[Cerebral hemorrhage after diving].
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Brain Hemorrhage, Traumatic↗
Biomedical subjects
J Risberg
Publications and source records attributed to J Risberg.
The cognitive neuroscience of signed language.
The present article is an assessment of the current state of knowledge in the field of cognitive neuroscience of signed language. Reviewed lesion data show that the left hemisphere is dominant for perception and production of signed language in aphasics, in a fashion similar to spoken language aphasia. Several neuropsychological dissociations support this claim: Non-linguistic visuospatial functions can be dissociated from spatial functions and general motor deficits can be dissociated from execution of signs. Reviewed imaging data corroborate the lesion data in that the importance of the left hemisphere is re-confirmed. The data also establish the role of the right hemisphere in signed language processing. Alternative hypotheses regarding what aspects of signed language processing are handled by the right hemisphere are currently tested. The second section of the paper starts by addressing the role that early acquisition of signed and spoken language play for the neurofunctional activation patterns in the brain. Compensatory cognitive and communicative enhancements have also been documented as a function of early sign language use, suggesting an interesting interaction between language and cognition. Recent behavioural data on sign processing in working memory--a cognitive system important for language perception and production suggest e.g. phonological loop effects analogous to those obtained for speech processing. Neuroimaging studies will have to address this potential communality.
Functional Laterality↗
On the neurobiology of creativity. Differences in frontal activity between high and low creative subjects.
The aim was to investigate the relationship between creativity and hemispheric asymmetry, as measured by regional cerebral blood flow (rCBF). Two groups, each consisting of 12 healthy male subjects, who got either very high or low scores on a creativity test, were pre-selected for the rCBF investigation. rCBF was measured during rest and three verbal tasks: automatic speech (Auto), word fluency (FAS) and uses of objects (Brick). State and trait anxiety inventories were answered after the rCBF measurements. Intelligence tests were also administered. It was predicted that highly creative subjects would show a bilateral frontal activation on the divergent thinking task (Brick), while low creative subjects were expected to have a unilateral increase. Calculations were made of differences in blood flow levels between the FAS and the Brick measurements in the anterior prefrontal, frontotemporal and superior frontal regions. In accordance with our prediction, repeated measure-ANOVAs showed that the creativity groups differed significantly in all three regions. The highly creative group had increases, or unchanged activity, while the low creative group had mainly decreases. The highly creative group had higher trait anxiety than the low creative group. On the intelligence tests the low creative group was superior both on logical-inductive ability and on perceptual speed, while the groups were equal on verbal and spatial tests. The results are discussed in terms of complementary functions of the hemispheres.
Adult↗
A speechreading expert: the case of MM.
The present case study of MM, who acquired both sign language and spoken language in her early preschool years-and then reached the normal milestones of development in each language--revealed that her speechreading expertise is associated with cognitive functions such as high working memory capacity and phonological skills. Her cognitive profile is in accord with previous case studies of extremely good speechreading skill. MM's enhanced right prefrontal/frontal cerebral blood flow activation during speechreading seems to be indicative of efficient visual scanning, but it is also possibly due to her strategy for phonological decoding of visual speech.
Adult↗
Synapse density related to cerebral blood flow and symptomatology in frontal lobe degeneration and Alzheimer's disease.
In order to evaluate the functional significance of synaptic pathology, synaptic density was quantitated and related to clinical symptomatology and regional cerebral blood flow (rCBF) in 8 patients with frontal lobe degeneration of non-Alzheimer type (FLD) and 19 patients with Alzheimer's disease (AD). Synaptic density was measured in all layers of prefrontal and parietal cortex. The clinical picture of FLD was dominated by a frontal lobe syndrome with changes in personality and behavior, while AD was dominated by temporoparietal symptoms. This parallels the finding of frontal rCBF reductions in FLD patients and temporoparietal reductions in AD patients. Synaptic density was significantly decreased in both FLD and AD, with a regional severity which closely correlated with that of the degeneration, symptomatology and rCBF deficit. The results suggest that synaptic pathology is a likely cause of clinical symptoms and regional metabolic decrement in dementia.
