82 research outputs found
The Issue of Equity: research on selection processes for educational programmes in developing countries
SUMMARY The project described is concerned with designing selection processes for ‘upgrading programmes’ in science and mathematics, to be used especially in southern African countries. There is a conflict between the objectives of maximum effectiveness and equity — which is both a technical and a socio?political problem. Mutual understanding and agreement between all parties is essential for a workable programme. RESUMEN El asunto de la equidad: investigación en procesos de selección de programas educacionales en países en desarrollo El proyecto descrito se preocupa del diseño de procesos de selección de programas de promoción’ en ciencias y matemáticas, destinados especialmente a paises del sur africano. Existe un conflicto entre los objetivos de eficiencia y equidad, lo que constituye no solo un problema técnico, sino también sociopolitico. El acuerdo y la comprensión entre todas las partes involucradas, son esenciales para un programa factible. SOMMAIRE Le problème d'équité: recherches sur les procédés de sélection de programmes pédagogiques dans les pays en voie de développement Le projet décrit concerne la création de procédés de sélection pour ‘adapter les programmes’ en sciences et mathématiques, en vue de leur utilisation dans les pays d'Afrique du sud plus spécialement. Il y a un conflit entre les objectifs d'une rentabilité maximale, et l'équité — qui est à la fois un problème technique et socio?politique. Une compréhension mutuelle et une entente entre tous les partis sont essentielles pour la viabilité du programme
Support for an independent familial segregation of executive and intelligence endophenotypes in ADHD families
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70924.pdf (publisher's version ) (Open Access)BACKGROUND: Impairments in executive functioning (EF) and intelligence quotient (IQ) are frequently observed in children with attention deficit hyperactivity disorder (ADHD). The aim of this paper was twofold: first, to examine whether both domains are viable endophenotypic candidates for ADHD and second to investigate whether deficits in both domains tend to co-segregate within families. METHOD: A large family-based design was used, including 238 ADHD families (545 children) and 147 control families (271 children). Inhibition, visuospatial and verbal working memory, and performance and verbal IQ were analysed. RESULTS: Children with ADHD, and their affected and non-affected siblings were all impaired on the EF measures and verbal IQ (though unimpaired on performance IQ) and all measures correlated between siblings. Correlations and sibling cross-correlations were not significant between EF and IQ, though they were significant between the measures of one domain. Group differences on EF were not explained by group differences on IQ and vice versa. The discrepancy score between EF and IQ correlated between siblings, indicating that siblings resembled each other in their EF-IQ discrepancy instead of having generalized impairments across both domains. Siblings of probands who had an EF but not IQ impairment, showed a comparable disproportionate lower EF score in relation to IQ score. The opposite pattern was not significant. CONCLUSIONS: The results supported the viability of EF and IQ as endophenotypic candidates for ADHD. Most findings support an independent familial segregation of both domains. Within EF, similar familial factors influenced inhibition and working memory. Within IQ, similar familial factors influenced verbal and performance IQ
Motor coordination problems in children and adolescents with ADHD rated by parents and teachers: effects of age and gender
Summary.
Objective. ADHD is frequently accompanied by motor coordination problems. However, the co-occurrence of poor motor performance has
received less attention in research than other coexisting problems in ADHD. The underlying mechanisms of this association
remain unclear. Therefore, we investigated the prevalence of motor coordination problems in a large sample of children with
ADHD, and the relationship between motor coordination problems and inattentive and hyperactive/impulsive symptoms. Furthermore,
we assessed whether the association between ADHD and motor coordination problems was comparable across ages and was similar
for both genders.
Method. We investigated 486 children with ADHD and 269 normal controls. Motor coordination problems were rated by parents (Developmental
Coordination Disorder Questionnaire) and teachers (Groningen Motor Observation Scale).
Results. Parents and teachers reported motor coordination problems in about one third of children with ADHD. Problems of fine and
gross motor skills, coordination skills and motor control were all related to inattentive rather than hyperactive/impulsive
symptoms. Relative to controls, motor coordination problems in ADHD were still present in teenagers according to parents;
the prevalence diminished somewhat according to teachers. Boys and girls with ADHD were comparably affected, but motor performance
in controls was better in girls than in boys.
