Coma scales: a historical review

Touching the unconscious in the unconscious - hypnotic communication with unconscious patients

If hypnosis means contact to the unconscious to modulate psychological and physiological functions by means of suggestions, and if this is facilitated by attenuation of the critical mind, then the question arises as to whether suggestions also have an effect when waking consciousness is otherwise eliminated, namely by coma or anesthesia. A prerequisite would be perception, which actually is evidenced by reports of patients after traumatic brain injury, artificial coma, resuscitation or general anesthesia. Moreover, posttraumatic stress disorder (PTSD) frequently observed after these medical situations is hardly explainable without some sort of awareness under such conditions. Even advanced neurophysiological diagnostic cannot yet rule out consciousness or sensory processing. Especially reference to perception during unconsciousness is given by the results of a recent multicenter study on the effects of hypnotic communication with patients under controlled adequate deep general anesthesia. The observed reductions in incidence and severity of postoperative pain, opioid use, nausea and vomiting cannot be explained by the reaction of a few but only by a considerable proportion of patients. This leads to a strong plea for a more careful treatment of unconscious patients in the emergency room, operating theater or intensive care unit, for the abandonment of the restriction of therapeutic communication to awake patients, and for new aspects of communication and hypnosis research. Obviously, loss of consciousness does not protect against psychological injury, and continuation of communication is needed. But how and what to talk to unconscious patients? Generally addressing the unconscious mind with suggestions that generally exert their effects unconsciously, hypnotic communication appears to be the adequate language. Especially addressing meaningful topics, as derived from the basic psychological needs and known stressors, appears essential. With respect to negative effects by negative or missing communication or to the proposed protective and supporting effects of therapeutic communication with patients clinically rated as unconscious, the role of consciousness is secondary. For the effects of perceived signals and suggestions it does not matter whether consciousness is absent, or partial, or unrecognized present.

The Message of the Glasgow Coma Scale: A Comprehensive Bibliometric Analysis and Systematic Review of Clinical Practice Guidelines Spanning the Past 50 years

BACKGROUND

Despite the ubiquitous use of the Glasgow Coma Scale (GCS) worldwide, no study to date has objectively and quantitatively assessed its impact on the scientific literature and clinical practice. Therefore, we comprehensively analyzed scientific publications and clinical practice guidelines employing the GCS to gauge its clinical and academic impact, identify research hotspots, and inform future research on the topic.

METHODS

A cross-sectional bibliometric analysis was performed on Scopus to obtain relevant publications incorporating the GCS from 1974 to 2022. In addition, a systematic review of existing clinical practice guidelines in PubMed, Scopus, Web of Science, and Trip Database was performed. Validated bibliometric parameters including article title, journal, publication year, authors, citation count, country, institution, keywords, impact factor, and references were assessed. When evaluating clinical practice guidelines, the sponsoring organization, country of origin, specialty, and publication year were assessed.

RESULTS

A total of 37,633 articles originating from 3924 different scientific journals spanning 1974-2022 were included in the final analysis. The compound annual growth rate of publications referencing the GCS was 16.7%. Of 104 countries, the United States had the highest total number of publications employing the GCS (n = 8517). World Neurosurgery was the scientific periodical with the highest number of publications on the GCS (n = 798). The top trending author-supplied keyword was "traumatic brain injury" (n = 3408). The 97 included clinical practice guidelines most commonly employed the GCS in the fields of internal medicine (n = 22, 23%), critical care (n = 21, 22%), and neurotrauma (n = 19, 20%).

CONCLUSIONS

At the turn of the 50th anniversary of the GCS, we provided a unique and detailed description of the "path to success" of the GCS both in terms of its scientific and clinical impact. These results have not only a historical but also an important didactic value. Ultimately our detailed analysis, which revealed some of the factors that led the GCS to become such a widespread and highly influential score, may assist future researchers in their development of new outcome measures and clinical scores, especially as such tools become increasingly relevant in an evidence-based data-driven age.

