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Biomedical subjects

K Dalen

Publications and source records attributed to K Dalen.

17 recordsLinked to original sources
PubMed2006

Non-verbal learning disabilities in children with infantile hydrocephalus, aged 4-7 years: a population-based, controlled study.

The aim of this population-based, controlled study was to investigate non-verbal learning disabilities (NLD) in children with infantile hydrocephalus (IH). For this purpose, the results from subtests measuring either assets or deficits within Rourke's model of NLD were analyzed. Children with myelomeningocele (MMC), intracranial tumors, or IQ < 70 were excluded. Of the 52 IH children included in the study, 46 were shunt-treated, whereas 6 were not shunted. The 44 controls were matched according to age, gender, and geographic variables. The Neuropsychological Assessment of Children (NEPSY) was administered to 52 children (age 4-7) with IH; (F = 17, M = 35), and to 44 controls (F = 17, M = 27). The tests used were classified along each of the dimensions "assets" or "deficits", according to Rourke's model of the elements and the dynamics of the NLD syndrome. Differences between sum scores for the subtests classified as "assets", versus "deficits" were significantly higher in the IH group as compared with the controls (p < 0.005). These findings are compatible with a higher frequency of NLD in the IH group, in which neurological confounding factors have been excluded. In addition, the model of the elements and the dynamics of the NLD syndrome may be useful when analyzing neuropsychological test results obtained with traditional and comprehensive test batteries.

Case-Control Studies↗
PubMed2003

Memory functions in persons with dental amalgam.

Memory and psychophysiological variables in persons with self-reported reactions to dental amalgam (amalgam patients: N=26) and in persons without such symptoms (controls: N=21) were compared. The groups were matched regarding age, education, and amount of amalgam. Wechsler Memory Scale-Revised was obtained for all subjects and compared to amalgam points in a dose-response design. The results demonstrated that amalgam patients function on the same level as the controls regarding memory variables, attention, concentration, and delayed recall. Psychophysiological measures of skin conductance as correlates of attention and basal memory functions, were compared in the two groups. No differences between the two groups were observed and no correlation between memory variables and exposure to amalgam could be detected.

Adult↗
PubMed1993

CT in abdominal and pelvic trauma.

Computed tomography (CT) is valuable in the evaluation of the abdomen and pelvis in victims of blunt trauma and stab wounds to the back if their condition is stable or if results of their physical examination are unreliable (eg, due to altered mental status). The appearance of blood at CT depends on window width, hematocrit, physical state of blood, use of intravenous contrast material, and attenuation of adjacent organs. Rapid infusion of contrast material improves visualization of hematoma. CT is most useful in evaluating injuries to the spleen, liver, pancreas, kidney, duodenum, and small and large bowel. Although CT can be accurate in demonstrating lacerations and hematoma, radiologists must beware of pitfalls in the CT diagnosis of splenic injuries (normal lobulation or cleft within the spleen, elongation of the left hepatic lobe, adjacent unopacified bowel loop, previous splenic infarct), hepatic injuries (beam-hardening artifact from adjacent ribs, air-contrast level in the stomach), and pancreatic injuries (streak artifacts from nasogastric tubes, folding of the pancreas, misinterpretation of adjacent structures, pancreatic contusion or hematoma, intrinsic elasticity of the pancreas). Delayed scanning or scanning with slow infusion rates may also obscure hematoma. Knowledge of the various appearances of the posttraumatic abdomen and pelvis on CT scans is essential for prompt and effective treatment of patients.

Abdominal Injuries↗
PubMed1992

Congenital anomalies of the branchial apparatus: embryology and pathologic anatomy.

Various congenital anomalies of branchial origin are found in the neck region. Understanding the varied radiologic appearances of these anomalies is greatly aided by familiarity with their embryologic origins. By considering the anatomic location and radiologic appearance, the precise embryologic origin can be accurately predicted. Defects of the branchial apparatus include branchial, thymic, and parathyroid anomalies, which may manifest as cysts, sinuses, fistulas, and ectopic glands. The embryologic model is used to explain the origins of all branchial apparatus anomalies. The most accepted theory proposes that vestigial remnants result from incomplete obliteration of the branchial apparatus or buried cell rests, and, thus, if cells are trapped in the branchial apparatus during the embryologic stage, they can form branchial cysts later in life. By understanding the embryologic basis for these defects, the radiologist is better able to interpret the findings encountered with the various imaging modalities used in the evaluation of these anomalies.