Adult↗
Brain function in spider phobia.
Measurements of regional cerebral blood flow (rCBF) were performed in 16 women suffering from spider phobia. The non-invasive 133Xe inhalation method, giving information about the blood flow of superficial areas, was used. The subjects were studied under three conditions: during resting, when exposed to a videotape showing nature scenery, and finally when watching a video with living spiders. During the rCBF measurements the subjects' behaviour was registered systematically and respiration, blood pressure, Pco2, and heart rate were monitored. Eight subjects who showed and reported severe panic during the spider exposure had marked rCBF decreases in frontal areas, especially in the right hemisphere. The remaining eight subjects displayed a more efficient control of their emotions and became frightened, but not panic-stricken, during the spider exposure. These showed a consistent rCBF increase in the right frontal area compared to neutral stimulation. Thus, results revealed significant functional changes in the frontal cortex in subjects with spider phobia during phobogenic exposure. It seems likely that these frontal changes are related to the experience and control of phobic anxiety.
Adult↗
Lateralized frontal blood flow increases during fluency tasks: influence of cognitive strategy.
Difficulties with verbal fluency tasks (VFIT) have been shown mainly to be associated with left frontal lobe pathology in lesion studies. The design fluency test (DFT) is a non-verbal analogue of word fluency tasks and has, in patients with right frontal lobe pathology, been coupled to an inability to perform well. Regional cerebral blood flow measurements (rCBF) were made in normals to elucidate the involvement of frontal and frontotemporal brain regions during the performance of VFT and DFT. In addition, the subjects' reports were used for obtaining information about the cognitive strategy used when solving the tasks. The results confirm previous CBF findings showing a mainly left-sided frontal activation during the VFT. During the DFT significant flow augmentations were seen in both frontal lobes compared to baseline. Furthermore, the use of different strategies was reflected in different patterns of brain activation. Our results support the proposal that the left frontal cortical area is engaged in the generation of internally driven responses. Furthermore, we argue that the cortical areas engaged during the execution of these tasks may reflect differences in cognitive strategy.
Adult↗
Diver's hand: a skin disorder common in occupational saturation diving.
Saturation divers regularly inspect North Sea installations, working at depth for periods of 12-16 days. Diver's hand is a particular problem in saturation diving, and there is no effective protection or treatment available. This paper presents the occurrence of diver's hand and describes the disease in clinical and epidemiological terms. Three studies of diver's hand have been carried out, in 1990, 1994, and 1995. Most long term saturation divers have had diver's hand at some time in their professional career. Diver's hand seems able to occur without any previous skin symptoms, and divers without diver's hand can have several other skin symptoms during a saturation period. It is likely that diver's hand is a specific phenomenon associated with saturation diving.
Diving↗
Alcohol activates the cerebral reward system in man.
OBJECTIVE: We investigated the effect of 0.07% alcohol on regional brain activity at rest and during cognitive performance in order to elucidate the anatomical substrate for the effects of alcohol in man as well as to clarify the interaction between changes in cerebral activity induced by cognitive performance and alcohol inebriation. METHOD: Regional cerebral blood flow (3D-PET, 15O Butanol) was measured in 13 male, nonalcoholic volunteers. Each subject was scanned 12 times, three scans in each of the following four situations: sober/rest, sober/test and inebriated/rest, inebriated/test. We used statistical parametric mapping and a computerized brain atlas for localization. RESULTS: Alcohol induced a sense of inebriation and elation as well as a relative increase of the cerebral blood flow in medial parts of the temporal lobes, in the anterobasal parts of the anterior cingulate cortex including the septal region. In addition, there was an increase of blood flow in midline parts of the lower brain stem. Relative decreases of flow were observed in the cerebellum and in the occipital cortex bilaterally. In the sober state, a computerized perceptual maze test and a (silent) serial seven test induced two distinct neocortical activation patterns that were specific to the tasks. Alcohol did not change these patterns and the test performance was also uninfluenced. CONCLUSIONS: A moderate dose of alcohol selectively activates target structures that pertain to the so-called cerebral reward system and the ascending reticular activating system. Alcohol (approximately 0.07%) appears to have only minor effects in the neocortical systems that are involved in on-line cognitive activity. This apparent independence between the subcortical alcohol target and the neocortical cognitive mechanisms is a new finding that appears to be of importance for an understanding of the effect of moderate doses of alcohol on the brain.
