Minimally Conscious State Research Articles

The case of food botulism F

This case describes a rare case of food botulism F in a 42-year-old man, which developed after he ate dried fish. The disease proceeded in a severe form with the development of ophthalmoplegia, tetraparesis, and respiratory failure. Monovalent antitoxic serums against botulinum toxins A, B, and E were administered to the patient. However, on the third day of the disease, he developed fulminant toxic myocarditis with asystole. Despite successful resuscitation, the patient developed a post-resuscitation disease and anoxic encephalopathy. The disease was complicated by severe aspiration pneumonia caused by Klebsiella pneumoniae (ESBL+). The duration of mechanical ventilation was 12 days. His hemodynamics stabilized on the eighth day of illness, and on the 19th day of illness, physical activity and a state of minimal consciousness appeared. The patient was transferred to the rehabilitation department on the 22nd day of the illness.
 Doctors should be informed about the possibility of the development and severity of botulism caused by botulinum toxin type F. It is necessary to introduce polyvalent antibotulinic serum into clinical practice, including antitoxins against rare types of botulinum toxin.

Long-term functional outcomes improved with deep brain stimulation in patients with disorders of consciousness

BackgroundDeep brain stimulation (DBS) has been preliminarily applied to treat patients with disorders of consciousness (DoCs). The study aimed to determine whether DBS was effective for treating patients with DoC...

Transauricular vagus nerve stimulation for patients with disorders of consciousness: A randomized controlled clinical trial.

Disorders of consciousness (DoCs) are a frequent complication of brain injury disease, and effective treatments are currently lacking. Transauricular vagus nerve stimulation (tVNS) has been proposed as a promising therapeutic method for neurological disorders such as epilepsy and depression. In our previous study, we demonstrated that vagus nerve stimulation promoted recovery in rats with DoCs caused by traumatic brain injury. However, the clinical effect of vagus nerve stimulation on consciousness disorders is unclear. We aimed to investigate the therapeutic efficacy and safety of tVNS in patients with DoCs. We conducted a randomized, double-blinded, sham-controlled trial. Patients (N = 60) with DoCs, including minimally conscious state (MCS) and vegetative state/unresponsive wakefulness syndrome, were enrolled and randomized to groups receiving either active or sham tVNS. A frequency of 20 Hz and pulse wave of 200 us was used in the active-tVNS protocol, which was performed in the auricular branch of the vagus nerve in the left outer ear. The sham-tVNS protocol was the same as the active-tVNS protocol although without current input. Both groups of patients also received conventional treatments. Consciousness was evaluated according to the Coma Recovery Scale-Revised before and after the 4-week intervention. We also recorded the type and number of behavioral responses. Safety was primarily assessed according to the incidence of treatment-emergent adverse events. Each patient's heart rate and blood pressure were monitored during all treatment sessions. Ultimately, 57 patients completed the study: 28 patients underwent active tVNS and 29 patients underwent sham tVNS. No significant differences were observed in Coma Recovery Scale-Revised scores between the active- and sham-tVNS groups before the tVNS sessions. Compared with patients in the sham-tVNS group (9.28 ± 4.38), patients with DoCs treated with active tVNS showed improved consciousness (10.93 ± 4.99), although not statistically significant. Further analysis revealed obvious differences between patients with MCS receiving active and sham tVNS, but no significant difference in patients with vegetative state/unresponsive wakefulness syndrome in both groups. All side effects were considered common medical conditions with no obvious correlation to tVNS. These preliminary data provide early evidence that tVNS may be an effective and safe approach for promoting the recovery of consciousness, especially in patients with MCS. https://www.chictr.org.cn/edit.aspx?pid=175938&htm=4, identifier: ChiCTR2200066629.

Czy można uśmiercić pacjenta z powodu niskiej jakości życia? Uwagi na tle orzecznictwa Europejskiego Trybunału Praw Człowieka

The subject of the article is the issue of legal protection of the life of patients in a state of minimal consciousness, in a vegetative state or other form of serious health condition. The analyses the problem from the point of view of three high-profile court cases involving the termination of treatment of Vincent Lambert, Charlie Gard and Alfie Evans.

Repetitive transcranial magnetic stimulation over the posterior parietal cortex improves functional recovery in nonresponsive patients: A crossover, randomized, double-blind, sham-controlled study.

