Signs Of Consciousness In Patients Research Articles

Perspectives on consciousness in patients with disorders of consciousness from brain injury: group concept mapping study across clinic, research, and families

BackgroundAn effective healthcare system depends on clinic, research, and patient/relatives interactions. Such interactions may at their core be challenged by misalignments of concepts and the practices that constitute them. The concept of consciousness and what is experienced and understood as signs of consciousness in patients with severe acquired brain injury is one of these potential areas of misalignment. Different perspectives and experiences of consciousness are challenging the delivery of care and the high-stake decision-making process on the potential withdrawal of treatment. The enhanced uncertainties call for reflections on how key stakeholders perceive and identify consciousness in current clinical encounters and practice.MethodsThe study empirically explores the actual experiences and conceptions of consciousness concerning patients with disorders of consciousness (DoC) from the perspectives of researchers, health professionals, and relatives of patients, to understand the challenges of the diversity of understandings of consciousness. Engaging the stakeholders by employing Group Concept Mapping methodology, the study developed a situated conceptual map, which reflects nuances and the importance of perspectives on and signs of consciousness.ResultsTwenty-seven participants contributed to the generation of ideas, 14 took part in the structuring of statements and 10 took part in the validation meeting to interpret the cluster rating map. A total of 85 unique statements were identified and organized into six clusters: (1) Presence, (2) Intentional Activity, (3) Experience of self, (4) Participation in Social Interaction, (5) (Repeated) Response, and (6) Unspecific Reaction. The conceptual mapping demonstrates an extensive overlap in perspectives on consciousness among participants, prioritizing signs that are observable at the bedside.ConclusionsThe study provides a first step toward a future framework for the difficult process of decision-making concerning a segment of patients with DoC. The study highlights the importance of repeatable signs of consciousness observed at the bedside and the patient’s ability to participate in social interactions, while also considering the importance of non-clinically observable signs of consciousness.

DETECTING PHENOMENON OF “COVERT COGNITION” IN PATIENTS WITH CHRONIC DISORDERS OF CONSCIOUSNESS: A REVIEW OF fMRI DATA WITH PARADIGMS

In recent decades, the use of instrumental methods has significantly expanded the diagnosis of signs of consciousness in patients with chronic disorders of consciousness (DOC). The phenomenon of “covert cognition” was described with their help. This review highlights studies on the detection of “covert cognition” in patients with DOC using functional magnetic resonance imaging. Most types of passive and active paradigms used for this purpose are analyzed and systematized. Special attention is paid to an integrated approach with a combination of different paradigms and research methods. The importance of detecting the phenomenon of “covert cognition” for the neurorehabilitation of patients with DOC is emphasized.

New Behavioral Signs of Consciousness in Patients with Severe Brain Injuries.

Diagnostic and prognostic assessment of patients with disorders of consciousness (DoC) presents ethical and clinical implications as they may affect the course of medical treatment and the decision to withdraw life-sustaining therapy. There has been increasing research in this field to lower misdiagnosis rates by developing standardized and consensual tools to detect consciousness. In this article, we summarize recent evidence regarding behavioral signs that are not yet included in the current clinical guidelines but could detect consciousness. The new potential behavioral signs of consciousness described here are as follows: resistance to eye opening, spontaneous eye blink rate, auditory localization, habituation of auditory startle reflex, olfactory sniffing, efficacy of swallowing/oral feeding, leg crossing, facial expressions to noxious stimulation, and subtle motor behaviors. All of these signs show promising results in discriminating patients' level of consciousness. Multimodal studies with large sample sizes in different centers are needed to further evaluate whether these behaviors reliably indicate the presence of consciousness. Future translation of these research findings into clinical practice has potential to improve the accuracy of diagnosis and prognostication for patients with DoC.

Transcranial Pulsed-Current Stimulation versus Transcranial Direct Current Stimulation in Patients with Disorders of Consciousness: A Pilot, Sham-Controlled Cross-Over Double-Blind Study.

