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Biomedical subjects

R B Minderaa

Publications and source records attributed to R B Minderaa.

At least 19 recordsLinked to original sources
PubMed2005

Drug utilisation by children and adolescents with mental retardation: a population study.

OBJECTIVE: Little is known about the utilisation of drugs by mentally retarded children; population studies are even more sparse. In this study the chronic drug utilisation in children aged 4-18 years with mental retardation in a large population in the Netherlands was investigated. METHODS: Throughout all special schools and (day) care facilities for children with mental retardation in Friesland, parents/representatives were approached requesting participation of their children. Participants were interviewed about a number of aspects including medication use. For 921 of the 1,057 participants, information was available on medication use for those physical and psychiatric illnesses that bothered them or was expected to bother them for at least 3 months per year; 912 of the participants were within the age category under study: 4-18 years. RESULTS: About 22% of the 912 participants used chronic medication, 47% of whom used two or more drugs. The prevalence of drug use increased with severity of mental retardation from about 17% to 49%. The exception was the 6% of children with borderline intellectual functioning: their medication prevalence was 27%. Overall, 17% of the study population used a nervous system drug, 4% used a respiratory system drug and 3% used an alimentary tract drug. Of the drugs for the nervous system, alimentary tract and respiratory tract, 32% was prescribed off-label. For 3%, we were unable to establish on/off-label use. CONCLUSIONS: Chronic drug utilisation patterns in children and adolescents with mental retardation are different from those in the general paediatric population. These different patterns suggest the need for additional research.

Adolescent↗
PubMed2005

Internalizing and externalizing problems in adolescence: general and dimension-specific effects of familial loadings and preadolescent temperament traits.

BACKGROUND: We investigated the links between familial loading, preadolescent temperament, and internalizing and externalizing problems in adolescence, hereby distinguishing effects on maladjustment in general versus dimension-specific effects on either internalizing or externalizing problems. METHOD: In a population-based sample of 2230 preadolescents (10-11 years) familial loading (parental lifetime psychopathology) and offspring temperament were assessed at baseline by parent report, and offspring psychopathology at 2.5-years follow-up by self-report, teacher report and parent report. We used purified measures of temperament and psychopathology and partialled out shared variance between internalizing and externalizing problems. RESULTS: Familial loading of internalizing psychopathology predicted offspring internalizing but not externalizing problems, whereas familial loading of externalizing psychopathology predicted offspring externalizing but not internalizing problems. Both familial loadings were associated with Frustration, low Effortful Control, and Fear. Frustration acted as a general risk factor predicting severity of maladjustment; low Effortful Control and Fear acted as dimension-specific risk factors that predicted a particular type of psychopathology; whereas Shyness, High-Intensity Pleasure, and Affiliation acted as direction markers that steered the conditional probability of internalizing versus externalizing problems, in the event of maladjustment. Temperament traits mediated one-third of the association between familial loading and psychopathology. Findings were robust across different composite measures of psychopathology, and applied to girls as well as boys. CONCLUSIONS: With regard to familial loading and temperament, it is important to distinguish general risk factors (Frustration) from dimension-specific risk factors (familial loadings, Effortful Control, Fear), and direction markers that act as pathoplastic factors (Shyness, High-Intensity Pleasure, Affiliation) from both types of risk factors. About one-third of familial loading effects on psychopathology in early adolescence are mediated by temperament.

Adolescent↗
PubMed2005

Differential effects of DRD4 and DAT1 genotype on fronto-striatal gray matter volumes in a sample of subjects with attention deficit hyperactivity disorder, their unaffected siblings, and controls.

Genetic influences on behavior are complex and, as such, the effect of any single gene is likely to be modest. Neuroimaging measures may serve as a biological intermediate phenotype to investigate the effect of genes on human behavior. In particular, it is possible to constrain investigations by prior knowledge of gene characteristics and by including samples of subjects where the distribution of phenotypic variance is both wide and under heritable influences. Here, we use this approach to show a dissociation between the effects of two dopamine genes that are differentially expressed in the brain. We show that the DAT1 gene, a gene expressed predominantly in the basal ganglia, preferentially influences caudate volume, whereas the DRD4 gene, a gene expressed predominantly in the prefrontal cortex, preferentially influences prefrontal gray matter volume in a sample of subjects including subjects with ADHD, their unaffected siblings, and healthy controls. This demonstrates that, by constraining our investigations by prior knowledge of gene expression, including samples in which the distribution of phenotypic variance is wide and under heritable influences, and by using intermediate phenotypes, such as neuroimaging, we may begin to map out the pathways by which genes influence behavior.