Recent studies have shown that patients with disorders of consciousness (DoC) can benefit from repetitive transcranial magnetic stimulation (rTMS) therapy. The posterior parietal cortex (PPC) is becoming increasingly important in neuroscience research and clinical treatment for DoC as it plays a crucial role in the formation of human consciousness. However, the effect of rTMS on the PPC in improving consciousness recovery remains to be studied. We conducted a crossover, randomized, double-blind, sham-controlled clinical study to assess the efficacy and safety of 10 Hz rTMS over the left PPC in unresponsive patients. Twenty patients with unresponsive wakefulness syndrome were recruited. The participants were randomly divided into two groups: one group received active rTMS treatment for 10 consecutive days (n = 10) and the other group received sham treatment for the same period (n = 10). After a 10-day washout period, the groups crossed over and received the opposite treatment. The rTMS protocol involved the delivery of 2000 pulses/day at a frequency of 10 Hz, targeting the left PPC (P3 electrode sites) at 90% of the resting motor threshold. The primary outcome measure was the JFK Coma Recovery Scele-Revised (CRS-R), and evaluations were conducted blindly. EEG power spectrum assessments were also conducted simultaneously before and after each stage of the intervention. rTMS-active treatment resulted in a significant improvement in the CRS-R total score (F = 8.443, p = 0.009) and the relative alpha power (F = 11.166, p = 0.004) compared to sham treatment. Furthermore, 8 out of 20 patients classified as rTMS responders showed improvement and evolved to a minimally conscious state (MCS) as a result of active rTMS. The relative alpha power also significantly improved in responders (F = 26.372, p = 0.002) but not in non-responders (F = 0.704, p = 0.421). No adverse effects related to rTMS were reported in the study. This study suggests that 10 Hz rTMS over the left PPC can significantly improve functional recovery in unresponsive patients with DoC, with no reported side effects. www.ClinicalTrials.gov, identifier: NCT05187000.

Disturbed functional connectivity and topological properties of the frontal lobe in minimally conscious state based on resting-state fNIRS.

Patients in minimally conscious state (MCS) exist measurable evidence of consciousness. The frontal lobe is a crucial part of the brain that encodes abstract information and is closely related to the conscious state. We hypothesized that the disturbance of the frontal functional network exists in MCS patients. We collected the resting-state functional near-infrared spectroscopy (fNIRS) data of fifteen MCS patients and sixteen age- and gender-matched healthy controls (HC). The Coma Recovery Scale-Revised (CRS-R) scale of MCS patients was also composed. The topology of the frontal functional network was analyzed in two groups. Compared with HC, the MCS patients showed widely disrupted functional connectivity in the frontal lobe, especially in the frontopolar area and right dorsolateral prefrontal cortex. Moreover, the MCS patients displayed lower clustering coefficient, global efficiency, local efficiency, and higher characteristic path length. In addition, the nodal clustering coefficient and nodal local efficiency in the left frontopolar area and right dorsolateral prefrontal cortex were significantly reduced in MCS patients. Furthermore, the nodal clustering coefficient and nodal local efficiency in the right dorsolateral prefrontal cortex were positively correlated to auditory subscale scores. This study reveals that MCS patients' frontal functional network is synergistically dysfunctional. And the balance between information separation and integration in the frontal lobe is broken, especially the local information transmission in the prefrontal cortex. These findings help us to understand the pathological mechanism of MCS patients better.

Disorder of consciousness: Structural integrity of brain networks for the clinical assessment.

When studying brain networks in patients with Disorders of Consciousness (DoC), it is important to evaluate the structural integrity of networks in addition to their functional activity. Here, we investigated whether structural MRI, together with clinical variables, can be useful for diagnostic purposes and whether a quantitative analysis is feasible in a group of chronic DoC patients. We studied 109 chronic patients with DoC and emerged from DoC with structural MRI: 65 in vegetative state/unresponsive wakefulness state (VS/UWS), 34 in minimally conscious state (MCS), and 10 with severe disability. MRI data were analyzed through qualitative and quantitative approaches. The qualitative MRI analysis outperformed the quantitative one, which resulted to be hardly feasible in chronic DoC patients. The results of the qualitative approach showed that the structural integrity of HighOrder networks, altogether, had better diagnostic accuracy than LowOrder networks, particularly when the model included clinical variables (AUC=0.83). Diagnostic differences between VS/UWS and MCS were stronger in anoxic etiology than vascular and traumatic etiology. MRI data of all LowOrder and HighOrder networks correlated with the clinical score. The integrity of the left hemisphere was associated with a better clinical status. Structural integrity of brain networks is sensitive to clinical severity. When patients are chronic, the qualitative analysis of MRI data is indicated.

