scholarly journals Statistical learning in patients in the minimally conscious state

Author(s):  
Chuan Xu ◽  
Jian Gao ◽  
Jiaxin Gao ◽  
Lingling Li ◽  
Fangping He ◽  
...  

When listening to an unknown language, listeners could learn the transitional probability between syllables and group frequently co-occurred syllables into a whole unit. Such statistical learning ability has been demonstrated for both pre-verbal infants and adults, even during passive listening. Here, we investigated whether statistical learning occurred in patients in minimally conscious state (MCS) and patients emerged from the minimally conscious state (EMCS) using electroencephalography (EEG). We presented to participants an isochronous sequence of syllables, which were composed of either 2-word real phrases or 2-word artificial phrases that were defined by the transitional probability between words. An inter-trial phase coherence (ITPC) analysis revealed that the phrase-rate EEG response was weakened in EMCS patients compared with healthy individuals, and was even more severely weakened in MCS patients. Although weak, the phrase-rate response or its harmonics remained statistically significant in MCS patients, suggesting that the statistical learning ability was preserved in MCS patients. The word-rate response was also weakened with a decreased level of consciousness. The harmonics of the word-rate response, however,were more salient in MCS than EMCS patients in the alpha and beta bands. Together with previous studies, the current results suggest that MCS patients retain residual learning ability, which can potentially be harnessed to induce neural plasticity, and that different frequency bands are differentially related to the consciousness level.

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Manon Carrière ◽  
Helena Cassol ◽  
Charlène Aubinet ◽  
Rajanikant Panda ◽  
Aurore Thibaut ◽  
...  

Abstract Auditory localization (i.e. turning the head and/or the eyes towards an auditory stimulus) is often part of the clinical evaluation of patients recovering from coma. The objective of this study is to determine whether auditory localization could be considered as a new sign of minimally conscious state, using a multimodal approach. The presence of auditory localization and the clinical outcome at 2 years of follow-up were evaluated in 186 patients with severe brain injury, including 64 with unresponsive wakefulness syndrome, 28 in minimally conscious state minus, 71 in minimally conscious state plus and 23 who emerged from the minimally conscious state. Brain metabolism, functional connectivity and graph theory measures were investigated by means of 18F-fluorodeoxyglucose positron emission tomography, functional MRI and high-density electroencephalography in two subgroups of unresponsive patients, with and without auditory localization. These two subgroups were also compared to a subgroup of patients in minimally conscious state minus. Auditory localization was observed in 13% of unresponsive patients, 46% of patients in minimally conscious state minus, 62% of patients in minimally conscious state plus and 78% of patients who emerged from the minimally conscious state. The probability to observe an auditory localization increased along with the level of consciousness, and the presence of auditory localization could predict the level of consciousness. Patients with auditory localization had higher survival rates (at 2-year follow-up) than those without localization. Differences in brain function were found between unresponsive patients with and without auditory localization. Higher connectivity in unresponsive patients with auditory localization was measured between the fronto-parietal network and secondary visual areas, and in the alpha band electroencephalography network. Moreover, patients in minimally conscious state minus significantly differed from unresponsive patients without auditory localization in terms of brain metabolism and alpha network centrality, whereas no difference was found with unresponsive patients who presented auditory localization. Our multimodal findings suggest differences in brain function between unresponsive patients with and without auditory localization, which support our hypothesis that auditory localization should be considered as a new sign of minimally conscious state. Unresponsive patients showing auditory localization should therefore no longer be considered unresponsive but minimally conscious. This would have crucial consequences on these patients’ lives as it would directly impact the therapeutic orientation or end-of-life decisions usually taken based on the diagnosis.


2021 ◽  
Vol 70 (5) ◽  
pp. 23-36
Author(s):  
Ekaterina A. Kondratyeva ◽  
Alina O. Ivanova ◽  
Maria I. Yarmolinskaya ◽  
Elena G. Potyomkina ◽  
Natalya V. Dryagina ◽  
...  

