Pharmacotherapy for disorders of consciousness: are 'awakening' drugs really a possibility?

Disorders of consciousness and pharmacotherapy: A systematic update on drugs inducing consciousness improvement

BACKGROUND

Disorders of consciousness (DOC) represent some of the least comprehended and challenging conditions within contemporary neurology. Pharmacological interventions are capable of enhancing neurotransmitter levels, synaptic plasticity and functional connectivity within consciousness networks.

OBJECTIVE

This systematic work aims to provide a comprehensive 10-year update regarding the use of drugs that may induce consciousness improvement in patients with DOC.

METHODS

A review of current literature was performed for articles published between 2014 and 2023. A study was excluded if there was a lack of data or information about pharmacological treatment in patients with DOC.

RESULTS

12 studies with a total amount of 429 patients were identified as eligible for this paper. From our data review, 2 studies with 34 patients were identified on Baclofen. The latter was identified as the most effective treatment with an 82.35 % efficacy rate. On the other hand, 2 studies with 53 patients were identified for Amantadine that also show a substantial effectiveness of 68.42 %. Zolpidem was the most widely used medication as it was employed in 6 studies with 289 patients. Nevertheless, its efficacy showed high variability among individuals resulting in a comparatively lower average efficacy rate of 18.42 %. Finally, Opioids were evaluated in two studies with 53 patients showing an efficacy of 44 %. Within this category, the effectiveness of Propofol remained inconclusive due to the lack of specific improvement data. Overall, Baclofen and Amantadine emerged as the most effective treatments for improving conditions in patients with Disorders of Consciousness DoC.

CONCLUSIONS

Over the last 10 years, amantadine and baclofen have proven to be the most promising treatments in terms of efficacy.

The Dipeptidyl Peptidase-4 Inhibitor Saxagliptin as a Candidate Treatment for Disorders of Consciousness: A Deep Learning and Retrospective Clinical Analysis

BACKGROUND

Despite advancements in the neuroscience of consciousness, no new medications for disorders of consciousness (DOC) have been discovered in more than a decade. Repurposing existing US Food and Drug Administration (FDA)-approved drugs for DOC is crucial for improving clinical management and patient outcomes.

METHODS

To identify potential new treatments among existing FDA-approved drugs, we used a deep learning-based drug screening model to predict the efficacy of drugs as awakening agents based on their three-dimensional molecular structure. A retrospective cohort study from March 2012 to October 2024 tested the model's predictions, focusing on changes in Glasgow Coma Scale (GCS) scores in 4047 patients in a coma from traumatic, vascular, or anoxic brain injury.

RESULTS

Our deep learning drug screens identified saxagliptin, a dipeptidyl peptidase-4 inhibitor, as a promising awakening drug for both acute and prolonged DOC. The retrospective clinical analysis showed that saxagliptin was associated with the highest recovery rate from acute coma among diabetes medications. After matching patients by age, sex, initial GCS score, coma etiology, and glycemic status, brain-injured patients with diabetes on incretin-based therapies, including dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 analogues, recovered from coma at significantly higher rates compared to both brain-injured patients with diabetes on non-incretin-based diabetes medications (95% confidence interval of 1.8-14.1% higher recovery rate, P = 0.0331) and brain-injured patients without diabetes (95% confidence interval of 2-21% higher recovery rate, P = 0.0272). Post matching, brain-injured patients with diabetes on incretin-based therapies also recovered at a significantly higher rate than patients treated with amantadine (95% confidence interval for the difference 2.4-25.1.0%, P = 0.0364). A review of preclinical studies identified several pathways through which saxagliptin and other incretin-based medications may aid awakening from both acute and chronic DOC: restoring monoaminergic and GABAergic neurotransmission, reducing brain inflammation and oxidative damage, clearing hyperphosphorylated tau and amyloid-β, normalizing thalamocortical glucose metabolism, increasing neural plasticity, and mitigating excitotoxic brain damage.

CONCLUSIONS

Our findings suggest incretin-based medications in general, and saxagliptin in particular, as potential novel therapeutic agents for DOC. Further prospective clinical trials are needed to confirm their efficacy and safety in DOC.

Cognitive Effects of Transcranial Direct Current Stimulation Plus Robotic Verticalization in Minimally Conscious State

BACKGROUND AND OBJECTIVES

Transcranial direct current stimulation (tDCS) is a non-invasive therapeutic method that modulates cortical excitability and shows promising results for treating disorders of consciousness (DoCs). Robotic verticalization training (RVT) has been shown to enhance motor and cognitive recovery. This study evaluates the effects of an innovative approach combining RVT with tDCS in individuals with DoCs.

METHODS

Twenty-four subjects with DoCs, particularly those with chronic minimally conscious state (MCS) due to vascular or traumatic brain injury, participated in a quasi-randomized study at the Neurorehabilitation Unit, IRCCS Neurolesi (Messina, Italy). Participants were divided into either a control group (CG) receiving RVT alone or an experimental group (EG) receiving combined tDCS and RVT. Both groups underwent treatments five times weekly for four weeks, with tDCS/sham sessions over the dorsolateral prefrontal cortex (DLPFC) lasting 20 min before Erigo training sessions, which lasted 45 min.

RESULTS

The findings indicate that combining tDCS with Erigo® Pro RTT could lead to greater improvements in cognitive functioning and P300 latency compared to the CG.

CONCLUSIONS

These results suggest that the integrated approach of tDCS with RVT could offer significant benefits for patients with MCS, highlighting its potential to enhance cognitive recovery, such as reducing P300 latency.

