1/35. Neglect without extinction.A patient, AB, is reported who showed clear signs of neglect but no extinction (N E-). Several hypotheses proposed to account for this dissociation were put to the test. The postulated association between motor neglect and extinction did not hold good, nor did the possibility that the N E- dissociation may be traced back to the difference in test requirements and therefore observed only in patients with object-centred neglect. Likewise, manipulating the physical features of the stimuli (relative size, exposure time, presentation synchrony) did not elicit extinction. However, when the task demands were modified by asking the patient to perform a further spatial analysis of the stimuli, rather than simply detect them, extinction emerged. Since AB performed well on several neglect tasks requiring parallel processing, while failing all tasks calling for serial processing, the hypothesis is put forward that AB's N E- dissociation could be interpreted within the parallel/serial distinction framework.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/35. Delineating necessary and sufficient neural systems with functional imaging studies of neuropsychological patients.This paper demonstrates how functional imaging studies of neuropsychological patients can provide a way of determining which areas in a cognitive network are jointly necessary and sufficient. The approach is illustrated with an investigation of the neural system underlying semantic similarity judgments. functional neuroimaging demonstrates that normal subjects activate left temporal, parietal, and inferior frontal cortices during this task relative to physical size judgments. neuropsychology demonstrates that damage to the temporal and parietal regions results in semantic deficits, indicating that these areas are necessary for task performance. In contrast, damage to the inferior frontal cortex does not impair task performance, indicating that the inferior frontal cortex might not be necessary. However, there are two other possible accounts of intact performance following frontal lobe damage: (1) there is functional reorganization involving the right frontal cortex and (2) there is peri-infarct activity around the damaged left-hemisphere tissue. Functional imaging of the patient is required to discount these possibilities. We investigated a patient (SW), who was able to associate words and pictures on the basis of semantic relationships despite extensive damage to the left frontal, inferior parietal, and superior temporal cortices. Although SW showed peri-infarct activation in left extrasylvian temporal cortices, no activity was observed in either left or right inferior frontal cortices. These findings demonstrate that activity in extrasylvian temporo-parietal and medial superior frontal regions is sufficient to perform semantic similarity judgments. In contrast, the left inferior frontal activations detected in each control subject appear not to be necessary for task performance. In conclusion, necessary and sufficient brain systems can be delineated by functional imaging or brain-damaged patients who are not functionally impaired.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
3/35. Rectus sheath hematoma in an elderly woman under anti-coagulant therapy.Rectal sheath hematoma has been a well-known clinical entity from the ruin of the ancient greece. It is relatively rare, however, to encounter this abdominal disorder in the clinical setting. Furthermore, the initial symptoms of rectus sheath hematoma are often similar to those of acute abdominal disorders. Therefore, the majority of the patients with rectus sheath hematoma have been treated with operative procedures because of the difficulty of a differential diagnosis from other abdominal disorders. We recently treated a 74-year female diagnosed with rectus sheath hematoma with the anticoagulants after an episode of cerebral infarction. From the findings of the physical examinations, ultrasound, and computed tomography, we could correctly diagnose, and could treat her with completely conservative methods without any invasive techniques. It is stressed that it is important to recognize this entity of rectus sheath hematoma when patients are examined, after complaining of acute abdominal pain and with evidence abdominal masses in the clinical setting.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
4/35. Dissecting hematoma of intracranial internal carotid artery in an 8-year-old girl.BACKGROUND: An 8-year-old girl had a minor fall without head trauma and she collapsed the following day while playing. She was awake but mute with focal neurologic signs when admitted to hospital. Radiologic imaging studies showed a progressive left cerebral infarct with left hemisphere vascular narrowing and beading. She died on the third hospital day. methods: autopsy including exploration of neck vessels and neuropathological examination was performed. Postmortem studies included immunostaining for immunoglobulins and fixed complement. RESULTS: Subtotal subintimal dissections of both proximal supraclinoid internal carotid arteries were found microscopically. On the left, the subintimal dissection extended into the major branches of the left internal carotid artery as dissecting hematomas with a major compromise of the arterial lumina. Specific IgM deposition at the dissection sites was found. A literature review shows that subintimal dissection of the intracranial internal carotid artery or its branches occurs rarely, it is often fatal, and it is present in patients with a mean age of 17.5 years in cases studied pathologically. Trauma and physical exertion are the most common associated factors. CONCLUSIONS: Among the causes of ischemic stroke in young individuals, dissecting hematomas of the intracranial portions of the internal carotid artery system rank low. Few reported cases have identifiable pre-existing pathology. The pathogenesis of dissecting hematomas in this region is reviewed and expanded with speculation regarding relevant developmental, anatomical, flow stress and possibly humoral factors that are involved in the disruption of the arterial elastica and subsequent development and extension of a subintimal hematoma resulting in luminal closure and often death.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
5/35. Psychophysical and pupillometric study of spatial channels of visual processing in blindsight.To date no systematic method has been used for characterising the residual capacity of blindsight subjects that would allow comparison and generalisation across all subjects. The detection of isoluminant gratings of varying spatial and temporal frequencies commends itself for detailed between-subject comparison, and for mapping results onto physiological properties in relation to neuronal circuitry. We report the ability of a blindsight subject (CS) to detect suprathreshold sine-wave gratings over a range of spatial and temporal frequencies using psychophysical techniques. A band-pass spatial channel with an upper cutoff below 3.5 cycles/deg is specified. The data also have been analysed to compare differences between two types of blindsight performances, type I and type II. Spatial gratings were also used to elicit a pupillary grating response, offering an objective method that is free of verbal nuances and response bias, and the resulting band-pass channel can be used both for clinical screening and for prediction and comparisons with psychophysical profiles. Finally, we have compared our results with those reported in studies of a well-known subject, GY, which demonstrate remarkable similarities. Implications are discussed in relation to blindsight research.- - - - - - - - - - ranking = 6keywords = physical (Clic here for more details about this article) |