BACKGROUND: Consciousness is the state of being awake and aware of oneself and the environment. The disorders of consciousness result from pathologies that impair awareness. The development of effective comprehensive personalized interventions contributing to the recovery of consciousness in patients with chronic disorders of consciousness is one of the most pressing and challenging tasks in modern rehabilitation. AIM: The aim of this study was to understand structural problems of the pituitary gland, blood levels of gonadotropins and melatonin as well as brain damage markers in the blood and cerebrospinal fluid in patients with chronic disorders of consciousness and to analyze the levels of the above markers among different groups of patients depending on the level of impaired consciousness. MATERIALS AND METHODS: We examined 61 chronic disorders of consciousness patients and identified three groups depending on the level of consciousness including 24 patients with unresponsive wakefulness syndrome, 24 patients with a minus minimally conscious state, and 13 patients with minimally conscious state plus. We performed magnetic resonance imaging of chiasmatic-sellar region and determined blood serum levels of follicle-stimulating and luteinizing hormones and melatonin, as well as urinary level of 6-sulfatoxymelatonin and the content of brain derived neurotrophic factor (BDNF), apoptosis antigen (APO-1), FasL, glutamate, and S100 protein in the blood serum and cerebrospinal fluid. RESULTS: The patients were examined in the age ranging from 15 to 61 years old. Patient groups were homogeneous by the level of consciousness in terms of age and duration of chronic disorders of consciousness by the time of examination. The patients did not differ in the pituitary volume regardless of the level of consciousness. No significant differences were found between the groups with different levels of consciousness when studying the levels of melatonin in the blood serum and its metabolite in the urine. A peak in melatonin secretion was detected at 3 a.m. in 54.5 % of the patients, which can be considered as a favorable prognostic marker for further recovery of consciousness. Hypogonadotropic ovarian failure was found in 34 % of the patients, with normogonadotropic ovarian failure in the remaining patients. Serum APO-1 and BDNF levels were significantly higher in patients with minimally conscious state relative to those with unresponsive wakefulness syndrome. Significantly lower levels of glutamate in the cerebrospinal fluid were detected in women with unresponsive wakefulness syndrome compared to patients with minimally conscious state. CONCLUSIONS: Further in-depth examination and accumulation of data on patients with chronic disorders of consciousness may provide an opportunity to identify highly informative markers for predicting outcomes and to develop new effective approaches to rehabilitation of consciousness in this category of patients.


2019 ◽  
Vol 9 (5) ◽  
pp. 103 ◽  
Author(s):  
Liudmila Legostaeva ◽  
Alexandra Poydasheva ◽  
Elizaveta Iazeva ◽  
Dmitry Sinitsyn ◽  
Dmitry Sergeev ◽  
...  

Background: Navigated repetitive transcranial magnetic stimulation (rTMS) is a promising tool for neuromodulation. In previous studies it has been shown that the activity of the default mode network (DMN) areas, particularly of its key region—the angular gyrus—is positively correlated with the level of consciousness. Our study aimed to explore the effect of rTMS of the angular gyrus as a new approach for disorders of consciousness (DOC) treatment; Methods: A 10-session 2-week high-frequency rTMS protocol was delivered over the left angular gyrus in 38 DOC patients with repeated neurobehavioral assessments obtained at baseline and in 2 days after the stimulation course was complete; Results: 20 Hz-rTMS over left angular gyrus improved the coma recovery scale revised (CRS-R) total score in minimally conscious state (MCS) patients. We observed no effects in vegetative state (VS) patients; and Conclusions: The left angular gyrus is likely to be effective target for rTMS in patients with present signs of consciousness.


2014 ◽  
Vol 35 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Johan Stender ◽  
Ron Kupers ◽  
Anders Rodell ◽  
Aurore Thibaut ◽  
Camille Chatelle ◽  
...  

The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS ( n=14), MCS ( n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers ( n=29). Global cortical CMRglc in VS/UWS and MCS averaged 42% and 55% of normal, respectively. Differences between VS/UWS and MCS were most pronounced in the frontoparietal cortex, at 42% and 60% of normal. In brainstem and thalamus, metabolism declined equally in the two conditions. In EMCS, metabolic rates were indistinguishable from those of MCS. Ordinal logistic regression predicted that patients are likely to emerge into MCS at CMRglc above 45% of normal. Receiver-operating characteristics showed that patients in MCS and VS/UWS can be differentiated with 82% accuracy, based on cortical metabolism. Together these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients.


2018 ◽  
Vol 128 (4) ◽  
pp. 1189-1198 ◽  
Author(s):  
Darko Chudy ◽  
Vedran Deletis ◽  
Fadi Almahariq ◽  
Petar Marčinković ◽  
Jasenka Škrlin ◽  
...  