Do All Interesting Experiences Add to the Quality of Life?

In “ReImagining the Quality of Life,” Lorraine Besser challenges the frameworks typically used for evaluating the quality of people’s lives, especially those with Alzheimer’s disease or those in minimally conscious states (MCS). These frameworks rely on two standards: agency and sentience. The first assumes that the absence of agency makes a life prudentially worthless (worthless to the individual whose life it is), because cognitive activity is prudentially valuable “only when it reflects agency;” whereas the second assumes that the absence of pleasure makes a life prudentially worthless, because pleasure is the only experiential value. Besser argues, however, that cognitive engagement with an activity or experience that a patient finds interesting is also prudentially valuable, even if it doesn’t reflect agency, and even if it isn’t pleasurable. The interesting “describes a qualitative aspect of our experience of a robust form of cognitive engagement, which resonates with us in a fashion similar to pleasure.” Besser’s view is an important contribution to the literature on the quality of life, and to the lives of patients with Alzheimer’s or MCS. However, I challenge Besser’s view that interesting experiences need not have a positive resonance to such patients, even though they are similar to pleasure.

Consformer: consciousness detection using transformer networks with correntropy-based measures.

Consciousness detection is important in diagnosis and treatment of disorders of consciousness (DOC). Recent studies have demonstrated that electroencephalography (EEG) signals contain effective information for consciousness state evaluation. We propose two novel EEG measures: the spatiotemporal correntropy and the neuromodulation intensity, to reflect the temporal-spatial complexity in brain signals for consciousness detection. Then, we build a pool of EEG measures with different spectral, complexity and connectivity features, and propose Consformer, a transformer network to learn an adaptive optimization of features for different subjects with the attention mechanism. Experiments are carried out using a large dataset of 280 resting-state EEG recordings of DOC patients. Consformer discriminates minimally conscious state (MCS) from vegetative state (VS) with an accuracy of 85.73% and an F1-score of 86.95%, which achieves the state-of-the-art performance.

542: AWAKENING AFTER EXTRACORPOREAL LIFE SUPPORT: ASSESSING AWARENESS IN UNRESPONSIVE WAKEFULNESS

Introduction: Emergence from coma have many stages. Patients enter unresponsive wakefulness (UW) from coma when they open eyes with only reflexive motor responses. The development of voluntary responses to stimuli indicates a minimally conscious state (MCS). The addition of functional communication or object use signifies emergence from MCS. Cognitive motor dissociation has been reported in unresponsive patients with evidence of appropriate brain activation. We present a pediatric case where we detected awareness with bedside electroencephalogram (EEG) and the patient showed eventual emergence from UW. Description: A depressed teenage girl was admitted after suicidal attempt with fluoxetine and lamotrigine ingestion with subsequent cardiopulmonary arrest. After prolonged cardiopulmonary resuscitation, she was cannulated on veno-arterial extracorporeal membrane oxygenation. Initial head computed tomography showed preserved gray-white differentiation. On post-arrest day 5, she was successfully decannulated but remained in an unresponsive wakefulness state. Brain magnetic resonance imaging showed diffuse cerebral microhemorrhages. To assess preserved awareness, we performed protocolized stimulation with EEG. Consistent reactivity with increased frequency and amplitude were observed after both nociceptive and auditory stimulation, with greater response to stimuli from her parent. After slow improvement she emerged from UW on post-arrest day 35 and showed consistent appropriate responses. She was discharged to inpatient rehabilitation on post-arrest day 50. Discussion: Analysis of quantitative EEG data often requires advanced machine learning algorithms that were not readily available to bedside providers. Assessing EEG reactivity with protocolized stimulation is an effective alternative to assess preserved awareness. Our case adds to limited pediatric literature on emergence from coma and detection of preserved awareness early after brain injury. Clinically she was unresponsive to external stimuli but demonstrated signs of arousal to nociceptive and auditory stimuli on EEG, especially when from her parents. Our case demonstrates the feasibility of assessing preserved awareness at bedside via protocolized stimulation with EEG, which may assist in prognosis.