Coping Strategies in Patients with Acquired Brain Injury: A Scoping Review

In recent years, there has been marked interest in looking at the psychological consequences of medical conditions, such as traumatic or acquired brain injuries. Coping strategies are essential for clinical recovery and for dealing with the stressful events that a clinical condition brings with it. The purpose of this review is to analyze studies that explore how coping strategies influence psychological changes in patients with acquired brain injury. Studies were identified from research in the PubMed, Scopus, and Embase databases. According to our findings, patients with ABI utilize different coping strategies based on the circumstances and factors such as the diagnosis severity, their age, time lived with the pathology, and personal characteristics, which have an influence on quality of life and rehabilitation. This review demonstrated that coping strategies have an impact on different aspects of the clinical and personal lives of patients with ABI. The rehabilitation process must consider the influence of these mechanisms on dealing with situations, as they can change cognitive and emotional perceptions of patients' experience with the disease, as well as laying the foundations for functional or dysfunction in terms of the propensity of a person for the path of psychological and physical recovery.

Distinct Spectral Profiles of Awake Resting EEG in Disorders of Consciousness: The Role of Frequency and Topography of Oscillations

The prolonged disorders of consciousness (PDOC) pose a challenge for an accurate clinical diagnosis, mainly due to patients' scarce or ambiguous behavioral responsiveness. Measurement of brain activity can support better diagnosis, independent of motor restrictions. Methods based on spectral analysis of resting-state EEG appear as a promising path, revealing specific changes within the internal brain dynamics in PDOC patients. In this study we used a robust method of resting-state EEG power spectrum parameter extraction to identify distinct spectral properties for different types of PDOC. Sixty patients and 37 healthy volunteers participated in this study. Patient group consisted of 22 unresponsive wakefulness patients, 25 minimally conscious patients and 13 patients emerging from the minimally conscious state. Ten minutes of resting EEG was acquired during wakefulness and transformed into individual power spectra. For each patient, using the spectral decomposition algorithm, we extracted maximum peak frequency within 1-14 Hz range in the centro-parietal region, and the antero-posterior (AP) gradient of the maximal frequency peak. All patients were behaviorally diagnosed using coma recovery scale-revised (CRS-R). The maximal peak frequency in the 1-14 Hz range successfully predicted both neurobehavioral capacity of patients as indicated by CRS-R total score and PDOC diagnosis. Additionally, in patients in whom only one peak within the 1-14 Hz range was observed, the AP gradient significantly contributed to the accuracy of prediction. We have identified three distinct spectral profiles of patients, likely representing separate neurophysiological modes of thalamocortical functioning. Etiology did not have significant influence on the obtained results.

A scoping review for building a criticality-based conceptual framework of altered states of consciousness

The healthy conscious brain is thought to operate near a critical state, reflecting optimal information processing and high susceptibility to external stimuli. Conversely, deviations from the critical state are hypothesized to give rise to altered states of consciousness (ASC). Measures of criticality could therefore be an effective way of establishing the conscious state of an individual. Furthermore, characterizing the direction of a deviation from criticality may enable the development of treatment strategies for pathological ASC. The aim of this scoping review is to assess the current evidence supporting the criticality hypothesis, and the use of criticality as a conceptual framework for ASC. Using the PRISMA guidelines, Web of Science and PubMed were searched from inception to February 7th 2022 to find articles relating to measures of criticality across ASC. N = 427 independent papers were initially found on the subject. N = 378 were excluded because they were either: not related to criticality; not related to consciousness; not presenting results from a primary study; presenting model data. N = 49 independent papers were included in the present research, separated in 7 sub-categories of ASC: disorders of consciousness (DOC) (n = 5); sleep (n = 13); anesthesia (n = 18); epilepsy (n = 12); psychedelics and shamanic state of consciousness (n = 4); delirium (n = 1); meditative state (n = 2). Each category included articles suggesting a deviation of the critical state. While most studies were only able to identify a deviation from criticality without being certain of its direction, the preliminary consensus arising from the literature is that non-rapid eye movement (NREM) sleep reflects a subcritical state, epileptic seizures reflect a supercritical state, and psychedelics are closer to the critical state than normal consciousness. This scoping review suggests that, though the literature is limited and methodologically inhomogeneous, ASC are characterized by a deviation from criticality, though its direction is not clearly reported in a majority of studies. Criticality could become, with more extensive research, an effective and objective way to characterize ASC, and help identify therapeutic avenues to improve criticality in pathological brain states. Furthermore, we suggest how anesthesia and psychedelics could potentially be used as neuromodulation techniques to restore criticality in DOC.

Sleep in Disorders of Consciousness: A Brief Overview on a Still under Investigated Issue

Consciousness is a multifaceted concept, involving both wakefulness, i.e., a condition of being alert that is regulated by the brainstem, and awareness, a subjective experience of any thoughts or perception or emotion. Recently, the European Academy of Neurology has published international guidelines for a better diagnosis of coma and other disorders of consciousness (DOC) through the investigation of sleep patterns, such as slow-wave and REM, and the study of the EEG using machine learning methods and artificial intelligence. The management of sleep disorders in DOC patients is an increasingly hot topic and deserves careful diagnosis, to allow for the most accurate prognosis and the best medical treatment possible. The aim of this review was to investigate the anatomo-physiological basis of the sleep/wake cycle, as well as the main sleep patterns and sleep disorders in patients with DOC. We found that the sleep characteristics in DOC patients are still controversial. DOC patients often present a theta/delta pattern, while epileptiform activity, as well as other sleep elements, have been reported as correlating with outcomes in patients with coma and DOC. The absence of spindles, as well as REM and K-complexes of NREM sleep, have been used as poor predictors for early awakening in DOC patients, especially in UWS patients. Therefore, sleep could be considered a marker of DOC recovery, and effective treatments for sleep disorders may either indirectly or directly favor recovery of consciousness.