Glasgow Coma Scale on admission as predictor of neurological sequelae at discharge and acute respiratory failure in patients with heatstroke

BACKGROUND

Transient neuronal dysfunction may occur in most brain regions with heatstroke (HS). This study aimed to explore the prognostic significance of initial Glasgow Coma Scale (GCS) scores in HS.

METHODS

Retrospective data regarding HS were obtained from six hospitals. The primary outcome was neurological sequelae at discharge. Secondary outcomes included acute respiratory failure (ARF) and intensive care unit (ICU) admission. Logistic regression models and random forest imputation were used to assess the independent association between GCS score and outcomes. Interaction and stratified analyses of body temperature (BT) at 0.5 hours were also conducted. Receiver operating characteristic curves and decision curve analysis were used to estimate prognostic values.

RESULTS

Of 206 patients, 44 (21.36%) had neurological sequelae at discharge. The mean ± standard deviation initial GCS score was 8.17 ± 4.05. After adjustment for confounders, GCS, as a continuous variable, was significantly related to neurological sequelae at discharge [odds ratio (OR): 0.65; 95% confidence interval (CI): 0.50-0.85; P = 0.002], ARF (OR: 0.76; 95% CI: 0.66-0.87; P = 0.001), and ICU admission (OR: 0.68; 95% CI: 0.53-0.87; P = 0.003). These relationships were consistent in the random forest imputation cohort. The OR between GCS and neurological sequelae at discharge was much lower (P = 0.048) in participants with BT at 0.5 hours ≤39°C than in those with BT at 0.5 hours >39°C. The GCS and National Early Warning Score (NEWS) had similar prognostic ability for all outcomes, whereas the net benefits were greater with the GCS compared with the NEWS.

CONCLUSIONS

Initial GCS score was an independent prognostic factor for neurological sequelae at discharge in HS. Rapid cooling played a positive role in this relationship. Key messages What is already known on this topic Brain damage caused by heatstroke (HS) can be transient or result in irreversible injury. Early recognition of those at risk of death or developing neurological complications is very important for improving the outcomes of HS. What this study adds Initial Glasgow Coma Scale (GCS) score was an independent prognostic factor for neurological sequelae at discharge, acute respiratory failure, and intensive care unit (ICU) admission in HS. Rapid cooling played a positive role in this relationship. How this study might affect research, practice, or policy The GCS upon emergency department admission can be a useful predictor of prognosis in patients with HS.

A functional near-infrared spectroscopy study on hemodynamic changes of patients with prolonged disorders of consciousness responding to different auditory stimuli

Treating prolonged disorders of consciousness (pDoC) is challenging. Thus, accurate assessment of residual consciousness in patients with pDoC is important for the management and recovery of patients. Functional near-infrared spectroscopy (fNIRS) can be used to detect brain activity through changes of oxygenated hemoglobin/deoxygenated hemoglobin (HbO/HbR) concentrations changes and has recently gained increasing attention for its potential applications in assessing residual consciousness. However, the number of fNIRS studies assessing residual awareness in patients with pDoC is still limited. In this study, fNIRS was used to evaluate the brain function in 18 patients with pDoC, including 14 vegetative states (VS) and 4 minimally conscious states (MCS), and 15 healthy controls (HC). All participants accepted two types of external stimuli, i.e., active stimulation (motor imagery, MI) and passive stimulation (subject's own name, SON). The results showed that the mean concentrations of HbO/HbR in the prefrontal cortex of the HC during the passive stimulation were significantly lower than those of the active stimulation, and the fitting slope was high. However, the hemodynamic responses of the patients with pDoC were opposite to those of the HC. Additionally, the mean concentrations of HbO/HbR increased as the level of consciousness decreased during passive stimulation. Our findings suggest that the residual level of consciousness in pDoC patients can be assessed by measuring brain responses to different stimulations using fNIRS. The present study further demonstrates the feasibility and reliability of fNIRS in assessing residual consciousness in patients with pDoC, providing a basis for its expanded clinical application.