Transcranial direct-current stimulation (tDCS) over the prefrontal cortex can improve signs of consciousness in patients in a minimally conscious state. Transcranial pulsed-current stimulation (tPCS) over the mastoids can modulate brain activity and connectivity in healthy controls. This study investigated the feasibility of tPCS as a therapeutic tool in patients with disorders of consciousness (DoC) and compared its neurophysiological and behavioral effects with prefrontal tDCS. This pilot study was a randomized, double-blind sham-controlled clinical trial with three sessions: bi-mastoid tPCS, prefrontal tDCS, and sham. Electroencephalography (EEG) and behavioral assessments were collected before and after each stimulation session. Post minus pre differences were compared using Kruskal–Wallis and Wilcoxon signed-rank tests. Twelve patients with DoC were included in the study (eight females, four traumatic brain injury, 50.3 ± 14 y.o., 8.8 ± 10.5 months post-injury). We did not observe any side-effects following tPCS, nor tDCS, and confirmed their feasibility and safety. We did not find a significant effect of the stimulation on EEG nor behavioral outcomes for tPCS. However, consistent with prior findings, our exploratory analyses suggest that tDCS induces behavioral improvements and an increase in theta frontal functional connectivity.

Development of paradigms for the diagnosis of "covert cognition" and cognitive motor dissociation in patients with chronic disorders of consciousness

The detection of signs of consciousness in patients with chronic disorders of consciousness is a complex clinical task. In recent decades, instrumental methods have been used to improve the accuracy of diagnostics. The phenomenon of covert cognition and cognitive motor dissociation have been demonstrated in a small proportion of patients in studies using instrumental methods in combination with different paradigms. This article describes the main features of the diagnostic paradigms used for such purposes. Currently, the development of its own complex of paradigms is held at the Research Center of Neurology collaboratively with group of neuropsychologists from Lomonosov Moscow State University. The general characteristics of this complex of paradigms are indicated. The practical significance of detecting the phenomenon of covert cognition and cognitive motor dissociation in patients with chronic disorders of consciousness is discussed.

Combined Behavioral and Mismatch Negativity Evidence for the Effects of Long-Lasting High-Definition tDCS in Disorders of Consciousness: A Pilot Study.

ObjectiveTo evaluate the effects of long-term High-definition transcranial direct current stimulation (HD-tDCS) over precuneus on the level of consciousness (LOC) and the relationship between Mismatch negativity (MMN) and the LOC over the therapy period in patients with Disorders of consciousness (DOCs).MethodsWe employed a with-in group repeated measures design with an anode HD-tDCS protocol (2 mA, 20 min, the precuneus) on 11 (2 vegetative state and nine minimally conscious state) patients with DOCs. MMN and Coma Recovery Scale-Revised (CRS-R) scores were measured at four time points: before the treatment of HD-tDCS (T0), after a single session of HD-tDCS (T1), after the treatment of 7 days (T2) and 14 days (T3). A frequency-deviant oddball paradigm with two deviation magnitudes (standard stimulus: 1000 Hz, small deviant stimuli: 1050 Hz, large deviant stimuli: 1200 Hz) was adopted to elicit MMN.ResultsSignificant improvements of CRS-R score were found after 7-day (T2) and 14-day (T3) treatment compared with baseline (T0). Regarding the MMN, significant improvements of MMN amplitudes were observed after a single session of stimulation (T1), 7-day (T2) and 14-day treatment (T3) compared with baseline (T0). Additionally, there were significant negative correlations between CRS-R scores and MMN amplitudes elicited by both large and small deviant stimuli.ConclusionLong-term HD-tDCS over precuneus might improve signs of consciousness in patients with DOCs as measured by CRS-R total scores, and MMN could be an assistant assessment in the course of tDCS treatment.

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

BackgroundThe 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.ObjectiveTo identify the moment of recovery of consciousness in documented cases of late emergence from a vegetative state.MethodsFour 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.ResultsAll 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.ConclusionsDelayed 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.

