Depth of sedation with dexmedetomidine increases transcranial magnetic stimulation-evoked potential amplitude non-linearly.

Background: Cortical excitability is higher in unconsciousness than in wakefulness, but it is unclear how this relates to anaesthesia. We investigated cortical excitability in response to dexmedetomidine, the effects of which are not fully known.

Methods: We recorded transcranial magnetic stimulation (TMS) and EEG in frontal and parietal cortex of 20 healthy subjects undergoing dexmedetomidine sedation in four conditions (baseline, light sedation, deep sedation, recovery).

Preservation of Brain Activity in Unresponsive Patients Identifies MCS Star.

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

Decreased Evoked Slow-Activity After tDCS in Disorders of Consciousness.

Due to life-saving medical advances, the diagnosis and treatment of disorders of consciousness (DOC) has become a more commonly occurring clinical issue. One recently developed intervention option has been non-invasive transcranial direct current stimulation. This dichotomy of patient responders may be better understood by investigating the mechanism behind the transcranial direct current stimulation (tDCS) intervention.

Simplified evaluation of CONsciousness disorders (SECONDs) in individuals with severe brain injury: A validation study.

Background: The Coma Recovery Scale-Revised (CRS-R) is the gold standard to assess severely brain-injured patients with prolonged disorders of consciousness (DoC). However, the amount of time needed to complete this examination may limit its use in clinical settings.

Objective: We aimed to validate a new faster tool to assess consciousness in individuals with DoC.

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

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

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

Setting: Patients were evaluated in a tertiary care hospital.

Nociception Coma Scale-Revised Allows to Identify Patients With Preserved Neural Basis for Pain Experience.

The Nociception Coma Scale-Revised (NCS-R) was developed to help assess pain in patients with disorders of consciousness (DOC). Several studies have shown its sensitivity in assessing response to acute noxious stimuli. However, they failed to determine a reliable cut-off score that could be used to infer pain processing in these patients.

Resting-state functional connectivity and cortical thickness characterization of a patient with Charles Bonnet syndrome.

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in elderly people. Although studies suggested that visual hallucinations may be caused by brain damage in the visual system in CBS patients, alterations in specific brain regions in the occipital cortex have not been studied. Functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI; without hallucinations) in CBS patients, has never been explored.

Reappearance of Command-Following Is Associated With the Recovery of Language and Internal-Awareness Networks: A Longitudinal Multiple-Case Report.

The recovery of patients with disorders of consciousness is a real challenge, especially at the chronic stage. After a severe brain injury, patients can regain some slight signs of consciousness, while not being able to functionally communicate. This entity is called the minimally conscious state (MCS), which has been divided into MCS- and MCS+, respectively based on the absence or presence of language-related signs of consciousness.

Brain, Behavior, and Cognitive Interplay in Disorders of Consciousness: A Multiple Case Study.

Patients with prolonged disorders of consciousness (DoC) after severe brain injury may present residual behavioral and cognitive functions. Yet the bedside assessment of these functions is compromised by patients' multiple impairments. Standardized behavioral scales such as the (CRS-R) have been developed to diagnose DoC, but there is also a need for neuropsychological measurement in these patients.

Randomized controlled trial of home-based 4-week tDCS in chronic minimally conscious state.

Background: Patients with chronic disorders of consciousness face a significant lack of treatment options.

Objective: We aimed at investigating the feasibility and the behavioral effects of home-based transcranial direct current stimulation (tDCS), applied by relatives or caregivers, in chronic patients in minimally conscious state (MCS).

Methods: Each participant received, in a randomized order, 20 sessions of active and 20 sessions of sham tDCS applied over the prefrontal cortex for 4 weeks; separated by 8 weeks of washout.

Resistance to eye opening in patients with disorders of consciousness.

Introduction: Resistance to eye opening (REO) is a commonly encountered phenomenon in clinical practice. We aim to investigate whether REO is a sign of consciousness or a reflex in severely brain-injured patients.

Methods: We recorded REO in chronic patients with disorders of consciousness during a multimodal diagnostic assessment.

Is oral feeding compatible with an unresponsive wakefulness syndrome?

Objective: The aim of the study is to explore the possibility of oral feeding in unresponsive wakefulness syndrome/vegetative state (UWS/VS) patients.