Branchial Region↗
PubMed1992

Congenital malformations of the cervicothoracic lymphatic system: embryology and pathogenesis.

Familiarity with the embryology of the lymphatic system is helpful in understanding the pathogenesis and radiologic appearance of lymphangiomas of the cervicothoracic region. By considering anatomic location and radiologic appearance, one can predict the type of lymphangioma present, the primordial lymph sac from which the malformation arose, and when it formed in embryonic life. Cystic hygromas are composed of large, dilated lymphatic spaces. They form when a primordial lymph sac fails to reestablish communication with the central venous system from which it arose. These lesions may also result from an aberrant bud arising from a primordial lymph sac. Cavernous and capillary lymphangiomas are composed of smaller lymphatic channels. They form from abnormally sequestered buds of the developing lymphatic mesenchyme responsible for the fine meshwork of terminal branches in the periphery of the embryo. Their growth may be inhibited by the relatively tougher tissues in the periphery (eg, skin and muscle) compared with the relatively loose fatty connective tissue in which cystic hygromas form. Not only can all types of lymphangioma occur in one lesion, but lymphatic and vascular malformations may also coexist.

Humans↗
PubMed1990

Dichotic listening, forced attention, and brain asymmetry in righthanded and lefthanded children.

Righthanded and lefthanded 7-year-old children (both boys and girls) were compared for dichotic listening performance under free report and forced attention conditions. Previous findings from our laboratory have shown that, while adults reverse the right ear advantage (REA) during the forced-left condition, children do not. Since the finding in children was unexpected, the first aim of the present study was to replicate our previous results. A second aim was to include lefthanded children with the hypothesis that they should more easily revert to a LEA, because of less homogeneous lateralization. The results essentially replicated our previous findings, during all three recall conditions. No sex differences were observed, and both handedness groups showed the same overall response pattern.

Attention↗
PubMed1989

Effects of arousal and directed attention on hemispheric asymmetry in a finger-tapping dual-task paradigm.

In the present study we investigated the effects of concurrent verbal (reading) and nonverbal (humming) cognitive tasks on right- and left-hand finger-tapping in relation to hemispheric asymmetry in right- and left-handed females and males. The aim of the study was to investigate effects of attending either to the cognitive or manual task, and effects of differences in arousal attributed to the various tasks. The results revealed decreased finger-tapping frequency in males, and especially in right-handers, during execution of both the reading and humming task. For the reading task, the interference was lateralized, with a greater decrease in tapping frequency in the right hand. No interference was observed in the female groups. Biased attention to the cognitive or manual task did not have any effect on finger-tapping. However, increased arousal was observed during execution of the humming task, thus indicating this to be a mediating factor in finger-tapping interference.

Adult↗
PubMed1988

Imaging of vascular complications after hepatic transplantation.

Vascular complications after hepatic transplantation can compromise graft and patient survival. Angiography defines the need for revascularization or retransplantation, but the value of noninvasive imaging in this setting is not clear. To assess the relative merit of noninvasive imaging techniques (sonography, scintigraphy, CT, and MR), we retrospectively reviewed 19 major vascular complications that occurred in 15 of 98 hepatic recipients over a 3 1/2-year period. Portal venous thrombosis was seen in seven patients, donor aortic or hepatic arterial thrombosis in seven, and inferior vena caval thrombosis in five. Sonography provided the initial diagnosis of portal venous thrombosis in three, arterial compromise in five, and caval obstruction in four. CT was the first diagnostic examination to identify portal occlusion in two, donor aortic thrombosis in one, and inferior vena caval thrombosis in one. Scintigraphy and MR imaging provided complementary data. Both sonography and CT are useful in the evaluation of vascular complications that occur after hepatic transplantation; however, neither is sufficiently sensitive to obviate angiographic assessment.

Adolescent↗
PubMed1988

Hemispheric asymmetry and finger-tapping in right-handed females.

The purpose of the present experiment was to investigate effects of concurrent verbal and nonverbal tasks on right- and left-hand finger-tapping in an adult female group. In addition to the verbal versus nonverbal distinction, both motor and sensory tasks were used. Previous experiments have demonstrated lateralized right-hand decrement in finger-tapping in males during a motor verbal task; increases in both hands during a motor nonverbal task; and increase in left-hand tapping frequencies during sensory verbal and sensory nonverbal tasks. In the present study, significant increases in finger-tapping was observed in all the experimental conditions compared to pre- and postbaseline measures. It is concluded that both facilitation and interference may be observed in a finger-tapping paradigm. Thus, a cautious interpretation concerning the relation of finger-tapping and hemispheric asymmetry is encouraged.

