Jun
22
2010
0

The neural correlates of impaired consciousness in coma and unresponsive states.

Over the last few years, functional neuroimaging studies have provided new insights into cerebral activity in subjects with severe brain damage leading to coma and other clinical states characterized by unresponsiveness. The present paper introduces the clinical picture of patients with impaired consciousness, and reviews the nosological criteria and functional neuroanatomical basis for brain death, coma, vegetative state, minimally conscious state, and the locked-in syndrome. Converging evidence suggests that disrupted activity in higher-order association areas, especially prefrontal and posteromedial parietal regions, plays a pivotal role within the neural correlates of impaired consciousness in the unresponsive patient.

Written by admin in: Brain Damage |
Jun
22
2010
0

Challenges for rear hospital care of Wenchuan Earthquake casualties: experience from West China Hospital.

To review the challenges and countermeasures in the hospital care for Wenchuan earthquake casualties and draw lessons for the protective response in the future. Medical records and laboratory findings of the victims admitted in West China Hospital (WCH) were retrospectively analyzed. Related data were compared between beforemath and aftermath of the earthquake and between WCH and frontier county hospitals. One thousand and thirty-one earthquake survivors were hospitalized, 1 358 victims underwent surgery and 142 victims were transferred to intensive care unit. The incidence of infection, crush syndrome and multiple organ dysfunction syndrome (MODS) was 39.6%, 20.7% and 2.3% respectively. Wound classification showed that the incidence of extremity damage was 72%, while the incidence of chest trauma, abdominal trauma and brain trauma was less than 10% respectively. Isolating rates of environmental pathogens were increased in the aftermath of earthquake, and the spectrum of the pathogens and related antibiotic sensitivities were quite different from those in the beforemath of earthquake. The social economic and population conditions in the earthquake-stricken areas affected the composition of the victims and the geographic features restricted the efficiency of rescue. Trauma-induced MODS, crush syndrome and severe infections all constituted the dilemma for the hospital care, to resolve whether the multidiscipline team work was proved to be an optimizing choice. For a more effective disaster protective response in the future, the study on rescue plan and the ladder therapies for massive casualties should be potentiated.

Written by admin in: Brain Damage |
Jun
22
2010
0

Cognitive reserve in paediatric traumatic brain injury: Relationship with neuropsychological outcome.

Primary objective: The current study examined the relationship between neuropsychological performance and cognitive reserve (as measured by word reading and vocabulary tasks) in children with TBI. Research design: Retrospective records analysis of the neuropsychological test results of 52 participants with medically documented traumatic brain injuries, ranging from 6-16 years of age. Main outcome and results: Indicators of cognitive reserve were not correlated with the majority of well-recognized neuropsychological measures. Conclusions: Although past research has found that verbal ability is a valid indicator of CR in adult populations, the present study found evidence against the validity of this traditional reserve proxy when applied to the paediatric population. These findings suggest one of two conclusions: (1) measures used to indicate CR in adult populations (word reading, vocabulary) are not valid indicators of cognitive reserve in paediatric populations; and/or (2) the measures themselves are valid, yet there is simply not a significant relationship between cognitive reserve and short-term (i.e. less than 6 months) neuropsychological outcome in paediatric TBI.

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Jun
22
2010
0

Noninvasive detection of the distinction between progressive and compensated hydrocephalus in infants: is it possible?

Object Clinical signs and symptoms of hydrocephalus can be clear and specific, but also subtle, nonspecific, or even absent. It may be difficult to decide whether shunt placement is indicated, especially in infants. Therefore, there is a need for the development of better noninvasive detection methods to distinguish between compensated and (slowly) progressive hydrocephalus. Early interference can reverse the cerebral damage, whereas the detection of a nonpathological state in infants with compensated hydrocephalus avoids the complications of unnecessary shunt procedures. Using MR imaging, the authors investigated cerebral blood flow (CBF) and apparent diffusion coefficients (ADCs) measured in infants with clinically compensated hydrocephalus. Methods The diagnosis of compensated hydrocephalus was made on the basis of clinical criteria, consisting of no signs or symptoms of increased intracranial pressure (ICP), measurement of a normal ICP, and standard MR imaging showing enlarged ventricles. Flow measurements through both internal carotid arteries and the basilar artery were considered to represent the total CBF. In addition, ADC values were assessed in 5 different regions of interest in the brain parenchyma using diffusion weighted imaging. Brain volumetric measurement was performed to express CBF in ml/100 cm(3) brain/min, thus compensating for physiological CBF growth over time. Mean arterial blood pressure was manually measured to exclude this factor as a cause of a possible change in CBF. Intracranial pressure measurement was performed noninvasively using the Rotterdam Teletransducer. Results Eighteen infants with clinically compensated hydrocephalus were included. The mean CBF was 53.5 ml/100 cm(3) of brain/min. The individual CBF values were graphically compared with age-related normal CBF values and fell in the normal range. Mean ADC value was 890.0 x10(-6) mm(2)/sec. Apparent diffusion coefficient values per region of interest were graphically compared with normal ADC values per region of interest and fell within the normal range. Conclusions In infants with hydrocephalus, normal CBF and low ADC values, as measured using MR imaging, are associated with compensated hydrocephalus and may support a conservative approach with respect to the decision on whether to place a shunt.