Opioid-induced short-term consciousness improvement in patients with disorders of consciousness

Introduction

Effective treatment to facilitate recovery from prolonged disorders of consciousness is a complex topic for the medical community. In clinical practice, we have found that a subset of patients has a short-term improvement of consciousness after general anesthesia.

Methods

To determine the clinical factors responsible for the consciousness improvement, we enrolled 50 patients with disorders of consciousness who underwent surgery from October 2021 to June 2022. Their states of consciousness were evaluated before surgery, within 48 h after surgery, and 3 months after surgery. Clinical-related factors and intraoperative anesthetic drug doses were collected and compared between patients with and without consciousness improvement. Independent associations between selected factors and postoperative improvement were assessed using multivariate logistical regression analyses.

Results

Postoperative short-term consciousness improvement was found in 44% (22/50) of patients, with significantly increased scores of auditory and visual subscales. Patients with traumatic etiology, a preoperative diagnosis of minimally conscious state, and higher scores in the auditory, visual, and motor subscales were more likely to have postoperative improvement. This short-term increase in consciousness after surgery correlated with patients' abilities to communicate in the long term. Furthermore, the amount of opioid analgesic used was significantly different between the improved and non-improved groups. Finally, analgesic dose, etiology, and preoperative diagnosis were independently associated with postoperative consciousness improvement.

Discussion

In conclusion, postoperative consciousness improvement is related to the residual consciousness of the patient and can be used to evaluate prognosis. Administration of opioids may be responsible for this short-term improvement in consciousness, providing a potential therapeutic approach for disorders of consciousness.

Clinical Decision on Disorders of Consciousness After Acquired Brain Injury: Stepping Forward

Major advances have been made over the past few decades in identifying and managing disorders of consciousness (DOC) in patients with acquired brain injury (ABI), bringing the transformation from a conceptualized definition to a complex clinical scenario worthy of scientific exploration. Given the continuously-evolving framework of precision medicine that integrates valuable behavioral assessment tools, sophisticated neuroimaging, and electrophysiological techniques, a considerably higher diagnostic accuracy rate of DOC may now be reached. During the treatment of patients with DOC, a variety of intervention methods are available, including amantadine and transcranial direct current stimulation, which have both provided class II evidence, zolpidem, which is also of high quality, and non-invasive stimulation, which appears to be more encouraging than pharmacological therapy. However, heterogeneity is profoundly ingrained in study designs, and only rare schemes have been recommended by authoritative institutions. There is still a lack of an effective clinical protocol for managing patients with DOC following ABI. To advance future clinical studies on DOC, we present a comprehensive review of the progress in clinical identification and management as well as some challenges in the pathophysiology of DOC. We propose a preliminary clinical decision protocol, which could serve as an ideal reference tool for many medical institutions.

Esketamine Increases Neurotransmitter Releases but Simplifies Neurotransmitter Networks in Mouse Prefrontal Cortex

General anesthesia induces a profound but reversible unconscious state, which is accompanied by changes in various neurotransmitters in the cortex. Unlike the "brain silencing" effect of γ-aminobutyric acid (GABA) receptor potentiator anesthesia, ketamine anesthesia leads the brain to a paradoxical active state with higher cortical activity, which is manifested as dissociative anesthesia. However, how the overall neurotransmitter network evolves across conscious states after ketamine administration remains unclear. Using in vivo microdialysis, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, and electroencephalogram (EEG) recording technique, we continuously measured the concentrations of six neurotransmitters and the EEG signals during anesthesia with esketamine, an S-enantiomer of ketamine racemate. We found that there was an increase in the release of five cortical neurotransmitters after the administration of esketamine. The correlation of cortical neurotransmitters was dynamically simplified along with behavioral changes until full recovery after anesthesia. The esketamine-increased gamma oscillation power was positively correlated only with the concentration of 5-hydroxytryptamine (5-HT) in the medial prefrontal cortex. This study suggests that the transformation of the neurotransmitter network rather than the concentrations of neurotransmitters could be more indicative of the consciousness shift during esketamine anesthesia.

Sleep Treatments in Disorders of Consciousness: A Systematic Review

Sleep disorders are among the main comorbidities in patients with a Disorder of Consciousness (DOC). Given the key role of sleep in neural and cognitive functioning, detecting and treating sleep disorders in DOCs might be an effective therapeutic strategy to boost consciousness recovery and levels of awareness. To date, no systematic reviews have been conducted that explore the effect of sleep treatments in DOCs; thus, we systematically reviewed the existing studies on both pharmacological and non-pharmacological treatments for sleep disorders in DOCs. Among 2267 assessed articles, only 7 were included in the systematic review. The studies focused on two sleep disorder categories (sleep-related breathing disorders and circadian rhythm dysregulation) treated with both pharmacological (Modafinil and Intrathecal Baclofen) and non-pharmacological (positive airway pressure, bright light stimulation, and central thalamic deep brain stimulation) interventions. Although the limited number of studies and their heterogeneity do not allow generalized conclusions, all the studies highlighted the effectiveness of treatments on both sleep disorders and levels of awareness. For this reason, clinical and diagnostic evaluations able to detect sleep disorders in DOC patients should be adopted in the clinical routine for the purpose of intervening promptly with the most appropriate treatment.

