Akinetic mutism following stroke

Nagaratnam, Nages; Nagaratnam, Kujan; Ng, Kevin; Diu, Patrick

doi:10.1016/j.jocn.2003.04.002

Cited by 91 publications

(42 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…51 The inability to integrate planned movements into a sequence 52 underlies this injury to the SMA, which may be partially responsible for the inability to follow commands in our series. Interestingly, electroencephalography data gathered during deep brain stimulation of a single minimally conscious patient's central thalamus suggest that activation of midline frontal cortices, including the SMA and anterior cingulate, were correlated with behavioral improvements associated with deep brain stimulation.…”

Section: Discussionmentioning

confidence: 88%

Frontal Networks Associated With Command Following After Hemorrhagic Stroke

Mikell

Banks

Frey

et al. 2015

Stroke

View full text Add to dashboard Cite

Background and Purpose-Level of consciousness is frequently assessed by command-following ability in the clinical setting. However, it is unclear what brain circuits are needed to follow commands. We sought to determine what networks differentiate command following from noncommand following patients after hemorrhagic stroke. Methods-Structural MRI, resting-state functional MRI, and electroencephalography were performed on 25 awake and unresponsive patients with acute intracerebral and subarachnoid hemorrhage. Structural injury was assessed via volumetric T1-weighted MRI analysis. Functional connectivity differences were analyzed against a template of standard resting-state networks. The default mode network (DMN) and the task-positive network were investigated using seedbased functional connectivity. Networks were interrogated by pairwise coherence of electroencephalograph leads in regions of interest defined by functional MRI. Results-Functional imaging of unresponsive patients identified significant differences in 6 of 16 standard resting-state networks. Significant voxels were found in premotor cortex, dorsal anterior cingulate gyrus, and supplementary motor area. Direct interrogation of the DMN and task-positive network revealed loss of connectivity between the DMN and the orbitofrontal cortex and new connections between the task-positive network and DMN. Coherence between electrodes corresponding to right executive network and visual networks was also decreased in unresponsive patients. Conclusions-Resting

show abstract

Section: Discussionmentioning

confidence: 88%

Frontal Networks Associated With Command Following After Hemorrhagic Stroke

Mikell

Banks

Frey

et al. 2015

Stroke

View full text Add to dashboard Cite

show abstract

“…In AM, speech, movement, thought and emotional expression are uniformly reduced 16,17 but, unlike in MCS, these responses may be facilitated following exposure to high-intensity sensory or personally salient stimuli. This phenomenon is exemplified in the so-called 'telephone effect' , originally described by C. Miller Fisher.…”

Section: Comamentioning

confidence: 98%

Disorders of consciousness after acquired brain injury: the state of the science

et al. 2014

View full text Add to dashboard Cite

| The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest.

show abstract

“…The role of DMPFC is less clear, but, as speculated by Binder et al (2009), it might be involved in "self-guided retrieval" aspects of semantic processing. Lesions to this region have been found to induce symptoms of very little spontaneous speech or action despite the preserved ability to speak or act when prompted (Nagaratnam et al, 2004).…”

Section: Lmtg As a Core Semantic Regionmentioning

confidence: 99%

Predicting Conceptual Processing Capacity from Spontaneous Neuronal Activity of the Left Middle Temporal Gyrus

Tao

Liang²,

He³

et al. 2012

J. Neurosci.

162

125

View full text Add to dashboard Cite

Conceptual processing is a crucial brain function for humans. Past research using neuropsychological and task-based functional brainimaging paradigms indicates that widely distributed brain regions are related to conceptual processing. Here, we explore the potential contribution of intrinsic or spontaneous brain activity to conceptual processing by examining whether resting-state functional magnetic resonance imaging (rs-fMRI) signals can account for individual differences in the conceptual processing efficiencies of healthy individuals. We acquired rs-fMRI and behavioral data on object conceptual processing tasks. We found that the regional amplitude of spontaneous low-frequency fluctuations in the blood oxygen level-dependent signal in the left (posterior) middle temporal gyrus (LMTG) was highly correlated with participants' semantic processing efficiency. Furthermore, the strength of the functional connectivity between the LMTG and a series of brain regions-the left inferior frontal gyrus, bilateral anterior temporal lobe, bilateral medial temporal lobe, posterior cingulate gyrus, and ventromedial and dorsomedial prefrontal cortices-also significantly predicted conceptual behavior. The regional amplitude of low-frequency fluctuations and functionally relevant connectivity strengths of LMTG together accounted for 74% of individual variance in object conceptual performance. This semantic network, with the LMTG as its core component, largely overlaps with the regions reported in previous conceptual/semantic task-based fMRI studies. We conclude that the intrinsic or spontaneous activity of the human brain reflects the processing efficiency of the semantic system.

show abstract

Akinetic mutism following stroke

Cited by 91 publications

References 23 publications

Frontal Networks Associated With Command Following After Hemorrhagic Stroke

Frontal Networks Associated With Command Following After Hemorrhagic Stroke

Disorders of consciousness after acquired brain injury: the state of the science

Predicting Conceptual Processing Capacity from Spontaneous Neuronal Activity of the Left Middle Temporal Gyrus

Contact Info

Product

Resources

About