Written by admin in: Brain Damage |
Jun
22
2010
0

Peroxisome Proliferator-Activated Receptor-gamma (PPAR-gamma) Activation Confers Functional Neuroprotection in Global Ischemia.

The neuroprotective effect of rosiglitazone, a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, has been investigated using both in vivo and in vitro models of global ischemia in CD1 mice. Behavioral tests were carried out prior to and at various times (up to 14 days) subsequent to bilateral common carotid artery occlusion followed by reperfusion. Mice at each time point were euthanized under anesthesia and the brain was removed, serially sliced and stained with 1% triphenyltetrazolium (TTC) to quantify infarct size. Administration of rosiglitazone (5 or 10 mg/kg, i.p.) 10 min prior to occlusion significantly reduced the postsurgical mortality rate (10-11 vs. 36%, P < 0.05). The higher dose of rosiglitazone (10 mg/kg) also significantly reduced the mean area of brain infarct at 1, 3, 7 and 14 days post-ischemia, reduced post-occlusion deficits in limb grasping and forelimb placing at various time points, and reduced total nitrite concentration in serum and brain homogenate at day 7 post-occlusion. To model global ischemia in vitro, coronal brain slices were incubated in oxygenated artificial cerebrospinal fluid (ACSF) in the presence of either glutamate (1 mM) or hydrogen peroxide (H(2)O(2)) (5 muM) for 30 min. Both H(2)O(2) and glutamate caused significant tissue damage, and co-incubation with rosiglitazone (5 muM) significantly reduced H(2)O(2)-induced damage but did not significantly reduce glutamate-induced brain damage in this model. Our observations provide further evidence for a neuroprotective effect of rosiglitazone in rodent models of ischemia.

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Jun
22
2010
0

A graph-theoretical approach in brain functional networks. Possible implications in EEG studies.

ABSTRACT : BACKGROUND : Recently, it was realized that the functional connectivity networks estimated from actual brain-imaging technologies (MEG, fMRI and EEG) can be analyzed by means of the graph theory, that is a mathematical representation of a network, which is essentially reduced to nodes and connections between them. METHODS : We used high-resolution EEG technology to enhance the poor spatial information of the EEG activity on the scalp and it gives a measure of the electrical activity on the cortical surface. Afterwards, we used the Directed Transfer Function (DTF) that is a multivariate spectral measure for the estimation of the directional influences between any given pair of channels in a multivariate dataset. Finally, a graph theoretical approach was used to model the brain networks as graphs. These methods were used to analyze the structure of cortical connectivity during the attempt to move a paralyzed limb in a group (N=5) of spinal cord injured patients and during the movement execution in a group (N=5) of healthy subjects. RESULTS : Analysis performed on the cortical networks estimated from the group of normal and SCI patients revealed that both groups present few nodes with a high out-degree value (i.e. outgoing links). This property is valid in the networks estimated for all the frequency bands investigated. In particular, cingulate motor areas (CMAs) ROIs act as ”hubs” for the out fl ow of information in both groups, SCI and healthy. Results also suggest that spinal cord injuries affect the functional architecture of the cortical network sub-serving the volition of motor acts mainly in its local feature property.In particular, a higher local efficiency El can be observed in the SCI patients for three frequency bands, theta (3-6 Hz), alpha (7-12 Hz) and beta (13-29 Hz).By taking into account all the possible pathways between different ROI couples, we were able to separate clearly the network properties of the SCI group from the CTRL group. In particular, we report a sort of compensatory mechanism in the SCI patients for the Theta (3-6 Hz) frequency band, indicating a higher level of “activation” Omega within the cortical network during the motor task. The activation index is directly related to diffusion, a type of dynamics that underlies several biological systems including possible spreading of neuronal activation across several cortical regions. CONCLUSIONS : The present study aims at demonstrating the possible applications of graph theoretical approaches in the analyses of brain functional connectivity from EEG signals. In particular, the methodological aspects of the i) cortical activity from scalp EEG signals, ii) functional connectivity estimations iii) graph theoretical indexes are emphasized in the present paper to show their impact in a real application.

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Jun
22
2010
0

Water Extract of Triticum aestivum L. and Its Components Demonstrate Protective Effect in a Model of Vascular Dementia.

