PubMed Health⌕ Search

Biomedical subjects

B C Touwen

Publications and source records attributed to B C Touwen.

At least 19 recordsLinked to original sources
PubMed1998

Neurological condition in 42-month-old children in relation to pre- and postnatal exposure to polychlorinated biphenyls and dioxins.

Adverse neurological effects of exposure to PCBs have been found up to 18 months of age. Now we report on the effect of pre- and postnatal exposure to PCBs and dioxins on the neurological condition at 42 months of age. For this purpose, PCB levels were determined in cord and maternal plasma, and used as a measure of prenatal exposure. Breast milk was analyzed for PCBs and dioxins. In addition, PCBs were determined in plasma sampled from the child at 42 months of age. We evaluated the neurological condition of 394 children using the Touwen/Hempel method. After adjustment for covariates, neither prenatal PCB exposure nor postnatal exposure to PCBs and dioxins was found to be related to the neurological condition at 42 months of age.

Child, Preschool↗
PubMed1995

Neurological condition in 18-month-old children perinatally exposed to polychlorinated biphenyls and dioxins.

The neurological optimality of 418 Dutch children was evaluated at the age of 18 months, in order to determine whether prenatal and breast milk mediated exposure to polychlorinated biphenyls (PCBs) and dioxins affected neurological development. Half of the infants were breast-fed, the other half were formula-fed. PCB concentrations in cord and maternal plasma were used as a measure of prenatal exposure to PCBs. To measure postnatal exposure, PCB and dioxin congeners were determined in human milk and in formula milk. After adjusting for covariates, transplacental PCB exposure was negatively related to the neurological condition at 18 months. Although greater amounts of PCBs and dioxins are transferred via nursing than via placental passage, an effect of lactational exposure to PCBs and dioxins could not be detected. We even found a beneficial effect of breast-feeding on the fluency of movements. We conclude that transplacental PCB passage has a small negative effect on the neurological condition in 18-month-old toddlers.

Dioxins↗
PubMed1995

Perinatal exposure to polychlorinated biphenyls and dioxins and its effect on neonatal neurological development.

Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs)) are widespread environmental contaminants which are neurotoxic in animals. Perinatal exposure to PCBs, PCDDs, and PCDFs occurs prenatally via the placenta and postnatally via breast milk. To investigate whether such an exposure affects the neonatal neurological condition, the neurological optimality of 418 Dutch newborns was evaluated with the Prechtl neurological examination. Half of the infants were breast-fed, the other half were formula-fed, representing a relatively high against a relatively low postnatally exposed group, respectively. As an index of prenatal exposure, four non-planar PCBs in cord and maternal plasma were used. These PCB levels were not related to neurological function. As measures of combined pre- and early neonatal exposure, 17 dioxin congeners, three planar, and 23 non-planar PCB congeners were determined in human milk in the second week after delivery. Higher levels of PCBs, PCDDs, and PCDFs in breast milk were related to reduced neonatal neurological optimality. Higher levels of planar PCBs in breast milk were associated with a higher incidence of hypotonia. This study confirms previous reports about the neurotoxic effects of these compounds on the developing brain of newborn infants.

Benzofurans↗
PubMed1995

The neurological development of prehension: a developmental neurologist's view.

From the developmental neurological point of view prehension is an important function as it involves the total sensorimotor nervous system. In order to make efficient performance possible both postural activity and motility of arms and hands must be coordinated, implying an intricate interplay between tonic and phasic activities. The analysis of the development of the different contributors suggests that they are based on independently developing brain mechanisms. This independency guarantees the variability which is required for adequately adaptive and purposeful functioning. A lack of this ability to vary, i.e. monotonous and stereotyped function resulting from deficient or deficiently coupled brain mechanisms leads to maladaptive and impaired motor function. Identification of the dysfunctioning brain mechanisms may inform treatment strategies.

Arm↗
PubMed1994

Neurological differences between 9-year-old children fed breast-milk or formula-milk as babies.

The presence of minor neurological dysfunction is associated with behavioural and cognitive development at school age. We have previously shown a relation between minor neurological dysfunction and perinatal disorders, especially abnormal neonatal neurological condition. We have now investigated the relation between breastfeeding and long-term neurological development. We studied 135 breastfed (for > or = 3 weeks) and 391 formula-fed children, born at term in the University Hospital Groningen between 1975 and 1979. A standard neonatal neurological examination was used to classify the infants as normal (247), slightly abnormal (213), or frankly abnormal (66). At 9 years of age the children were reexamined. In 1993 their mothers were asked to complete a questionnaire about how the children were fed as infants. After adjustment for obstetric, perinatal, neonatal neurological, and social differences, a small advantageous effect of breastfeeding on neurological status at 9 years of age was found (odds ratio for neurological non-normality 0.54 [95% CI 0.30-0.97]). Although a retrospective design cannot lead to definite conclusions, our data suggest a beneficial effect of breast-feeding on postnatal neurological development. Longer-chain polyunsaturated fatty acids, which are present in breast-milk but not in most formula-milks, may have a role since they are vital for brain development.

