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Biomedical subjects

S Samuelsson

Publications and source records attributed to S Samuelsson.

At least 19 recordsLinked to original sources
PubMed1999

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↗
PubMed1999

Intelligence and dyslexia: implications for diagnosis and intervention.

In this paper we critically examine theoretical issues and practical consequences of including IQ in the definition of dyslexia. According to the discrepancy criterion individuals are classified as dyslexic if their reading skills are below what would be expected from their IQ scores. However, we argue that intelligence is a fuzzy concept and that there is no clear causal relationship between intelligence level and word decoding skills. Also, high and low IQ poor readers show the same reading performance patterns, indicating that both groups might benefit from the same remedial activities. Evidence for the critical role of phonological skills in dyslexia is presented and a more recent definition of dyslexia is discussed in relation to these findings. Finally, two alternative, more outcome-based classifications of poor readers are suggested and some critical consequences for individual interventions are outlined.

Adult↗
PubMed1998

Cognition as a bridge between signal and dialogue: communication in the hearing impaired and deaf.

This paper is an overview of the research we have carried out at Linköping University on cognitive aspects of visual language processing and related communicative forms. In the first section, a cognitive individual difference perspective on speechreading is introduced. In the second, compensatory perceptual mechanisms are discussed on the basis of behavioral and neurophysiological data. The third section addresses further the issue of perceptual versus cognitive compensation, and the fourth and fifth sections apply a set of cognitive tests based on the concept of working memory for poorly specified language input to data on the successes and failures with cochlear implants, tactile aids and hearing aids.

Cognition↗
PubMed1997

Left ventricular function after repeated episodes of ventricular fibrillation and defibrillation assessed by transoesophageal echocardiography.

BACKGROUND: Investigators studying the effects of cardioverter-defibrillators on left ventricular systolic function have given only minor attention to the diastolic effects. OBJECTIVES: The purpose of this study was to investigate the impact of repeated episodes of ventricular fibrillation and defibrillation on systolic function and diastolic filling of the left ventricle during non-thoracotomy implantation of a cardioverter-defibrillator. METHODS: Systolic function and diastolic filling of the left ventricle were assessed peri-operatively on a beat-by-beat basis using a transoesophageal echo-Doppler technique in 12 patients during > or = 4 episodes of ventricular fibrillation and defibrillation. Systolic function was assessed from the fractional area change and diastolic filling from the E/A ratio. Arterial blood pressure and the ECG were recorded continuously. RESULTS: Blood pressure and heart rate did not change significantly throughout the procedure. The systolic function, similarly, was not significantly affected; the only changes were seen in the first two beats after defibrillation when the mean fractional area increased from 0.2 +/- 0.01 to 0.4 +/- 0.02 and 0.3 +/- 0.02, respectively (P < 0.001). Diastolic filling was, however, impaired as reflected by a decrease in the E/A ratio from 2.6 +/- 0.5 before to 1.6 +/- 0.4 (P < 0.01) after repeated threshold tests. CONCLUSIONS: While the combined ischaemic and electrical trauma caused by repeated episodes of ventricular fibrillation and defibrillation during the implantation of a cardioverter-defibrillator did not cause any systolic dysfunction, diastolic filling was significantly impaired.

Adult↗
PubMed1997

Brief episodes of ventricular fibrillation do not influence postischemic cerebral perfusion assessed by positron emission tomography.

OBJECTIVES: To establish the defibrillation threshold in patients receiving an implantable cardioverter defibrillator, at least three episodes of ventricular fibrillation are induced and converted back to regular rhythm, using direct current countershocks. The aim of this study was to examine the influence of repeated short episodes of ventricular fibrillation on global and regional cerebral perfusion. DESIGN: A prospective, descriptive study. SETTING: A positron emission tomography laboratory at a university hospital. PATIENTS: Four patients, admitted for defibrillation threshold tests 2 yrs after the implantation of a cardioverter defibrillator, were included in the study. Global and regional cerebral blood flow was measured by cerebral positron emission tomography, using an 15O-labeled tracer under propofol-induced general anesthesia. Electroencephalograms (EEGs) were concomitantly recorded. INTERVENTIONS: Induction and conversion of ventricular fibrillation. MEASUREMENTS AND MAIN RESULTS: No effect on global cerebral perfusion was observed after induced ventricular fibrillation lasting 21 +/- 3 secs. The average global cerebral perfusion was 23 +/- 1 mL/100 g/min after induction of anesthesia and 31 +/- 8 mL/100 g/min and 24 +/- 2 mL/100 g/min immediately after the termination of the first and second ventricular fibrillation episodes, respectively. Ten minutes after the second and the third threshold tests, global cerebral perfusion was 21 +/- 1 mL/100 g/min and 21 +/- 2 mL/100 g/min, respectively. Regional cerebral perfusion and EEGs were not influenced. CONCLUSION: Short episodes of ventricular fibrillation did not induce any measurable effects on global and regional cerebral perfusion detectable by positron emission tomography 30 secs and 10 mins after restitution of sinus rhythm.