Nursing, Caregiving and Psychological support in Chronic Disorders of Consciousness: a scoping review

BACKGROUND AND AIMS

The major disorders of consciousness include Coma, Vegetative State, and Minimally Conscious State. The care and the management of patients with Disorders of Consciousness (DOC) have raised several important ethical, social and medical issues. Aim of this review is to evaluate the role of nursing and psychological support in DOC management, in order to improve the quality of life of both patients and their caregivers.

METHODS

Studies dealing with DOC, nursing and caregiving pubblished in the last 20 years (from January 2000 to June 2020) were identified by searching on PubMed, Web of Science and Cochrane databases.

RESULTS

This review highlights the important role of DOC carevigers in the complex management of these frail patients, as well as the need for a specific support and counselling of caregivers. This psychological support may be given by nurses, as they are the healthcare professionals more involved in DOC care and cure.

DISCUSSION

Over the last years, specific recommendations for the assessment and rehabilitation of patients with DOC have been promulgated by neurorehabilitation organizations to provide some guidelines for the care and cure of such frail patients. Indeed, DOC patients need a multidisciplinary approach in which both caregivers and nurses have a pivotal role.

CONCLUSIONS

As the family is a critical and fundamental aspect in the management of DOC patients, it should be considered an integral part of care in the future guidelines.

[Results of treatment with intravenous amantadine sulfate (PK-Merz) patients with chronic disorders of consciousness]

The article presents literature review of the recent publications devoted to the drugs with dopaminergic, antiglutamatergic and GABA-ergic effects in the treatment of patients with vegetative state/areactive wakefulness syndrome (VS/AWS). The authors analyzed their own results of the effects of intravenous form of amantadine sulfate (PK Merz) in 142 VS/AWS patients caused by different etiological factors. Depending on the dominant neurological symptoms, patients were divided into three main groups: areactive type of course (group 1 - 61 patients), predominance of primitive limbic reactions (group 2 - 35 patients) and predominance of extrapyramidal symptoms (group 3 - 46 patients). Therapy results were evaluated one month later by CRS-R scale, which showed that the most distinct positive dynamics was observed in group 3.

P2RX7 in Dopaminergic Neurons of Ventral Periaqueductal Gray Mediates HTWP Acupuncture-Induced Consciousness in Traumatic Brain Injury

The induction of a coma by traumatic brain injury (TBI) is a crucial factor for poor clinical prognoses. We report that acupuncture at the hand 12 Jing-Well points (HTWP) improved consciousness and neurologic function in TBI rats. Gene chip analyses showed that HTWP acupuncture mostly activated genes modulating neuronal projections (P2rx7, P2rx3, Trpv1, Tacr1, and Cacna1d), protein secretion (Exoc1, Exoc3l1, Fgb, and Fgr), and dopamine (DA) receptor D3 (Drd3) in the ventral periaqueductal gray (vPAG), among which the expression rate of P2rx7 was the most obviously increased. Acupuncture also increased the expression and excitability of DA and P2RX7 neurons, and the DA neurons expressed P2RX7, P2RX3, and TRPV1 in the vPAG. Intracerebroventricular administration of P2RX7, P2RX3, or TRPV1 antagonists blocked acupuncture-induced consciousness, and the subsequent injection of a P2RX7 antagonist into the vPAG nucleus also inhibited this effect. Our findings provide evidence that acupuncture alleviates TBI-induced comas via DA neurons expressing P2RX7 in the vPAG, so as to reveal the cellular and molecular mechanisms of the improvement of TBI clinical outcomes by HTWP acupuncture.

The minimal self hypothesis

For millennia self has been conjectured to be necessary for consciousness. But scant empirical evidence has been adduced to support this hypothesis. Inconsistent explications of "self" and failure to design apt experiments have impeded progress. Advocates of phenomenological psychiatry, however, have helped explicate "self," and employed it to explain some psychopathological symptoms. In those studies, "self" is understood in a minimalist sense, sheer "for-me-ness." Unfortunately, explication of the "minimal self" (MS) has relied on conceptual analysis, and applications to psychopathology have been hermeneutic, allowing for many degrees of interpretive latitude. The result is that MS's current scientific status is analogous to that of the "atom," at the time when "atom" was just beginning to undergo transformation from a philosophical to a scientific concept. Fortunately, there is now an opportunity to promote a similar transformation for "MS." Discovery of the brain's Default Mode Network (DMN) opened the door to neuroimaging investigations of self. Taking the DMN and other forms of intrinsic activity as a starting point, an empirical foothold can be established, one that spurs experimental research and that enables extension of research into multiple phenomena. New experimental protocols that posit "MS" can help explain phenomena hitherto not thought to be related to self, thereby hastening development of a mature science of self. In particular, targeting phenomena wherein consciousness is lost and recovered, as in some cases of Unresponsive Wakefulness Syndrome (UWS), allow for design of neuroimaging probes that enable detection of MS during non-conscious states. These probes, as well as other experimental protocols applied to NREM Sleep, General Anesthesia (GA), and the waking state, provide some evidence to suggest that not only can self and consciousness dissociate, MS might be a necessary precondition for conscious experience. Finally, these findings have implications for the science of consciousness: it has been suggested that "levels of consciousness" (LoC) is not a legitimate concept for the science of consciousness. But because we have the conceptual and methodological tools with which to refine investigations of MS, we have the means to identify a possible foundation-a bifurcation point-for consciousness, as well as the means by which to measure degrees of distance from that foundation. These neuroimaging investigations of MS position us to better assess whether LoC has a role to play in a mature science of consciousness.

