1/12. Impaired effective cortical connectivity in vegetative state: preliminary investigation using PET.Vegetative state (VS) is a condition of abolished awareness with persistence of arousal. awareness is part of consciousness, which itself is thought to represent an emergent property of cerebral neural networks. Our hypothesis was that part of the neural correlate underlying VS is an altered connectivity, especially between the associative cortices. We assessed regional cerebral glucose metabolism (rCMRGlu) and effective cortical connectivity in four patients in VS by means of statistical parametric mapping and [18F]fluorodeoxyglucose-positron emission tomography. Our data showed a common pattern of impaired rCMRGlu in the prefrontal, premotor, and parietotemporal association areas and posterior cingulate cortex/precuneus in VS. In a next step, we demonstrated that in VS patients various prefrontal and premotor areas have in common that they are less tightly connected with the posterior cingulate cortex than in normal controls. These results provide a strong argument for an alteration of cortical connectivity in VS patients.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
2/12. Consciousness in congenitally decorticate children: developmental vegetative state as self-fulfilling prophecy.According to traditional neurophysiological theory, consciousness requires neocortical functioning, and children born without cerebral hemispheres necessarily remain indefinitely in a developmental vegetative state. Four children between 5 and 17 years old are reported with congenital brain malformations involving total or near-total absence of cerebral cortex but who, nevertheless, possessed discriminative awareness: for example, distinguishing familiar from unfamiliar people and environments, social interaction, functional vision, orienting, musical preferences, appropriate affective responses, and associative learning. These abilities may reflect 'vertical' plasticity of brainstem and diencephalic structures. The relative rarity of manifest consciousness in congenitally decorticate children could be due largely to an inherent tendency of the label 'developmental vegetative state' to become a self-fulfilling prophecy.- - - - - - - - - - ranking = 2keywords = consciousness (Clic here for more details about this article) |
3/12. Late occurrence of diffuse cerebral swelling after intracerebral hemorrhage in a patient with the hellp syndrome--Case report.hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome can occur at any time in the course of pregnancy and is associated with many complications including fatal stroke. A 37-year-old female presented with hellp syndrome causing an intracerebral hematoma, which was treated by evacuation and mild hypothermia. Unexpected diffuse cerebral swelling occurred on the 15th day of the initially favorable postoperative course. Considerable impairment of consciousness persisted despite conservative therapy. Serial computed tomographic findings indicated delayed cerebral vasospasm as the cause of the swelling. Particularly careful management is required even beyond the first 2 weeks for patients with stroke as a complication of hellp syndrome.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
4/12. Residual cerebral activity and behavioural fragments can remain in the persistently vegetative brain.This report identifies evidence of partially functional cerebral regions in catastrophically injured brains. To study five patients in a persistent vegetative state (PVS) with different behavioural features, we employed [(18)F]fluorodeoxyglucose-positron emission tomography (FDG-PET), MRI and magnetoencephalographic (MEG) responses to sensory stimulation. Each patient's brain expressed a unique metabolic pattern. In three of the five patients, co-registered PET/MRI correlate islands of relatively preserved brain metabolism with isolated fragments of behaviour. Two patients had suffered anoxic injuries and demonstrated marked decreases in overall cerebral metabolism to 30-40% of normal. Two other patients with non-anoxic, multifocal brain injuries demonstrated several isolated brain regions with relatively higher metabolic rates, that ranged up to 50-80% of normal. Nevertheless, their global metabolic rates remained <50% of normal. MEG recordings from three PVS patients provide clear evidence for the absence, abnormality or reduction of evoked responses. Despite major abnormalities, however, these data also provide evidence for localized residual activity at the cortical level. Each patient partially preserved restricted sensory representations, as evidenced by slow evoked magnetic fields and gamma band activity. In two patients, these activations correlate with isolated behavioural patterns and metabolic activity. Remaining active regions identified in the three PVS patients with behavioural fragments appear to consist of segregated corticothalamic networks that retain connectivity and partial functional integrity. A single patient who suffered severe