Impulsive Responses In Children with Conduct Disorder and Borderline Intellectual Functioning

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual “go” signal is presented on the screen. In a second condition the “go” signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the “go” signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

Are Sensation Seeking and Emotion Processing Related to or Distinct from Cognitive Control in Children with ADHD?

This study evaluated the relationship of (a) reactive inhibition and right-lateralized emotion processing to each other and (b) to executive control of response suppression, and (c) with regard to ADHD in 134 children ages 7–12 years. Reactive inhibition was indexed by child ratings of sensation seeking on the Sensation Seeking Scales, executive control by the Stop Signal Task, emotion processing by performance on the Chimeric Faces Test, and ADHD by parent- and teacher-reported symptoms. The results were consistent with a two-process model in which executive control, conceived as a right-hemisphere lateralized function, was distinct from sensation seeking and lateralized emotion processing. Supporting this distinction, ADHD was associated with executive control, but not with sensation seeking/reactive inhibition or lateralized emotion processing. The findings suggest that ADHD cannot be understood as a global right-lateralized neuropsychological weakness, but rather that it involves only particular functions that may be right lateralized. Findings further suggest that risk for comorbid disorders in ADHD (e.g., conduct disorder or mood disorders) may increase as a function of independent factors such as temperament. Mechanisms underlying executive inhibition and emotional processing could be functionally independent yet interact to multiply psychopathological risk in some children (leading, for example, to comorbid disorders).     

Differences in cognitive control in children and adolescents with combined and inattentive subtypes of ADHD

The aim of the present study was to investigate the ability of children with attention deficit/hyperactivity disorder-combined subtype (ADHD-C) and predominantly inattentive subtype (ADHD-PI) to direct their attention and to exert cognitive control in a forced attention dichotic listening (DL) task. Twenty-nine, medication-naive participants with ADHD-C, 42 with ADHD-PI, and 40 matched healthy controls (HC) between 9 and 16 years were assessed. In the DL task, two different auditory stimuli (syllables) are presented simultaneously, one in each ear. The participants are asked to report the syllable they hear on each trial with no instruction on focus of attention or to explicitly focus attention and to report either the right- or left-ear syllable. The DL procedure is presumed to reflect different cognitive processes: perception (nonforced condition/NF), attention (forced-right condition/FR), and cognitive control (forced-left condition/FL). As expected, all three groups had normal perception and attention. The children and adolescents with ADHD-PI showed a significant right-ear advantage also during the FL condition, while the children and adolescents in the ADHD-C group showed a no-ear advantage and the HC showed a significant left-ear advantage in the FL condition. This suggests that the ADHD subtypes differ in degree of cognitive control impairment. Our results may have implications for further conceptualization, diagnostics, and treatment of ADHD subtypes.     

Very Low Birth Weight and Attention Deficit/Hyperactivity Disorder

It is well recognized that reaction time performance of term-born children with a normal birth weight (NBW > 2500 g) who fulfill the DSM-IV criteria for attention deficit/hyperactivity disorder (ADHD) in the primary school age is sensitive for the presentation rate of stimuli. They have been found to perform more poorly in conditions of relatively slow event rates as compared with fast event rates. The purpose of the current study was to explore whether reaction time performance of children with very low birth weight (VLBW < 1500 g) with or without ADHD showed the same sensitivity for the factor presentation rate of stimuli compared to children with a normal birth weight plus ADHD. To this end, reaction time performance of four groups of children was compared on a Go/No-Go test with a fast presentation rate of 1 second and a slow presentation rate of 6 seconds. Groups were: children with VLBW plus ADHD, children with VLBW only, children born full term with normal birth weight (NBW >2500 g) plus ADHD, and children born full term without ADHD (the control group). Findings indicated that, compared to the non-ADHD groups, the groups with ADHD (NBW and VLBW) showed a more dramatic decline in their reaction time performance in the slow condition: a state regulation deficit. In addition, both groups showed a response inhibition deficit. No difference was found in reaction time performance between the groups of children with VLBW only and the control group.     

Conners’ continuous performance test (CCPT-II) in children with ADHD,ODD, or a combined ADHD/ODD diagnosis

The current study investigated if results on the Conners’ Continuous Performance Test (CCPT-II) could discriminate between children with ADHD (n = 59), ODD (n = 10), ADHD+ODD (n = 15), and normal controls (n =160), and how the results are associated with and explained by the intellectual function of the child. The sample was derived from the Bergen Child Study (BCS), a longitudinal, ongoing, population-based study of children’s development and mental health. CCPT-II performance did not differentiate between the three diagnostic groups (i.e., ADHD, ODD, and ADHD+ODD). Children with ODD (with or without comorbid ADHD) did not differ from children in the control group on any CCPT-II parameters. Children with ADHD made statistically significant more errors of omissions and showed a more variable response time to targets than the control group. The correlations between CCPT-II measures and IQ were mild to moderate, and there was a statistically significant group difference in IQ: Children with ADHD, and children with ADHD+ODD, obtained lower IQ scores than normal controls. A hierarchical multiple regression analysis showed that IQ, but not diagnostic group status, was significant predictors of CCPT-II performance. CCPT-II performance should be interpreted with caution when assessing ADHD and/or ODD in children.     

