Demystifying Enigmatic Undershoot in Setpoint Command Following [Focus on Education]

2022 ◽  
Vol 42 (1) ◽  
pp. 103-125
Author(s):  
Mohammadreza Kamaldar ◽  
Syed Aseem Ul Islam ◽  
Jesse B. Hoagg ◽  
Dennis S. Bernstein
Keyword(s):  
Command Following

scholarly journals Delta band activity contributes to the identification of command following in disorder of consciousness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gonzalo Rivera-Lillo ◽  
Emmanuel A. Stamatakis ◽  
Tristan A. Bekinschtein ◽  
David K. Menon ◽  
Srivas Chennu
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Disorder Of Consciousness ◽  
Fine Grained ◽  
Electrical Brain Activity ◽  
Delta Band ◽  
Delta Modulation ◽  
Command Following ◽  
Band Activity

AbstractThe overt or covert ability to follow commands in patients with disorders of consciousness is considered a sign of awareness and has recently been defined as cortically mediated behaviour. Despite its clinical relevance, the brain signatures of the perceptual processing supporting command following have been elusive. This multimodal study investigates the temporal spectral pattern of electrical brain activity to identify features that differentiated healthy controls from patients both able and unable to follow commands. We combined evidence from behavioural assessment, functional neuroimaging during mental imagery and high-density electroencephalography collected during auditory prediction, from 21 patients and 10 controls. We used a penalised regression model to identify command following using features from electroencephalography. We identified seven well-defined spatiotemporal signatures in the delta, theta and alpha bands that together contribute to identify DoC subjects with and without the ability to follow command, and further distinguished these groups of patients from controls. A fine-grained analysis of these seven signatures enabled us to determine that increased delta modulation at the frontal sensors was the main feature in command following patients. In contrast, higher frequency theta and alpha modulations differentiated controls from both groups of patients. Our findings highlight a key role of spatiotemporally specific delta modulation in supporting cortically mediated behaviour including the ability to follow command. However, patients able to follow commands nevertheless have marked differences in brain activity in comparison with healthy volunteers.

scholarly journals Automated pupillometry to detect command following in neurological patients: a proof-of-concept study

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6929 ◽  
Author(s):  
Alexandra Vassilieva ◽  
Markus Harboe Olsen ◽  
Costanza Peinkhofer ◽  
Gitte Moos Knudsen ◽  
Daniel Kondziella
Keyword(s):  
Brain Injury ◽  
Healthy Volunteers ◽  
Neurological Disorders ◽  
Mental Arithmetic ◽  
Proof Of Concept ◽  
Icu Patients ◽  
Wide Range ◽  
Level Of Consciousness ◽  
Neurological Patients ◽  
Command Following

Background Levels of consciousness in patients with acute and chronic brain injury are notoriously underestimated. Paradigms based on electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) may detect covert consciousness in clinically unresponsive patients but are subject to logistical challenges and the need for advanced statistical analysis. Methods To assess the feasibility of automated pupillometry for the detection of command following, we enrolled 20 healthy volunteers and 48 patients with a wide range of neurological disorders, including seven patients in the intensive care unit (ICU), who were asked to engage in mental arithmetic. Results Fourteen of 20 (70%) healthy volunteers and 17 of 43 (39.5%) neurological patients, including 1 in the ICU, fulfilled prespecified criteria for command following by showing pupillary dilations during ≥4 of five arithmetic tasks. None of the five sedated and unconscious ICU patients passed this threshold. Conclusions Automated pupillometry combined with mental arithmetic appears to be a promising paradigm for the detection of covert consciousness in people with brain injury. We plan to build on this study by focusing on non-communicating ICU patients in whom the level of consciousness is unknown. If some of these patients show reproducible pupillary dilation during mental arithmetic, this would suggest that the present paradigm can reveal covert consciousness in unresponsive patients in whom standard investigations have failed to detect signs of consciousness.

Probing command following in patients with disorders of consciousness using a brain–computer interface

2013 ◽  
Vol 124 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Dorothée Lulé ◽  
Quentin Noirhomme ◽  
Sonja C. Kleih ◽  
Camille Chatelle ◽  
Sebastian Halder ◽  
...  
Keyword(s):  
Brain Computer Interface ◽  
Disorders Of Consciousness ◽  
Computer Interface ◽  
Command Following

scholarly journals MRI–EEG correlation for outcome prediction in postanoxic myoclonus

Neurology ◽  
2020 ◽  
Vol 95 (4) ◽  
pp. e335-e341
Author(s):  
Isabelle Beuchat ◽  
Adithya Sivaraju ◽  
Edilberto Amorim ◽  
Emily J. Gilmore ◽  
Vincent Dunet ◽  
...  
Keyword(s):  
Hospital Discharge ◽  
Predictive Value ◽  
Epileptiform Activity ◽  
Cerebral Performance Category ◽  
Primary Outcome Measure ◽  
Good Outcome ◽  
Anoxic Injury ◽  
Continuous Background ◽  
Fluid Attenuated Inversion Recovery ◽  
Command Following

