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Biomedical subjects

A Tolvanen

Publications and source records attributed to A Tolvanen.

8 recordsLinked to original sources
PubMed2001

Chiral HPLC separation and CD spectra of the enantiomers of the alkaloid tacamonine and related compounds.

The HPLC enantiomeric separation of racemic indole alkaloids tacamonine, 17 alpha-hydroxytacamonine, deethyleburnamonine, and vindeburnol was accomplished using Chiralpak AD and Chiralcel OD as chiral stationary phases. Small structural differences affect the enantioselectivity ability of these phases. Single enantiomers of tacamonine and vindeburnol were isolated by semipreparative HPLC and their CD spectra and optical rotations were measured.

Chromatography, High Pressure Liquid↗
PubMed2001

Practice effects on visuomotor and problem-solving tests by children.

Practice effects on a visuomotor test (the Developmental Test of Visuo-Motor Integration), a timed visual discrimination test (the Underlining Test), and two problem-solving tests (the Porteus Mazes Test and the Tower of Hanoi Test) were analyzed. Children of two age groups (Ms: 7.7 and 11.6 yr.) were chosen to study the effect of age on practice effects. The tests were repeated nine times with test-retest intervals of 2 mo. The Developmental Test of Visuo-Motor Integration showed no practice effects, while the Porteus Mazes Test, the Underlining Test, and the Tower of Hanoi Test showed significant practice effects. Practice effects were larger for the older age group on all the tests, except the Developmental Test of Visuo-Motor Integration. The Developmental Test of Visuo-Motor Integration and the Underlining Test showed good reliability, but those of the problem-solving tasks were less satisfactory. The stability of all the tests, except the Tower of Hanoi Test, was good.

Child↗
PubMed2000

Working memory structure and intellectual disability.

The working memory of people with intellectual disability has been found to generally lag behind their mental age. However, studies concerning the structure of working memory or its connections to other cognitive functions are rare. The present study employs a versatile battery of tests for the evaluation of working memory structure in adults with intellectual disability of unknown aetiology. In addition, connections between working memory and cognitive skills valid for everyday functioning are evaluated. Working memory performance in the study participants was found to stem from two distinct components which could be regarded to represent phonological and general working memory. General working memory was closely related to intelligence, whereas phonological working memory was not. The subjects in the study group differed in their working memory profiles. These distinct profiles were significantly related to academic skills (e.g. reading, writing and mathematics) and sentence comprehension because the profile of the working memory predicted these abilities even when the intelligence and educational background of the participants was taken into consideration.

Achievement↗
PubMed2000

Repeated assessment of the Tower of Hanoi test: reliability and age effects.

The purpose of this research was to analyze the effects of repeating an executive function test. Three versions of the Tower of Hanoi (TOH) test were repeated three times each, with test-retest intervals of 2 months. Two groups of children participated in the research (7.7 and 11.6 years, n = 22 and n = 28). Repeating the assessment improved the performance and decreased the total performance time in both of the groups. The older participants improved their performance faster than the younger ones. The reliability of all the scores, besides the error scores, seemed to be satisfactory after the first few assessments. The stability of the scores was maintained through all the assessments. The planning time did not explain the variations of the achieved score. The reasons for the initially low reliabilities are discussed, and modifications for the test administration and scoring are suggested.

Age Factors↗
PubMed1993

Speech perception and brain laterality: the effect of ear advantage on auditory event-related potentials.

Dichotic listening has been used for assessing asymmetries in processing auditory stimuli. It is known that there is better recognition of dichotic stimuli in the right ear with verbal stimuli (right ear advantage, REA) by the majority of the subjects. We were interested in the psychophysiological correlates of ear advantage as it is manifested in event-related potentials (ERP). We compared ERPs to monaural and dichotic syllables in stable REA and LEA subjects. The most consistent finding was that REA subjects show larger positive ERP deflections over the left hemisphere (maximal at T5) and LEA subjects over the right hemisphere (maximal at T6) both at the latency range of 320-340 msec. Thus, brain event-related potentials support the contention that the REA and LEA reflect differential activation of the left and right hemispheres, respectively.

Acoustic Stimulation↗
PubMedDate not supplied

Comparing efficacies of neurocognitive treatment and homework assistance programs for children with learning difficulties.

The purpose of the study was to analyze the relative efficacies of two treatments for children with learning difficulties. The first treatment consisted of multiple training components targeting specific cognitive and behavioral factors; the second treatment provided emotional support and supervision of school tasks. The participants were 94 Chilean schoolchildren (6 to 11 years of age). The efficacies were compared on (a) neurocognitive tests, (b) school achievement tests, and (c) behavior in school and at home. The results indicated that both groups improved on most of the outcome measures. The first group showed best results in parents' rating of home behavior, and the second group in reading. The findings also emphasized the importance of emotional support and the inclusion of a parents' group in treatment for children with learning difficulties.

Achievement↗
PubMedDate not supplied

Two-year group treatment for children with learning difficulties: assessing effects of treatment duration and pretreatment characteristics.

The results of a 2-year treatment study of children with learning problems are reported. During the first treatment year, half of the children participated in a multifaceted neurocognitive treatment and the other half in a treatment that provided supervision of school tasks and peer group support. During the second treatment year, all children participated in the neurocognitive treatment. The participants were 74 Chilean children 6 to 11 years old. The issues under investigation were the effect of treatment duration, and the relationship between pretreatment neurocognitive and behavioral characteristics and academic treatment outcome. The results indicated that significant gains occurred during both the first and the second treatment year. No major differences were found between the treatment groups. Pretreatment negative behavioral traits were associated with lesser academic growth in the group participating in the homework supervision treatment but not in the neurocognitive treatment group.

Analysis of Variance↗