Interference control, working memory, concept shifting, and verbal fluency in adults with attention-deficit/hyperactivity disorder (ADHD)

In this study, the authors aimed to examine 4 domains of executive functioning in adults with attention-deficit/hyperactivity disorder (ADHD)-namely interference control, concept shifting, verbal fluency, and verbal working memory. Four groups of participants were included: (a) adults diagnosed with ADHD (ADHD(-): n = 20), (b) adults diagnosed with both ADHD and 1 or more comorbid disorder(s) (ADHD(+): n = 22), (c) adults referred for ADHD because of ADHD symptomatology but not diagnosed as such (non-ADHD; n = 34), and (d) healthy controls (n = 136). ADHD-related deficits (independent of comorbidity) were revealed for concept shifting and verbal working memory. In addition. the ADHD(+) and non-ADHD groups displayed deficits in terms of general processing speed. Given that these deficits were not found in the ADHD(-) group, the authors contend that these deficits are likely attributable to comorbidity rather than ADHD itself. Contrary to the authors' expectations, these findings do not correspond with the cognitive subtype hypothesis

Age-related improvement in complex language comprehension: Results of a cross-sectional study with 361 children aged 5 to 15

We investigated age-related improvement in speed and accuracy of complex language comprehension with 361 children attending kindergarten and the 2nd, 4th, 6th, 7th, and 8th grades. Language comprehension was measured using both the neuropsychological procedure proposed by Luria (1966, 1980) and an adapted version of the Token Test. Levels of short-term memory and verbal intelligence were controlled for in the evaluation of language comprehension. The findings show that the accuracy of language comprehension continued to develop until the 6th grade, whereas the speed of language comprehension continued to improve up until the 7th grade. We thus conclude that the complex language comprehension of children is not fully developed until early adolescence. We further contend that the speed of complex language comprehension appears to be more sensitive than accuracy with respect to measuring developmental differences

Low- and high-level controlled processing in executive motor control tasks in 5-6-year-old children at risk of ADHD

Low- and high-level controlled processing in executive motor control tasks in 5-6-year-old children at risk of ADHD. Kalff AC, de Sonneville LM, Hurks PP, Hendriksen JG, Kroes M, Feron FJ, Steyaert J, van Zeben TM, Vles JS, Jolles J. Department of Psychiatry and Neuropsychology, University of Maastricht, The Netherlands. [email protected] BACKGROUND: The scant research on the characteristics of Attention-Deficit/Hyperactivity Disorder (ADHD) in kindergarten years curtails progress on early assessment of ADHD. METHOD: By screening a general population sample of 1317 five- to six-year-old children, four groups of children were selected. The performance of 30 children later diagnosed with ADHD was compared with 74 children later diagnosed with 'borderline ADHD' (children exhibiting all ADHD symptoms but without disruptions on two situations), 113 children later diagnosed with other psychopathology, and 126 healthy controls on computerised motor control tasks involving low- and high-level controlled processing. In addition, motor control was compared with movement speed. RESULTS: The children at risk of ADHD were in general less accurate and more variable in their movements than the children with other psychopathology and healthy controls. Under conditions of high-level controlled processing, the children at risk of ADHD were disproportionately more inaccurate and had a more unstable performance with their preferred hand than the other children. In addition, linear effects were found, with the children at risk of ADHD having the worst performance, followed by the children with 'borderline ADHD', and then both groups of control children. No significant group differences were found in movement speed. CONCLUSIONS: The main findings are interpreted as evidence for a specific deficit in high-level controlled processing in young children at risk of ADHD, now found in a motor task, rather than a response task. Furthermore, the results support the notion that ADHD represents a dimensional trait. In addition, problems in movement control (the need to allocate attentional capacity) rather than problems in movement speed distinguish children at risk of ADHD from other children. The findings are interpreted as evidence that higher-order executive processes, such as self-control and self-r

Does Instruction in Semantic Clustering and Switching Enhance Verbal Fluency in Children?

This study investigated (1) test-retest reliabilities of Verbal Fluency (VF) outcome measures (i.e., word productivity, clustering, and switching) and (2) the effects of a brief training on semantic clustering to improve performance on a VF task. A total of 81 children enrolled in grades 3-6 completed a traditional VF task twice. In between task administrations half of the children were given instruction on using semantic clustering and switching to improve their VF, while the other half served as a control group. Test-retest reliability coefficients of the control group (N = 40) were substantial for "word productivity over 60 seconds" (riccs varied between 0.45 and 0.64) but only moderate for "clustering" (0.31) and "switching" (0.31). Next only the older children improved on VF after instruction on semantic clustering; the younger children appeared to understand the instruction but had to use up a great deal of cognitive load trying to implement this new strategy. This paper describes (1) the impact of strategy instruction on performance and (2) the need to analyze, at a process level, multifactorial tasks, so as to gain a better understanding of their functional components