What is the nutritional status of patients with prolonged disorders of consciousness? A retrospective cross-sectional study

ABSTRACT Background Nutritional status of patients with disorders of consciousness (DoC) is poorly studied. Objectives To evaluate the relationship between nutritional status (body mass index, daily calories intake) and clinical variables (level of consciousness, time since injury, diagnosis, etiology and spastic muscle overactivity; SMO,) in patients with prolonged DoCor emerging. Our main hypotheses are i) patients with lower level of consciousness (UWS) have worse nutritional status compared to patients in minimally conscious state (MCS) and ii) SMO could influence nutritional status. Methods and results Among the 80 patients included in the study (19 UWS, 47 MCS, 14 emerging MCS; 43 ± 15 yo; 3 ± 4 years post-injury, 35 traumatic etiology, 34 females), 9% were at risk to be undernourished, with no differences between UWS and MCS. Patients without SMO had a higher BMI compared to patients with severe SMO. Compared to the recommended daily calories intake, patients with the highest BMI received less calories and patients with the lowest BMI received more calories. We observed a negative correlation between SMO (in lower limbs) and BMI. Conclusion Our study shows that most patients are well nourished, independently from the level of consciousness. SMO may require additional calories in patients’ daily needs; however, longitudinal studies are needed to explore the causal relationship between these variables.

A Potential Prognosis Indicator Based on P300 Brain-Computer Interface for Patients with Disorder of Consciousness.

For patients with disorders of consciousness, such as unresponsive wakefulness syndrome (UWS) patients and minimally conscious state (MCS) patients, their long treatment cycle and high cost commonly put a heavy burden on the patient's family and society. Therefore, it is vital to accurately diagnose and predict consciousness recovery for such patients. In this paper, we explored the role of the P300 signal based on an audiovisual BCI in the classification and prognosis prediction of patients with disorders of consciousness. This experiment included 18 patients: 10 UWS patients and 8 MCS- patients. At the three-month follow-up, we defined patients with an improved prognosis (from UWS to MCS-, from UWS to MCS+, or from MCS- to MCS+) as "improved patients" and those who stayed in UWS/MCS as "not improved patients". First, we compared and analyzed different types of patients, and the results showed that the P300 detection accuracy rate of "improved" patients was significantly higher than that of "not improved" patients. Furthermore, the P300 detection accuracy of traumatic brain injury (TBI) patients was significantly higher than that of non-traumatic brain injury (NTBI, including acquired brain injury and cerebrovascular disease) patients. We also found that there was a positive linear correlation between P300 detection accuracy and CRS-R score, and patients with higher P300 detection accuracy were likely to achieve higher CRS-R scores. In addition, we found that the patients with higher P300 detection accuracies tend to have better prognosis in this audiovisual BCI. These findings indicate that the detection accuracy of P300 is significantly correlated with the level of consciousness, etiology, and prognosis of patients. P300 can be used to represent the preservation level of consciousness in clinical neurophysiology and predict the possibility of recovery in patients with disorders of consciousness.

Deep brain stimulation improves electroencephalogram functional connectivity of patients with minimally conscious state.

Deep brain stimulation (DBS) is a potential neuromodulatory therapy that enhances recovery from disorders of consciousness, especially minimally conscious state (MCS). This study measured the effects of DBS on the brain and explored the underlying mechanisms of DBS on MCS. Nine patients with MCS were recruited for this study. The neuromodulation effects of 100 Hz DBS were explored via cross-control experiments. Coma Recovery Scale-Revised (CRS-R) and EEG were recorded, and corresponding functional connectivity and network parameters were calculated. Our results showed that 100 Hz DBS could improve the functional connectivity of the whole, local and local-local brain regions, while no significant change in EEG functional connectivity was observed in sham DBS. The whole brain's network parameters (clustering coefficient, path length, and small world characteristic) were significantly improved. In addition, a significant increase in the CRS-R and functional connectivity of three MCS patients who received 100 Hz DBS for 6months were observed. This study showed that DBS improved EEG functional connectivity and brain networks, indicating that the long-term use of DBS could improve the level of consciousness of MCS patients.