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

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

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

ABSTRACTDifferent 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. We analysed behavioural assessments of 282 patients diagnosed in MCS based on the CRS-R. Results showed that some items are particularly frequent among patients in MCS, namely fixation, visual pursuit, and reproducible movement to command, which were observed in more than 50% of patients. These responses were also the most probably observed items when the patients only showed one sign of consciousness. On the other hand, some items were rarely or never observed alone, e.g., object localisation (reaching), object manipulation, intelligible verbalisation, and object recognition. The results also showed that limiting the CRS-R assessment to the five most frequently observed items (i.e., fixation, visual pursuit, reproducible movement to command, automatic motor response and localisation to noxious stimulation) detected 99% of the patients in MCS. If clinicians have only limited time to assess patients with disorders of consciousness, we suggest to evaluate at least these five items of the CRS-R.

Brain stimulation in patients with disorders of consciousness

Background and Aim : There is a long history of brain stimulation in medical science, and it was tested for years trying to treat several neurological diseases. On the other hand, the treatment choices for patients with severe brain injury resulting in disorders of consciousness (DOC) are still limited and research in this field remains challenging. In the current literature, only a few techniques of brain stimulation were studied in this population of patients. This review describes noninvasive techniques, namely transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), which permit to stimulate the brain through the scalp, as well as the current status of deep brain stimulation (DBS) as treatment for patients with DOC. For each technique (i.e. TMS, tDCS and DBS) a systematic search on Pubmed was performed including the term “vegetative state” or “minimally conscious state” or “disorders of consciousness” and 16 articles matched the criteria. Conclusion : Currently, repetitive TMS (rTMS) and tDCS studies have shown encouraging results, with transient improvements of behavioral signs of consciousness in patients in minimally conscious state (MCS). DBS showed more impressive and extensive behavioral improvement after the implantation of an electrical stimulator in the thalamus. However, this procedure is riskier and the number of patients who can benefit from this intervention is limited. All these therapeutic approaches are still in their infancy. In the years to follow, controlled clinical studies on potential treatments for patients with DOC should multiply and therapeutic measures should be more accessible, controlled and effective. Key-words: disorders of consciousness; unresponsive wakefulness syndrome/vegetative state; minimally conscious state, transcranial magnetic stimulation; transcranial direct current stimulation; deep brain stimulation, mesocircuit model.

Interfaces cerveau-ordinateur,locked-in syndromeet troubles de la conscience

Detecting signs of consciousness in patients with severe brain injury constitutes a real challenge for clinicians. The current gold standard in clinical diagnosis is the behavioral scale relying on motor abilities, which are often impaired or nonexistent in these patients. In this context, brain-computer interfaces (BCIs) could offer a potential complementary tool to detect signs of consciousness whilst bypassing the usual motor pathway. In addition to complementing behavioral assessments and potentially reducing error rate, BCIs could also serve as a communication tool for paralyzed but conscious patients, e.g., suffering from Locked-In Syndrome. In this paper, we report on recent work conducted by the Coma Science Group on BCI technology, aiming to optimize diagnosis and communication in patients with disorders of consciousness and Locked-In syndrome.

Detection of response to command using voluntary control of breathing in disorders of consciousness

Background: Detecting signs of consciousness in patients in a vegetative state/unresponsive wakefulness syndrome (UWS/VS) or minimally conscious state (MCS) is known to be very challenging. Plotkin et al. (2010) recently showed the possibility of using a breathing-controlled communication device in patients with locked in syndrome. We here aim to test a breathing-based “sniff controller” that could be used as an alternative diagnostic tool to evaluate response to command in severely brain damaged patients with chronic disorders of consciousness (DOC).Methods: Twenty-five DOC patients were included. Patients’ resting breathing-amplitude was measured during a 5 min resting condition. Next, they were instructed to end the presentation of a music sequence by sniffing vigorously. An automated detection of changes in breathing amplitude (i.e., >1.5 SD of resting) ended the music and hence provided positive feedback to the patient.Results: None of the 11 UWS/VS patients showed a sniff-based response to command. One out of 14 patients with MCS was able to willfully modulate his breathing pattern to answer the command on 16/19 trials (accuracy 84%). Interestingly, this patient failed to show any other motor response to command.Discussion: We here illustrate the possible interest of using breathing-dependent response to command in the detection of residual cognition in patients with DOC after severe brain injury.