injury to the tegmental mesencephalon and paramedian thalamus showed widely preserved cortical metabolism, and a global average metabolic rate of 65% of normal. The relatively high preservation of cortical metabolism in this patient defines the first functional correlate of clinical- pathological reports associating permanent unconsciousness with structural damage to these regions. The specific patterns of preserved metabolic activity identified in these patients do not appear to represent random survivals of a few neuronal islands; rather they reflect novel evidence of the modular nature of individual functional networks that underlie conscious brain function. The variations in cerebral metabolism in chronic PVS patients indicate that some cerebral regions can retain partial function in catastrophically injured brains.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
5/12. Medical aspects of the minimally conscious state in children.The minimally conscious state is a condition of severely altered consciousness in which minimal but definite behavioral evidence of self or environmental awareness is demonstrated. This must be established on a reproducible or sustained basis by one or more of four types of behaviors including simple command-following, gestural or verbal 'yes/no' responses, intelligible verbalizations, or purposeful behaviors. The minimally conscious state can occur in children and usually is due to acquired brain injuries (traumatic and non-traumatic), central nervous system degenerative and neurometabolic disorders or congenital or developmental disorders. It is assumed that the lower limit of the minimally conscious state occurs when patients emerge from a vegetative state. What remains uncertain is how we can assess the upper limits, that is the degree of improvement that indicates that an individual is no longer minimally conscious. It also is unknown if, when and to what extent children can emerge from a minimally conscious state and whether their prognosis is better than children who are vegetative. It is assumed that the minimally conscious state may become 'permanent' 12 months after traumatic brain injury and 3 months after non-traumatic injury although there have been no studies that have examined this issue. Medical and rehabilitative treatment of children in a minimally conscious state should be provided to maintain comfort, reduce complications, and optimize functional recovery.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
6/12. Awakenings from persistent vegetative state: report of three cases with parkinsonism and brain stem lesions on MRI.Three patients with a persistent vegetative state after severe head injury are reported. They recovered from a prolonged disturbance of consciousness after the administration of levodopa. These patients all had parkinsonian features. On magnetic resonance imaging, the distribution of lesions implied a diffuse axonal injury involving the substantia nigra or ventral tegmental area. The existence of patients whose dopaminergic systems may have been selectively damaged by a severe head injury should be recognised because such individuals may respond to levodopa treatment.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
7/12. Cerebral fat embolism diagnosed by magnetic resonance imaging at one, eight, and 50 days after hip arthroplasty: a case report.PURPOSE: To describe cardiovascular collapse during a cemented hip hemiarthroplasty in a patient who, despite a successful cardiopulmonary resuscitation, remained in a persistent vegetative state due to cerebral fat embolism diagnosed by magnetic resonance imaging (MRI). CLINICAL FEATURES: A 75-yr-old woman with no medical history underwent cemented hip hemiarthroplasty under spinal anesthesia for a right femoral neck fracture. Shortly after insertion of the prosthesis, a sudden oxygen desaturation, hypotension, bradycardia, and cardiac arrest occurred. The patient was successfully resuscitated, but did not regain consciousness. The patient developed high-grade fever, thrombocytopenia, anemia, and oliguria. MRI scans of the brain revealed multiple high intensity signals throughout the white matter, the basal ganglia, the cerebellum, and the brain stem. The diagnosis of fat embolism was made on the basis of clinical findings and MRI images. Although her cardiorespiratory status improved over the next week, the patient remained in a persistent vegetative state. CONCLUSION: When fat embolism is suspected, serial MRI scans of the brain should be performed to diagnose the etiology of cerebral embolism as well as to evaluate the severity of brain damage.- - - - - - - - - - ranking = 1keywords = consciousness (Clic here for more details about this article) |