Conclusions. Motor coordination problems were reported in one third of children with ADHD and affected both boys and girls. These problems
were also apparent in adolescents with ADHD. Clinicians treating children with ADHD should pay attention to co-occurring motor
coordination problems because of the high prevalence and the negative impact of motor coordination problems on daily life
PDD symptoms in ADHD, an independent familial trait?
The aims of this study were to investigate whether subtle PDD symptoms in the context of ADHD are transmitted in families independent of ADHD, and whether PDD symptom familiality is influenced by gender and age. The sample consisted of 256 sibling pairs with at least one child with ADHD and 147 healthy controls, aged 5-19 years. Children who fulfilled criteria for autistic disorder were excluded. The Children's Social Behavior Questionnaire (CSBQ) was used to assess PDD symptoms. Probands, siblings, and controls were compared using analyses of variance. Sibling correlations were calculated for CSBQ scores after controlling for IQ, ADHD, and comorbid anxiety. In addition, we calculated cross-sibling cross-trait correlations. Both children with ADHD and their siblings had higher PDD levels than healthy controls. The sibling correlation was 0.28 for the CSBQ total scale, with the CSBQ stereotyped behavior subscale showing the strongest sibling correlation (r = 0.35). Sibling correlations remained similar in strength after controlling for IQ and ADHD, and were not confounded by comorbid anxiety. Sibling correlations were higher in female than in male probands. The social subscale showed stronger sibling correlations in elder than in younger sibling pairs. Cross-sibling cross-trait correlations for PDD and ADHD were weak and not-significant. The results confirm that children with ADHD have high levels of PDD symptoms, and further suggest that the familiality of subtle PDD symptoms in the context of ADHD is largely independent from ADHD familiality
Differential family and peer environmental factors are related to severity and comorbidity in childresn with ADHD
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70260.pdf (publisher's version ) (Closed access)Behavioral genetic studies imply that salient environmental influences operate within families, making siblings in a family different rather than similar. This study is the first one to examine differential sibling experiences (as measured with the Sibling Inventory of Differential Experience) and its effect on behavioral outcomes within ADHD families. Subjects were 45 Dutch ADHD probands and their unaffected siblings (n = 45) aged 10-18 years. ADHD probands and their unaffected siblings reported differences in sibling interaction, parental treatment, and peer characteristics. These nonshared environmental influences were related to both the severity of ADHD symptoms as well as to comorbid problem behaviors. These findings suggest that environmental influences that operate within ADHD families appear relevant to the severity of problem behaviors of ADHD children and their siblings
Effects of maternal and paternal smoking on attentional control in children with and without ADHD
Maternal smoking during pregnancy is a risk factor for attention-deficit/hyperactivity disorder (ADHD), but data on its adverse effects on cognitive functioning are sparse and inconsistent. Since the effect of maternal smoking during pregnancy may be due to correlated genetic risk factors rather than being a pure environmental effect, we examined the effect of prenatal exposure to smoking on attentional control, taking into account the effects of both maternal and paternal smoking, and examined whether these effects were genetically mediated by parental genotypes. We further examined whether the effect of prenatal exposure to smoking on attentional control interacted with genotypes of the child. Participants were 79 children with ADHD, ascertained for the International Multi-centre ADHD Gene project (IMAGE), and 105 normal controls. Attentional control was assessed by a visual continuous performance task. Three genetic risk factors for ADHD (DRD4 7-repeat allele of the exon 3 variable number of tandem repeats (VNTR), DAT1 10/10 genotype of the VNTR located in the 3′ untranslated region, and the DAT1 6/6 genotype of the intron 8 VNTR) were included in the analyses. Paternal smoking had a negative effect on attentional control in children with ADHD and this effect appeared to be mediated by genetic risk factors. The prenatal smoking effect did not interact with genotypes of the child. Maternal smoking had no main effect on attentional control, which may be due to lower smoking rates. This study suggests that the effects of paternal smoking on attentional control in children with ADHD should be considered a proxy for ADHD and/or smoking risk genes. Future studies should examine if the results can be generalized to other cognitive domains
Are motor inhibition and cognitive flexibility dead ends in ADHD?
