Alex Kalverboer

Physiotherapy for clumsy children: an evaluation study.

This study reports the findings of an effect‐evaluation study of physiotherapy for clumsy children. 18 children were identified by school doctors as having poor motor co‐ordination. They were followed for three months in order to exclude spontaneous improvement of motor problems; none spontaneously improved. Subsequently, these children were enrolled on a regular physiotherapy programme. Treatment was administered individually twice a week over three months. The effects of treatment for clumsy children appeared to be promising: important improvements were found on various motor skills. These benefits were maintained for a three‐month period after the end of treatment.

The relationship between physical growth, the level of activity and the development of motor skills in adolescence: Differences between children with DCD and controls

Abstract This study uses a longitudinal design to explore the relationships between physical growth, motor competence and level of participation in physical activity, during the adolescent growth spurt. Thirty boys were selected, representing the range of motor competence. Out of this sample two groups were formed, eight boys with clumsy child syndrome (DCD) and 16 boys with adequate motor skills. The size of the DCD group was increased to 15 by an additional selection. During a period of 2 1 2 years, starting from the age of 11 years and six months, general motor skills were assessed half-yearly with the Movement Assessment Battery for Children (ABC). Growth was measured monthly and a crude measure of level of activity was obtained with a questionnaire. Multi-level regression modelling was used to examine the relationships between these variables. Among the sample representing the whole range of motor competence, the results support the view that high velocities in physical growth are negatively related to motor competence, with high levels of activity showing a positive relationship with competence. Surprisingly, children with DCD do not seem to be affected by the growth spurt. A majority of the children with DCD catches up with controls to some extent and five even reach full competence. The results are discussed in terms of theories of both normal and atypical development. PsycINFO classification 2330; 2800; 3250

Behaviour and school achievement in patients with early and continuously treated phenylketonuria

Thirty patients with early and continuously treated phenylketonuria (PKU) between 8 and 20 years of age were compared with 30 controls, matched individually for age, sex, and educational level of both parents, on behaviour rating scales for parents and teachers as well as a school achievement scale. PKU patients, as a group, demonstrated more problems in task-oriented behaviour and average academic performance than did matched controls. Interestingly, whereas male PKU patients were rated significantly lower on introversion by their teachers, female patients were rated significantly higher on introversion and lower on extraversion than matched controls. This sex difference was also reflected in the relationship between measures of dietary control and the behaviour clusters, suggesting that male and female patients respond differently to elevated Phe levels or the stress associated with PKU. The teacher rating on average academic performance of the PKU patients was associated with recent level of dietary control, which suggests that it might be improved by more strict adherence to the diet. In addition, academic performance correlated negatively with the behaviour cluster negative task orientation. Further studies are recommended to obtain a more complete evaluation of this relationship and to replicate the current findings on larger samples.

Sustained attention problems in children with early treated congenital hypothyroidism

Sustained attention was studied in 48 children with early treated congenital hypothyroidism and 35 healthy controls, using a computer‐paced and a self‐paced continuous performance task. The performance of the patients, particularly those in the low T4 group (38 patients with T4 levels < 50 nmol/1 at neonatal screening), declined in the final stage of the computer‐paced task, suggesting a problem in remaining attentive over time. The performance of all children declined in the first and improved in the final stage of the self‐paced task. This pattern was most pronounced in the low T4 group, reflecting greater variability in their task performance over time, again indicating a problem in sustaining attention. No correlation was found between onset of treatment and sustained attention. The small size of the intermediate T4 group (10 patients with T4 levels ≥ 250 nmol/1 at neonatal screening) made the results more difficult to interpret and may have concealed a problem with sustained attention in this group.

Infants' shifts of gaze from a central to a peripheral stimulus : a longitudinal study of development between 6 and 26 weeks

Abstract This article reports the results of an intensive, longitudinal investigation of the development of infants’ ability to shift gaze from a central to a peripheral stimulus. Sixteen infants were followed at 2-week intervals from 6 to 26 weeks of age. A high degree of discontinuity was found in the development of both frequency and latency of shifts of gaze, with rapid improvement between 9 and 16 weeks, followed by more gradual improvement between 16 and 26 weeks. Individual developmental trajectories for frequency were highly similar to the group trajectory. Trajectories for latency cost differed more across infants. Inter-infant differences had not become stable for either measure at 26 weeks. The findings are consistent with explanations of the development of gaze shifting in terms of changes in the relative strength of processes which maintain the focus of attention and gaze, and processes which interrupt and shift it.