Detecting residual brain networks in disorders of consciousness: A resting-state fNIRS study

Functional near infrared spectroscopy (fNIRS) is an emerging non-invasive technique that allows bedside measurement of blood oxygenation level-dependent hemodynamic signals. We aimed to examine the efficacy of resting-state fNIRS in detecting the residual functional networks in patients with disorders of consciousness (DOC). We performed resting-state fNIRS in 23 DOC patients of whom 12 were in minimally conscious state (MCS) and 11 were in unresponsive wakefulness state (UWS). Ten regions of interest (ROIs) in the prefrontal cortex (PFC) were selected: both sides of Brodmann area (BA) 9, BA10, BA44, BA45, and BA46. Graph-theoretical analysis and seed-based correlation analyses were used to investigate the network topology and the strength of pairwise connections between ROIs and channels. MCS and UWS exhibited varying degrees of the loss of topological architecture, and the regional nodal properties of BA10 were significantly different between them (Nodal degree, PLeft BA10 = 0.01, PRight BA10 < 0.01; nodal efficiency, PLeft BA10 = 0.03, PRight BA10 < 0.01). Compared to healthy controls, UWS had impaired functions in both short- and long-distance connectivity, however, MCS had significantly impaired functions only in long-distance connectivity. The functional connectivity of right BA10 (AUC = 0.88) and the connections between left BA46 and right BA10 (AUC = 0.86) had excellent performance in differentiating MCS and UWS. MCS and UWS have different patterns of topological architecture and short- and long-distance connectivity in PFC. Intraconnections within BA10 and interhemispheric connections between BA10 and 46 are excellent resting-state fNIRS classifiers for distinguishing between MCS and UWS.

Improving diagnosis for disorders of consciousness: The case for a novel multi-paradigm approach

After a traumatic brain injury, patients often experience a period of impaired consciousness characterized by a diminished ability to perceive external stimuli (i.e., awareness) and a diminished responsiveness to stimuli, when perceived (i.e., arousal) [1,2]. These impaired levels of consciousness are defined as disorders of consciousness (DoC), a spectrum typically defined by three states of consciousness: coma, unresponsive wakefulness syndrome (UWS, formerly known as vegetative state), and minimally conscious state (MCS) [1].

Neuropsychological assessment through Coma Recovery Scale-Revised and Coma/Near Coma Scale in a sample of pediatric patients with disorder of consciousness

BackgroundThe Coma Recovery Scale-Revised (CRS-R) has become a standard tool in assessing Disorders of consciousness (DoC) in adults. However, its measurement validity in pediatrics has only been ascertained in healthy cases. Increasing use of CRS-R in children with DoC imposes appropriate comparison against previously validated tools. The aims of the study were to describe the emergence to a conscious state (eMCS) in pediatric acquired brain injury (ABI); to explore the agreement between the CRS-R and Coma Near Coma Scale (CNCS) and to discuss the advantage of administering the CRS-R in pediatric age.Materials and methodsIn this observational prospective study, 40 patients were recruited. Inclusion criteria were age 5 to 18 years, Glasgow Coma Scale (GCS) score ≤ 8 at the insult, and unresponsive wakefulness syndrome (UWS) or minimally conscious state (MCS) at admission. Patients were assessed with CRS-R, and CNCS was used as standard.ResultsThe agreement between scales was moderate (r = − 0.71). The analysis of the CRS-R domain scores also confirmed that decreasing CNCS levels (from a coma to eMCS) corresponded to concurrent increas of CRS-R scores in all domains. Moreover, CRS-R better defined patients’ status in the emergency phase from MCS. Conversely, CRS-R had lower DoC scoring ability in the presence of severe motor impairment.ConclusionWe show that CRS-R can track changes in DoC in children as young as 5 years old, and we provide evidence that the agreement with CNCS scores is good.

An innovative approach for the evaluation of prolonged disorders of consciousness using NF-L and GFAP biomarkers: a pivotal study

Behavioral assessments during the clinical evaluation in prolonged disorders of consciousness patients could be not sufficient for a correct diagnosis and prognostication. To this aim, we used an innovative approach, involving the ultra-sensitive determination of biological markers, correlating them with imaging parameters to investigate the prolonged disorders of consciousness (pDoC).We assessed the serum concentration of neurofilament light chain(NF-L) and glial fibrillary acidic protein (GFAP) in pDoC (n = 16), and healthy controls (HC, n = 6) as well as several clinical imaging parameters such as Fractional Anisotropy (FA), Whole Brain SUV, and White Matter Hyperintensities volumes (WMH) using PET-MRI acquisition. As for differential diagnosis task, only the imaging WMH volume was able to discriminate between vegetative state/unresponsive wakefulness syndrome (VS/UWS), and minimally conscious state (MCS) patients (p-value < 0.01), while all selected markers (both imaging and in vitro) were able to differentiate between pDoC patients and HC. At subject level, serum NF-L concentrations significantly differ according to clinical progression and consciousness recovery (p-value < 0.01), highlighting a potential play for the longitudinal management of these patients.