Adolescent↗
PubMed2004

Neurobiology and neuroimmunology of Tourette's syndrome: an update.

Tourette's syndrome is a childhood-onset neuropsychiatric disorder characterized by the presence of both multiple motor and vocal tics. While the pathogenesis at a molecular and cellular level remains unknown, structural and functional neuroimaging studies point to the involvement of the basal ganglia and related cortico-striato-thalamo-cortical circuits as the neuroanatomical site for Tourette's syndrome. Moreover, Tourette's syndrome has a strong genetic component, and considerable progress has been made in understanding the mode of transmission and in identifying potential genomic loci. Summaries of recent findings in these areas will be reviewed, followed by a critical overview of findings both supporting and challenging the proposed autoimmune hypothesis of Tourette's syndrome. We conclude that Tourette's syndrome is a heterogeneous disorder, and that immune factors may indeed be involved in some patients.

B-Lymphocytes↗
PubMed2003

A whole-genome scan in 164 Dutch sib pairs with attention-deficit/hyperactivity disorder: suggestive evidence for linkage on chromosomes 7p and 15q.

A genome scan was performed on 164 Dutch affected sib pairs (ASPs) with attention-deficit/hyperactivity disorder (ADHD). All subjects were white and of Dutch descent and were phenotyped according to criteria set out in the Diagnostic and Statistical Manual Of Mental Disorders, 4th edition. Initially, a narrow phenotype was defined, in which all the sib pairs met the full ADHD criteria (117 ASPs). In a broad phenotype, additional sib pairs were included, in which one child had an autistic-spectrum disorder but also met the full ADHD criteria (164 ASPs). A set of 402 polymorphic microsatellite markers with an average intermarker distance of 10 cM was genotyped and analyzed using the Mapmaker/sibs program. Regions with multipoint maximum likelihood scores (MLSs) >1.5 in both phenotypes were fine mapped with additional markers. This genome scan indicated several regions of interest, two of which showed suggestive evidence for linkage. The most promising chromosome region was located at 15q, with an MLS of 3.54 under the broad phenotype definition. This region was previously implicated in reading disability and autism. In addition, MLSs of 3.04 and 2.05 were found for chromosome regions 7p and 9q in the narrow phenotype. Except for a region on chromosome 5, no overlap was found with regions mentioned in the only other independent genome scan in ADHD reported to date.

Adolescent↗
PubMed2003

Face recognition in children with a pervasive developmental disorder not otherwise specified.

This study investigates the accuracy and speed of face recognition in children with a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS; DSM-IV, American Psychiatric Association [APA], 1994). The study includes a clinical group of 26 nonretarded 7- to 10-year-old children with PDDNOS and a control group of 65 normally developing children of the same age. Two computerized reaction time tasks were administered: a face recognition task and a control task designed to measure the recognition of abstract visuospatial patterns. The latter were either easy or difficult to distinguish from a set of alternative patterns. The normally developing children recognized the faces much faster than the hardly distinguishable abstract patterns. The children in the PDDNOS group needed an amount of time to recognize the faces that almost equalled the time they needed to recognize the abstract patterns that were difficult to distinguish. The results suggest that, when processing faces, children with PDDNOS use a strategy that is more attention-demanding and, hence, less automatic or "Gestalt-like" than the one used by the control children. The results are discussed in the light of a theory that explains the development of coherent mental representations.

Attention↗
PubMed2002

Is Tourette's syndrome an autoimmune disease?

We provide a review of recent research findings which support the involvement of autoimmunity in childhood-onset tic disorders, in particular the presence of antineuronal autoantibodies, D8/17 B lymphocyte overexpression, a marker of chorea associated with streptococcal infection, and possible beneficial effects of immunomodulatory intervention. One of the most controversial areas in this field is the validity of the proposed PANDAS concept. Some researchers have delineated a putatively unique subgroup of patients, from the spectrum of illness encompassing Tourette's syndrome and obsessive-compulsive disorder (OCD), whose tics and obsessive-compulsive symptoms are shown to arise in response to beta-hemolytic streptococcal infections. They designated it by the term pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). Herein we additionally present pros and cons concerning the concept of PANDAS. Finally, recommendations for future research directions are given.

Autoantibodies↗
PubMed2002

Theory of mind in children with 'lesser variants' of autism: a longitudinal study.

