Biomedical subjects

H Sigmundsson

Publications and source records attributed to H Sigmundsson.

16 recordsLinked to original sources

PubMed2005

Do visual processing deficits cause problem on response time task for dyslexics?

This study was set out to explore the prediction that dyslexics would be likely to have particular problems compared to control group, on response time task when 'driving' a car simulator. The reason for doing so stems from the fact that there is considerable body of research on visual processing difficulties manifested by dyslexics. The task was to drive a car and at the same time, the driver had to use either signal button on the right side of the wheel (condition 1) or a voice-activated microphone (condition 2) immediately when a road sign appears. In condition 1, the sign appears only in the mid-field zone and in condition 2, it appears in one of six possible positions in relations to the car ahead. As predicted, it was found that the dyslexics had significantly higher response time in both conditions than their controls. Dyslexics may have visual processing deficit which not only cause reading problems but also problems perceiving rapid changes in their environment such as responding on a sign when driving.

Adolescent↗

PubMed2005

Do 'clumsy' children have visual recognition problems?

OBJECTIVE: Visual recognition by 8-year-old children with hand-eye co-ordination problems (HECP), and by a control group of children without such problems was tested using a task of visual closure. DESIGN: The task required the children to identify common objects from an incomplete visual presentation. RESULT: As predicted, it was found that the HECP children, who were designated as such solely on the basis of their motor difficulties, identified significantly fewer correct objects than their control counterparts. CONCLUSIONS: This finding raises the possibility that the visual processing problems of clumsy children contribute to, or even strongly determine, not only their movement problems but also their learning difficulties.

Case-Control Studies↗

PubMed2003

Do 'clumsy' children have visual deficits.

Visual processing by 10-year-old children diagnosed on the basis of standardised tests as having developmental 'clumsiness' syndrome, and by a control group of children without motor difficulties, was tested using three different psychophysical tasks. The tasks comprised a measure of global motion processing using a dynamic random dot kinematogram, a measure of static global pattern processing where the position of the target was randomised, and a measure of static global pattern processing in which the target position was fixed. The most striking finding was that the group of clumsy children, who were diagnosed solely on the basis of their motor difficulties, were significantly less sensitive than the control group on all three tasks of visual sensitivity. Clumsy children may have impaired visual sensitivity in both the dorsal and ventral streams in addition to their obvious problems with motor control. These results support the existence of generalised visual anomalies associated with impairments of cerebellar function.

Case-Control Studies↗

PubMed2003

Sex differences in lateralisation of fine manual skills in children.

One hundred and twelve children (55 boys and 57 girls) were tested using two tasks taken from the Movement Assessment Battery for Children. The girls had a larger between-hands asymmetry than boys on the threading nuts on bolt task, thus indicating they were more lateralised. On the other task, placing pegs, no such sex differences were found. We present our findings as a warning to others that even though two tasks are assumed to measure the same, in this case unimanual performance, differences in task constraints will exist. Such differences may constitute a confounding factor when trying to infer about lateralisation based on behavioural tasks.

Child↗

PubMed2003

Static balance in children with hand-eye co-ordination problems.

OBJECTIVE: The aim of the present study was to examine static balance on one leg in 10-year-old children with and without hand-eye co-ordination problems (HECP) in an attempt to come closer to an understanding of developmental co-ordination disorder in children. METHOD: The children were compared on three different balance tasks with the right and/or left leg together with a systematic manipulation of vision. RESULTS: The results showed that when the scores for both legs were combined, the control group, in general, had superior performance in all conditions. Separate preferred and non-preferred leg analyses demonstrated that the differences between the HECP group and control group could be accounted for by lowered performances when the non-preferred leg was used in only one static balance task, stork stand with vision. In the two other balance tasks, balance on beam and one-board balance, the HECP group displayed significantly worse performance than the control group irrespective of the use of the preferred or non-preferred leg. CONCLUSIONS: Explanation related to the development of the hemispheres controlling the preferred and non-preferred leg is invoked to account for the poor performance in the HECP group.

