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

Present classifications of bleeding events used in antithrombotic and/or antiplatelet clinical trials are based on the criteria developed by the Thrombolysis In Myocardial Infarction (TIMI) and Global Use of Strategies to Open Coronary Arteries (GUSTO) groups. Introduced more than a decade ago, the 2 classifications used the criteria to better categorize hemorrhagic events after therapy with thrombolytic agents. Recent advances in interventional cardiology, resulting in a domination of percutaneous intracoronary procedures over systemic drug-induced thrombolysis, have substantially changed the clinical characteristics and magnitude of bleeding complications. Moreover, disturbances of the coagulation cascade, as well as platelet inhibition caused directly by antithrombotic and antiplatelet agents, share very specific and well-recognized clinical features not reflected in the existing classifications. Bleeding events after aspirin or clopidogrel, and especially those after more delicate antiplatelet regimens with dipyridamole used in patients after ischemic stroke or transient ischemic attack, are impossible to classify by the present guidelines, other than categorically triaging them altogether to the "minor" category. Uniting entirely different bleeding events as "minor" under-rates their importance and diminishes affiliated risks, creating an illusion that they do not require monitoring and/or changes in antiplatelet or antithrombotic regimens. In reality, such unrecognized and unreported mild complications may transform into more serious bleeds or lead to noncompliance. Unauthorized withdrawal from antiplatelet agents in turn causes rebound platelet activation and higher risk for secondary vascular events. In conclusion, a new classification of bleeding events is introduced (the BleedScore), based on a point accumulation depending on the severity of hemorrhage, which is believed to be more suitable for the assessment of modern, more delicate antithrombotic and antiplatelet therapies, particularly for their realistic assessment in clinical trials.
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PMID:Assessment of bleeding events in clinical trials--proposal of a new classification. 1765 51

After a low brainstem stroke, a 73-year-old man experienced episodes of 90 degrees tilting of the visual environment in the sagittal plane evoked or terminated by voluntarily changing his head position. The episodes ceased 10 days after the stroke. This provocation by head position supports the idea that pathologic visual-vestibular interaction is at the basis of the room tilt illusion.
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PMID:Room tilt illusion influenced by head position. 1809 May 65

We introduce a novel technique to generate painterly art map (PAM) for 3D non-photorealistic rendering. Our technique can automatically transfer brush stroke textures and color changes to 3D models from samples of a painted image. Therefore, the generation of stylized images/animation in the style of a given artwork can be achieved. This new approach works particularly well for a rich variety of brush strokes ranging from simple 1D and 2D line-art strokes to very complicated ones with significant variations in stroke characteristics. During the rendering/animation process, the coherence of brush stroke textures and color changes over 3D surfaces can be well maintained. With PAM, we can also easily generate the illusion of flow animation over a 3D surface to convey the shape of a model.
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PMID:Stylized rendering using samples of a painted image. 1819 23

The sense of body ownership represents a fundamental aspect of our self-awareness, but is disrupted in many neurological, psychiatric, and psychological conditions that are also characterized by disruption of skin temperature regulation, sometimes in a single limb. We hypothesized that skin temperature in a specific limb could be disrupted by psychologically disrupting the sense of ownership of that limb. In six separate experiments, and by using an established protocol to induce the rubber hand illusion, we demonstrate that skin temperature of the real hand decreases when we take ownership of an artificial counterpart. The decrease in skin temperature is limb-specific: it does not occur in the unstimulated hand, nor in the ipsilateral foot. The effect is not evoked by tactile or visual input per se, nor by simultaneous tactile and visual input per se, nor by a shift in attention toward the experimental side or limb. In fact, taking ownership of an artificial hand slows tactile processing of information from the real hand, which is also observed in patients who demonstrate body disownership after stroke. These findings of psychologically induced limb-specific disruption of temperature regulation provide the first evidence that: taking ownership of an artificial body part has consequences for the real body part; that the awareness of our physical self and the physiological regulation of self are closely linked in a top-down manner; and that cognitive processes that disrupt the sense of body ownership may in turn disrupt temperature regulation in numerous states characterized by both.
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PMID:Psychologically induced cooling of a specific body part caused by the illusory ownership of an artificial counterpart. 1872 30

Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks. Assessments of maximal grasp and pinch strengths, and upper limb function measured by the Shriner's Hospital Upper Extremity Evaluation were performed at weeks 0 (baseline), 3, 6 (intervention), and 9 (wash-out). Testing of grasp strength behind the mirror improved performance by 15% (p=0.004). Training with the mirror significantly improved grasp strength (with mirror +20.4%, p=0.033; without +5.9%, p>0.1) and upper limb dynamic position (with mirror +4.6%, p=0.044; without +1.2%, p>0.1), while training without a mirror significantly improved pinch strength (with mirror +6.9%, p>0.1; without +21.9%, p=0.026). This preliminary study demonstrates the feasibility of mirror therapy in children with hemiplegia and that it may improve strength and dynamic function of the paretic arm.
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PMID:Mirror therapy in children with hemiplegia: a pilot study. 2141 Jun 93

The feeling of "body ownership" may be experimentally investigated by perceptual illusions. The "rubber hand illusion" (RHI) leads human subjects to experience an artificial hand as their own. According to functional imaging, the ventral premotor cortex (PMv) plays a key role in the integration of multisensory inputs allowing the "incorporation" of the rubber hand into body representation. However, causal structure-function relationships can only be obtained by lesion studies. Here, we tested the RHI in 70 stroke patients and in 40 age-matched healthy controls. Additionally, asomatognosia, the unawareness of one's own body parts, was assessed in a subgroup of 64 stroke patients. Ischemic lesions were delineated on diffusion-weighted magnetic resonance images and normalized. Right-hemispheric lesions were mirrored across the midline. Voxels that might be essential for RHI and/or somatognosia were defined by voxel-based lesion-symptom mapping. Probabilistic diffusion tractography was used to identify tracts passing through these voxels. Contralesional rubber hand illusion failure (RHIF) was observed in 18 (26%) of 70 stroke patients, an additional ipsilesional RHIF in seven of these patients. RHIF-associated lesion voxels were located subcortically adjacent to the insula, basal ganglia, and within the periventricular white matter. Tractography revealed fiber tract connections of these voxels with premotor, parietal, and prefrontal cortex. Contralesional asomatognosia was found in 18 (28%) of 64 stroke patients. In contrast to RHIF, asomatognosia-associated lesion voxels showed no connection with PMv. The results point to a role of PMv and its connections in mediating changes in the sense of limb ownership driven by multisensory stimulation.
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PMID:Ventral premotor cortex may be required for dynamic changes in the feeling of limb ownership: a lesion study. 2171 8

A student volunteer was asked to stand just behind a mannequin so that the student was looking at the back of the mannequin's plastic head. The experimenter stood off to one side and used her two hands to stroke and tap the back of the student's head in perfect synchrony with the back of the mannequin's head. After 1-2 min the majority of naive subjects tested began experiencing the sensations as emerging from the mannequin's head rather than from their own, demonstrating a novel 'phantom-head' illusion. The fact that sensory referral here occurs to a part of the body that is not normally visually accessible challenges the leading Hebbian explanation of the well-studied rubber-hand illusion.
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PMID:The phantom head. 2169 26

