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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A variety of surgical treatments for intractable epilepsy with hypothalamic hamartoma (HH) are described, although most are derived from limited patient experience gathered from several centres. We describe the results of transcallosal resection of HH in 29 consecutive patients undergoing surgery at one centre. Twenty-nine patients aged 4-23 years (mean 10 years) underwent HH surgery with a minimum of 12 months follow-up. A comprehensive, presurgical epilepsy evaluation, supplemented with endocrine and ophthalmological assessments was performed in all cases. HH were resected via a transcallosal, interforniceal approach to the third ventricle, with the assistance of frameless stereotaxy, limiting the resection to the margins of the third ventricular walls and floor and minimising traction and diathermy. Complete or near-complete (>95%) resection of the HH was achieved in 18/29 patients, 75-95% resection was achieved in seven patients (four of whom had complete or near-complete disconnection of residual HH) and less than 50% resection was achieved in four. Postoperatively (follow-up 12-70 months, mean 30 months), 15 became seizure-free (nine off antiepileptic medication), seven had >90% reduction in seizure frequency, three had 55-80% reduction in seizure frequency, and four had less than 40% reduction in seizure frequency. Of 16 patients who had seizures in the early postoperative period, six became seizure. No patient or lesion characteristics were associated with postoperative seizure freedom, including features of symptomatic generalised epilepsy. Neurobehavioural improvement and resolution of EEG abnormalities were seen in the majority. Complications were transient hemiparesis in two, transient hypernatraemia in 17, short-term memory impairment in 14 (persistent in four), weight gain in ten (persistent in five), need for supplemental thyroxine in five, and lowered growth hormone (uncertain clinical significance) in six. Transcallosal resection of HH is an effective treatment for intractable epilepsy, with 76% patients in our seizures being seizure-free or having >90% seizure reduction. The operative risks include stroke, short-term memory disturbance, weight gain and minor endocrine disturbances. Based on published data, the transcallosal approach appears to be safer and more effective than other operative strategies.
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PMID:Transcallosal resection of hypothalamic hamartomas in patients with intractable epilepsy. 1497 95

Cognitive impairment is common after ischemic stroke. In rodent stroke models using occlusion of the middle cerebral artery (MCA) this is reflected by impaired spatial memory associated with the size of the ischemic lesion. Housing in an enriched environment enhances brain plasticity and improves recovery of sensorimotor functions after experimental stroke in rats. In this study we report that postischemic housing in an enriched environment also attenuates the long-term spatial memory impairment after MCA occlusion and extinguishes the association between spatial memory and infarct volume. An enriched environment did not significantly alter the expression of selected neuronal plasticity-associated genes 1 month after MCA occlusion, indicating that most of the adaptive changes induced by an enriched environment have already occurred at this time point. We conclude that the attenuated memory impairment induced by environmental enrichment after MCA occlusion provides a useful model for further studies on the neurobiological mechanisms of recovery of cognitive functions after ischemic stroke.
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PMID:Environmental enrichment reverses learning impairment in the Morris water maze after focal cerebral ischemia in rats. 1509 55

Soman, an anticholinesterase and dangerous nerve agent, produces convulsions, memory impairment, and cell loss in the brain, especially in the hippocampus. Soman-induced accumulation of acetylcholine initiates mechanisms responsible for the development of incapacitating seizures. The prolonged epileptiform nature of these seizures causes the release of another excitatory neurotransmitter, glutamate, which has been linked to the toxic action of the nerve agent. Here, we tested whether subtoxic soman exposures influence the brain's sensitivity to glutamate-based excitotoxicity. Over a 1-week period, hippocampal slice cultures were exposed daily to a transient level of soman that produced no evidence of synaptic deterioration. After the subtoxic soman treatments, however, the tissue became vulnerable to a brief episode of glutamate receptor overstimulation that normally resulted in little or no excitotoxic damage. In those slice cultures treated with subtoxic soman, a decline in synaptic markers as well as an increase in spectrin breakdown occurred 24 hr after the mild excitotoxic event. Exposure to high soman concentrations alone produced similar synaptic degeneration, but without evident cell death, suggesting that synaptic decline is an early neurotoxicological response to the nerve agent. Interestingly, enhanced excitotoxic sensitivity caused the brain tissue to become susceptible to disparate insults initiated before or after the soman contact. These findings indicate that seemingly innocuous soman exposures leave the hippocampus sensitive to the types of insults implicated in traumatic brain injury and stroke. They also warn that asymptomatic contact with soman may lead to progressive synaptopathogenesis and that early indicators of soman exposure are critical to prevent potential brain injury.
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PMID:Repeated contact with subtoxic soman leads to synaptic vulnerability in hippocampus. 1535 21

