| 1. |
- Brocki, Karin C., et al.
(author)
-
Early concurrent and longitudinal symptoms of ADHD and ODD : Relations to different types of inhibitory control and working memory
- 2007
-
In: Journal of Child Psychology and Psychiatry. - : Wiley. - 0021-9630 .- 1469-7610. ; 48:10, s. 1033-1041
-
Journal article (peer-reviewed)abstract
- Background: The aim of the present study was to investigate how three different types of inhibitory control - interference control within task, interference control outside task, and prepotent response inhibition - and two types of working memory - verbal and spatial - would relate to early symptoms of attention deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD), both concurrently and longitudinally. Methods: Seventy-two preschoolers, 1/3 who had been identified as being at risk for developing ADHD and/or ODD, completed neuropsychological tasks designed to measure inhibitory control and working memory. Behavioral symptoms were measured through parental and teacher ratings of the DSM-IV criteria for ADHD and ODD. Results: Our results suggest distinct types of inhibitory control as being good predictors of concurrent and longitudinal symptoms of ADHD, rather than ODD. However, no associations were obtained between working memory and ADHD or ODD symptoms either concurrently or longitudinally. Conclusions: This study emphasizes the need to isolate complex executive processes and break them down into components in order to properly understand the neuropsychological roots involved in ADHD and ODD.
|
|
| 2. |
- Brocki, Karin C., et al.
(author)
-
Working memory in school-aged children with attention-deficit/hyperactivity disorder combined type : Are deficits modality specific and are they independent of impaired inhibitory control?
- 2008
-
In: Journal of Clinical and Experimental Neuropsychology. - : Informa UK Limited. - 1380-3395 .- 1744-411X. ; 30:7, s. 749-759
-
Journal article (peer-reviewed)abstract
- This study examines differences between children with attention-deficit/ hyperactivity disorder combined type (ADHD-C) and normal controls on verbal and visuospatial working-memory (WM) tasks. The extent to which WM deficits in children with ADHD-C are independent of impaired inhibitory control was also examined. Two groups of 7- to 12-year-old boys participated in this study. The first group included 31 boys diagnosed with ADHD-C, and the second group included 34 boys without ADHD. Various verbal and visuospatial WM tasks and two inhibitory control tasksprepotent response inhibition and interference controlwere used. Overall, our results suggest impaired verbal and visuospatial WM processes in children with ADHD-C, as well as a lower level of performance on prepotent response inhibition. WM deficits in ADHD have previously been suggested to be particularly salient in the spatial domain, our results instead showed the largest effect for a verbal WM task thought to put heavy load on the executive or attentional control component of the WM system. An interpretation of this finding is that it is variation in terms of difficulty level or load on the executive WM processes, rather than variation in modality (verbal versus visuospatial), that is important in demonstrating WM deficits in ADHD-C. Finally, findings from logistic regression analyses showed that deficits in WM and inhibitory control seem to be semi-independent in children with ADHD-C, at least with regard to the elementary school age.
|
|
| 3. |
- Tillman, Carin M., et al.
(author)
-
Motor Response Inhibition and Execution in the Stop-Signal Task : Development and Relation to ADHD Behaviors
- 2008
-
In: Child Neuropsychology. - : Informa UK Limited. - 0929-7049 .- 1744-4136. ; 14:1, s. 42-59
-
Journal article (peer-reviewed)abstract
- The main aim of this study was to investigate the developmental course of motor response inhibition and execution as measured by the stop-signal task in a population-based sample of 525 4- to 12-year-olds. A further aspiration of the study was to enhance the limited knowledge on how the various stop-signal measures relate to ADHD behaviors in a normal sample. We also wanted to contribute to the theoretical understanding of the various stop-signal measures by examining the relations between the stop-signal measures and performance on tasks reflecting other aspects of response inhibition and execution. Our results showed that the ability to inhibit as well as to execute a motor response as measured by the stop-signal task improved with age during childhood. Of specific interest are the findings suggesting that this task captures the development of motor response inhibition in the late preschool years (age 5 years). Both of the inhibition measures derived from the stop-signal task (i.e., SSRT and probability of inhibition) related significantly to teacher ratings of inattention as well as to performance on tasks tapping other aspects of inhibition. The data provided by this study have thus contributed to the scarce knowledge on early development of motor response inhibition, as well as suggested that the stop-signal task may be a valuable tool for capturing deficient motor response inhibition in ADHD behaviors in normal samples.
|
|