Adult↗
The Swedish Centenarian Study: a multidisciplinary study of five consecutive cohorts at the age of 100.
UNLABELLED: Centenarians born 1887-91, who lived in southern Sweden were asked to participate in this multidisciplinary study (N = 164). Of the survivors (N = 143), 70 percent agreed (N = 100). The purpose was to describe the population from physical, social, and psychological points of view; to characterize centenarians with various health conditions and diverse degrees of autonomy and life satisfaction; and to identify factors at 100 years that predict future survival. RESULTS: Eighty-two percent were women, 25 percent lived in their own home, 37 percent in old age homes, and 38 percent in nursing homes. Socioeconomic status showed a similar distribution compared to nationally representative data. Fifty-two percent managed activities of daily living with or without minor assistance. The incidence of severe diseases was low. In 39 percent a disorder of the circulatory system was found. Thirty-nine percent (women) and 11 percent (men) had had at least one hip fracture. Twenty percent had good hearing and good vision. Twenty-seven percent were demented according to DSM III-R criteria. Means on cognitive tests (word-list, digit-span, learning, and memory) were lower compared to seventy to eighty year old groups. The variation in performance was extremely widespread. Personality profiles (MMPI) indicated that the centenarians were more responsible, capable, easygoing and less prone to anxiety than the population in general. Extensive neuropathological investigation revealed no major diseases or large lesions but mild through multiple changes. RESULTS suggest that centenarians are a special group genetically. A causal structure model emphasized body constitution, marital status, cognition and blood pressure as particularly important determinants for survival after 100 years.
Aged↗
[Spider-phobia is treatable. Therapy changes cerebral activation patterns].
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Adult↗
[Hyperbaric oxygen therapy. Now an established treatment in Norway].
Hyperbaric oxygen therapy can be a life-saving form of treatment for certain acute medical conditions, e.g. cerebral gas embolism, clostridial infections, and smoke/carbon monoxide inhalation. It has long been used for treating decompression illness in divers. As from 1994 our hospital has been delegated the national responsibility for hyperbaric medicine in Norway. This paper describes the physiological basis, indications, and contraindications for hyperbaric oxygen treatment, and summarises hyperbaric oxygen treatment in Bergen over the last two years.
Humans↗
Diagnosis of dementia by regional cerebral blood flow measurements using 133Xe and stationary detectors.
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Aged↗
Cerebral dysfunction in fibromyalgia: evidence from regional cerebral blood flow measurements, otoneurological tests and cerebrospinal fluid analysis.
Measurements of regional cerebral blood flow (rCBF), analysis of cerebrospinal fluid, auditory brain stem responses (ABR) and oculomotor tests were performed in 19 patients with fibromyalgia. The results from the rCBF measurements showed a normal flow level with slight but significant focal flow decreases in dorsolateral frontal cortical areas of both hemispheres. The ABR results showed signs of dysfunction at least at the brain stem level and the oculomotor tests showed high frequency of pathology. The cerebrospinal fluid analysis showed discrete changes in the cell differential count. Possible explanations for the involvement of the central nervous system in fibromyalgia are discussed.
Adult↗
Effects of venous gas microemboli on pulmonary gas transfer function.