Wake-Promoting Effect of Bloodletting Puncture at Hand Twelve Jing-Well Points in Acute Stroke Patients: A Multi-center Randomized Controlled Trial

OBJECTIVE

To assess the effect and safety of bloodletting puncture at hand twelve Jing-Well points (HTWPs) in acute stroke patients with conscious disturbance.

METHODS

In this multi-center and randomized controlled trial, 360 patients suffered from ischemic or hemorrhagic stroke with conscious disturbance within 48 h from the onset of symptom were divided into bloodletting (180 cases) and control (180 cases) groups using a block randomization. Patients in both groups received routine Western medicine, and patients in the bloodletting group received additional bloodletting puncture at HTWPs on admission immediately before conventional treatment. The primary outcome measure was Glasgow Coma Scale (GCS) score and the secondary outcomes included blood pressure, respiratory rate and pulse rate. All variables were evaluated at baseline (before bloodletting), 0 (after bloodletting immediately), 15, 30, 50 and 80 min post bloodletting.

RESULTS

At 80 min post bloodletting, the proportion of patients with improved consciousness in the bloodletting group was greater than the control group (P<0.05). In the separate analysis of moderate consciousness disturbance subgroup, bloodletting therapy benefited ischemic patients, and improved the eye and language response of GCS score at 15, 30, 50, 80 min post bloodletting (P<0.05 or P<0.01). No significant differences were observed regarding the secondary outcomes between two groups (P>0.05).

CONCLUSION

The bloodletting puncture at HTWPs was safe and could improve conscious levels of ischemic stroke patients, highlighting a first-aid intervention for acute stroke. (Registration No. ChiCTR-INR-16009530).

Persistent vegetative state after severe cerebral hemorrhage treated with amantadine: A retrospective controlled study

Amantadine is currently recommended for use in patients of posttraumatic brain injury with unconsciousness. However, the application of amantadine in consciousness disturbance after cerebral hemorrhage has only been rarely reported. This allows for a further exploration of the role of amantadine in the treatment of PVS resulting from severe cerebral hemorrhage.Retrospective cohort study from 1/2015 to 7/2019 in Beijing Chaoyang hospital. We included adult patients treated with amantadine after severe cerebral hemorrhage in PVS. Primary outcome was time of consciousness recovery and Glasgow Out Scale scores after 5 months from onset. We compared characteristics and outcomes to a control cohort. matched on age, Coma Recovery Scale-Revised score, volume and location of hemorrhage.Among the 12 patients who received amantadine treatment, 6 patients regained consciousness (50%) after 5 months of disease onset, but were still severely disabled. Besides, the time for regaining consciousness was within 3 months of disease onset. The remaining 6 patients were still in a PVS. Compared with the amantadine group, the consciousness recovery rate (50% vs 33.3%, P = .68) after 5 months in the nested control group was not significantly different. The awakening time for patients in the amantadine group was earlier than the control group (100% vs 25%, P = .03).In this study, amantadine can accelerate the recovery of consciousness in patients following severe cerebral hemorrhage. We recommend further randomized controlled studies to determine the efficacy of amantadine.

Neurophysiology and Treatment of Disorders of Consciousness Induced by Traumatic Brain Injury: Orexin Signaling as a Potential Therapeutic Target

BACKGROUND

Traumatic brain injury (TBI) can cause disorders of consciousness (DOC) by impairing the neuronal circuits of the ascending reticular activating system (ARAS) structures, including the hypothalamus, which are responsible for the maintenance of the wakefulness and awareness. However, the effectiveness of drugs targeting ARAS activation is still inadequate, and novel therapeutic modalities are urgently needed.

METHODS

The goal of this work is to describe the neural loops of wakefulness, and explain how these elements participate in DOC, with emphasis on the identification of potential new therapeutic options for DOC induced by TBI.

RESULTS

Hypothalamus has been identified as a sleep/wake center, and its anterior and posterior regions have diverse roles in the regulation of the sleep/wake function. In particular, the posterior hypothalamus (PH) possesses several types of neurons, including the orexin neurons in the lateral hypothalamus (LH) with widespread projections to other wakefulness-related regions of the brain. Orexins have been known to affect feeding and appetite, and recently their profound effect on sleep disorders and DOC has been identified. Orexin antagonists are used for the treatment of insomnia, and orexin agonists can be used for narcolepsy. Additionally, several studies demonstrated that the agonists of orexin might be effective in the treatment of DOC, providing novel therapeutic opportunities in this field.

CONCLUSION

The hypothalamic-centered orexin has been adopted as the point of entry into the system of consciousness control, and modulators of orexin signaling opened several therapeutic opportunities for the treatment of DOC.

[Bromocriptine in disorders of consciouness due to traumatic brain injury]

INTRODUCTION

The aim of this study was to assess the results and adverse effects of bromocriptine in patients with traumatic brain injury-vegetative state (TBI-VS) or traumatic brain injury-minimally conscious state (TBI-MCS).