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53518.pdf (publisher's version ) (Closed access)Executive dysfunction has been postulated as the core deficit in ADHD, although many deficits in lower order cognitive processes have also been identified. By obtaining an appropriate baseline of lower order cognitive functioning light may be shed on as to whether executive deficits result from problems in lower order and/or higher order cognitive processes. We examined motor inhibition and cognitive flexibility in relation to a baseline measure in 816 children from ADHD and control families. Multiple children in a family were tested in order to examine the familiality of the measures. No evidence was found for deficits in motor inhibition or cognitive flexibility in children with ADHD or their nonaffected siblings: Compared to their baseline speed and accuracy of responding, children with ADHD and their (non)affected siblings were not disproportionally slower or inaccurate when demands for motor inhibition or cognitive flexibility were added to the task. However, children with ADHD and their (non)affected siblings were overall less accurate than controls, which could not be attributed to differences in response speed. This suggests that inaccuracy of responding is characteristic of children having (a familial risk for) ADHD. Motor inhibition and cognitive flexibility as operationalized with mean reaction time were found to be familial. It is concluded that poorer performance on executive tasks in children with ADHD and their (non)affected siblings may result from deficiencies in lower order cognitive processes and not (only) from higher order cognitive processes/executive functions
Comorbid problems in ADHD: degree of association, shared endophenotypes, and formation of distinct subtypes: Implications for a future DSM
We aimed to assess which comorbid problems (oppositional defiant behaviors, anxiety, autistic traits, motor coordination problems, and reading problems) were most associated with Attention-Deficit/Hyperactivity Disorder (ADHD); to determine whether these comorbid problems shared executive and motor problems on an endophenotype level with ADHD; and to determine whether executive functioning (EF)-and motor-endophenotypes supported the hypothesis that ADHD with comorbid problems is a qualitatively different phenotype than ADHD without comorbid problems. An EF-and a motor-endophenotype were formed based on nine neuropsychological tasks administered to 816 children from ADHD-and control-families. Additional data on comorbid problems were gathered using questionnaires. Results indicated that oppositional defiant behaviors appeared the most important comorbid problems of ADHD, followed by autistic traits, and than followed by motor coordination problems, anxiety, and reading problems. Both the EF-and motor-endophenotype were correlated and cross-correlated in siblings to autistic traits, motor coordination problems and reading problems, suggesting ADHD and these comorbid problems may possibly share familial/genetic EF and motor deficits. No such results were found for oppositional defiant behaviors and anxiety. ADHD in co-occurrence with comorbid problems may not be best seen as a distinct subtype of ADHD, but further research is warranted
Speed, Variability, and Timing of Motor Output in ADHD: Which Measures are Useful for Endophenotypic Research?
Attention-Deficit/Hyperactivity Disorder (ADHD) shares a genetic basis with motor coordination problems and probably motor timing problems. In line with this, comparable problems in motor timing should be observed in first degree relatives and might, therefore, form a suitable endophenotypic candidate. This hypothesis was investigated in 238 ADHD-families (545 children) and 147 control-families (271 children). A motor timing task was administered, in which children had to produce a 1,000 ms interval. In addition to this task, two basic motor tasks were administered to examine speed and variability of motor output, when no timing component was required. Results indicated that variability in motor timing is a useful endophenotypic candidate: It was clearly associated with ADHD, it was also present in non-affected siblings, and it correlated within families. Accuracy (under- versus over-production) in motor timing appeared less useful: Even though accuracy was associated with ADHD (probands and affected siblings had a tendency to under-produce the 1,000 ms interval compared to controls), non-affected siblings did not differ from controls and sibling correlations were only marginally significant. Slow and variable motor output without timing component also appears present in ADHD, but not in non-affected siblings, suggesting these deficits not to be related to a familial vulnerability for ADHD. Deficits in motor timing could not be explained by deficits already present in basic motor output without a timing component. This suggests abnormalities in motor timing were predominantly related to deficient motor timing processes and not to general deficient motor functioning. The finding that deficits in motor timing run in ADHD-families suggests this to be a fruitful domain for further exploration in relation to the genetic underpinnings of ADHD
Electron paramagnetic resonance versus spin-dependent recombination: Excited triplet states of structural defects in irradiated silicon
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