Dynamic lung volumes and flows, slope of phase III of the single breath oxygen test (delta-N2), closing volume (CV), and transfer factor for carbon monoxide (TICO) were measured before and 1 h after an air dive in a hyperbaric chamber to a pressure of 0.49 MPa for 40 min. Six divers had a bottom time of 20 min and a rate of decompression of 50 kPa x min-1, and six divers had a bottom time of 24 min and a rate of decompression of 100 kPa x min-1. Decompression stops were 5 min at 0.16 MPa and 10 min at 0.13 MPa for both groups. As control exposure they were breathing O2 at atmospheric pressure for 40 min. The dive and control exposure were done on different days within 1 wk, in random order. Doppler ultrasound monitoring for venous gas microemboli (VGM) was done during the first hour after the dive. VGM were detectable in all six divers with the fast decompression rate and in one subject with the slow rate (P < 0.01). In the subjects having VGM there was a significant reduction in TICO of -5.9 +/- 4.4% compared with -0.5 +/- 3.4% after the control exposure (P = 0.034). In the five subjects without detectable VGM, the changes in TICO were -2.8 +/- 3.7% and 0.2 +/- 3.8%, respectively. There were no significant changes in dynamic lung volumes and flows, CV, or delta-N2. A reduction in TICO may reflect effects of VGM after dives in which the effect of O2 exposure is negligible.
Adult↗
Effects of gas density and ambient pressure on myocardial contractility in the rat.
BACKGROUND: Cardiac contractility and myocardial blood flow have been shown to increase when anesthetized and awake rats were exposed to normoxic 0.5 MPa ambient pressure, independent of inert gas composition. Similar changes have been demonstrated in anesthetized rats breathing a dense (relative density (RD) 5) SF6-O2 gas mixture at normobaric pressure. HYPOTHESIS: The purpose of the present study was to further explore whether cardiac contractility increases during hyperbaric exposure as a response to the elevated atmospheric pressure per se or rather as a response to increased breathing gas density. METHODS: Arterial pressure, left ventricular pressure (LVP), central venous pressure and intra-esophageal pressure were monitored in anesthetized rats during simulated dives. The rats were exposed to various gas mixtures (air, SF6-N2-O2, He-N2-O2), partial pressures of O2 (PIO2 0.02 and 0.03 MPa) ambient pressure (PTot 0.1-0.3 MPa) and gas density (RD 1-10.1). RESULTS: Cardiac contractility increased briefly by 5-10% (p < 0.05) during mild hyperoxia (PIO2 0.03 MPa). A concomitant stepwise increase in RD (1-10.1) and PTot (0.1-0.3 MPa) by adding SF6 to air, increased maximal rate of LVP rise (+dP/dt) and fall (-dP/dt) by 30% (p < 0.01). Two groups of rats exposed to either a high density SF6-N2-O2 (RD 5.5) or a normal density He-N2-O2 (RD 1.2) breathing gas of identical PTot 0.2 MPa demonstrated similar rise in dP/dt (peak 72%, p < 0.05). CONCLUSION: At moderately increased ambient pressure, pressure per se increases cardiac contractility independently of the breathing gas density.
Animals↗
Cortical activation during visual spatial processing: relation between hemispheric asymmetry of blood flow and performance.
Regional cerebral blood flow was studied in normal males and females during rest and three spatial tasks: counting of rectangular shapes, mental rotation, and cube analysis. Whereas gender caused no significant differences in performance scores or asymmetries, a highly significant relation was found between performance on the cube analysis task and right > left hemisphere flow asymmetry in the parietotemporooccipital border zone (PTO region) during cube analysis. This indicates that subjects utilizing a right hemisphere strategy when solving certain spatial tasks are superior to subjects with more bilateral involvement.
Adult↗
Regional cerebral blood flow in sign language users.
Cerebral activation was compared during sign and spoken language comprehension. Nine hearing children of deaf parents were studied and the cerebral activation was measured by recordings of the regional cerebral blood flow. Comprehension of a complex material gave a bilateral activation of posterior temporal regions for both spoken and signed language. It seems that sign language activates the cortex in a way which is very similar to spoken language, when the listener watches the speaker. Cortical areas usually regarded to be important for spatial ability do not show enhanced activation during sign language perception.
Adult↗