BACKGROUND: The study investigated the development of theory-of-mind (ToM) knowledge in children with lesser variants' of autism (PDD-NOS) over a period thought to be critical for ToM development (i.e., 3 to 5 years of age). METHOD: The sample included 11 children with PDD-NOS; 23 normally developing children were included for cross-sectional comparison and 13 normally developing children for longitudinal comparison. The groups were comparable in verbal and non-verbal mental age. Two storybooks were used for repeated assessment of various aspects of the children's theory of mind: emotion recognition, the distinction between physical and mental entities, prediction of behaviour and emotions on the basis of desires and prediction of behaviour and emotions on the basis of beliefs. RESULTS: The results showed that the children with PDD-NOS had specific difficulties in understanding and predicting other people's emotions on the basis of situational cues, desires and beliefs. However, their ability to predict actions from beliefs and desires were relatively intact. Compared to the normally developing children, these children achieved lower levels of theory-of-mind knowledge, both at time of initial assessment and approximately 6 months later. CONCLUSIONS: The data suggest that the theory-of-mind development of children with PDD-NOS is both delayed and deviant. The growth pattem of theory-of-mind skills in children with PDD-NOS seemed to be qualitatively different from the growth pattern found in the group of normally developing children.

Child Development Disorders, Pervasive↗
PubMed2001

Elevated D8/17 expression on B lymphocytes, a marker of rheumatic fever, measured with flow cytometry in tic disorder patients.

OBJECTIVE: Elevated D8/17 expression on B lymphocytes is a known susceptibility marker of rheumatic fever. Previous studies have reported higher than usual D8/17 expression on B lymphocytes of patients with tic disorders. The purpose of this study was to assess D8/17 expression on B lymphocytes of tic disorder patients by using an objective method in which no operator variability was involved. METHOD: D8/17 expression on B lymphocytes was assessed with flow cytometry by using an immunoglobulin M (IgM) monoclonal D8/17-specific antibody in an unselected group of Dutch patients with tic disorders (N=33) and healthy volunteers (N=20). Binding of this monoclonal antibody was compared with binding of an irrelevant IgM monoclonal antibody, and the shift in mean fluorescence intensity of the D8/17-specific antibody compared to that of the irrelevant IgM monoclonal antibody was used as a measure of D8/17 overexpression. For the patients, Yale Global Tic Severity Scale scores were used to assess disease severity. RESULTS: D8/17 overexpression in the patient group (mean=16.8 arbitrary units, SD=30.5) was significantly higher than in the comparison group (mean=3.2, SD=3.0). A significant minority of the patients (N=13, 39.4%), however, had levels of D8/17 overexpression within the range of that of the healthy comparison subjects. Flow cytometric analysis did not indicate a separate subpopulation of D8/17-positive B cells. CONCLUSIONS: These data confirm the utility of D8/17 B cell overexpression as a peripheral blood marker in patients with tic disorders and are compatible with a streptococcus-related pathogenesis for at least a subgroup of patients with tic disorders.

Adolescent↗
PubMed1999

Cardiac adaptivity to attention-demanding tasks in children with a pervasive developmental disorder not otherwise specified (PDD-NOS).

BACKGROUND: Decreases in heart rate variability (HRV) have been repeatedly demonstrated to be an index of effort allocation to attention-demanding tasks. Children with autistic-type problems in social interaction and in adapting to unfamiliar situations (DSM-IV: PDD-NOS) have been shown to have specific attention deficits. These children were hypothesized to exhibit less cardiac adaptivity to attention-demanding tasks. METHODS: Two groups of 18 children with PDD-NOS, judged to be hyperactive and nonhyperactive, were compared to 18 healthy children with respect to their performances on a visual attention task and the differences in HRV measured during periods of task performance and periods of rest. RESULTS: Compared to the control group, both clinical groups were found to have a stronger capacity limitation in processing high loads of information, and to be less capable of maintaining a stable task performance throughout the whole task. Both clinical groups showed significantly less decreases in HRV during the periods of task performance. The magnitude of rest-task differences in HRV was found to correlate significantly with a behavioral measure of resistance to unexpected changes in daily routines. CONCLUSIONS: Children with PDD-NOS are significantly less flexible in their autonomic adaptation to attention-demanding tasks. The findings are interpreted as reflecting a deficiency in the functional organization of those neural pathways that provide cortical control of the visceral efferents.

Adaptation, Physiological↗
PubMed1999

Social-cognitive abilities in children with lesser variants of autism: skill deficits or failure to apply skills?

