Biomedical subjects

Aryan van der Leij

Publications and source records attributed to Aryan van der Leij.

6 recordsLinked to original sources

PubMed2006

Efficiency of visual information processing in children at-risk for dyslexia: habituation of single-trial ERPs.

To investigate underlying learning mechanisms in relation to the development of dyslexia, event-related potentials to visual standards were recorded in five-year-old pre-reading children at-risk for familial dyslexia (n=24) and their controls (n=14). At the end of second grade the children aged 8 years were regrouped into three groups according to literacy level and risk factor. Single-trial analyses revealed N1 habituation in the normal-reading controls, but not in the normal-reading at-risks, and a N1 amplitude increase in the group of poor-reading at-risks and poor-reading controls. No P3 habituation was found in either group. The normal-reading at-risk group exhibited the longest N1 and P3 latencies, possibly compensating for their reduced neuronal activity during initial information extraction. In contrast, the poor-reading group only showed prolonged P3, and their increase in (initial small) N1 amplitude together with normal N1 latencies, suggests inefficient processing in an early time window, which might explain automatisation difficulties in dyslexic readers.

Brain↗

PubMed2006

Mismatch response is absent in 2-month-old infants at risk for dyslexia.

This study examined auditory processing in 2-month-old infants at genetic risk for dyslexia and in controls. Manipulated natural speech stimuli (/bAk/ and /dAk/), at either side of the phoneme boundary, were presented to these infants and their automatic cortical deviance responses were recorded. Control infants showed two distinct mismatch responses, thus extending similar findings reported with kindergartners in terms of topographical distribution and cortical sources. The absence of such mismatch responses in the infants at risk supports the hypothesis of basic auditory (temporal) processing impairments in the disorder. The results suggest that these early signs of deficient auditory processing may point to problematic categorical perception at a later age.

Acoustic Stimulation↗

PubMed2006

Treatment integrity in a home-based pre-reading intervention programme.

Treatment integrity is an underexposed issue in the phonological awareness intervention research. The current study assessed the integrity of treatment of the families (N = 32) participating in the experimental condition of a home-based pre-reading intervention study. The participating kindergartners were all genetically at risk for developing dyslexia. Two aspects of treatment integrity, the number of lessons completed (quantity) and the quality of the administration of the programme (observed in a videotaped session), were investigated. The level of treatment integrity turned out to be 66% when completion of all lessons was taken as quantitative criterion, and about 74% when quality of the parent-child interaction was assessed. The two measures could predict the pre-reading skills at the end of kindergarten. Together they accounted for 43% of the variance in this dependent variable. Together with pre-reading scores at the pre-test the total predicted variance was 87%. The number of lessons completed still contributed 12% to the prediction after controlling for pre-test scores. The results indicated that treatment integrity indeed appears to be an important aspect of treatment outcome and should therefore be included in intervention studies.

Dyslexia↗

PubMed2004

Inhibition and shifting in children with learning deficits in arithmetic and reading.

The executive functions of inhibition and shifting were studied in arithmetic-disabled children, reading-disabled children, reading plus arithmetic-disabled children, and controls (N = 74). Measures involved the rapid naming of objects, digits, letters, or quantities with or without additional task requirements that reflected inhibition or shifting. Also, the Making Trails task, reflecting shifting, was administered. For tasks without executive demands, arithmetic-disabled children were slower in the naming of digits and quantities, whereas reading-disabled children were slower in the naming of digits and letters. For the executive tasks, arithmetic-disabled children as well as reading plus arithmetic-disabled children were impaired on the Making Trails task and on an object naming task that required both inhibition and shifting. Reading-disabled children exhibited no problems in executive functioning. Furthermore, it was shown that reading plus arithmetic-disabled children experienced the combination of problems that characterize children with a single learning deficit.

Child↗

PubMed2004

Internalizing behaviors among kindergarten children: measuring dimensions of social withdrawal with a checklist.

Three studies examined whether different types of withdrawal among young children could be assessed with a short checklist. In Study 1, kindergarten teachers rated 487 children on a modified version of the Behavior Questionnaire for Two- to Six-Year-Olds (BQTSYO). Exploratory factor analyses yielded 2 withdrawal factors, Social Inhibition and Solitary Behavior, and a factor of Emotional Dysregulation. In Study 2, an adjusted version of the checklist was completed for 858 kindergartners. The 3 factors of Social Inhibition, Solitary Behavior, and Emotional Dysregulation were identified in one half of the sample and confirmed in the other. They could be measured with 3 internally consistent scales. No gender differences were found on the scales. Their content validity was supported by unique associations with teachers' free descriptions of children's behaviors in Study 3. Results suggest that the instrument is adequate for the assessment of different types of withdrawal.

Adult↗

PubMedDate not supplied

Working memory in Dutch children with reading- and arithmetic-related LD.

The aim of the two studies presented in this article was to examine working memory performance in Dutch children with various subtypes of learning disabilities. The performance of children with reading disabilities (RD) was compared to that of children with arithmetic disabilities (AD), children with both reading and arithmetic disabilities (RAD), and chronological age-matched controls (CA). Measures covered the phonological loop, the visuospatial sketchpad, and the central executive. In both studies, the children with RD showed no working memory deficits whatsoever. Children with AD showed a single impairment on the task tapping working memory for dynamic visual information. Children with RAD performed lower only on the digit span backward task. The failure to replicate the expected working memory deficits in children with reading-related disabilities is discussed.

Child↗