Aged↗
PubMed1996

Lipreading with auditory low-frequency information. Contextual constraints.

The present experimental study investigated potential relations among three variables: (1) an audiovisual speech signal (i.e., low-frequency supplemented lipreading as opposed to pure lipreading), (2) typical, as opposed to atypical, sentences in a particular script (e.g., in a restaurant), and (3) the presence/absence of additional context (in the particular script) in 60 normal hearing subjects. All three variables revealed significant main effects, but no interactions were observed. The general facilitatory effect for the audiovisual signal is in line with previous research, but this effect was relatively weak compared to the main effect of typicality, which relies on cognitive activation of scripts. In a separate analysis, the typicality variable was also the only variable that interacted significantly with speechreading skill, typical sentences being perceived relatively easier by the skilled as opposed to the less skilled individual. The clinical implications of cognitive factors in hearing-aid fitting procedures, the construction of speech materials, and selection of individuals for rehabilitation were discussed.

Humans↗
PubMed1995

Clinical estimation of left and right ventricular volume with open chest compared with transesophageal echocardiography and fast-response thermodilution.

OBJECTIVE: A clinical measure--inspection of the relation of the heart (acute margin) to the diaphragm--has shown a strong positive correlation to transesophageal echocardiographic (TEE) determination of left ventricular end-diastolic area (LVEDA) during weaning from cardiopulmonary bypass (CPB). The present study examines the correlation between right ventricular end-diastolic volumes (RVEDV) before and after CPB when using the same clinical measure of left ventricular dimension. DESIGN: Prospective study. SETTING: Operating room, university hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass grafting. INTERVENTIONS: After induction of anesthesia and endotracheal intubation, a transesophageal echo-probe was inserted. A pulmonary artery right ventricular ejection fraction/volumetric TD catheter was placed in the pulmonary artery. MEASUREMENTS AND MAIN RESULTS: Before going on CPB, a mark was made with cautery at the line of contact between the acute margin and the diaphragm. After CPB, the patients were transfused to the same level. At these two times, TEE recordings of the LVEDA and hemodynamic measurements including calculations of RVEDV were obtained. The LVEDA before and after CPB showed a positive correlation, r = 0.81, p < 0.001. The RVEDV after CPB showed a weak correlation, r = 0.54, p < 0.05, to RVEDV before CPB. There were no significant changes in right ventricular (RV) wall tension calculated as right atrial pressure x RVEDV and pulmonary artery systolic pressure x right ventricular end-systolic volume products. The only significant change regarding hemodynamic parameters was a decrease in mean arterial pressure. CONCLUSIONS: It is concluded that there is only a weak correlation regarding RVEDV before and after CPB when the patient is transfused to the line of contact, whereas this clinical measure correlates well with LVEDA.

Aged↗
PubMed1995

Comparison between transesophageal Doppler echocardiography and nuclear cardioangiography for the evaluation of left ventricular filling during coronary artery bypass grafting.

This study examines the relative contribution of early (E) and atrial (A) filling of the left ventricle. Ten patients were studied under anesthesia before and after coronary artery bypass grafting (CABG) using measurements of the mitral velocity-time integral (VTI) with transesophageal pulsed Doppler echocardiography and nuclear angiocardiography simultaneously. Thermodilution cardiac output measurements were made simultaneously in order to express the E and A filling in quantitative terms. The mean difference between methods in estimating E filling was -1.0 mL and the figures for the mean +/- 2 SD were 5.7 and -7.8 mL, r = 0.98 using regression analysis. The mean difference during A filling was 0.9 mL and the corresponding figures for the mean +/- 2 SD were 7.9 and -6.1 mL, r = 0.88. There was a reduction in the volume entering the left ventricle during the E filling (42-26 mL) and in the A phase (27-22 mL) from before surgery in comparison to after CABG. There was good agreement between transesophageal Doppler echocardiographic and nuclear angiocardiographic methods concerning the volume contribution during E and A phases of left ventricular filling.