The Location Learning Test is a neuropsychological test that can be used to assess memory for object locations. The test has originally been developed for the assessment of visuo-spatial memory impairment in patients with dementia. However, ceiling effects may be present in other patient groups. This study has examined the applicability of a modified administration procedure with a shorter presentation duration and longer delay. The test was administered in a group of stroke patients (n = 105), a group of patients with diabetes (n = 93), as well as a group of healthy volunteers (n = 97). The results indicate that the Location Learning Test can be used to discriminate the diabetes and stroke patients from the control group. Furthermore, differences between patients with a left and a right-hemisphere stroke were found. The test has a high correlation with another memory test. The performance of the group healthy volunteers was used to calculate normative data for use in clinical practice.
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PMID:[The Location Learning Test as a measure of spatial memory: applicability of a modified administration procedure and normative data]. 1547 19

The concept of Vascular Cognitive Impairment (VCI) encompasses patients across the entire continuum of cognitive impairment resulting from cerebrovascular disease (CVD), ranging from high-risk patients with no frank cognitive deficit (the "brain-at-risk" stage) through vascular dementia (VaD). There are accepted differences in the neuropsychological profile of patients with Alzheimer's disease (AD) and VaD. In patients with VaD, executive functions that tend to be disproportionately impaired include planning and sequencing, speed of mental processing, performance on unstructured tasks, and attention. Language production may be impaired in patients with VaD but primary language functions otherwise tend to be preserved. Patients with VaD also exhibit significantly more perseverations than patients with AD. Memory impairment is typically evident in patients with AD+CVD but memory impairment may also occur as a primary consequence of stroke in the posterior cerebral artery territory with involvement of the medial temporal lobe, or as a secondary consequence of a cognitive syndrome involving inattention due to primary executive dysfunction. Compared to VaD, patients with AD may exhibit greater deficits in functions (including memory) mediated by posterior cortical structures, such as the temporal and parietal lobes. AD patients exhibit a faster rate of information decay, reduced ability to benefit from cues to facilitate retrieval, and higher frequency of intrusion errors; in addition, certain aspects of language function, such as naming, may exacerbate deficits on verbal memory tasks. AD tends to affect lexicon while VaD tends to affect syntax. When patients with AD exhibit perseverations, they tend to be elicited by tests of semantic knowledge.
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PMID:The neuropsychology of vascular cognitive impairment: is there a specific cognitive deficit? 1553 10

The active role (participation) that patients with chronic conditions are able to achieve has increasingly been recognised as a measure for the effectiveness of prevention- and rehabilitation strategies. An empowerment scale is an especially effective instrument for measuring social participation, and was applied to stroke patients in neurological rehabilitation for the first time. 26 stroke survivors and 26 informal carers, who participated in self-help groups in Lower Austria, were surveyed. The mean age was 63.9 (+/- 10.4) (stroke survivors) and 61.9 (+/- 9.6) years (informal carers). The mean duration of disease was 7.3 (+/- 3.2) years and the mean length of self-help group participation approximately 4 years. Every other stroke survivor and every fifth informal carer had to give up their professional life because of the stroke. Financial burden, reduction of vacations and social activities was found for both groups. Informal carers more frequently reported an increased fear of a relapse and generally of the future. One third of the stroke survivors had insomnia, depression, and nervousness. Reduced mobility, memory impairment, and increased sensitivity to temperature-changes were seen as the largest burdens. In spite of the large overlap in many domains of empowerment- and quality-of-life measures, empowerment measures also seem to reflect aspects of social participation. Therefore, measures of empowerment should be included in long-term outcome measurements following stroke.
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PMID:[Empowerment, quality of life and participation in neurological rehabilitation. Empirical study with stroke patients and their relatives]. 1567 32

Progressive memory impairment, beta-amyloid (Abeta) plaques associated with local inflammation, neurofibrillary tangles, and loss of neurons in selective brain areas are hallmarks of Alzheimer's disease (AD). Although beta-amyloid precursor protein (APP) and Abeta have a central role in the etiology of AD, it is not clear which forms of APP or Abeta are responsible for the neuronal vulnerability in AD brain. Brain ischemia, another cause of dementia in the elderly, has recently been recognized to contribute to the pathogenesis of AD and individuals with severe cognitive decline and possibly underlying AD are at increased risk for ischemic events in the brain. Moreover, the epsilon4 allele of apolipoprotein E (ApoE) is a risk factor for both AD and poor outcome following brain ischemia and hemorrhage. Several factors and molecular mechanisms that lower the threshold of neuronal death in models of AD have recently been described. Among these neuroinflammation seems to play an important role. The development and maturation of both AD neuropathology and ischemic lesions in the central nervous system are characterized by activation of glial cells and upregulation of inflammatory mediators. Indeed, anti-inflammatory approaches have proven to be beneficial in the prevention and treatment of AD-like neuropathology and ischemic injuries in vivo. This review summarizes some of the findings suggesting that neuronal overexpression of human APP renders the brain more vulnerable to ischemic injury and describes the factors that are involved in increased neuronal susceptibility to ischemic stroke.
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PMID:Interactions between Alzheimer's disease and cerebral ischemia--focus on inflammation. 1585 Jun 63

