Noninvasive brain stimulation for patients with a disorder of consciousness: a systematic review and meta-analysis

2020 ◽  
Vol 31 (8) ◽  
pp. 905-914 ◽  
Author(s):  
Yali Feng ◽  
Jiaqi Zhang ◽  
Yi Zhou ◽  
Zhongfei Bai ◽  
Ying Yin

AbstractNoninvasive brain stimulation (NIBS) techniques have been used to facilitate the recovery from prolonged unconsciousness as a result of brain injury. The aim of this study is to systematically assess the effects of NIBS in patients with a disorder of consciousness (DOC). We searched four databases for any randomized controlled trials on the effect of NIBS in patients with a DOC, which used the JFK Coma Recovery Scale-Revised (CRS-R) as the primary outcome measure. A random-effects meta-analysis was conducted to pool effect sizes. Fourteen studies with 273 participants were included in this review, of which 12 studies with sufficient data were included in the meta-analysis. Our meta-analysis showed a significant effect on increasing CRS-R scores in favor of real stimulation as compared to sham (Hedges’ g = 0.522; 95% confidence interval [CI], 0.318–0.726; P < 0.0001, I2 = 0.00%). Subgroup analysis demonstrated that only anodal transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) significantly enhances the CRS-R scores in patients with a DOC, as compared to sham (Hedges’ g = 0.703; 95% CI, 0.419–0.986; P < 0.001), and this effect was predominant in patients in a minimally conscious state (MCS) (Hedges’ g = 0.815; 95% CI, 0.429–1.200; P < 0.001). Anodal tDCS of the left DLPFC appears to be an effective approach for patients with MCS.

2021 ◽  
Vol 11 (5) ◽  
pp. 665
Author(s):  
Rocco Salvatore Calabrò ◽  
Loris Pignolo ◽  
Claudia Müller-Eising ◽  
Antonino Naro

Pain perception in individuals with prolonged disorders of consciousness (PDOC) is still a matter of debate. Advanced neuroimaging studies suggest some cortical activations even in patients with unresponsive wakefulness syndrome (UWS) compared to those with a minimally conscious state (MCS). Therefore, pain perception has to be considered even in individuals with UWS. However, advanced neuroimaging assessment can be challenging to conduct, and its findings are sometimes difficult to be interpreted. Conversely, multichannel electroencephalography (EEG) and laser-evoked potentials (LEPs) can be carried out quickly and are more adaptable to the clinical needs. In this scoping review, we dealt with the neurophysiological basis underpinning pain in PDOC, pointing out how pain perception assessment in these individuals might help in reducing the misdiagnosis rate. The available literature data suggest that patients with UWS show a more severe functional connectivity breakdown among the pain-related brain areas compared to individuals in MCS, pointing out that pain perception increases with the level of consciousness. However, there are noteworthy exceptions, because some UWS patients show pain-related cortical activations that partially overlap those observed in MCS individuals. This suggests that some patients with UWS may have residual brain functional connectivity supporting the somatosensory, affective, and cognitive aspects of pain processing (i.e., a conscious experience of the unpleasantness of pain), rather than only being able to show autonomic responses to potentially harmful stimuli. Therefore, the significance of the neurophysiological approach to pain perception in PDOC seems to be clear, and despite some methodological caveats (including intensity of stimulation, multimodal paradigms, and active vs. passive stimulation protocols), remain to be solved. To summarize, an accurate clinical and neurophysiological assessment should always be performed for a better understanding of pain perception neurophysiological underpinnings, a more precise differential diagnosis at the level of individual cases as well as group comparisons, and patient-tailored management.


NeuroSci ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 254-265
Author(s):  
Jihad Aburas ◽  
Areej Aziz ◽  
Maryam Butt ◽  
Angela Leschinsky ◽  
Marsha L. Pierce

According to the Centers for Disease Control and Prevention (CDC), traumatic brain injury (TBI) is the leading cause of loss of consciousness, long-term disability, and death in children and young adults (age 1 to 44). Currently, there are no United States Food and Drug Administration (FDA) approved pharmacological treatments for post-TBI regeneration and recovery, particularly related to permanent disability and level of consciousness. In some cases, long-term disorders of consciousness (DoC) exist, including the vegetative state/unresponsive wakefulness syndrome (VS/UWS) characterized by the exhibition of reflexive behaviors only or a minimally conscious state (MCS) with few purposeful movements and reflexive behaviors. Electroceuticals, including non-invasive brain stimulation (NIBS), vagus nerve stimulation (VNS), and deep brain stimulation (DBS) have proved efficacious in some patients with TBI and DoC. In this review, we examine how electroceuticals have improved our understanding of the neuroanatomy of consciousness. However, the level of improvements in general arousal or basic bodily and visual pursuit that constitute clinically meaningful recovery on the Coma Recovery Scale-Revised (CRS-R) remain undefined. Nevertheless, these advancements demonstrate the importance of the vagal nerve, thalamus, reticular activating system, and cortico-striatal-thalamic-cortical loop in the process of consciousness recovery.


2020 ◽  
Vol 10 (12) ◽  
pp. 930
Author(s):  
Caroline Schnakers ◽  
Michaela Hirsch ◽  
Enrique Noé ◽  
Roberto Llorens ◽  
Nicolas Lejeune ◽  
...  