METHODS

We conducted a retrospective review of 10 patients, six with TBI-VS and four with TBI-MCS. All patients received bromocriptine at a starting dose of 2.5mg twice daily. Bromocriptine was titrated up to 7.5 or 12.5mg twice daily according to response and was maintained for at least 4 weeks. Various assessment scales were used in the following stages: before bromocriptine administration, at 4 weeks post bromocriptine prescription, and at hospital discharge. The assessment scales used were the Coma Recovery Scale-Revised (CRS-R), Disability Rating Scale, Glasgow Coma Scale, Barthel Scale, and Marshall Scale.

RESULTS

Of the 10 patients, four with TBI-MCS and four with TBI-VS achieved a score of 23 points at discharge in the CRS-R, thus emerging from VS or MCS and regaining functional status. There were only two patients who emerged from VS but remained in MCS (8 to 11 and 5 to 10 points in CRS-R).

CONCLUSIONS

Considering the poor prognosis for recovery in these patients, bromocriptine use has a positive risk-benefit ratio at a dosage of at least 7.5mg twice daily for 4 weeks.

Psychedelics as a treatment for disorders of consciousness

Based on its ability to increase brain complexity, a seemingly reliable index of conscious level, we propose testing the capacity of the classic psychedelic, psilocybin, to increase conscious awareness in patients with disorders of consciousness. We also confront the considerable ethical and practical challenges this proposal must address, if this hypothesis is to be directly assessed.

Neuroimaging characterization of recovery of impaired consciousness in patients with disorders of consciousness

Elucidation of critical brain areas or structures that are responsible for recovery of impaired consciousness in patients with disorders of consciousness is important because it can provide information that is useful when developing therapeutic strategies for neurorehabilitation or neurointervention in patients with disorders of consciousness. In this review, studies that have demonstrated brain changes during recovery of impaired consciousness were reviewed. These studies used positron emission tomography, electroencephalography/transcranial magnetic stimulation, diffusion tensor tractography, and diffusion tensor tractography/electroencephalography. The majority of these studies reported on the importance of supratentorial areas or structures in the recovery of impaired consciousness. The important brain areas or structures that were identified were the prefrontal cortex, basal forebrain, anterior cingulate cortex, and parietal cortex. These results have a clinically important implication that these brain areas or structures can be target areas for neurorehabilitation or neurointervention in patients with disorders of consciousness. However, most of studies were case reports; therefore, further original studies involving larger numbers of patients with disorders of consciousness are warranted. In addition, more detailed information on the brain areas or structures that are relevant to the recovery of impaired consciousness is needed.

Treating Disorders of Consciousness With Apomorphine: Protocol for a Double-Blind Randomized Controlled Trial Using Multimodal Assessments

Background: There are few available therapeutic options to promote recovery among patients with chronic disorders of consciousness (DOC). Among pharmacological treatments, apomorphine, a dopamine agonist, has exhibited promising behavioral effects and safety of use in small-sample pilot studies. The true efficacy of the drug and its neural mechanism are still unclear. Apomorphine may act through a modulation of the anterior forebrain mesocircuit, but neuroimaging and neurophysiological investigations to test this hypothesis are scarce. This clinical trial aims to (1) assess the treatment effect of subcutaneous apomorphine infusions in patients with DOC, (2) better identify the phenotype of responders to treatment, (3) evaluate tolerance and side effects in this population, and (4) examine the neural networks underlying its modulating action on consciousness. Methods/Design: This study is a prospective double-blind randomized parallel placebo-controlled trial. Forty-eight patients diagnosed with DOC will be randomized to receive a 30-day regimen of either apomorphine hydrochloride or placebo subcutaneous infusions. Patients will be monitored at baseline 30 days before initiation of therapy, during treatment and for 30 days after treatment washout, using standardized behavioral scales (Coma Recovery Scale-Revised, Nociception Coma Scale-Revised), neurophysiological measures (electroencephalography, body temperature, actigraphy) and brain imaging (magnetic resonance imaging, positron emission tomography). Behavioral follow-up will be performed up to 2 years using structured phone interviews. Analyses will look for changes in behavioral status, circadian rhythmicity, brain metabolism, and functional connectivity at the individual level (comparing before and after treatment) and at the group level (comparing apomorphine and placebo arms, and comparing responder and non-responder groups). Discussion: This study investigates the use of apomorphine for the recovery of consciousness in the first randomized placebo-controlled double-blind trial using multimodal assessments. The results will contribute to define the role of dopamine agonists for the treatment of these challenging conditions and identify the neural correlates to their action. Results will bring objective evidence to further assess the modulation of the anterior forebrain mesocircuit by pharmacological agents, which may open new therapeutic perspectives. Clinical Trial Registration: EudraCT n°2018-003144-23; Clinicaltrials.gov n°NCT03623828 (https://clinicaltrials.gov/ct2/show/NCT03623828).

Early rehabilitation of Disorders of Consciousness (DOC): management, neuropsychological evaluation and treatment

In order to ensure the best possible rehabilitation plan and best outcome for patients with Disorders of Consciousness (DOC), optimal management of the early phase of rehabilitation is fundamental. This includes a correct diagnosis, accurate assessment of the patient's state of alertness and the main comorbidities, appropriate neurophysiological and neuroradiology examinations, and education of the caregiver and family so that they can provide the best assistance. Thirty years ago, specialists first began applying a systematic approach to the rehabilitation of patients with DOC, but still today many problems remain unsolved: the rate of misdiagnosis is still high, and recommendations about the most appropriate mode of rehabilitation are lacking, both as regards the timing of interventions and what the best techniques to use are. In a medical sector where nosography has changed over the last decade and where the documented evidence, though increasing, still remains insufficient, we discuss in this brief review the main assessment tools and disability scales to use and the key issues that need to be considered when a patient with DOC is admitted to the rehabilitation unit and decisions about the early rehabilitation plan are made.