Vascular dementia and vascular cognitive impairment have attracted more attention recently due to their association with increased risk of death and institutionalization. The purpose of the present study was to detect and identify the characteristics of cognitive impairments during the early stage of lacunar stroke. The subjects consisted of 23 consecutive first-ever acute lacunar infarction patients who were admitted to the Department of Neurology, Kaohsiung Municipal Hsiao-Kang Hospital, Taiwan, from November 2001 to October 2002. The National Institutes of Health Stroke Scale and Cognitive Abilities Screening Instrument (CASI) were used to evaluate stroke severity and cognitive function, and assessments were performed by a neurologist and psychologist, within 10 days of stroke onset. Of the 23 patients, 21 (91.3%) had CASI scores below their respective cutoff values and all patients had cognitive impairment in at least one cognitive domain in CASI. There were no significant correlations between CASI abnormality (below the cutoff value) and patient age, education, or the interval from stroke onset. Recent memory impairment was the most often impaired cognitive domain on CASI (19 patients, 82.6%). There were significant correlations between recent memory and "attention or concentration"(correlation coefficient, 0.52; p < 0.05), and "abstraction and judgment" (correlation coefficient, 0.44; p < 0.05). The correlations between recent memory and other domains were not significant. It was concluded that cognitive impairment after acute lacunar infarct is quite common and recent memory is the most often impaired cognitive domain. This may have been caused by the location of the specific lesion as well as by the impairment in "attention or concentration" or "abstraction and judgment".
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PMID:Cognitive dysfunction after acute lacunar infarct. 1603 69

We examined the evidence for widely held clinical beliefs about memory impairment following right hemisphere stroke (RHS), conducting both narrative and meta-analytic reviews of the literature [MEDLINE (1966-January 2003), PsycINFO (1974-January 2003), and CINAHL (1982-December 2002)]. We sought to determine whether RHS patients experience more problems with non-verbal memory than non-stroke controls (NSCs) and left hemisphere stroke (LHS) patients. Secondarily, we sought to determine whether RHS patients experience more problems with verbal memory than NSCs and fewer verbal memory problems than LHS patients. We also examined the effect of type of memory assessment (recall versus recognition) on reported findings. As regards non-verbal memory, narrative and meta-analytic reviews found that RHS patients had deficits relative to NSCs, on tests of both recall and recognition. The evidence for RHS non-verbal memory deficits relative to LHS was mixed in the narrative review, whereas the meta-analysis found RHS deficits on non-verbal recognition tests, but no difference between RHS and LHS patients on non-verbal recall tests. Deficits on recognition tests imply problems with early encoding of material or possibly its storage. Regarding verbal memory, the narrative review found that RHS patients performed more poorly than NSCs in about half of all studies. The meta-analytic review confirmed poorer RHS performance on tests of verbal recall, but none of the studies that compared RHS and NSCs on verbal recognition could be included in this type of review. The narrative review found mixed evidence as regards the performance of RHS and LHS patients on verbal memory tests, but the meta-analysis pointed to RHS superiority for both verbal recall and recognition. The relative strengths of both types of review are discussed.
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PMID:Memory impairment following right hemisphere stroke: a comparative meta-analytic and narrative review. 1639 21

Receptors have a prominent role in brain function, as they are the effector sites of neurotransmission at the postsynaptic membrane, have a regulatory role on presynaptic sites for transmitter reuptake and feedback, and are modulating various functions on the cell membrane. Distribution, density, and activity of receptors in the brain can be visualized by radioligands labeled for SPECT and PET, and the receptor binding can be quantified by appropriate tracer kinetic models, which can be modified and simplified for particular application. Selective radioligands are available for the various transmitter systems, by which the distribution of these receptors in the normal brain and changes in receptor binding during various physiologic activities or resulting from pathologic conditions can be visualized. The quantitative imaging for several receptors has gained clinical importance-for example, dopamine (D2)) receptors for differential diagnosis of movement disorders and for assessment of receptor occupancy by neuroleptics drugs; serotonin (5-hydroxytryptamine, 5-HT) receptors and the 5-HT transporter in affective disorders and for assessment of activity of antidepressants; nicotinic receptors and acetylcholinesterase as markers of cognitive and memory impairment; central benzodiazepine-binding sites at the gamma-aminobutyric acid A (GABAA) receptor complex as markers of neuronal integrity in neurodegenerative disorders, epilepsy, and stroke and as the site of action of benzodiazepines; peripheral benzodiazepine receptors as indicators of inflammatory changes; opioid receptors detecting increased cortical excitability in focal epilepsy but also affected in perception of and emotional response to pain; and several receptor systems affected in drug abuse and craving. Further studies of the various transmitter/receptor systems and their balance and infraction will improve our understanding of complex brain functions and will provide more insight into the pathophysiology of neurologic and psychiatric disease interaction.
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PMID:Brain receptor imaging. 1645 37


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