Ataxia↗

PubMed2003

Perceptual deficits in clumsy children: inter- and intra-modal matching approach--a window into clumsy behavior.

This article will focus on the underlying perceptual deficits that might lead to inadequacies in motor performance in children. Two lines of enquiry have dominated the literature: visual-perceptual deficit and/or visual-motor deficits and proprioceptive deficits. The theoretical and methodological shortcomings in these approaches are discussed. Then attention is primarily directed toward the concept of inter- and intra-modal matching (sensory integration), particularly with respect to vision and proprioception, an ability deemed to underlie many real-life motor skills. Such an approach allows parallels to be drawn between behavioral manifestations of motor impairment and potential underlying neurological information-processing disorders, particularly as these relate to hemispheric competence.

Child↗

PubMed2002

Dynamics of hand preference in 4 year-old children.

Hand preference in groups of 4 year-old children towards either end of the skill continuum (as determined by the Movement ABC test) was explored by means of a catching task in which the 'direction of approach of the ball' was used as a control parameter within a dynamical systems framework. In Condition 1, the ball direction was systematically scaled in degrees from the right side of the subject to the left and vice versa. In Condition 2, the spatial location of the ball direction was varied randomly, rather than systematically, over the same range as for Condition 1. In both conditions, the two groups of children were shown to switch between hands (from left to right and vice versa) at well-defined positions on the scale. The different scale values obtained when ball direction was scaled from left to right compared with right to left were used to define hysteresis areas. These areas were more extensive and located more to the left of the midline for the group towards the less skilled end of the continuum than for those towards the more skilled end. Additionally, the less-skilled children were shown to use the right hand more to catch the balls delivered to the left side than did the more skilled children. In Condition 3, objects were placed on the table of the ball-delivery apparatus in order to make the catching action more complicated. The less skilled group were shown to use the right hand more than the left hand in all catching positions whereas the more skilled group showed an equal usage of both catching regimes.

Attention↗

PubMed2002

Hand preference in children with developmental coordination disorders: cause and effect?

Inter- and intra-modal matching by eight-year-old children diagnosed as having hand-eye coordination problems (HECP) and categorized as left-handed, together with a left-handed control group of children without such problems, were tested using a manual sensory matching task. The task required the children to locate target pins, visually (seen target), proprioceptively (felt target) or in combination (felt and seen target), while matching to the located target was always carried out without vision. Performance was superior when the target was located visually or visually/proprioceptively for both groups of children. These results question the conclusion that intra-modal will always be more accurate than inter-modal matching. When the combined scores for both hands were analyzed, the HECP children showed inferior performance to the control children in both inter- and intra-modal matching. Separate right and left hand analyses, demonstrated that the differences between the HECP group and control children could be accounted for by lowered performances when the right hand (nonpreferred) was used to match the located target position. Putative neurological disorders related to the development of the hemisphere controlling the nonpreferred hand (left hemisphere) are invoked to account for the poor performance with the nonpreferred hand of the HECP children.

Brain↗

PubMed2000

[Children and motor competence].

Recently, the topic of motor competence has figured prominently in the media. The claims made are many, but the research that support the statements is seldom cited. The aim of this review article is to address that deficiency by documenting what is really known about the motor competence of children. Motor competence not only allows children to carry out everyday practical tasks, but it is also an important determinant of their level of self-esteem and of their popularity and status in their peer group. While many studies have shown a significant correlation between motor problems and other problems in the social sphere, it has been difficult to establish causal relationships with any degree of confidence, as there appear to be several interactions which need to be taken into account. Research has shown that 6-10% of Norwegian children in the 7 to 10 year age group have a motor competence well below the norm. It is unusual for motor problems to simply disappear over time. In the absence of intervention the syndrome is likely to continue to manifest itself. More recent research points to some of the circularity in this causal network, children with motor problems having been shown to be less physically active than their peers. In a larger health perspective this in itself can have very serious consequences for the child.

Child↗

PubMed2000

Development of proprioceptive sensitivity.