Information processing in patients with early and continuously-treated phenylketonuria

A total of 33 patients with early and continuously-treated phenylketonuria (PKU) between 7 and 16 years of age and 33 matched controls participated in a study examining perceptual, central, and response-related mechanisms of information processing. The specific mechanisms studied were: perceptual filtering, memory search, response selection, response execution, and motor presetting. In addition, groups were compared on mean intelligence level and task oriented behaviour. The performance of the PKU patients practically matched that of the controls on all three tasks, suggesting that PKU patients who are continuously maintained on a well-controlled phenylalanine-restricted diet are not impaired in the elementary mechanisms of information processing. Furthermore, groups did not differ in mean IQ or task-oriented behaviour.

A longitudinal study of the development of shifts of gaze to a peripheral stimulus in preterm infants with transient periventricular echogenicity

Shifts of gaze to peripheral targets were studied longitudinally, between 6 and 26 weeks corrected age, in full-term and very preterm infants with transient periventricular echogenicity (PVE). Before 10 weeks, simple shifts of gaze were faster and more frequent in preterms with PVE<14 days than in full-terms, suggesting these preterms profited from additional early visual experience. After 16 weeks, there were subtle differences between full- and preterm infants in the development of shifts of gaze requiring disengagement. The differences suggest that, after disengagement had become established, its fine-tuning occurred more slowly in the preterms. Slower fine-tuning of disengagement was not associated with duration of PVE, since it was more marked in preterms with PVE<14 days than in preterms with PVE> or =14 days. The differences in performance between full- and preterm infants were small. However, even small differences may affect the efficiency of visually guided behaviors.

Inhibition of return in very young infants: a longitudinal study

Inhibition of return (IOR) was measured at 2-week intervals from 6 weeks to 6 months of age in 16 infants. IOR refers to the tendency not to return attention to a recently attended location. A spatial cueing task adapted to the attentional and oculomotor skills of the youngest infants was used. At 6 weeks, infants looked more frequently and faster to cued targets. Looks to uncued targets were more frequent than looks to cued targets from 16 weeks, and faster than looks to cued targets from 18 weeks. Infants differed in the tempo of development and the level of performance on both indices of IOR in the final session. Individual preferences for uncued targets fluctuated from session to session. Unstable looking biases were observed in all infants. They explained a significant part of the intra-individual differences in preference. Latency to look to uncued targets was stable from the 18-week session.

Timing variability in children with early-treated congenital hypothyroidism

This study reports on central and peripheral determinants of timing variability in self-paced tapping by children with early-treated congenital hypothyroidism (CH). A theoretical model of the timing of repetitive movements developed by Wing and Kristofferson was applied to estimate the central timekeeper (clock) and peripheral implementation (motor delay) variances from the variability in the response intervals. Before it is diagnosed and treated, CH is known to affect proper development of the cerebellum. If this would affect the time-keeper function of the cerebellum, it should be reflected by an increased central clock variability rather than by an increased peripheral motor-delay variability in terms of the Wing and Kristofferson model. Results of 46 children with early-treated CH, differing in severity (21 severe, 25 mild), and 34 normal controls are reported. A refinement of the Wing and Kristofferson model is applied to estimate central clock and peripheral motor delay timing variability more precisely than has been done before. Results show that for children with early-treated CH the estimate of the motor delay variance is four times higher than for the controls, while the estimate of the clock variance does not differ between the groups. It is concluded that motor problems in early-treated CH are associated with peripheral rather than with central timing deficiencies.

Phenylketonuria and some aspects of emotional development

Early dietary treatment of phenylketonuria (PKU) prevents intellectual retardation and gross neurological impairment although not all neuropsychological problems. This study investigates to what extent the illness and its treatment imposes a burden on emotional development of early-treated PKU patients and on rearing practices of their parents. It is concluded that in early-treated PKU it is particularly difficult to find constructive ways to adapt to the situation for children as well as for parents. As coping with PKU and its treatment is so complicated, paediatric control should be combined with psychocounselling.