques are promoting the clinical characterization of this challenging population. With such technology-based "objective" tools, patients are also differentially able to follow simple commands and in some cases even communicate through modified brain activity. Consequently, the vegetative state and minimally conscious state have been revised and new nosologies have been proposed, namely the unresponsive wakefulness syndrome, the minimally conscious state plus and minus, and the functional locked-in syndrome. AIM: To our mind, an integration of different technical modalities is important to gain a holistic vision of the underlying pathophysiology of disorders of consciousness in general and to promote single-patient medical management in particular.

Assessment of visual fixation in vegetative and minimally conscious states.

BACKGROUND: Visual fixation plays a key role in the differentiation between vegetative state/unresponsive wakefulness (VS/UWS) syndrome and minimally conscious state (MCS). However, the use of different stimuli changes the frequency of visual fixation occured in patients, thereby possibly affecting the accuracy of the diagnosis. In order to establish a standardized assessment of visual fixation in patients in disorders of consciousness (DOC), we compared the frequency of visual fixation elicited by mirror,a ball and a light. METHOD: Visual fixation was assessed in eighty-one post-comatose patients diagnosed with a MCS or VS/UWS. Occurrence of fixation to different stimuli was analysis used Chi-square testing. RESULT: 40 (49%) out of the 81 patients showed fixation to visual stimuli. Among those, significantly more patients (39, 48%) had visual fixation elicited by mirror compared to a ball (23, 28%) and mirror compared to a light (20, 25%). CONCLUSION: The use of a mirror during the assessment of visual fixation showed higher positive response rate, compared to other stimuli in eliciting a visual fixating response. Therefore, fixation elicited by a mirror can be a very sensitive and accurate test to differentiate the two disorders of consciousness.

Biased binomial assessment of cross-validated estimation of classification accuracies illustrated in diagnosis predictions.

Multivariate classification is used in neuroimaging studies to infer brain activation or in medical applications to infer diagnosis. Their results are often assessed through either a binomial or a permutation test. Here, we simulated classification results of generated random data to assess the influence of the cross-validation scheme on the significance of results. Distributions built from classification of random data with cross-validation did not follow the binomial distribution. The binomial test is therefore not adapted. On the contrary, the permutation test was unaffected by the cross-validation scheme. The influence of the cross-validation was further illustrated on real-data from a brain-computer interface experiment in patients with disorders of consciousness and from an fMRI study on patients with Parkinson disease. Three out of 16 patients with disorders of consciousness had significant accuracy on binomial testing, but only one showed significant accuracy using permutation testing. In the fMRI experiment, the mental imagery of gait could discriminate significantly between idiopathic Parkinson's disease patients and healthy subjects according to the permutation test but not according to the binomial test. Hence, binomial testing could lead to biased estimation of significance and false positive or negative results. In our view, permutation testing is thus recommended for clinical application of classification with cross-validation.

Spasticity after stroke: physiology, assessment and treatment.

BACKGROUND: Spasticity following a stroke occurs in about 30% of patients. The mechanisms underlying this disorder, however, are not well understood. METHOD: This review aims to define spasticity, describe hypotheses explaining its development after a stroke, give an overview of related neuroimaging studies as well as a description of the most common scales used to quantify the degree of spasticity and finally explore which treatments are currently being used to treat this disorder. RESULTS: The lack of consensus is highlighted on the basis of spasticity and the associated absence of guidelines for treatment, use of drugs and rehabilitation programmes. CONCLUSIONS: Future studies require controlled protocols to determine the efficiency of pharmacological and non-pharmacological treatments for spasticity. Neuroimaging may help predict the occurrence of spasticity and could provide insight into its neurological basis.

Assessment of localisation to auditory stimulation in post-comatose states: use the patient's own name.

BACKGROUND: At present, there is no consensus on how to clinically assess localisation to sound in patients recovering from coma. We here studied auditory localisation using the patient's own name as compared to a meaningless sound (i.e., ringing bell). METHODS: Eighty-six post-comatose patients diagnosed with a vegetative state/unresponsive wakefulness syndrome or a minimally conscious state were prospectively included. Localisation of auditory stimulation (i.e., head or eyes orientation toward the sound) was assessed using the patient's own name as compared to a ringing bell. Statistical analyses used binomial testing with bonferroni correction for multiple comparisons. RESULTS: 37 (43%) out of the 86 studied patients showed localisation to auditory stimulation. More patients (n=34, 40%) oriented the head or eyes to their own name as compared to sound (n=20, 23%; p<0.001). CONCLUSIONS: When assessing auditory function in disorders of consciousness, using the patient's own name is here shown to be more suitable to elicit a response as compared to neutral sound.