The development of proprioceptive sensitivity was studied in 140 children between the ages of 5.8 and 11.8 years using a so-called foot-hand task. Ten boys and ten girls were included in each age group. The task required the children to locate a target pin with the "big toe" (felt target) and match the located target position with the hand, without vision. There were four conditions: location of targets by the right big toe: matching located target position with the right hand (RfRh) and left hand (RfLh); and location of targets by the left big toe: matching located target position with the left hand (LfLh) and right hand (LfRh). The results showed a significant developmental trend in proprioceptive sensitivity, when the absolute error scores for boys and girls were combined, with most of the improvement occurring between the ages of 5.8 and 7.8 years. The most interesting and novel finding seems to be the significant two-way interaction between age and sex--the clearest differences manifesting themselves in the age group 9.9 years. Separate within-sex group analyses showed the trend to be determined by the results for the girls, the trend being absent in the results for the boys. Furthermore only the boys showed a significant difference between the intra- and inter-hemispheric conditions. We propose that these differences may only manifest themselves in particular tasks, i.e. there may be a sex-task interaction. The implications of this proposal for theoretical interpretations of the phenomenon of inter-hemispheric processing as well as possible sources of the task differences are briefly discussed.

Aging↗

PubMed2000

Differential contributions of the two hemispheres in intra-modal proprioceptive sensory matching in 7-10-year-old boys.

This study explores putative differential contributions of the two hemispheres when 7-10-year-old right-hand and left-hand preferent boys are required to carry out a 'foot-hand' target location and matching task. The task required subjects to locate a target pin with the big-toe (felt target), and match the located target position with the hand, without vision. Right-handed (n=25) and left-handed (n=22) boys were tested in a four-condition design. Two intra-hemispheric conditions (right foot locating-right hand matching, left foot locating-left hand matching), and two inter-hemispheric conditions (right foot locating-left hand matching, left foot locating-right hand matching) were used. When the criterion for handedness was writing hand only the results were found to be confounded by the large number of subjects with indeterminate handedness (isolated by use of the Edinburgh Handedness Inventory) originally assigned to the left-handed group. Reclassification of the handedness groups, on the basis of this inventory, showed the pure-left handers to be as good on those conditions mediated by the right hemisphere as pure right handers were with those conditions mediated by the left. These findings are discussed with respect to the contention that left handers are not just 'reversed' right handers.

Child↗

PubMed1999

'Putting your foot in it'! A window into clumsy behaviour.

Intra-modal matching by 7-year-old children diagnosed as having hand-eye co-ordination problems (HECP) and a control group of children without such problems was tested using a target location and matching task. The 'foot-hand' task required the children to locate a target pin with the 'big-toe' (felt target) and match the located target position with the hand, without vision. There were four conditions: location via right foot-matching the located target with the right hand (RfRh) and left hand (RfLh) and location via left foot-matching the located target with the left hand (LfLh) and right hand (LfRh). Both groups demonstrated better performance in the intra- as compared to the inter-hemispheric conditions, suggesting that the corpus callosum is not yet fully mature at this age. The HECP children showed inferior performance to the control children in three of the four conditions, the conditions where the right hemisphere was involved and/or information had to be transported across the corpus callosum (RfLh; LfLh; LfRh). Two possible explanations of these findings are put forward and discussed: right hemisphere insufficiency with or without dysfunctional corpus callosum.

Child↗

PubMed1999

Proximal versus distal control in proprioceptively guided movements of motor-impaired children.

Two groups of 7-year-old children diagnosed as motor-impaired (N = 6) or as controls (N = 6) were required to perform a task that involved locating targets under a table-top with one hand while attempting to match the position of the target with the other, on the table-top (intra-modal matching), always without visual control. The experimental design involved three different conditions: proximal control (P), distal control (D) or both (PD). Target distance errors were analysed in terms of absolute (AE) and variable error. When the scores for each hand were combined, the motor-impaired group showed inferior mean performance (AE scores) on all three conditions as compared with the control children and were also more variable in their behaviour. Analyses of scores achieved with the right and the left hand separately, however, demonstrated that the difference could largely be attributed to the scores obtained when matching with the right hand in conditions P and PD, and matching with the left hand in condition D. Possible explanations of these findings are discussed in the context of 'delay' (developmental lag) and/or 'deviancy' (neurological lesion/disconnection).