Assessment of Correlation Between Brain Function Index and Three Common Sedation Scales in Intensive Care Unit Patients

Objectives: This study aimed to evaluate the correlation of the Brain Function Index (BFI) with three criteria of consciousness (Glasgow, Richmond, and FOUR score) in the intensive care unit. Methods: We enrolled patients aged over 15 years who required no muscle relaxants and had no hearing and visual impairment, mental retardation, mental disorder, hemodynamic instability (MAP < 60 mmHg), and hypoxia (SpO2 < 90%), as well as patients with no brain electrical activity disorders such as epilepsy and focal brain disease, and those who had not undergone anesthesia and surgery for the past 24 hours. Results: All ICU patients were enrolled in the study in the autumn and winter based on inclusion and exclusion criteria (n = 85). During 24 hours, BFI and three clinical criteria of sedation and consciousness including RASS, GCS, and FOUR score were assessed three times with a minimum of four-hour intervals. Among the patients, 45 (52.9%) were males, and 40 (47.1%) were females; 24 (28.2%) patients were under 40 years of age, 13 (15.3%) patients were between 41 and 60 years old, and 48 (56.5%) patients were over 61 years old. There was a significant positive relationship between the BFI score of ICU patients and the score of patient consciousness based on RASS, FOUR score, and GCS. The correlation of BFI with the FOUR score was higher than those with the other two criteria. Conclusions: Objective criteria for assessing the consciousness level such as BFI are sufficiently accurate and can be used instead of clinical criteria to assess the level of consciousness in special wards.

Association of the Verbal Component of the GCS With Mortality in Patients With Encephalopathy Who Are Not Undergoing Mechanical Ventilation

BACKGROUND AND OBJECTIVES

The utility of the Glasgow Coma Scale (GCS) in intubated patients is limited due to reliance on language function evaluation. The Full Outline of UnResponsiveness (FOUR) Score was designed to circumvent this shortcoming, instead adding evaluations of brainstem reflexes (FOUR B) and specific respiratory patterns (FOUR R). We aimed to determine if the verbal component of the GCS (GCS V) among encephalopathic non-intubated patients significantly contributes to mortality prediction and to assess GCS vs. FOUR Score performance.

METHODS

All prospectively consented patients ≥18 years admitted to the Internal Medicine service at Zambia's University Teaching Hospital from October 3^rd, 2017 to May 21^st, 2018 with a GCS of ≤10 have undergone simultaneous GCS and FOUR Score assessments. The patients were not eligible for mechanical ventilatory support per local standards. Patients' demographics and clinical characteristics were presented as either percentage frequencies or numerical summaries of spread. The predictive power of the GSC without Verbal component vs. total GCS vs. FOUR Score on mortality were estimated using the area under the receiver operating characteristic (AU-ROC).

RESULTS

235 patients (50% women; mean age 47.5 years) were enrolled. All patients were Black. Presumed etiology was CNS infection (64; 27%), stroke (63; 27%), systemic infection (39; 16.6%), metabolic encephalopathy (3; 14.5 %), 14.9% unknown. In-hospital mortality was 83%. AU ROC for GCS Eye+Motor (0.662) vs. total GCS (0.641) vs. total FOUR Score (0.657) did not differ. Odds ratio mortality for GCS > 6 vs. < 6 was 0.32, 95% CI 0.14-0.72 (p 0.01); for FOUR Score >10 vs. <10 was 0.41, 95% CI 0.19-0.86 (p 0.02).

CONCLUSION

Absence of a verbal component of GCS had no significant impact on total GCS's performance and either GCS or FOUR Score are acceptable scoring tools for mortality prediction in the resource-limited setting. These findings need further validation in the countries with readily available mechanical ventilatory support.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that the verbal component of the GCS does not significantly contribute to a total GCS score in mortality prediction among encephalopathic patients who are not intubated.

A Novel INCNS Score for Prediction of Mortality and Functional Outcome of Comatose Patients

Objectives: The purpose of this study was to verify the veracity and reliability of the INCNS score for prediction of neurological ICU (NICU) mortality and 3-month functional outcome and mortality in comatose patients.

