Biomedical subjects

Einar Heiervang

Publications and source records attributed to Einar Heiervang.

5 recordsLinked to original sources

PubMed2004

The Strengths and Difficulties Questionnaire in the Nordic countries.

BACKGROUND: The Strengths and Difficulties Questionnaire (SDQ) has been translated into the different Nordic languages between 1996 and 2003. During the past few years, SDQs have been completed for nearly 100,000 children and adolescents in population-based studies as well as in clinical samples. The largest studies have been performed in Norway and Denmark, and in these countries the diagnostic interview DAWBA has also been used in conjunction with the SDQ. AIMS: In addition to a brief overview of past and ongoing SDQ work in Sweden, Finland, Norway, Denmark, and Iceland, we present scale means and standard deviations from selected community studies with comparable age groups, including parental reports for 7, 9 and 11 year-old children and self-reports of 13 and 15 year-olds. CONCLUSIONS: The descriptive statistics suggest that the distributions of SDQ scores are very similar across the Nordic countries. Further collaborative efforts in establishing norms and evaluating the validity of the SDQ as a screening instrument are encouraged.

Adolescent↗

PubMed2003

Significant relation between MR measures of planum temporale area and dichotic processing of syllables in dyslexic children.

In the present study, we investigated differences between dyslexic and normal reading children in asymmetry of the planum temporale area in the upper posterior part of the temporal lobe and dichotic listening performance to consonant-vowel syllables. The current study was an extension of previous studies in our laboratory on the same participants, now including also girls and left-handers. There were 20 boys and 3 girls in the dyslexic group and 19 boys and 4 girls in the normal reading group. The age of the participants was 10-12 years for both groups. The participants were screened from a population of 950 students in the fourth school grade in the greater Bergen district. The planum temporale area was measured in sagittal magnetic resonance (MR) images. Mean left and right area and asymmetry index were compared between the groups. Dichotic presentations of consonant-vowel syllables made it possible to separately probe left and right hemisphere phonological function, and to correlate this with planum temporale area. The results showed a significantly larger left than right planum temporale area for both groups. However, while the right planum temporale area was similar for the dyslexic and control groups, the left planum temporale was significantly (one-tailed t-test) smaller in the dyslexic group. Both groups also showed a significant right ear advantage to the consonant-vowel syllables in the dichotic listening test. The relation between planum temporale and dichotic listening asymmetry showed a significant correlation for the dyslexic group only, indicating a positive relation between brain structure and function in dyslexic children. The results are discussed in terms of important subject characteristics with regard to brain markers of dyslexia.

Case-Control Studies↗

PubMed2002

Less developed corpus callosum in dyslexic subjects--a structural MRI study.

BACKGROUND: Based on previous studies and due to the characteristics of dyslexia as an auditory phonological decoding disorder, we predicted that the shape of the posterior corpus callosum (CC) would differ between dyslexic and control subjects. METHOD: Twenty right-handed boys with developmental dyslexia were selected from a carefully screened general population sample (mean age 11 years) and compared to a matched control group. The CC contour was manually traced on the aligned midsagittal MR slice and total callosal area and its subregions were compared between the groups. A statistical shape analysis and subsequent CC classification was performed using a recently developed shape model method. RESULTS: The shape analysis revealed shorter CC shape in the dyslexic group, localised in the posterior midbody/isthmus region. This region contains interhemispheric fibers from primary and secondary auditory cortices. A shape length difference larger than a fixed threshold in the posterior midbody region could correctly discriminate between control and dyslexic subject in 78% of the cases, where a dyslexic CC was shorter in this region than a control CC. However, there were no significant group differences with respect to overall CC area or subregions. CONCLUSION: A clear shape difference in the posterior midbody of the CC was found between dyslexic and control subjects. This fits with recent other studies that have reported a strong growth factor in this CC region during the late childhood years, coinciding with literacy acquisition. Our results show that the dyslexic group has not undergone the same growth pattern as the normal reading group.

Agenesis of Corpus Callosum↗

PubMed2002

Auditory processing in children with dyslexia.

BACKGROUND: It has been claimed that children with dyslexia show a general impairment in the processing of rapid auditory stimuli. However, most previous studies in this field have focused on children with language impairment or children who do not meet accepted criteria for dyslexia. METHODS: In the present study, the processing of rapid non-verbal auditory stimuli (complex tones) was examined in a population-based sample of 24 children with dyslexia, 10 to 12 years of age, and a matched control group. RESULTS: The dyslexia group showed reduced tone processing relative to the control group, with significant main effects of tone duration, inter-stimulus interval and task complexity. The deficit was not specific for temporal order errors, and could not be explained by differences in short-term memory or verbal IQ. However, correlations between tone processing and reading ability were generally low or absent. CONCLUSION: Although a general processing deficit for rapid auditory stimuli in dyslexia was confirmed, its relevance for reading problems and hence for treatment programmes for dyslexia is questioned.

Acoustic Stimulation↗

PubMedDate not supplied

Impaired visual attention in children with dyslexia.

Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue-target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue-target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue-target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading.

Attention↗