Child↗

PubMed1998

We can cure your child's clumsiness! A review of intervention methods.

Intervention procedures for treatment of clumsiness have come in many guises. We have looked at some of the most powerful methods put forward in the past 30 years--Perceptual-motor training (PMT), Sensory Integration Therapy (SIT), and some promising new approaches. Both the PMT and the SIT have been heavily criticised. It is hard to find support for the idea that the programmes improve academic skills or that they have more than a limited effect on perceptual-motor development as claimed. The more recently introduced Kinaesthetic training is shown to have an effect on general motor competence but that this may be better explained in terms of the general principles on which this training procedure lies rather than the influence on Kinaesthesis per se. Since other recent studies have also shown a dependence on similar general principles, it might be asked whether it is the teacher rather than the programmes that accounts for the differences shown between different intervention programmes.

Child↗

PubMed1997

Inter- and intra-sensory modality matching in children with hand-eye co-ordination problems.

Inter- and intra-sensory modality matching by 8-year-old children diagnosed as having hand-eye co-ordination problems (HECP) and by a control group of children without such problems were tested using a target-location and pointing task. The task required the children to locate target pins visually (seen target), with the hand (felt target) or in combination (felt and seen target), while pointing to the located target was always carried out without vision. The most striking finding, for both the control and the HECP children, was the superiority of performance when the target had to be located visually. When combined scores for both hands were analysed, the HECP children showed inferior performance to the control children in both inter- and intra-modal matching. Analyses of the scores achieved with the preferred and non-preferred hand separately, however, demonstrated that the differences between the HECP and the control children could, in the main, be attributed to lowered performances when the non-preferred hand was used for pointing to the target. When pointing with the preferred hand, the only significant difference between the groups was when the target was visually located, the control children showing superior performance. Pointing with the non-preferred hand gave rise to significant differences, in favour of the control children, when the target was located visually, with the hand or in combination. These findings suggest that earlier studies, using only the preferred hand or a combination of the scores of both hands, might need to be qualified. Putative neurological disorders in the HECP children are invoked to account for the poor performance with the non-preferred hand.

Case-Control Studies↗

PubMed1997

Inter- and intrasensory modality matching in children with hand-eye coordination problems: exploring the developmental lag hypothesis.

This study set out to explore the suggestion that the problems experienced by 8-year-old children diagnosed as clumsy in the area of hand-eye coordination (HECP) might be attributed to a developmental lag. The performances of this group of HECP children were compared with those of groups of 5-year-old and 8-year-old controls without such deficits, when required to carry out a task involving pointing, without vision, to targets located, visually, visually/proprioceptively, or proprioceptively, the dependent variable being the distance error score from the centre of the target. The performances of the HECP children, when vision or vision/proprioception was used to locate the targets, were shown to be inferior to those of the two control groups of children thereby supporting a visual deficit hypothesis. When the targets had to be located proprioceptively, the performance of the HECP children was shown to be similar to that of the 5-year-olds, while both groups were inferior to the 8-year-olds, thereby supporting a developmental lag hypothesis in proprioceptive terms. However, when the scores for the preferred and non-preferred hands were analysed separately a marked deterioration in the performances of both the 5-year-old controls and the HECP children was observed while the 8-year-old controls were unaffected. While this finding supports a developmental lag explanation of the inferior performances of the HECP children, it was necessary to qualify such an explanation when the within-group performances using the preferred and non-preferred hands were compared. Only the HECP children, under the visual/proprioceptive or proprioceptive conditions, showed significant performance differences, in favour of the preferred hand. This finding was taken as a suggestion that the developmental lag exhibited by the HECP children might have pathological overtones possibly related to the development of the corpus callosum.

Age Factors↗