Effects on the diagnosis change and on the disability level for individuals with disorder of consciousness: which predictors?

Prediction of the functional recovery in patients with disorders of consciousness (DOC) is still complex because of the different numbers of variables that influence the possibility of observing changes in clinical outcome. The aim of the present study is to identify the best set of predictors of the change in DOC diagnosis among different pharmacotherapy and nonpharmacotherapy indicators. This study analyzed data collected in a longitudinal, two-evaluation, multicenter project conducted in 90 centers. We analyzed the predictor effects of physical and cognitive treatments, duration of disease, etiology, age, and sex (nonpharmacological treatments) as well as the use of antiparkinson, psycholeptic, psychoanaleptic, and muscle-relaxant drugs (pharmacological variables). Ordered logistic models, linear regression models with bootstrap estimation, and model averaging procedures were used. The results showed that physical and cognitive treatments [best predictor: odds ratio (OR)=413.3, P<0.001], age (OR=0.964, P<0.001), and use of psycholeptic drugs (negative effect: OR=0.373, P=0.039) were the variables that contributed in general toward a change in diagnosis. Notably, the use of psycholeptic drugs seemed to impede the functional recovery in patients with DOC, so serious reflections on its use will be made.

Effects of 20 Hz Repetitive Transcranial Magnetic Stimulation on Disorders of Consciousness: A Resting-State Electroencephalography Study

Repetitive transcranial magnetic stimulation (rTMS) has been proposed as an experimental approach for the treatment of disorders of consciousness (DOC). To date, there has been little research into the use of rTMS in DOC and the therapeutic effects have been variously documented. This study aimed to examine the effects of 20 Hz rTMS on the electroencephalography (EEG) reactivity and clinical response in patients with DOC and to explore the neuromodulatory effects of high-frequency rTMS. In this randomized, sham-controlled, crossover study, real or sham 20 Hz rTMS was applied to the left primary motor cortex (M1) of patients with DOC for 5 consecutive days. Evaluations were blindly performed at the baseline (T0), immediately after the end of the 5 days of treatment (T1) and 1 week after the treatment (T2) using the JFK coma recovery scale-revised (CRS-R) and resting-state EEG. Only one patient, with a history of 2 months of traumatic brain injury, showed long-lasting (T1, T2) behavioral and neurophysiological modifications after the real rTMS stimulation. The 5 remaining patients presented brain reactivity localized at several electrodes, and the EEG modification was not significant. rTMS stimulation may improve awareness and arousal of DOC. Additionally, EEG represents a potential biomarker for the therapeutic efficacy of rTMS. This trial is registered with (NCT03385278).

Improved Arousal and Motor Function Using Zolpidem in a Patient With Space-Occupying Intracranial Lesions: A Case Report

Patients with disorders of consciousness (DOC) have profound functional limitations with few treatment options for improving arousal and quality of life. Zolpidem is a nonbenzodiazepine hypnotic used to treat insomnia that has also been observed to paradoxically improve arousal in those with DOC, such as the vegetative or minimally conscious states. Little information exists on its use in patients with DOC who have intracranial space-occupying lesions. We present a case of a 24-year-old man in a minimally conscious state due to central nervous system lymphoma who was observed to have increased arousal and improved motor function after the administration of zolpidem.

LEVEL OF EVIDENCE

V.

Does Modafinil improve the level of consciousness for people with a prolonged disorder of consciousness? a retrospective pilot study

BACKGROUND AND AIM

Modafinil is best known as a sleep regulator among healthy individuals, but studies suggest that it reduces excessive daytime sleepiness in patients with brain injury. This retrospective pilot study evaluated the effectiveness of Modafinil for people with a prolonged disorder of consciousness and whether those with a traumatic brain injury did better than those with a non-traumatic brain injury.

METHOD

Twenty four prolonged disorder of consciousness patients who were prescribed Modafinil, were assessed at least four times both before and during treatment. The Coma Recovery Scale-Revised was used to determine if patients had a disorder of consciousness and the Wessex Head Injury Matrix was used to monitor behavior during baseline and treatment periods. Patients with a traumatic brain injury (N = 12) were compared with those with non-traumatic brain injury (N = 12). A chi-square test with significance at 0.05 was used and when frequencies were below 5 a Fisher's Exact Test was used.

RESULTS

Cognitive improvements were noted in domains of wakefulness, awareness, concentration, tracking and following commands. Significant differences were found for the whole group between baseline and Modafinil (x²=9.80; p = 0.002). Eleven of the 12 traumatic brain injury patients had higher Wessex Head Injury Matrix scores when on Modafinil (x²=8.33, p < 0.004). Six non-traumatic brain injury patients had higher scores with Modafinil, two had lower scores and four showed no change. There was no significant difference in the number of patients showing an increase compared to those showing a decrease (Fisher's exact test p = 0.29).

CONCLUSION

Modafinil appears to be beneficial for enhancing cognition in prolonged disorder of consciousness patients. Traumatic brain injury patients benefited more than non-traumatic brain injury patients. Implications for Rehabilitation People with prolonged disorders of consciousness are those in coma, a vegetative state or a minimally conscious state. Sensorimotor and neuromodulations (pharmacological and brain stimulation) are the available treatment strategies to this group. Modafinil promotes attention, concentration and maintains wakefulness in a patient with narcolepsy, obstructive sleep apnea and shift work sleep disorders. In a relatively small sample, this retrospective pilot study shows the effectiveness of Modafinil in conjunction with good care, suitable medications and multidisciplinary rehabilitation in enhancing arousal in prolonged disorders of consciousness patients.