Aged↗
PubMed1994

Internal speech functioning and speechreading in deafened and normal hearing adults.

The present study compared internal speech functioning in two groups of subjects: deafened and normal hearing adults. Internal speech functioning was assessed by means of either direct testing (i.e. rhyme-judgement tasks) or indirect testing (lexical access tests). No differences between the groups across tasks was obtained for speed. Neither was there any difference in accuracy level assessed by indirect tests. For direct testing the deafened group performed at a significantly lower level of accuracy. Accuracy was also correlated with the number of years that they had been deaf. It was concluded that one of the primary consequences of an acquired deafness is that the representational aspects of internal speech deteriorate over time, whereas the mechanical aspects remain relatively intact. Intercorrelations between accuracy level in direct testing and speechreading performance also suggest that speechreading ability declines. Clinical implications of the results are discussed.

Deafness↗
PubMed1992

Left ventricular filling as assessed by pulsed Doppler echocardiography after coronary artery bypass grafting.

Diastolic filling of the left ventricle, as assessed by transesophageal pulsed Doppler echocardiography during and in the early phase following coronary artery bypass grafting, was investigated in nine patients without valvular disease or left ventricular hypertrophy. The ratio between the maximal heights of the early diastolic flow-velocity peak and the late (atrial) diastolic flow-velocity peak, the E:A ratio, and also the deceleration time of the early peak were calculated as indices of left ventricular filling. The E:A ratio decreased from 1.01 +/- 0.06 after induction of anesthesia to 0.46 +/- 0.06 on arrival in the intensive care unit (ICU). The E:A ratio then increased and reached 0.87 +/- 0.08 after 6 hours in the ICU. This increase in E:A ratio in the ICU was due to an increasing peak velocity of the E wave. The deceleration time decreased after surgery and increased from 111 +/- 25 to 145 +/- 12 milliseconds in the ICU. Pulsed Doppler indices of diastolic filling are known to be altered by changes in hemodynamic parameters, to be load-dependent, and to vary with heart rate. In the ICU, pulmonary capillary wedge pressure remained unchanged, heart rate decreased by approximately 12%, and systemic vascular resistance decreased by approximately 40%. The changes in hemodynamic parameters could have affected the E:A ratio, but it is unlikely that they could explain the marked increase in the E:A ratio that occurred in the ICU. The results, therefore, imply the presence of impaired diastolic filling immediately after cardiopulmonary bypass with gradual, but not complete, recovery during the first 6 hours in the ICU.

Aged↗
PubMed1992

Memory effects following carbamazepine monotherapy in patients with complex partial epilepsy.

To evaluate the memory effects of carbamazepine (CBZ) monotherapy, a relatively large computerized neuropsychological test battery, specially developed to assess the properties of different memory systems, was administered to a group of patients with epilepsy in a pre-test--post-test control group design. Consistent with previous findings, the results show that CBZ treatment does not induce any general important or consistent negative signs of memory dysfunction. However, the epilepsy group as such demonstrates a relative inability to carry out more complex working memory tasks and they are also slower in simple long-term memory access tasks. Finally, the detailed findings suggest that CBZ plasma concentration levels within the therapeutic range are highly and negatively associated with short-term recency, which is a novel finding.

Adult↗
PubMed1992

Feto-maternal listeriosis in Denmark 1981-1988.

We collected clinical information about 30 cases of Listeria monocytogenes infections in pregnancy, which occurred in Denmark between 1981 and 1988. The incidence of feto-maternal listeriosis was approximately one case per 100,000 live births in the early 1980s but increased to 25.3 cases per 100,000 live births in 1986. Listeriosis in Denmark occurred in two different patterns: endemic, in which the feto-maternal cases were a small proportion of the total, and epidemic: cases due to strains which were indistinguishable by phage-typing, and having a higher proportion of feto-maternal cases, as was seen in the outbreak of 1985-1987. The study group comprised 11 cases of intra-uterine death, three of maternal septicaemia without infection of the fetus and 16 cases of neonatal infection. Most neonates were ill at birth or became so within the first 24 h. The overall mortality rate among liveborn infants was 10.5% (2/19).

Abortion, Spontaneous↗
PubMed1992

An outbreak of serogroup B:15:P1.16 meningococcal disease, Frederiksborg County, Denmark, 1987-9.