Methods: In this prospective study, data of the patients admitted to NICU from January 2013 to January 2019 were collected for validation. The 3-month functional outcomes were evaluated using modified Rankin Scale (mRS). By using the receiver operating characteristics curve (ROC) analysis, we compared the INCNS score with Glasgow Coma Scale (GCS), Full Outline of Un-Responsiveness Score (FOUR) and Acute Physiology and Chronic Health Evaluation II (APACHE II) for assessment of the predictive performance of these scales for 3-month functional outcome and mortality and NICU mortality performed at 24- and 72-h after admission to the NICU.

Results: Totally 271 patients were used for evaluation; the INCNS score achieved an AUC (area under the receiver operating characteristic curve) of 0.766 (95% CI: 0.711–0.815) and 0.824 (95% CI: 0.774–0.868) for unfavorable functional outcomes, an AUC of 0.848 (95% CI: 0.800–0.889) and 0.892 (95% CI: 0.848–0.926) for NICU mortality, and an AUC of 0.811 (95% CI: 0.760–0.856) and 0.832 (95% CI: 0.782–0.874) for the 3-month mortality after discharge from the NICU at 24- and 72-h. The INCNS score exhibited a significantly better predictive performance of mortality and 3-month functional outcomes than FOUR and GCS. There was no significant difference in predicting NICU mortality and 3-month functional outcomes between INCNS and APACHE II, but INCNS had better predictive performance of 3-month mortality than APACHE II.

Conclusions: The INCNS score could be used for predicting the functional outcomes and mortality rate of comatose patients.

The current significance of the FOUR score: A systematic review and critical analysis of the literature

BACKGROUND

The Full Outline of Un-Responsiveness Score (FOURs) is a scale for clinical assessment of consciousness that was introduced to overcome disadvantages of the widely accepted Glasgow Coma Scale (GCS).

OBJECTIVE

To carry out a systematic review and critical analysis of the available literature on the clinical application of FOURs and perform a comparison to GCS, in terms of reliability and predictive value.

METHODS

Initial search retrieved a total of 147 papers. After applying strict inclusion criteria and further article selection to overcome data heterogeneity, a statistical comparison of inter-rater reliability, in-hospital mortality and long-term outcome prediction between the two scales in the adult and pediatric population was done.

RESULTS

Even though FOURs is more complicated than GCS, its application remains quite simple. Its reliability, validity and predictive value have been supported by an increasing number of studies, especially in critical care. A statistically significant difference (p = .034) in predicting in-hospital mortality in adults, in favor of FOURs when compared to GCS, was found. However, whether it poses a clinically significant advantage in detecting patients' deterioration and outcome prediction, compared to other scaling systems, remains unclear.

CONCLUSIONS

Further studies are needed to discern the FOURs' clinical usefulness, especially in patients in non-critical condition, with milder disorders of consciousness.

Development and validation of a new score for predicting functional outcome of neurocritically ill patients: The INCNS score

Aims

To develop and validate a novel score for prediction of 3‐month functional outcome in neurocritically ill patients.

Methods

The development of the novel score was based on two widely used scores for general critical illnesses (Acute Physiology and Chronic Health Evaluation II, APACHE II; Simplified Acute Physiology Score II, SAPS II) and consideration of the characteristics of neurocritical illness. Data from consecutive patients admitted to neurological ICU (N‐ICU) between January 2013 and June 2016 were used for the validation. The modified Rankin Scale (mRS) was used to evaluate 3‐month functional outcomes. APACHE II scores, SAPS II scores, and our novel scores at 24 hours and 72 hours in N‐ICU were obtained. We compared the prognostic performance of our score with APACHE II and SAPS II.

Results

We developed a 44‐point scoring system named the INCNS score, and it includes 19 items which were categorized into five parts: inflammation (I), nutrition (N), consciousness (C), neurological function (N), and systemic function (S). We validated the INCNS score with a cohort of 941 N‐ICU patients. The 72‐hours INCNS score achieved an area under the receiver operating characteristic curve (AUC) of 0.828 (95% CI: 0.802‐0.854), and the 24‐hours INCNS score achieved an AUC of 0.788 (95% CI: 0.759‐0.817). The INCNS score exhibited significantly better discriminative and prognostic performance than APACHE II and SAPS II at both 24 hours and 72 hours in N‐ICU.