Bottle Feeding↗
PubMed1994

Late neurological, cognitive and behavioural sequelae of prenatal exposure to coumarins: a pilot study.

Neurological, cognitive and behavioural development were assessed in a group of 21, 8- to 10-year old children whose mothers took coumarins during pregnancy. Findings were compared with those in a group of 17 control children. The study was performed to test whether it is feasible to carry out a reliable retrospective study of late effects of prenatal exposure to coumarins. This turned out to be the case. In this small pilot study, no statistical significant differences were found between the study and control group, nevertheless a few findings were remarkable. One child showed severe neurological abnormalities, which may be due to prenatal exposure to oral anticoagulants. The children with the lowest scores on the neurological assessment and the lowest IQ-scores, were found in the exposed group. Obviously, the number of children in this study is too small to conclude if there has been definite effects from coumarin, but these results indicate that a large follow-up study is required. In the present paper, we have shown that such a study is feasible.

Administration, Oral↗
PubMed1994

Neurobehavioural relationships after the onset of puberty.

The behavioural and cognitive development were studied of 68 children with and 259 without minor neurological function (MND) at 14 years, when the majority of children showed three or more physical signs of puberty. MND was differentiated into fine manipulative disability, co-ordination problems, choreiform dyskinesia and hypotonia. The normal group was subdivided into those who had been normal at 12 years and those who had had MND. All types of MND were related to cognitive and behavioural problems. Fine manipulative disability was related to behavioural and cognitive difficulties; co-ordination problems to learning difficulties; and choreiform dyskinesia and hypotonia were related to attention difficulties and school failure, notwithstanding normal IQ. Besides MND, socio-economic class, family adversities and female gender contributed to the development of behavioural and cognitive problems. The behaviour of children with MND at 12 years who were normal at 14 years did not differ from that of normal children.

Adolescent↗
PubMed1994

Minor neurological dysfunction and quality of movement in relation to neonatal cerebral damage and subsequent development.

Minor neurological dysfunction (MND) and quality of movement were studied in relation to neonatal cerebral damage and developmental assessments at 3 1/2 years of age in 66 very low-birthweight children without obvious disability. MND was found in 19 children and was significantly related to the quality of movement. The results demonstrate that MND is associated with neonatal cerebral damage at preschool-age, but that the assessment of quality of movement is associated with more complex sensory motor tasks and simultaneous processing. At preschool-age, quality of movement might therefore be a better marker of later learning problems than traditional signs of minor neurological dysfunction.

Brain Diseases↗
PubMed1993

The effect of intra-uterine breech position on postnatal motor functions of the lower limbs.

The effect of intra-uterine movement restriction on the development of motor functions was studied longitudinally by comparing infants born after uncomplicated breech position (n = 13) with control infants (vertex position, n = 5-10). Before birth, fetal leg posture was studied at regular intervals by means of real time ultrasound observations, and classified as complete (n = 1), inconsistent (n = 6), or incomplete (n = 6) breech position. Limited extension of the hips, preference posture and joint position in percentage of time (each until 12 weeks), withdrawal reflex and magnet response (until 26 weeks) and posture while sitting, standing and walking without support (up to 12-18 months) were assessed longitudinally. The results showed statistically significant, positive relationships between intra-uterine breech position and neonatal limited extension of the hip-joint, between limited extension of the hip-joint and the percentage of time that the hips are in flexion during the first 12 weeks, between this flexion of the hips (in percentage of time) and an abnormally 'flexed' walking pattern at 12-18 months, and finally, between a positive magnet response at 6 months and an abnormal walking pattern at 12-18 months. These findings suggest that intra-uterine movement restriction of the legs can cause long term alterations in the development of motor functions (leg posture, reflexes and posture while walking), possibly mediated by alterations in proprioceptive feedback mechanisms.

Adult↗
PubMed1993

How normal is variable, or how variable is normal?

Variability is an important property of the central nervous system, and it shows characteristic changes during infancy and childhood. The large amount of variations in the performance of sensomotor functions in infancy is called indiscriminate or primary variability. During toddling age the child develops the capacity to select adaptive variations, and then automatize them: secondary or adaptive variability. The latter is required for the development of motor skills during later preschool age and school age. The question 'How normal is variable or how variable is normal is a wrong question, as any form of variability must be interpreted according to its extent, type and age adequacy.

Aging↗
PubMed1993

Minor neurological dysfunction after the onset of puberty: association with perinatal events.