ObjectiveTo examine the prognostic ability of the combination of EEG and MRI in identifying patients with good outcome in postanoxic myoclonus (PAM) after cardiac arrest (CA).MethodsAdults with PAM who had an MRI within 20 days after CA were identified in 4 prospective CA registries. The primary outcome measure was coma recovery to command following by hospital discharge. Clinical examination included brainstem reflexes and motor activity. EEG was assessed for best background continuity, reactivity, presence of epileptiform activity, and burst suppression with identical bursts (BSIB). MRI was examined for presence of diffusion restriction or fluid-attenuated inversion recovery changes consistent with anoxic brain injury. A prediction model was developed using optimal combination of variables.ResultsAmong 78 patients, 11 (14.1%) recovered at discharge and 6 (7.7%) had good outcome (Cerebral Performance Category < 3) at 3 months. Patients who followed commands were more likely to have pupillary and corneal reflexes, flexion or better motor response, EEG continuity and reactivity, no BSIB, and no anoxic injury on MRI. The combined EEG/MRI variable of continuous background and no anoxic changes on MRI was associated with coma recovery at hospital discharge with sensitivity 91% (95% confidence interval [CI], 0.59–1.00), specificity 99% (95% CI, 0.92–1.00), positive predictive value 91% (95% CI, 0.59–1.00), and negative predictive value 99% (95% CI, 0.92–1.00).ConclusionsEEG and MRI are complementary and identify both good and poor outcome in patients with PAM with high accuracy. An MRI should be considered in patients with myoclonus showing continuous or reactive EEGs.

scholarly journals Cortical Function in Acute Severe Traumatic Brain Injury and at Recovery: A Longitudinal fMRI Case Study

2020 ◽  
Vol 10 (9) ◽  
pp. 604
Author(s):  
Karnig Kazazian ◽  
Loretta Norton ◽  
Teneille E. Gofton ◽  
Derek Debicki ◽  
Adrian M. Owen
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Speech Perception ◽  
Severe Traumatic Brain Injury ◽  
Resting State ◽  
Cortical Function ◽  
Sound Perception ◽  
Command Following ◽  
Resting State Connectivity ◽  
Recovery Of Consciousness

Differences in the functional integrity of the brain from acute severe brain injury to subsequent recovery of consciousness have not been well documented. Functional magnetic resonance imaging (fMRI) may elucidate this issue as it allows for the objective measurement of brain function both at rest and in response to stimuli. Here, we report the cortical function of a patient with a severe traumatic brain injury (TBI) in a critically ill state and at subsequent functional recovery 9-months post injury. A series of fMRI paradigms were employed to assess sound and speech perception, command following, and resting state connectivity. The patient retained sound perception and speech perception acutely, as indexed by his fMRI responses. Command following was absent acutely, but was present at recovery. Increases in functional connectivity across multiple resting state networks were observed at recovery. We demonstrate the clinical utility of fMRI in assessing cortical function in a patient with severe TBI. We suggest that hallmarks of the recovery of consciousness are associated with neural activity to higher-order cognitive tasks and increased resting state connectivity.

scholarly journals Performance Differences Using a Vibro-Tactile P300 BCI in LIS-Patients Diagnosed With Stroke and ALS

2018 ◽  
Vol 12 ◽  
Author(s):  
Alexander Heilinger ◽  
Rupert Ortner ◽  
Vincenzo La Bella ◽  
Zulay R. Lugo ◽  
Camille Chatelle ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Behavioral Assessment ◽  
Event Related Potentials ◽  
Left Hand ◽  
Related Potentials ◽  
The Right ◽  
Command Following ◽  
Als Patients ◽  
Assessment Scales ◽  
Lateral Sclerosis

Patients with locked-in syndrome (LIS) are typically unable to move or communicate and can be misdiagnosed as patients with disorders of consciousness (DOC). Behavioral assessment scales are limited in their ability to detect signs of consciousness in this population. Recent research has shown that brain-computer interface (BCI) technology could supplement behavioral scales and allows to establish communication with these severely disabled patients. In this study, we compared the vibro-tactile P300 based BCI performance in two groups of patients with LIS of different etiologies: stroke (n = 6) and amyotrophic lateral sclerosis (ALS) (n = 9). Two vibro-tactile paradigms were administered to the patients to assess conscious function and command following. The first paradigm is called vibrotactile evoked potentials (EPs) with two tactors (VT2), where two stimulators were placed on the patient’s left and right wrist, respectively. The patients were asked to count the rare stimuli presented to one wrist to elicit a P300 complex to target stimuli only. In the second paradigm, namely vibrotactile EPs with three tactors (VT3), two stimulators were placed on the wrists as done in VT2, and one additional stimulator was placed on his/her back. The task was to count the rare stimuli presented to one wrist, to elicit the event-related potentials (ERPs). The VT3 paradigm could also be used for communication. For this purpose, the patient had to count the stimuli presented to the left hand to answer “yes” and to count the stimuli presented to the right hand to answer “no.” All patients except one performed above chance level in at least one run in the VT2 paradigm. In the VT3 paradigm, all 6 stroke patients and 8/9 ALS patients showed at least one run above chance. Overall, patients achieved higher accuracies in VT2 than VT3. LIS patients due to ALS exhibited higher accuracies that LIS patients due to stroke, in both the VT2 and VT3 paradigms. These initial data suggest that controlling this type of BCI requires specific cognitive abilities that may be impaired in certain sub-groups of severely motor-impaired patients. Future studies on a larger cohort of patients are needed to better identify and understand the underlying cortical mechanisms of these differences.

Is command following unrelated to top-down attention in consciousness disorders?

2016 ◽  
Vol 81 (1) ◽  
pp. 159-160
Author(s):  
Luca Bonfiglio ◽  
Maria Chiara Carboncini
Keyword(s):  
Top Down ◽  
Consciousness Disorders ◽  
Command Following
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