Infraclinical detection of voluntary attention in coma and post-coma patients using electrophysiology

ObjectiveEarly functional evaluation and prognosis of patients with disorders of consciousness is a major challenge that clinical assessments alone cannot solve. Objective measures of brain activity could help resolve this uncertainty. We used electroencephalogram at bedside to detect voluntary attention with a paradigm previously validated in healthy subjects. MethodsUsing auditory-oddball sequences, our approach rests on detecting known attentional modulations of Event Related Potentials that reflect compliance with verbal instructions. Sixty-eight unresponsive patients were tested in their first year after coma onset (37 coma and 31 first year post-coma patients). Their evolution 6 months after the test was considered. ResultsFourteen of the 68 patients, showed a positive response. Nine were in a coma and 5 in a minimally conscious state (MCS). Except for one who died early, all responders evolved to exit-MCS within 6 months (93%), while 35 (65%) among non-responders only. ConclusionsAmong those patients for whom the outcome is highly uncertain, 21% responded positively to this simple but cognitively demanding test. Strikingly, some coma patients were among responders. SignificanceThe proposed paradigm revealed cognitive-motor dissociation in some coma patients. This ability to sustain attention on demand predicted awakening within 6 months and represents an immediately useful information for relatives and caregivers.

Altered functional connectivity and regional brain activity in a triple-network model in minimally conscious state and vegetative-state/unresponsive wakefulness syndrome patients: A resting-state functional magnetic resonance imaging study.

The purpose of this study was to investigate changes in functional connectivity and regional brain activity between and within the default mode network (DMN), salience network (SN), and executive control network (ECN) among individuals with disorders of consciousness (DOC) in the conditions of minimally conscious state (MCS) and vegetative-state/unresponsive wakefulness syndrome (VS/UWS). Twenty-five VS/UWS patients, 14 MCS patients, and 30 healthy individuals as normal control, completed resting-state fMRI scans. ROI-wise functional connectivity and fractional amplitude of low-frequency fluctuation (fALFF) were implemented to examine group differences. All ROI-wise and fALFF analyses masks were identified from the triple-network model. ROI-wise analyses indicated significantly decreased functional connectivity between posterior cingulate cortex (DMN)-left anterior insula (SN), right anterior insula (SN)-left dorsolateral prefrontal cortex (ECN), and right anterior insula (SN)-right amygdala (SN) in VS/UWS patients compared to MCS patients. Moreover, fALFF were observed reduced in the triple-network across all DOC patients, and as the clinical manifestations of DOC deteriorated from MCS to VS/UWS, fALFF in dorsal DMN, anterior/posterior SN, and left ECN became significantly reduced. Moreover, a positive correlation between fALFF of the left ECN and Coma Recovery Scale-Revised (CRS-R) total scores was found across all DOC patients. These findings contribute to a better understanding of the underlying neural mechanism of functional connectivity and regional brain activity in DOC patients, and this triple-network model provides new connectivity pattern changes that may be integrated in future diagnostic tools based on the neural signatures of conscious states.

Cerebral Glucose Metabolism in Patients with Chronic Disorders of Consciousness.

To measure regional cerebral metabolic rate of glucose (CMRGlu) in patients with chronic disorders of consciousness (DOCs) using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). This retrospective cohort study examined 50 patients (mean age: 40.9 ± 20.1 years) with traumatic brain injury (TBI)-induced chronic DOCs [minimally conscious state (MCS)+, n = 20; MCS-, n = 15 and vegetative state (VS), n = 15]. We measured FDG-PET-based CMRGlu values in 12 regions of both brain hemispheres and compared those among MCS+, MCS - and VS patients. In both hemispheres, the regional CMRGlu reduced with consciousness deterioration in 11 of 12 regions (91.7%). In seven right hemisphere regions, CMRGlu values were markedly higher in MCS+ patients than in MCS- patients. Furthermore, CMRGlu was suggestively higher in the left occipital region in MCS- patients than in VS patients. Functional preservation in the left occipital region in patients with chronic DOCs might reflect an awareness of external environments, whereas extensive functional preservation in the right cerebral hemisphere might reflect communication motivation.