Covert cognition in patients with disorders of consciousness represents a real diagnostic conundrum for clinicians. In this meta-analysis, our main objective was to identify clinical and demographic variables that are more likely to be associated with responding to an active paradigm. Among 2018 citations found on PubMed, 60 observational studies were found relevant. Based on the QUADAS-2, 49 studies were considered. Data from 25 publications were extracted and included in the meta-analysis. Most of these studies used electrophysiology as well as counting tasks or mental imagery. According to our statistical analysis, patients clinically diagnosed as being in a vegetative state and in a minimally conscious state minus (MCS−) show similar likelihood in responding to active paradigm and responders are most likely suffering from a traumatic brain injury. In the future, multi-centric studies should be performed in order to increase sample size, with similar methodologies and include structural and functional neuroimaging in order to identify cerebral markers related to such a challenging diagnosis.


2018 ◽  
Author(s):  
Yuri Pavlov

A systematic search revealed 68 empirical studies of neurophysiological (EEG, ERP, fMRI, PET) variables as potential outcome predictors in patients with Disorders of Consciousness (diagnoses Unresponsive Wakefulness Syndrome [UWS] and Minimally Conscious State [MCS]). Data of 47 publications could be presented in a quantitative manner and systematically reviewed. Insufficient power and the lack of an appropriate description of patient selection each characterized about a half of all publications. In more than 80% studies, neurologists who evaluated the patients’ outcome were familiar with the results of neurophysiological tests conducted before, and may, therefore, have been influenced by this knowledge. In most subsamples of data sets effect size significantly correlated with its standard error, indicating publication bias toward positive results. Neurophysiological data predicted the transition from UWS to MCS substantially better than they predicted the recovery of consciousness (i.e., the transition from UWS or MCS to exit-MCS). A meta-analysis was carried out for predictor groups including at least three independent studies with N &gt; 10 per predictor per improvement criterion (i.e., transition to MCS versus recovery). Oscillatory EEG responses were the only predictor group whose effect attained significance for both improvement criteria. Other perspective variables, whose true prognostic value should be explored in future studies, are sleep spindles in the EEG and the somatosensory cortical response N20. Contrary to what could be expected on the basis of neuroscience theory, the poorest prognostic effects were shown for fMRI responses to stimulation and for the ERP component P300. The meta-analytic results should be regarded as preliminary given the presence of numerous biases in the data.


2020 ◽  
Vol 54 (6) ◽  
pp. 582-590 ◽  
Author(s):  
Binlong Zhang ◽  
Jiao Liu ◽  
Tuya Bao ◽  
Georgia Wilson ◽  
Joel Park ◽  
...  

Objective: Many noninvasive brain stimulation techniques have been applied to treat depressive disorders. However, the target brain region in most noninvasive brain stimulation studies is the dorsolateral prefrontal cortex. Exploring new stimulation locations may improve the efficacy of noninvasive brain stimulation for depressive disorders. We aimed to explore potential noninvasive brain stimulation locations for depressive disorders through a meta-analysis and a functional connectivity approach. Methods: We conducted a meta-analysis of 395 functional magnetic resonance imaging studies to identify depressive disorder–associated brain regions as regions of interest. Then, we ran resting-state functional connectivity analysis with three different pipelines in 40 depression patients to find brain surface regions correlated with these regions of interest. The 10–20 system coordinates corresponding to these brain surface regions were considered as potential locations for noninvasive brain stimulation. Results: The 10–20 system coordinates corresponding to the bilateral dorsolateral prefrontal cortex, bilateral inferior frontal gyrus, medial prefrontal cortex, supplementary motor area, bilateral supramarginal gyrus, bilateral primary motor cortex, bilateral operculum, left angular gyrus and right middle temporal gyrus were identified as potential locations for noninvasive brain stimulation in depressive disorders. The coordinates were: posterior to F3, posterior to F4, superior to F3, posterior to F7, anterior to C4, P3, midpoint of F7–T3, posterior to F8, anterior to C3, midpoint of Fz–Cz, midpoint of Fz–Fp1, anterior to T4, midpoint of C3–P3, and anterior to C4. Conclusion: Our study identified several potential noninvasive brain stimulation locations for depressive disorders, which may serve as a basis for future clinical investigations.


2019 ◽  
Author(s):  
Martin J. Dietz ◽  
Bochra Zareini ◽  
Risto Näätänen ◽  
Morten Overgaard

AbstractA patient who does not regain full consciousness after coma is typically classified as being in a vegetative state or a minimally conscious state. While the key determinants in this differential diagnosis are inferred uniquely from the observed behaviour of the patient, nothing can, in principle, be known about the patient’s awareness of the external world. Given the subjective nature of current diagnostic practice, the quest for neurophysiological markers that could complement the nosology of the coma spectrum is becoming more and more acute. We here present a method for the classification of patients based on electrophysiological responses using Bayesian model selection. We validate the method in a sample of fourteen patients with a clinical disorder of consciousness (DoC) and a control group of fifteen healthy adults. By formally comparing a set of alternative hypotheses about the nosology of DoC patients, the results of our validation study show that we can disambiguate between alternative models of how patients are classified. Although limited to this small sample of patients, this allowed us to assert that there is no evidence of subgroups when looking at the MMN response in this sample of patients. We believe that the methods presented in this article are an important contribution to testing alternative hypotheses about how patients are grouped at both the group and single-patient level and propose that electrophysiological responses, recorded invasively or non-invasively, may be informative for the nosology of the coma spectrum on a par with behavioural diagnosis.


2013 ◽  
Vol 80 (3-4) ◽  
pp. S30.e1-S30.e9 ◽  
Author(s):  
Takamitsu Yamamoto ◽  
Yoichi Katayama ◽  
Toshiki Obuchi ◽  
Kazutaka Kobayashi ◽  
Hideki Oshima ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document