Conclusion

We developed an INCNS score with superior predictive power for functional outcome of neurocritically ill patients.

Michel Jouvet as a clinical neurophysiologist and neurologist

While the world reputation of Michel Jouvet in sleep research is based on his huge work on sleep and paradoxical sleep, especially in cats, a far less-known part of his activity was dedicated to investigate and take care of patients with neurological diseases. Indeed, he was also a physician, specialized in neurophysiology and working at the neurological hospital of Lyon. He was most interested first in patients with disorders of consciousness and secondly in those with sleep/wake disorders, and especially in modafinil for the treatment of patients with narcolepsy and idiopathic hypersomnia.

Predisposing factors, clinical assessment, management and outcomes of agitation in the trauma intensive care unit

BACKGROUND

Agitation occurs frequently among critically ill patients admitted to the intensive care unit (ICU). We aimed to evaluate the frequency, predisposing factors and outcomes of agitation in trauma ICU.

METHODS

A retrospective analysis was conducted to include patients who were admitted to the trauma ICU between April 2014 and March 2015. Data included patient's demographics, initial vitals, associated injuries, Ramsey Sedation Scale, Glasgow Coma Scale, head injury lesions, use of sedatives and analgesics, head interventions, ventilator days, and ICU length of stay. Patients were divided into two groups based on the agitation status.

RESULTS

A total of 102 intubated patients were enrolled; of which 46 (45%) experienced agitation. Patients in the agitation group were 7 years younger, had significantly lower GCS and sustained higher frequency of head injuries (P<0.05). Patients who developed agitation were more likely to be prescribed propofol alone or in combination with midazolam and to have frequent ICP catheter insertion, longer ventilatory days and higher incidence of pneumonia (P<0.05). On multivariate analysis, use of propofol alone (OR=4.97; 95% CI=1.35-18.27), subarachnoid hemorrhage (OR=5.11; 95% CI=1.38-18.91) and ICP catheter insertion for severe head injury (OR=4.23; 95% CI=1.16-15.35) were independent predictors for agitation (P<0.01).

CONCLUSION

Agitation is a frequent problem in trauma ICU and is mainly related to the type of sedation and poor outcomes in terms of prolonged mechanical ventilation and development of nosocomial pneumonia. Therefore, understanding the main predictors of agitation facilitates early risk-stratification and development of better therapeutic strategies in trauma patients.

Identifying Disruptions in Intrinsic Brain Dynamics due to Severe Brain Injury

Recent studies suggest that disruptions in resting state functional connectivity - a measure of stationary statistical association between brain regions - can be used as an objective marker of brain injury. However, fewer characterizations have examined the disruption of intrinsic brain dynamics after brain injury. Here, we examine this issue using electroencephalographic (EEG) data from brain-injured patients, together with a control analysis wherein we quantify the effect of the injury on the ability of intrinsic event responses to traverse their respective state spaces. More specifically, the lability of intrinsically evoked brain activity was assessed by collapsing three sigma event responses in all channels of the obtained EEG signals into a low-dimensional space. The directional derivative of these responses was then used to assay the extent to which brain activity reaches low-variance subspaces. Our findings suggest that intrinsic dynamics extracted from resting state EEG signals can differentiate various levels of consciousness in severe cases of coma. More specifically the cost of moving from one state to another in the state-space trajectories of the underlying dynamics becomes lower as the level of consciousness of patients deteriorates.

Effect of Admission Glasgow Coma Scale Motor Score on Neurological Outcome in Out-of-Hospital Cardiac Arrest Patients Receiving Therapeutic Hypothermia

BACKGROUND

Because the initial (on admission) Glasgow Coma Scale (GCS) examination has not been fully evaluated in comatose survivors of cardiac arrest (CA) who receive therapeutic hypothermia (TH), the aim of the present study was to determine any association between the admission GCS motor score and neurologic outcomes in patients with out-of-hospital CA who receive TH.