8/12. Assessing level of consciousness and cognitive changes from vegetative state to full recovery.Although investigations addressing cognitive recovery from the vegetative state have been reported, to date there have been no detailed studies of these patients combining both neuropsychology and functional imaging to monitor and record the recovery of consciousness. This paper describes the recovery of a specific vegetative state (VS) case. The patient (OG) remained in the vegetative state for approximately two months, increasing her level of awareness to a minimally conscious state, where she continued for approximately 70 days. In the course of the ensuing 18 months, she was able to reach an acceptable level of cognitive functioning, with partial levels of independence. Throughout this two year period, she received continuous cognitive evaluation, for which several different tools were applied including coma and low functioning scales, full cognitive batteries, and structural and functional magnetic resonance imaging (MRI). We present here preliminary data on fMRI using a word presentation paradigm before and after recovery; we also discuss the difficulty of how to determine level of consciousness using the tools currently available, and the subsequent improvement in different cognitive domains. We confirm that accurate diagnosis and proper cognitive assessment are critical for the rehabilitation of patients with disorders of consciousness.- - - - - - - - - - ranking = 7keywords = consciousness (Clic here for more details about this article) |
9/12. Considerations for the use of assistive technology in patients with impaired states of consciousness.While there is limited literature addressing the application of assistive technology in patients in persistent vegetative state (PVS) and minimally conscious state (MCS), it is believed that it can assist with the assessment, diagnosis and treatment as well as management of these patients. The use of technology to assist in PVS and MCS is mostly limited to the application of simple binary switch devices to determine whether a motor response is consistent or otherwise. However, the application of such technology is often undermined due to a lack of established protocols for use by the multidisciplinary team (MDT), as well as a lack of available technical resources. Therefore the ongoing development of assessment instruments as well as effective outcome measures used by an MDT is imperative. This article aims to discuss some key aspects to consider in the use of assistive technology when assessing and treating people in impaired conscious states. Possible considerations and suggestions will be discussed through this paper and a case study will be used to demonstrate some of these interventions.- - - - - - - - - - ranking = 4keywords = consciousness (Clic here for more details about this article) |
10/12. Consciousness and altered consciousness.The notion of consciousness in the English scientific literature denotes a global ability to consciously perform elementary and intellectual tasks, to reason, plan, judge and retrieve information as well as the awareness of these functions belonging to the self, that is, being self-aware. consciousness can also be defined as continuous awareness of the external and internal environment, of the past and the present. The meaning of consciousness is different in various languages, but it invariably includes, the conscious person is capable to learn, retrieve and use information. Disturbance or loss of consciousness in the Hungarian medical language indicates decreased alertness or arousability rather than the impairment of the complex mental ability. awareness denotes the spiritual process of perception and analysis of stimuli from the inner and external world. Alertness is a prerequisite of awareness. Clinical observations suggest that the lesions of specific structures of the brain may lead to specific malfunction of consciousness, therefore, consciousness must be the product of neural activity. "Higher functions" of human mental ability have been ascribed to the prefrontal and parietal association cortices. The paleocerebrum, limbic system and their connections have been considered to be the center of emotions, feelings, attention, motivation and autonomic functions. Recent evidence indicates that these phylogenetically ancient structures play an important role in the processes of acquiring, storing and retrieving information. The hippocampus has a key role in regulating memory, learning, emotion and motivation. Impaired consciousness in the neurological practice is classified based on tests for conscious behavior and by analyzing the following responses: 1. elementary reactions to sensory stimuli--these are impaired in hypnoid unconsciousness, 2. intellectual reactions to cognitive stimuli--these indicate the impairment of cognitive contents in non-hypnoid unconsciousness. Obviously, disturbance of elementary reactions related to alertness and disturbance of intellectual performance overlap. In conditions with reduced ability to react to or to perceive external stimuli the cognitive disturbance of consciousness cannot fully be explored.- - - - - - - - - - ranking = 14keywords = consciousness (Clic here for more details about this article) |
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