In order to study the hypotheses that puberty is related to a decrease of minor neurological dysfunction (MND) and that persisting MND is associated with perinatal factors, two groups (174 normal, 172 MND) of the Groningen Perinatal Project were followed from 12 to 14 years. At 14 years almost all the children had entered puberty (n = 329) defined as the presence of three or more puberty signs. In the MND group 55% of the children were normal at 14 years and in 45% MND signs were still present, though in a less extensive form. The latter phenomenon was most clear in children who had just begun puberty. The effect of puberty was similar in both sexes. MND which persisted into puberty was related to neonatal neurological deviancy, lower social class, lower obstetrical optimality score and male sex. After differentiation with specific MND clusters, it appeared that fine manipulative disability was associated with neonatal neurological deviancy, with minor physical anomalies and with lower social class; choreiform dyskinesia with asphyxia; hypotonia with constitutionally related factors; and coordination problems with pre-maturity (< 32 weeks).

Adolescent↗
PubMed1993

Development of muscle power in preterm infants: individual trajectories after term age.

In a longitudinal study individual trajectories were traced for the developing relationship between active and passive muscle power in preterm (n = 37) and fullterm (n = 20) infants from term to 24 weeks (corrected) age. Such trajectories should enable the identification of those infants at highest risk for later neurological dysfunctions. This contention is supported by the findings of this study: those preterm infants who showed marked discrepancies between the two sorts of muscle power or rigidity in both beyond 12 weeks corrected age were most likely to manifest neurological problems at 52 weeks of age.

Female↗
PubMed1993

Is minor neurological dysfunction at 12 years related to behaviour and cognition?

Behavioural and cognitive development at 12 years were studied in 172 children with and 174 children without minor neurological dysfunction (MND). MND could be differentiated into fine manipulative disability, co-ordination problems, hypotonia and choreiform dyskinesia. Fine manipulative disability related significantly to problems of cognition and behaviour; co-ordination problems to cognitive problems; and hypotonia and choreiform dyskinesia to behavioural problems, the former more than the latter. Socio-economic status and family adversity contributed to the risk for development of both cognitive and behavioural problems; gender did not. The onset of puberty seemed to change these relationships: follow-up is needed for definite conclusions.

Achievement↗
PubMed1993

[Prenatal and early postnatal motor development and its importance in recognizing developmental disorders].

The normal central nervous system is characterized by both activity and reactivity. Under normal circumstances the former leads the latter. In abnormal conditions reactivity may predominate, usually in the form of reflexes and abnormal postural reactions. Ultrasound registration shows that the first spontaneous motor movements can be seen in the seventh to eighth gestational week. Movement patterns develop fast, and in mid-pregnancy all patterns are observed that can be found in the term newborn baby. During the second half of pregnancy movement patterns are refined: the first differentiation leading to variable and fluent movements. The intrauterine movements are qualitatively more or less similar to those seen in normal preterm babies, the main difference being that the latter as to counteract gravity forces to a greater extent. Qualitative changes of the movement patterns signal deteriorating intrauterine conditions. Stereotyped quality of movement can be a sign of abnormal development. During infancy normal development is characterized by great variability in performance, developmental sequences and relationships. Stereotype performance and strong relationship between the various motor functions, reactions and reflexes should arouse the suspicion that there may be a disturbance in development.

Child, Preschool↗
PubMed1992

A method to assess the development of muscle power in preterms after term age.

The purpose of this paper is to report a detailed description of an instrument for evaluating the development of active and passive muscle power in preterms beyond term age. The instrument is constructed on a basis of age-specific items that assess these two components of muscle power and on the assumption that a persistent discrepancy between them serves to detect those preterms at most risk for disturbances in motor development. The application of the instrument is illustrated by reporting the individual trajectories of five case studies without any serious medical complications. It is concluded that if a marked discrepancy between active and passive power persists beyond the corrected age of 3 months, then this may be a sign of underlying pathology which will eventuate in abnormal postural outcomes and thereby disturbances in the control and coordination of movement. Having now provided a detailed description of how this instrument should be applied in postterm follow-up of preterm infants, we are currently examining its sensitivity and specificity on a much larger sample of similar subjects.

Age Factors↗
PubMed1992

Development of the relationship between active and passive muscle power in preterms after term age.

Fifty-eight infants were assessed with an instrument which is designed to evaluate the development of the relationship between active and passive muscle power. The purpose of this longitudinal assessment was to investigate whether preterms show a different development course than fullterms in the relationship between these two components of muscle power. Thirty-seven low-risk preterms and twenty-one healthy fullterms were followed from term until 24 weeks corrected age. It is concluded that preterms differ markedly from fullterms in the developing interrelationship between active and passive muscle power. The value of the instrument for detecting signs of early pathology is discussed.

Age Factors↗