Preliminary evidence for reduced posterror reaction time slowing in hyperactive/inattentive preschool children

Background: Attention deficit/hyperactivity disorder (ADHD) has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in posterror slowing. Method: A computerized two-choice RT task was administered to an ethnically diverse sample of preschool-aged children classified as either “control” (n = 120) or “hyperactive/inattentive” (HI; n = 148) using parent- and teacher-rated ADHD symptoms. Analyses were conducted to determine whether HI preschoolers exhibit a deficit in this self-regulatory ability. Results: HI children exhibited reduced posterror slowing relative to controls on the trials selected for analysis. Supplementary analyses indicated that this may have been due to a reduced proportion of trials following errors on which HI children slowed rather than due to a reduction in the absolute magnitude of slowing on all trials following errors. Conclusions: High levels of ADHD symptoms in preschoolers may be associated with a deficit in error processing as indicated by posterror slowing. The results of supplementary analyses suggest that this deficit is perhaps more a result of failures to perceive errors than of difficulties with executive control.     

Neuropsychological Deficits in Relation to Symptoms of ADHD: Independent Contributions and Interactions

Twelve children with and without Down syndrome (DS) performed eight subtests of an apraxia battery to determine under what conditions children with DS had difficulty performing representational and nonrepresentational gestures. Participants with DS also completed a dichotic listening test. Participants with DS performed just as well as control participants on all aspects of the apraxia battery except a subtest in which they were required to pantomime tool use from verbal instruction. This suggests that children with DS have difficulty generating an action from memory following verbal instruction. Given the sufficient context or visual demonstration, children with DS performed similar to the other participants. As well, there was a great deal of within-group variability for dichotic listening ear advantage. Participants with a greater left ear advantage on the dichotic listening test committed more errors on an imitation test that also included a verbal component than participants with a greater right ear advantage.     

Attention and Executive Function Deficits in Adolescent Sex Offenders

Thirty male adolescent sex offenders and 20 age-matched male adolescents completed an extensive battery of attention and executive function tests. Controls were obtained from adolescents from a socially and economically deprived background, typical of the offending group. The attention battery was based on Mirksy, Anthony, Duncan, Ahearn, and Kellam (1991) and the executive function battery on Kelly (2000a). Successful matching for IQ was not achieved and therefore ANCOVA comparisons were made between the groups, with IQ as the covariate. In attention a highly significant difference was found on the focus-execute factor and a significant difference on the shift factor. In executive function there was a highly significant difference only on the response speed factor. In all cases better abilities were demonstrated by the control group. The importance of thorough neuropsychological investigation in the clinical assessment of this forensic group is supported. The clinical implications of neuropsychological deficits in terms of risk assessment and clinical management are discussed.     

Latent Inhibition and Asymmetrical Visual-Spatial Attention in Children with ADHD

The research was designed to determine whether the purported hemispheric asymmetries that are associated with attention deficit/hyperactivity disorder (ADHD) affect performance on a selective attention visual search task, and whether any obtained asymmetry will be modulated by methylphenidate. Two groups of children (8–15 years) with ADHD, one with methylphenidate treatment (ADHD+) and one without (ADHD+), were compared to matched controls on a two-stage visual search task. The task assessed right–left visual field asymmetries and the effects of changing a previous distractor into a target. Such a procedure, related to latent inhibition (LI; poorer performance to a previously irrelevant stimulus than to a novel one), can provide evidence for dysfunctional processing of irrelevant stimuli. All three groups exhibited the LI effect. The ADHD group, however, exhibited less LI for left- than right-side targets, an effect absent in the control and ADHD+ groups, suggesting a lateralized attentional deficit for ADHD+ that was normalized by methylphenidate.     

Do ADHD and Executive Dysfunctions,Measured by the Hebrew Version of Behavioral Rating Inventory of Executive Functions (BRIEF), Completely Overlap?

The centrality of executive function deficits (EFD) in attention deficit/ hyperactivity disorder (ADHD) is well accepted albeit EFD is not synonymous with ADHD. The purpose of the present study was to examine the extent to which ADHD and EF overlap and to validate the Hebrew version of the Behavioral Rating Inventory of Executive Functions (BRIEF). Parents of 178 children with and without ADHD completed the BRIEF and the ADHD-Rating Scale. Significant differences were found between groups on each scale even after controlling for the other scale. Internal consistency analysis supported the reliability of the Hebrew version of the BRIEF. We conclude that ADHD and Executive Dysfunctions do not completely overlap.