Recovery of consciousness and an injured ascending reticular activating system in a patient who survived cardiac arrest: A case report

We report on a patient who survived cardiac arrest and showed recovery of consciousness and an injured ARAS at the early stage of hypoxic-ischemic brain injury (HI- BI) for 3 weeks, which was demonstrated by diffusion tensor tractography (DTT).A 52-year-old male patient who had suffered cardiac arrest caused by acute coronary syndrome was resuscitated immediately by a layman and paramedics for ∼25 minutes. He was then transferred immediately to the emergency room of a local medical center. When starting rehabilitation at 2 weeks after onset, his consciousness was impaired, with a Glasgow Coma Scale (GCS) score of 8 and Coma Recovery Scale-Revised (GRS-R) score of 8. He underwent comprehensive rehabilitative therapy, including drugs for recovery of consciousness. He recovered well and rapidly so that his consciousness had recovered to full scores in terms of GCS:15 and GRS-R:23 at 5 weeks after onset.The left lower dorsal and right lower ventral ARAS had become thicker on 5-week DTT compared with 2-week DTT (Fig. 1B). Regarding the change of neural connectivity of the thalamic ILN, increased neural connectivity to the basal forebrain and prefrontal cortex was observed in both hemispheres on 5-week DTT compared with 2-week DTT.Recovery of an injured ARAS was demonstrated in a patient who survived cardiac arrest and his consciousness showed rapid and good recovery for 3 weeks at the early stage of HI-BI.

The Importance of Monitoring Patients' Responses to Medications: Increased Arousal after Administration of Zolpidem in Those with Hypoxic Ischemic Encephalopathy-A Case Study

In rehabilitation, nurses are the first team members to note or be told when a patient is having a positive or negative response to a medication. In brain injury medicine, medications are often used to augment cognitive or physical rehabilitation by increasing alertness, attention, focus, concentration, improving sleep, decreasing agitation, or easing spasticity and rigidity. Rehabilitation nurses not only should be aware of how medications work but also how medications may work differently in a chronically ill or disabled population. This article describes a 51-year-old man who suffered a hypoxic ischemic brain injury and how his neurological complications were managed with a nonbenzodiazepine medication which the Food and Drug Administration approved for the treatment of insomnia.

GABAA receptor deficits predict recovery in patients with disorders of consciousness: A preliminary multimodal [(11) C]Flumazenil PET and fMRI study

OBJECTIVES

Disorders of consciousness (DoC)-that is, unresponsive wakefulness syndrome/vegetative state and minimally conscious state-are debilitating conditions for which no reliable markers of consciousness recovery have yet been identified. Evidence points to the GABAergic system being altered in DoC, making it a potential target as such a marker.

EXPERIMENTAL DESIGN

In our preliminary study, we used [(11) C]Flumazenil positron emission tomography to establish global GABAA receptor binding potential values and the local-to-global (LTG) ratio of these for specific regions. These values were then compared between DoC patients and healthy controls. In addition, they were correlated with behavioral improvements for the patients between the time of scanning and 3 months later. Functional magnetic resonance imaging resting-state functional connectivity was also calculated and the same comparisons made.

PRINCIPAL OBSERVATIONS

lobal GABAA receptor binding was reduced in DoC, as was the LTG ratio in specifically the supragenual anterior cingulate. Both of these measures correlated with behavioral improvement after 3 months. In contrast to these measures of GABAA receptor binding, functional connectivity did not correlate with behavioral improvement.

CONCLUSIONS

Our preliminary findings point toward GABAA receptor binding being a marker of consciousness recovery in DoC.

A Single Session of Repetitive Transcranial Magnetic Stimulation Over the Dorsolateral Prefrontal Cortex in Patients With Unresponsive Wakefulness Syndrome

Background. The level of consciousness is regulated by the activation of the frontal parietal network since a disruption within this interregional cortical connectivity is associated with a consciousness breakdown. Objective. The primary aim of the present study was to examine the feasibility and the safety of a single session of repetitive transcranial magnetic stimulation (rTMS), delivered over the dorsolateral prefrontal cortex (DLPFC), in patients with unresponsive wakefulness syndrome (UWS). As a secondary aim, we investigated the efficacy of rTMS over DLPFC on cortico-cortical connectivity as tested with paired-pulse and dual-coil TMS techniques. Methods. We enrolled 10 healthy and 10 postanoxic UWS subjects. After clinical assessment, subjects underwent a single/paired pulse TMS paradigm evaluating the inhibitory and facilitatory intracortical circuits. In addition, several interregional interactions between primary motor, dorsal and ventral premotor, supplementary motor, and posterior parietal cortex areas were investigated by means of dual-coil TMS technique. These parameters were evaluated at baseline, immediately after, and 60 minutes after a protocol of 10-Hz rTMS delivered at the level of the DLPFC. Results. rTMS over DLPFC did not cause any adverse events. We showed that rTMS over DLPFC did not induce, at group level, any clinical improvement or intra-/intercortical connectivity changes. Interestingly, in 3 patients rTMS induced a significant, although transient, clinical improvement associated with a short-lasting reshaping of brain connectivity. Conclusions. We demonstrated that a single session of 10-Hz rTMS over the right DLPFC may transiently improve consciousness and partially restore the connectivity within several cortical areas in some patients with UWS.