6/35. Conversion sensory symptoms associated with parietal lobe infarct: case report, diagnostic issues and brain mechanisms.This case report suggests that diagnostic difficulties and brain mechanisms related to conversion disorder associated with cerebral lesions differ from those related to conversion disorder without cerebral lesions. A 35-year-old divorced woman was admitted to a psychiatric inpatient unit with multiple physical complaints. The symptoms first appeared 5 years previous and 2 months after a sexual assault. Three years later, she began to experience ill-defined sensory symptoms confined to the left half of her body (splitting the midline). Results of neurologic consultations were equivocal because of the subjective nature of the complaints, which were viewed as conversion symptoms. A magnetic resonance imaging scan demonstrated an old infarct in the right parietal lobe, suggesting a physical origin of the patient's symptoms. However, normal somatosensory-evoked responses from the affected area contributed little to establishing the diagnosis. The results of all further investigations to identify causes of the vascular pathology were negative. The multiple ill-defined somatic symptoms, the distribution of sensory symptoms and the resolution of symptoms with psychotherapy established the diagnosis of conversion disorder superimposed on a pre-existing right parietal lesion. This case highlights the importance of clinical features in establishing a diagnosis such as this. We suggest that reactivation of implicit sensory memories (represented at the thalamic level and resulting from decreased corticofugal inhibitions due to the lesion) may contribute to the formation of sensory conversion symptoms in individuals with parietal lobe lesions.- - - - - - - - - - ranking = 2keywords = physical (Clic here for more details about this article) |
7/35. Cases from the osler medical service at Johns Hopkins University.PRESENTING FEATURES: A 29-year-old woman with a history of rheumatic heart disease and one episode of endocarditis as an adolescent was admitted to the hospital after 1 week of headache, fever, and myalgia. Her past medical history was otherwise unremarkable and did not include illicit drug use. On physical examination, she had a previously noted 3/6 holosystolic murmur at the apex, which radiated to her back; a previously noted 1/4 diastolic murmur at the right upper sternal border; diminished strength in her right upper extremity; multiple painful erythematous nodules on her fingers (Figure 1); and red streaks under her nails (Figure 2). magnetic resonance imaging of the brain demonstrated multiple lesions; the largest was in the right frontal lobe with associated hemorrhage (Figure 3).What is the diagnosis?- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
8/35. Visual deficits in a patient with 'kaleidoscopic disintegration of the visual world'.We describe psychophysical, neuropsychological and neuro-ophthalmological studies of visual abilities in a patient who, following a right hemisphere stroke, had difficulty in combining parts of objects into a whole and in reading. Strikingly, her perceptual problems were accentuated when the objects moved or when she moved. Formal testing showed that her main deficits were in depth perception, various tasks of motion and object recognition of degraded stimuli. But low-level detection and discrimination of form and color were normal. Despite her deficits in visual motion and degraded static-object recognition, her visual recognition of 'biological motion' stimuli was normal. Structural magnetic resonance imaging revealed an infarct in the ventro-medial occipito-temporal region, extending ventro-laterally and leading to a 'kaleidoscopic disintegration of visible objects'.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
9/35. Somatosensory and skin temperature disturbances caused by infarction of the postcentral gyrus: a case report.Somatosensory functions are subdivided into 2 large groups: the elementary somatosensory functions, which consist of light touch, pain, thermal sensation, joint position sense, and vibration sense, and the intermediate somatosensory functions, which include 2-point discrimination, tactile localization, weight, texture, and shape perception. In this report, we describe a patient with somatosensory dysfunction after infarction of the postcentral gyrus. On physical examination a month after the onset of the infarction, voluntary movements were skillful, and both the elementary and intermediate somatosensory functions were disturbed in the right hand. The patient also displayed a decrease in the skin temperature of the right hand. The sensory-evoked potential in response to electrical stimulation of the right median nerve was normal, and brain MRI showed that the infarction was located in the posterior half of the left postcentral gyrus. These findings suggested that the lesion was situated at areas 1 and 2, and that area 3b was preserved. thermography revealed that the skin temperature of the right hand was decreased predominantly on the ulnar side, and that recovery from cooling with ice water was delayed. By comparing the results of our patient with a case report that showed no disturbance of the elementary somatosensory functions with a localized lesion in the postcentral gyrus, we suggest that area 1 participates in the elementary somatosensory functions and that skin temperature may be controlled somatotopically in the somatosensory cortex.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
10/35. Ischemic stroke after using over the counter products containing ephedra.dietary supplements containing ephedra used for weight loss and physical performance enhancement such as "herbal ecstasy" are widely available, and it is estimated that at least 1% of the adult population have taken these products. ephedra products including ephedra alkaloids such as phenylpropanolamine or other ephedrine compounds are sold under different names such as Metabolife 356, Ripped Fuel, Thermadrene, and Shape-Fast Plus. Over 2 years, five patients with ischemic infarctions associated with use of ephedra products were evaluated at indiana University Hospital. ephedrine, like other sympathomimetic agents, predisposes patients to both ischemic and hemorrhagic strokes. People who take over the counter ephedra products that claim to boost weight loss, increase energy, or bolster physical performance are at risk of adverse events including ischemic and hemorrhagic strokes.- - - - - - - - - - ranking = 2keywords = physical (Clic here for more details about this article) |
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