Abstract Although vascular dementia is the second leading cause of dementia and often underdiagnosed, there are no drugs yet approved for the treatment of vascular dementia. In this study, it is demonstrated that water extract of Triticum aestivum L. (TALE) and some of its components have protective effects against vascular dementia-induced damage by preserving the myelin sheath and inhibiting astrocytic activation. The memory test used a vascular dementia model utilizing bilateral ligation of the carotid arteries of rats. TALE, some of its components, such as starch, total dietary fiber (TDF), arabinoxylan, beta-glucan, and degraded products of arabinoxylan, such as arabinose and xylose, were administered to the animals from day 8 to day 14, following the surgery. Twenty-one days after the surgery, the water maze test was performed for 5 days, and the time taken to find the platform during training trials (mean escape latency) was measured. The mean escape latency was decreased consistently in the TALE-, starch-, TDF-, arabinoxylan-, and arabinose-treated groups, compared with that in the vascular dementia group. To measure brain damage, Luxol fast blue staining and immunohistochemistry of myelin basic protein (MBP) were performed to observe myelin sheath in the white matter, and immunohistochemistry of glial fibrillary acidic protein (GFAP) was performed to observe the astrocytic reaction. Vascular dementia reduced the MBP level and increased the GFAP level. Arabinose effectively inhibited the MBP and GFAP change, whereas arabinoxylan inhibited the GFAP change only. These results suggest that TALE and some of its components can be used as a medicinal material for the development of neuroprotective agents against vascular dementia.

Written by admin in: Brain Damage |
Jun
22
2010
0

Zizyphus Attenuates Ischemic Damage in the Gerbil Hippocampus via Its Antioxidant Effect.

Abstract The fruit of Zizyphus jujuba has been used as a traditional Chinese medicinal herb and considered for thousands of years to affect various physiological functions in the body. We obtained a Z. jujuba extract (ZJE) and observed the neuroprotective effects of ZJE against ischemic damage in gerbils that had received repeated oral administrations of ZJE for 10 days. In the ZJE-treated ischemia group, neuronal nuclei (a marker for neurons)-immunoreactive neurons were abundant (58.4% vs. sham group) in the hippocampal CA1 region 4 days after ischemia/reperfusion compared to those in the vehicle-treated ischemia group (11.3%). In addition, ZJE treatment significantly decreased the reactive gliosis of astrocytes and microglia in the CA1 region compared to that in the vehicle-treated group 4 days after ischemia/reperfusion. Immunoreactivities of Cu,Zn-superoxide dismutase (SOD1) and brain-derived neurotrophic factor in the ZJE-treated ischemia group were higher those in the vehicle-treated ischemia group 4 days after ischemia/reperfusion. In addition, in the ZJE-treated ischemia group, levels of hydroxynonenal, an indicator of lipid peroxidation, were much lower than those in the vehicle-treated ischemia group after ischemia/reperfusion. These results suggest that the repeated supplements of ZJE can protect neurons from ischemic damage via up-regulation of SOD1 and reduction of lipid peroxidation in the ischemic hippocampal CA1 region.

Written by admin in: Brain Damage |
Jun
22
2010
0

Posttraumatic Headache: A Review.

There has been intense controversy about postconcussion syndrome (PCS) since Erichsen’s publication in 1866 on railway brain and spine. Headache as a result of trauma is one of the most common secondary headache types. Posttraumatic headache (PTH) remains a very controversial disorder, particularly with relation to chronic PTH following mild closed-head injury. PTH is one of several symptoms of PCS, and therefore may be accompanied by additional cognitive, behavioral, and somatic problems. PTH also is an important public health issue due to its associated disability and often refractory clinical course. While current awareness of PTH has become more prominent due to increased scrutiny given to both combat-related and sports-related head injuries, directed treatment remains a difficult challenge for physicians. Because of the frequently associated medicolegal aspects, PTH is one of physicians’ least favorite types to treat. The article reviews both PCS and PTH.

Written by admin in: Brain Damage |
Jun
22
2010
0

Practitioner Review: Beyond shaken baby syndrome: what influences the outcomes for infants following traumatic brain injury?

Background: Traumatic brain injury (TBI) in infancy is relatively common, and is likely to lead to poorer outcomes than injuries sustained later in childhood. While the headlines have been grabbed by infant TBI caused by abuse, often known as shaken baby syndrome, the evidence base for how to support children following TBI in infancy is thin. These children are likely to benefit from ongoing assessment and intervention, because brain injuries sustained in the first year of life can influence development in different ways over many years. Methods: A literature search was conducted and drawn together into a review aimed at informing practitioners working with children who had a brain injury in infancy. As there are so few evidence-based studies specifically looking at children who have sustained a TBI in infancy, ideas are drawn from a range of studies, including different age ranges and difficulties other than traumatic brain injury. Results: This paper outlines the issues around measuring outcomes for children following TBI in the first year of life. An explanation of outcomes which are more likely for children following TBI in infancy is provided, in the areas of mortality; convulsions; endocrine problems; sensory and motor skills; cognitive processing; language; academic attainments; executive functions; and psychosocial difficulties. The key factors influencing these outcomes are then set out, including severity of injury; pre-morbid situation; genetics; family factors and interventions. Conclusions: Practitioners need to take a long-term, developmental view when assessing, understanding and supporting children who have sustained a TBI in their first year of life. The literature suggests some interventions which may be useful in prevention, acute care and longer-term rehabilitation, and further research is needed to assess their effectiveness.

Written by admin in: Brain Damage |

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