Macro- and micro-somatognosia refer to rare disorders of the cerebral representation of the body whereby patients perceive body parts as disproportionately large or small. Here we report the experimental study of a patient who, following a left lateral medullary stroke (Wallenberg's syndrome, including vestibular deficits) complained of a persistent somatosensory illusory sensation of swelling, confined to the left side of his face (i.e., left macrosomatognosia). This hemifacial somatosensory distortion was associated with a left facial anesthesia, and a neuropathic pain affecting the three branches of the left trigeminal nerve. In this study, we first document quantitatively the patient's somatosensory illusion by using a somatosensory-to-visual matching task in which the patient modified the picture of his own face to fit his left-sided somatosensory misperception. The patient's performance revealed that macrosomatognosia was confined to the second branch of the left trigeminal nerve. Perception of the size of visual objects was comparatively preserved. Second, we investigated the effects of two peripheral stimulations, which may affect the spatial component of somatosensory deficits (caloric vestibular stimulation, CVS; transcutaneous electrical nervous stimulation, TENS) and pain (TENS). Left CVS abolished the facial somatosensory illusion, for about 30min, but had no effect on the left facial pain. Conversely, left TENS substantially reduced the neuropathic pain during stimulation, but had no effect on macrosomatognosia, indicating a double dissociation between the two disorders. These results reveal that facial macrosomatognosia may be regarded as a high-order deficit of somatosensory perception of the shape and volume of the face, which fits the definition of 'hyperschematia' (i.e., when the body takes up too much room) originally proposed by Bonnier (1905). Our data also indicate that CVS may favor the restoration of the conscious representation of the shape and size of the face. Overall, these findings lend support to the view that afferent inputs from the vestibular system can affect in a specific fashion the activity of cerebral structures involved in the building up and updating of the topological description of body parts.
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PMID:Facial macrosomatognosia and pain in a case of Wallenberg's syndrome: selective effects of vestibular and transcutaneous stimulations. 2214 67

Converging evidence suggests that the left superior temporal sulcus (STS) is a critical site for multisensory integration of auditory and visual information during speech perception. We report a patient, SJ, who suffered a stroke that damaged the left tempo-parietal area, resulting in mild anomic aphasia. Structural MRI showed complete destruction of the left middle and posterior STS, as well as damage to adjacent areas in the temporal and parietal lobes. Surprisingly, SJ demonstrated preserved multisensory integration measured with two independent tests. First, she perceived the McGurk effect, an illusion that requires integration of auditory and visual speech. Second, her perception of morphed audiovisual speech with ambiguous auditory or visual information was significantly influenced by the opposing modality. To understand the neural basis for this preserved multisensory integration, blood-oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) was used to examine brain responses to audiovisual speech in SJ and 23 healthy age-matched controls. In controls, bilateral STS activity was observed. In SJ, no activity was observed in the damaged left STS but in the right STS, more cortex was active in SJ than in any of the normal controls. Further, the amplitude of the BOLD response in right STS response to McGurk stimuli was significantly greater in SJ than in controls. The simplest explanation of these results is a reorganization of SJ's cortical language networks such that the right STS now subserves multisensory integration of speech.
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PMID:Multisensory speech perception without the left superior temporal sulcus. 2263 92

Psychosis and psychosis-proneness are associated with abnormalities in subjective experience of the self, including distortions in bodily experience that are difficult to study experimentally due to lack of structured methods. In 55 healthy adults, we assessed the relationship between self-reported psychosis-like characteristics and susceptibility to the rubber hand illusion of body ownership. In this illusion, a participant sees a rubber hand being stroked by a brush at the same time that they feel a brush stroking their own hand. In some individuals, this creates the bodily sense that the rubber hand is their own hand. Individual differences in positive (but not negative) psychosis-like characteristics predicted differences in susceptibility to experiencing the rubber hand illusion. This relationship was specific to the subjective experience of rubber hand ownership, and not other unusual experiences or sensations, and absent when a small delay was introduced between seeing and feeling the brush stroke. This indicates that individual differences in susceptibility are related to visual-tactile integration and cannot be explained by differences in the tendency to endorse unusual experiences. Our findings suggest that susceptibility to body representation distortion by sensory information may be related or contribute to the development of psychosis and positive psychosis-like characteristics.
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PMID:Psychosis-proneness and the rubber hand illusion of body ownership. 2327 11


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