OBJECTIVEAn effective treatment of patients in a minimally conscious state (MCS) or vegetative state (VS) caused by hypoxic encephalopathy or traumatic brain injury (TBI) is not yet available. Deep brain stimulation (DBS) of the thalamic reticular nuclei has been attempted as a therapeutic procedure mainly in patients with TBI. The purpose of this study was to investigate the therapeutic use of DBS for patients in VS or MCS.METHODSFourteen of 49 patients in VS or MCS qualified for inclusion in this study and underwent DBS. Of these 14 patients, 4 were in MCS and 10 were in VS. The etiology of VS or MCS was TBI in 4 cases and hypoxic encephalopathy due to cardiac arrest in 10. The selection criteria for DBS, evaluating the status of the cerebral cortex and thalamocortical reticular formation, included: neurological evaluation, electrophysiological evaluation, and the results of positron emission tomography (PET) and MRI examinations. The target for DBS was the centromedian-parafascicular (CM-pf) complex. The duration of follow-up ranged from 38 to 60 months.RESULTSTwo MCS patients regained consciousness and regained their ability to walk, speak fluently, and live independently. One MCS patient reached the level of consciousness, but was still in a wheelchair at the time the article was written. One VS patient (who had suffered a cerebral ischemic lesion) improved to the level of consciousness and currently responds to simple commands. Three VS patients died of respiratory infection, sepsis, or cerebrovascular insult (1 of each). The other 7 patients remained without substantial improvement of consciousness.CONCLUSIONSSpontaneous recovery from MCS/VS to the level of consciousness with no or minimal need for assistance in everyday life is very rare. Therefore, if a patient in VS or MCS fulfills the selection criteria (presence of somatosensory evoked potentials from upper extremities, motor and brainstem auditory evoked potentials, with cerebral glucose metabolism affected not more than the level of hypometabolism, which is judged using PET), DBS could be a treatment option.


2021 ◽  
Vol 15 ◽  
Author(s):  
Maria Daniela Cortese ◽  
Francesco Arcuri ◽  
Idan E. Nemirovsky ◽  
Lucia Francesca Lucca ◽  
Paolo Tonin ◽  
...  

The Nociception Coma Scale (NCS) and its revised version (NCS-R) were used to evaluate behavioral responses to pain in non-communicative patients. We hypothesized that if patients demonstrate changes to their NCS(-R) scores over time, their evolving behavioral abilities could indicate a forthcoming diagnostic improvement with the Coma Recovery Scale-Revised (CRS-R). Forty-three Vegetative State/Unresponsive Wakefulness Syndrome (VS/UWS) patients were enrolled in the study. The patients were assessed weekly using the CRS-R and NCS(-R) for four consecutive weeks. The first assessment was within 10 days after hospitalization. The assessments were performed between 09:30 and 11:30 AM in a room with constant levels of humidity, light and temperature, as well as an absence of transient noise. Noxious stimuli were administered using a Newton-meter, with pressure applied to the fingernail bed for a maximum of 5 s unless interrupted by a behavioral response from subjects. Seventeen patients demonstrated improvements in their level of consciousness, 13 of whom showed significant behavioral changes through the NCS(-R) before being diagnosed with a Minimally Conscious State (MCS) according to the CRS-R. The behavioral changes observed using the NCS(-R) corresponded to a high probability of observing an improvement from VS/UWS to MCS. To characterize the increased likelihood of this transition, our results present threshold scores of ≥5 for the NCS (accuracy 86%, sensitivity 87%, and specificity 86%) and ≥3 for the NCS-R (accuracy 77%, sensitivity 89%, and specificity 73%). In conclusion, a careful evaluation of responses to nociceptive stimuli in DOC patients could constitute an effective procedure in assessing their evolving conscious state.


Author(s):  
Joshua Shepherd

This chapter argues for a normative distinction between disabilities that are inherently negative with respect to well-being and disabilities that are inherently neutral. After clarifying terms, the author discusses recent arguments according to which possession of a disability is inherently neutral with respect to well-being. He notes that although these arguments are compelling, they are only intended to cover certain disabilities and, in fact, that there exists a broad class regarding which they do not apply. He then discusses two problem cases: locked-in syndrome and the minimally conscious state, and explains why these are cases in which possession of these disabilities makes one worse off overall. He argues that disabilities that significantly impair control over one’s situation tend to be inherently negative with respect to well-being; other disabilities do not. The upshot is that we must draw an important normative distinction between disabilities that undermine this kind of control and disabilities that do not.


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