Method: We reviewed the clinical information of 68 UWS/VS patients (mean age 45 ± 11; range 16-79 years) searching for mention of oral feeding. UWS/VS diagnosis was made after repeated behavioural assessments using the Coma Recovery Scale-Revised.

Global structural integrity and effective connectivity in patients with disorders of consciousness.

Background: Previous studies have separately reported impaired functional, structural, and effective connectivity in patients with disorders of consciousness (DOC). The perturbational complexity index (PCI) is a transcranial magnetic stimulation (TMS) derived marker of effective connectivity. The global fractional anisotropy (FA) is a marker of structural integrity.

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.

Brain networks predict metabolism, diagnosis and prognosis at the bedside in disorders of consciousness.

Recent advances in functional neuroimaging have demonstrated novel potential for informing diagnosis and prognosis in the unresponsive wakeful syndrome and minimally conscious states. However, these technologies come with considerable expense and difficulty, limiting the possibility of wider clinical application in patients. Here, we show that high density electroencephalography, collected from 104 patients measured at rest, can provide valuable information about brain connectivity that correlates with behaviour and functional neuroimaging.

The repetition of behavioral assessments in diagnosis of disorders of consciousness.

Objective: To determine whether repeated examinations using the Coma Recovery Scale-Revised (CRS-R) have an impact on diagnostic accuracy of patients with disorders of consciousness and to provide guidelines regarding the number of assessments required for obtaining a reliable diagnosis.

Methods: One hundred twenty-three adult patients with chronic disorders of consciousness were referred to our tertiary center. They were assessed at least six times with the CRS-R within a 10-day period.

Prevalence of coma-recovery scale-revised signs of consciousness in patients in minimally conscious state.

Different behavioural signs of consciousness can distinguish patients with an unresponsive wakefulness syndrome from patients in minimally conscious state (MCS). The Coma Recovery Scale-Revised (CRS-R) is the most sensitive scale to differentiate the different altered states of consciousness and eleven items detect the MCS. The aim of this study is to document the prevalence of these items.

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.

Controlled clinical trial of repeated prefrontal tDCS in patients with chronic minimally conscious state.

Objectives: To assess the effects of repeated transcranial direct current stimulation (tDCS) sessions on the level of consciousness in chronic patients in minimally conscious state (MCS).

Methods: In this randomized double-blind sham-controlled crossover study, we enrolled 16 patients in chronic MCS. For 5 consecutive days, each patient received active or sham tDCS over the left prefrontal cortex (2 mA during 20 min).

Measures of metabolism and complexity in the brain of patients with disorders of consciousness.

Background: Making an accurate diagnosis in patients with disorders of consciousness remains challenging. F-fluorodeoxyglucose (FDG)-PET has been validated as a diagnostic tool in this population, and allows identifying unresponsive patients with a capacity for consciousness. In parallel, the perturbational complexity index (PCI), a new measure based on the analysis of the electroencephalographic response to transcranial magnetic stimulation, has also been suggested as a tool to distinguish between unconscious and conscious states.

Neural correlates of consciousness in patients who have emerged from a minimally conscious state: a cross-sectional multimodal imaging study.

Background: Between pathologically impaired consciousness and normal consciousness exists a scarcely researched transition zone, referred to as emergence from minimally conscious state, in which patients regain the capacity for functional communication, object use, or both. We investigated neural correlates of consciousness in these patients compared with patients with disorders of consciousness and healthy controls, by multimodal imaging.

Methods: In this cross-sectional, multimodal imaging study, patients with unresponsive wakefulness syndrome, patients in a minimally conscious state, and patients who had emerged from a minimally conscious state, diagnosed with the Coma Recovery Scale-Revised, were recruited from the neurology department of the Centre Hospitalier Universitaire de Liège, Belgium.

Detection and Interpretation of Impossible and Improbable Coma Recovery Scale-Revised Scores.

Objective: To determine the frequency with which specific Coma Recovery Scale-Revised (CRS-R) subscale scores co-occur as a means of providing clinicians and researchers with an empirical method of assessing CRS-R data quality.

Design: We retrospectively analyzed CRS-R subscale scores in hospital inpatients diagnosed with disorders of consciousness (DOCs) to identify impossible and improbable subscore combinations as a means of detecting inaccurate and unusual scores. Impossible subscore combinations were based on violations of CRS-R scoring guidelines.