Adult↗
PubMed1986

Inhibitory versus facilitory interference for finger-tapping to verbal and nonverbal, motor, and sensory tasks.

The purpose of the present experiment was to investigate lateralized effects of concurrent verbal and nonverbal tasks on right- and left-hand finger-tapping. In addition to the verbal vs. nonverbal dichotomy, both motor and sensory tasks were used. It was predicted that a verbal motor task (reading aloud) would lead to more inhibitory interference for right-hand tappings than would a sensory verbal task (watching and remembering slides with nonsense syllables). Similarly, it was predicted that a motor nonverbal task (humming a tune) would lead to more left-hand inhibitory interference than would a sensory nonverbal task (watching pairs of spatial patterns). Results showed a predicted lateralized right-hand decrement in finger-tapping during the motor verbal task. However, an increase in left-hand tapping frequency above baseline was observed during both sensory tasks, while no significant difference was observed between the hands for the motor nonverbal task.

Adult↗
PubMed1986

EMG feedback in the treatment of myofascial pain dysfunction syndrome.

The effect of electromyographic (EMG) biofeedback on frontalis and masseter muscle activity was compared with control conditions in two groups of patients with a diagnosis of myofascial pain dysfunction (MPD) syndrome. Patients were selected on the basis of clinical symptoms, radiographic evaluation, and a clinical examination. Depressed patients and patients with signs of a pathological condition in the temporomandibular joint were excluded. Both the experimental (EXP) and the control (CON) group went through two base-line screening sessions before treatment of the EXP group was started. Treatment consisted of eight biofeedback sessions, given twice a week for 4 weeks. Feedback was presented visually on a monitor. Treatment did not include any relaxation training. Control evaluations of both groups took place 1 week, 3 months, and 6 months after the end of treatment. The EXP group was able to reduce EMG levels in frontalis and masseter muscles significantly during training sessions. Follow-up data showed significantly reduced frontalis EMG levels in the EXP group after 3 and 6 months but not in the CON group. Both groups improved subjectively, as judged by reports on pain intensity and duration, but this improvement was significantly more pronounced in the EXP group. Objective clinical indices recorded throughout the study were uncorrelated with EMG changes or subjective reports. It is concluded that biofeedback training facilitated muscular relaxation and self-regulation in the EXP group and that visual EMG feedback, consisting of a patterning of frontalis and masseter muscle activity, can be recommended as an integrated part of MPD syndrome treatment.

Adolescent↗
PubMed1982

The effect of a threatening context upon motivation and task-induced physiological changes.

The effect of a threatening context upon tonic task-induced physiological changes was tested in an experiment where 14 male subjects performed a continuous perceptual motor task for 150 seconds, once with and once without threat of aversive electric shock (counterbalanced order). Results indicated that task-irrelevant muscular tension increased and skin temperature decreased over the course of a task, and these gradients were steeper with threat than for the no-threat treatment. Initial heart-rate increase was marked for the threat condition. For respiration, a trend parallel to muscular gradients emerged with no-threat as contrasted with a parallel respiratory-cardiac activation with threat. Subjects' ratings on items reflecting self-perception responded to the threat manipulation, but ratings on items reflecting task perception remained unaffected.

Adult↗
PubMedDate not supplied

Hemispheric asymmetry and dual-task performance in children: a finger-tapping study.

The aim of the present experiment was to investigate effects of concurrent verbal and nonverbal cognitive tasks on right- and left-hand finger-tapping in right-, and left-handed boys and girls, within a dual-task paradigm. There were three interference tasks used: one motor verbal (reading aloud), and two sensory-memory tasks (cards with nonsense syllables and random shapes). Interference has been observed in adults in previous studies, and the first question was whether interference would be observed in the same manner in children. Furthermore, when comparing right- and left-handed boys and girls within the same study, possible effects of sex and hand preference could be evaluated. The final question addressed was whether there would be differences between the verbal and nonverbal tasks. The results revealed decreased tapping frequency bilaterally for all groups during execution of the motor verbal task. Furthermore, significant differences were found between boys and girls when tapping to the two sensory tasks, and particularly when tapping with the right hand. In left-handers, interference was most pronounced for the left-handed girls. As a conclusion, dual-task interference seems to be more pronounced in children as compared to adults. This might be due to interference caused by increased requests for general process capacity.

Brain↗