Epidemiological features of an outbreak of group B:15:P1.16 meningococcal disease (MD) in Frederiksborg county, Denmark, 1987-9, were investigated. The study comprised 149 cases notified during the outbreak and the two preceding years; 115 were confirmed by the isolation of Neisseria meningitidis. In 1989 the incidence had increased to 14.1 per 100,000 population. Among group B strains, B:15:P1.16 accounted for 80% (77/97). The overall mortality rate was 10% (15/149). Regarding cases due to group B:15:P1.16 strains a significant time-space clustering, which exclusively occurred within the 10-19 years age group, was demonstrated. The link between cases within clusters was indirect or unknown, except for ten patients with contact to one particular school. The prophylactic measures used included administration of rifampicin to household contacts. During the outbreak the proportion of secondary cases was high (6-15%). All secondary cases occurred outside the household indicating that the household had been protected.

Adolescent↗
PubMed1991

Script activation in lipreading.

In three experiments the roles of script, basic and low-level contexts in lipreading (Abbott et al., 1985) were studied. Three scripts were used: a restaurant, a railway station, and a clothing store. Presence or absence of script headers constituted a between-subjects factor. Basic and low-level context, as well as test-sentences (referring to basic and low-level of abstraction), were within-subjects factors. Also, different kinds of working memory tests were employed to assess potentially important information-processing skills for lipreading. The results show that (a) lipreaders benefit from a compatibility between context level and sentence type, (b) the directions of inferences were asymmetric such that the basic context prevented inferences at the low-level of abstraction, but not vice versa, (c) low-level context in general was most useful for skilled lipreaders in the script group, (d) skilled lipreaders in the non-script group took most advantage of basic level sentences, and (e) working memory capacity did not prove to be important for lipreading skill. Guessing and pure lipreading control experiments established that each of these potentially confounding factors only accounted for about 5% of the lipreading performance, and thus, can not explain the obtained interactive effects between visual information conveyed by lip movements and context. Theorizing departing from prototypicality vs. script accounts of inference-making was critically evaluated, and a predictive script activation mechanism, relevant to lipreading skill, was suggested.

Adult↗
PubMed1991

Epidemiology of meningococcal disease in Denmark 1980-1988.

Based on epidemiological data of notified cases of meningococcal disease (MD) in Denmark during the period 1980-88 the recommendations for prophylaxis are evaluated. In 1986 the incidence of MD increased about 60% to 5.5 per 100,000 population. The clinical diagnosis of MD was verified by culture of Neisseria meningitidis in 79% of notified cases. About 40% of all patients were less than 4 years of age. The mortality in 1988 was found to be 10%. Serogroup B disease accounted for about 80% of the cases. Two co-primary and 28 secondary cases were registered. Two major outbreaks of serogroup C disease occurred in 1984 and 1986, respectively. In small clusters of 2-3 cases within socially well-defined groups the recommendations for prophylaxis are sufficient. But for the new pattern of clusters spread over months to years in certain geographical areas or open social groups, especially among teenagers, the existing recommendations are insufficient. The occurrence of localized clusters of serogroup B disease emphasises the need for a vaccine against serogroup B disease.

Adolescent↗
PubMed1990

Changes in women's sexual desire in middle life: the longitudinal study of women in Gothenburg.

In a general population survey, 677 urban middle-aged women were interviewed about their sexual desire at two occasions 6 years apart. Data from 497 subjects, who were married at both occasions or were cohabiting with a male partner, were analyzed. Twenty-seven percent reported a decrease in sexual desire between interviews, and 10% experienced an increased desire. There were no clear cohort differences. A decrease in sexual desire was predicted by age, high sexual desire at first interview, lack of a confiding relationship, insufficient support from spouse, alcoholism in spouse, and major depression. Predictors of an increase of sexual desire were weak desire at first interview, negative marital relations before first interview, and mental disorder at first interview. Although sexual desire showed considerable stability over time, a substantial proportion of married middle-aged women experienced major changes, mostly as a decrease. Age, psychosocial factors associated with quality of marital relationship, and mental health were major contributors towards change in sexual desire.

Adult↗
PubMed1990

Human listeriosis in Denmark 1981-1987 including an outbreak November 1985-March 1987.

Clinical manifestations, predisposing factors and outcome of listeriosis in Denmark during the period 1981-1987 are described. An increased incidence of the disease during the period November 1985-March 1987 was due mainly to 35 patients infected with strains of Listeria monocytogenes indistinguishable by phage-typing. These patients were younger, previously healthier and had a better prognosis. Also, there were more cases in pregnant women and neonates than in other persons. A strong correlation was found between predisposing factors and mortality. We conclude that there was an outbreak caused by a single source of infection and which was distributed all over the country. It lasted for more than a year and affected most categories of people. The source was not identified.

Adult↗