The present study re-examined the ability of children with lesser variants of autism (classified as PDD-NOS) to infer emotions of other people and to describe others in terms of inner, psychological characteristics. It also explores the hypothesis that these children may have the skill to infer mental states of other people, but fail to use these skills spontaneously. Children with lesser variants of autism and normal control children matched for age, sex and intelligence were given three structured emotional role-taking tasks and asked to give two spontaneous descriptions of peers. The results showed that both groups did not differ with respect to their ability to infer other people's emotions in the structured role-taking tasks. In contrast, significant differences were found on the free person descriptions: the children with PDD-NOS used fewer inner, psychological characteristics to describe peers.

Autistic Disorder↗
PubMed1998

Influence of respiratory activity on the cardiac response pattern to mental effort.

A group of 32 healthy adult volunteers completed three blocks of a reaction time task that varied in the degree of controlled processing load. A rest period preceded each of the task blocks. The task blocks were presented in the order of either increasing or decreasing cognitive load. For each of the six periods, mean values and spectral measures of heart rate and respiration variability were calculated. The spectral measures were obtained for three different frequency bands. Differences between the cardiac measures of the task and preceding rest periods were compared with respect to differences in task load and the order of task presentation. All comparisons were carried out while adjusting for respiratory variability in the corresponding frequency band. The frequency band in which task load-related changes in heart rate variability became manifest appeared to be dependent on the individual's breathing pattern.

Adult↗
PubMed1995

An exploration of person perception abilities in children with a pervasive developmental disorder not otherwise specified.

This explorative study investigates differences in person perception abilities between a group of children diagnosed as having a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) and a group of normal children of the same age and sex. Person perception, a social-cognitive skill, concerns the way in which children conceptualise other people, their intentions, attitudes, traits and emotions (central), as well as their overt behaviour and their physical characteristics (peripheral). Person perception was investigated by means of a free-person description, in which the child was asked to describe another person. Children with a PDDNOS used more peripheral and less central statements than the control group to describe another person. However, these differences seemed to reflect differences in intelligence between the two groups, rather than differences in a specific social-cognitive skill. The results need to be replicated, but seem to be in line with other studies that suggest that there may be subgroups of the autistic spectrum that show severe social impairment but have good social-cognitive abilities.

Child↗
PubMed1995

Emotional role-taking abilities of children with a pervasive developmental disorder not otherwise specified.

Seven to 12-year-old children with a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) were compared with normal, healthy children of the same age and sex on three different emotional role-taking tasks. In these tasks, children had to use person-specific information to make an inference about another child's emotional reaction and behaviour, Significant differences were found between the PDDNOS group and control group: PDDNOS children performed worse on all three role-taking tasks. However, the differences on one of these tasks could be completely explained by intelligence differences between the two groups. On the other tasks, differences could not or be partially explained by intelligence differences. The results of this study led to the formulation of a more specific hypothesis, namely that PDDNOS children might have problems interpreting social information when affectively charged background information has to be used.

Aptitude↗
PubMed1995

Lack of effect of clonidine on stuttering in children.

OBJECTIVE: The authors studied the effects of the alpha 2-receptor agonist clonidine on stuttering in children. METHOD: Using a double-blind crossover study, they gave placebo or 4 micrograms/kg body weight per day to 25 stuttering children who were 6-13 years old. Stuttering was measured by counting the occurrences of four elementary speech difficulties and by asking parents and teachers to give an overall impression of the amount of stuttering, as well as their impression of how troublesome the stuttering was to the children. RESULTS: Clonidine did not improve stuttering. CONCLUSIONS: Clonidine cannot be recommended as a useful drug for treating children who stutter.

Adolescent↗
PubMed1994

Noradrenergic and adrenergic functioning in autism.

A neurochemical assessment of noradrenergic and adrenergic functioning was carried out with autistic patients and normal control individuals. Norepinephrine and related compounds were measured in autistic (n = 17 unmedicated, 23 medicated; age range 9-29 years old) and normal controls (n = 27; age range 9-36 years old). Plasma levels and urinary excretion of 3-methoxy-4-hydroxy-phenylglycol (MHPG) were measured, as were urinary excretion rates of norepinephrine (NE), epinephrine (EPI), and vanillylmandelic acid (VMA). No significant group mean differences were seen between the autistic and control groups. In both the autistic and control groups urinary excretion rates of norepinephrine and epinephrine were substantially higher in the afternoon-evening (5-11 PM) compared to the overnight (11 PM-7 AM) collection period. Based on our neurochemical assessment, marked abnormalities in basal noradrenergic functioning do not appear to be present in autism.

Adolescent↗