METHODS AND RESULTS

In the J-PULSE-HYPO study registry, patients with bystander-witnessed CA were eligible for inclusion. Patients were divided into 3 groups based on GCS motor score (1, 2-3, and 4-5) to assess various effects on neurologic outcome. Univariate and multivariate analyses were performed to identify independent predictors of good neurologic outcome at 90 days. Of 452 patients, 302 were enrolled. There was a significant difference among the 3 patient groups with regard to neurologic outcome at 90 days in the univariate analysis. Multiple logistic regression analyses showed that the GCS motor score on admission, age >65 years, bystander cardiopulmonary resuscitation, the time from collapse to return of spontaneous circulation, and pupil size <4 mm were independent predictors of a good neurologic outcome at 90 days in cases of CA (GCS motor score, 4-5: odds ratio, 8.18; 95% confidence interval: 1.90-60.28; P<0.01).

CONCLUSIONS

GCS motor score is an independent predictor of good neurologic outcome at 90 days in patients sustaining out-of-hospital CA who receive TH.

The evolution of neurocritical care

Although neurocritical care as a subspecialty is a relatively young field of medicine, its origins can be traced back to ancient times. This article focuses on the progression of neurocritical care from prehistoric trepanation procedures, through the development of mechanical ventilation, management of increased intracranial pressure, and traumatic brain injury, to the establishment of the first "real" intensive care units, and finally to modern monitoring in neurocritical care, management of post-cardiac arrest patients, and the diagnosis of brain death. This article also focuses on the future direction of neurocritical care.

Eye movement measurement in diagnostic assessment of disorders of consciousness

We review the literature to appraise the evidence supporting or disputing the use of eye movement measurement in disorders of consciousness (DOC) with low levels of arousal or awareness, such as minimally conscious state (MCS), vegetative state (VS), and coma for diagnostic and prognostic purposes. We will focus on the effectiveness of each technique in the diagnostic classification of these patients and the gradual trend in research from manual to computerized tracking methods. New tools have become available at clinicians' disposal to assess eye movements with high spatial and temporal fidelity. The close relationship between eye movement generation and organic dysfunction in the brain allows these tools to be applied to the assessment of severe DOC as a unique supplementary toolset. We posit that eye tracking can improve clinical diagnostic precision for DOC, a key component of assessment that often dictates the course of clinical care in DOC patients. We see the emergence of long-term eye-tracking studies with seamless integration of technology in the future to improve the performance of clinical assessment in DOC.

A useful new coma scale in acute stroke patients: FOUR score

Assessment of the severity of unconsciousness in patients with impaired consciousness, prediction of mortality and prognosis are currently the most studied subjects in intensive care. The aim of this study was to investigate the usefulness of the Full Outline of UnResponsiveness (FOUR) score in intensive care unit patients with stroke and the associations of FOUR score with the clinical outcome and with other coma scales (Glasgow [GCS] and Acute Physiology and Chronic Health Evaluation II). One hundred acute stroke patients (44 male, 56 female), who were followed in a neurology intensive care unit, were included in this prospective study. The mean age of the patients was 70.49 ± 12.42 years. Lesion types were determined as haemorrhagic in 30 and ischaemic in 70 patients. FOUR scores on the day of admission and the first, third and 10th days of patients who died within 15 days were lower when compared to scores of patients who survived (P=0.005, P=0.000, P=0.000 and P=0.000 respectively). Receiver operating characteristic curve analysis showed significant trending with both FOUR score and GCS for prognosis; the area under curve ranged from 0.675 (95% confidence interval 0.565 to 0.786) when measurements had been made on day 3 to 0.922 (95% confidence interval 0.867 to 0.977) and 0.981 (95% confidence interval 0.947 to 1.015) for day 10. We suggest that FOUR score is a useful scale for evaluation of acute stroke patients in the intensive care unit as a homogeneous group, with respect to the outcome estimation.