Frontal lobe functioning in adolescents with attention deficit hyperactivity disorder

A prominent hypothesis regarding the etiology of attention deficit hyperactivity disorder (ADHD) is that its presence and magnitude reflect frontal lobe dysfunction. Past tests of this hypothesis have been inconsistent. The present study examined frontal lobe functioning in adolescents with ADHD. A sample of 10 ADHD adolescents and 10 controls between the ages of 12 and 17 served as participants for the study. The control group was matched on age (within six months) and gender. This study aided in clarifying past contradictory studies by using clearly defined criteria to determine ADHD, a representative age range of participants, carefully selected tests, and a control task. The two measures that were administered to assess frontal lobe functioning were the Wisconsin Card Sorting Test and the Stroop Color and Word Test. The Purdue Pegboard was used as a control measure that did not assess frontal lobe functioning. The findings indicate that the ADHD group performed significantly worse on the following: color score, color/word score, and interference score of the Stroop Color and Word Test; percent of perseverative responses, percent of perseverative errors, and number of completed categories of the Wisconsin Card Sorting Test. No differences were found on the Purdue Pegboard task.     

Trait Procrastination,Hoarding, and Continuous Performance Attention Scores

We examined the relationship between chronic procrastination, hoarding, attention deficit hyperactivity disorder (ADHD), and a computer measure of continuous performance with 84 adult patients evaluated for diagnoses. Patients were administered the General Procrastination Inventory, the Saving Inventory-Revised, the Adult ADHD Self-Report Scale and the IVA + Plus Continuous Performance Test. Procrastination scores correlated negatively with auditory attention scores, while self-reported hoarding tendencies correlated negatively with visual attention. Measures of procrastiation, hoarding, and ADHD were positively correlated. Implications and limitations of findings are discussed as well as directions for futher research.     

Effects of age on attention level: changes in performance between the ages of 12 and 90

ABSTRACT

The purpose of the present study was to assess the changes in attention level among individuals between the ages of 12 and 90 years. A cross-sectional design was used, with each participant tested once by means of the Mathematics Continuous Performance Test (MATH-CPT). Participants were 496 males and females who were divided into eight age-groups, with each group spanning a period of ten years. Attention level was assessed through comparison with nine variables assessing attention. As people aged, significant reductions in the quality of performance emerged on the five main measures of the MATH-CPT: Two of the four sustained attention variables showed an improvement with age. The peak attention level was in the 30 to a 40-age range, after that, there was a constant decline in the level of attention. The study offers encouraging results with respect to the effect of aging on cognitive functioning and specifically sustained attention.     

Inhibition, ADHD, and computer games: the inhibitory performance of children with ADHD on computerized tasks and games

Contrary to empirical reports of inhibitory dysfunction in ADHD, parental reports suggest that when playing computer games, the inhibitory abilities of children with ADHD are unimpaired. This small-scale preliminary investigation into this phenomenon looks at inhibition of an ongoing response and activity exhibited by children with ADHD between 6 and 14 years old on two commercially available games, on the Conners's Continuous Performance Test II (CPT II), and on a more game-like version of the same task that incorporates characteristics commonly found in commercially available computer games. The performance of participants with ADHD on commercially available games is equivalent to that of typically developing participants and is significantly better on the more game-like version of the CPT II.     

Does response variability predict distractibility among adults with attention-deficit/hyperactivity disorder?

Increased intraindividual variability in response time (RTSD) has been observed reliably in attention-deficit/hyperactivity disorder (ADHD) and has often been used as a measure of inattention. RTSD is assumed to reflect attentional lapses and distractibility, though evidence for the validity of this connection is lacking. We assessed whether RTSD is an indicator of inattention by comparing RTSD on the stop-signal task (SST) with performance on the delayed oculomotor response (DOR) task, a measure of distractibility. Participants included 30 adults with ADHD and 28 controls. Participants completed the SST and the DOR task, which measured subjects' ability to maintain attention and avoid distraction by inhibiting reflexive saccades toward distractors. On the SST, the ADHD group was slower to inhibit than were controls, indicating poorer inhibitory control in ADHD. The ADHD group also displayed slower reaction times (RTs), greater RTSD, and more omission errors. On the DOR task, the ADHD group displayed more premature saccades (i.e., greater distractibility) than did controls. Greater variability in RT was associated with increased distraction on the DOR task, but only in ADHD participants. Results suggest that RTSD is linked to distractibility among adults with ADHD and support the use of RTSD as a valid measure of inattention in ADHD.     

The Test of Everyday Attention for Children (TEA-Ch): patterns of performance in children with ADHD and clinical controls.

The present study explores the utility of the Test of Everyday Attention for Children (TEA-Ch) as a measure of the attentional impairments displayed by children with Attention Deficit Hyperactivity Disorder (ADHD). Sixty-three children with ADHD and 23 non-ADHD Clinical Control children were compared on subtests of the TEA-Ch reflecting three attentional domains: sustained, selective, and attentional control. Results show that children with ADHD performed significantly worse than clinical controls on subtests of sustained attention and attentional control. The groups did not differ, however, on subtests of selective attention. These findings suggest that the TEA-Ch is sensitive to attentional deficits unique to ADHD and holds promise as a useful tool in the assessment of ADHD. Performance patterns and future directions are discussed.     

Selective attention and inhibitory deficits in ADHD: Does subtype or comorbidity modulate negative priming effects?

Selective attention has durable consequences for behavior and neural activation. Negative priming (NP) effects are assumed to reflect a critical inhibitory component of selective attention. The performance of adolescents with Attention Deficit/Hyperactivity Disorder (ADHD) was assessed across two conceptually based NP tasks within a selective attention procedure. Comorbidity (non-comorbid ADHD vs. comorbid ADHD) and subtype (ADHD combined vs. ADHD inattentive) were considered key issues. Results found NP effects to differ as a function of comorbidity but not subtype. Findings are discussed in light of functional neuroimaging evidence for neuronal enhancement for unattended stimuli relative to attended stimuli that strongly complements an inhibitory-based explanation for NP. Implications for the ‘AD’ in ADHD and contemporary process models of the disorder are considered.     

Measuring impulsivity in adolescents with serious substance and conduct problems

Adolescents with substance use and conduct disorders have high rates of aggression and attention deficit hyperactivity disorder (ADHD), all of which have been characterized in part by impulsivity. Developing measures that capture impulsivity behaviorally and correlate with self-reported impulsivity has been difficult. One promising behavioral measure, however, is a variant of the continuous performance test, the Immediate Memory Test/Delayed Memory Test (IMT/DMT). The authors showed significant group differences between adolescents in treatment for serious substance and conduct problems and community controls on impulsivity measures, both behavioral and self-report, as well as on aggression and problem behavior measures. Furthermore, the IMT/DMT correlated significantly with self-reported impulsivity. In summary, the IMT/DMT may be an effective behavioral measure of impulsivity in adolescents.     

Computerized stroop test to assess selective attention in children with attention deficit hyperactivity disorder

Research shows abnormal function of the pre-frontal cortex in Attention Deficit Hyperactivity Disorder (ADHD). This cortex is involved in the control of executive functions related to planning and execution of goal-oriented strategies, working memory, inhibitions, cognitive flexibility, and selective attention. Selective attention involves focus on the target stimulus, ignoring competing distractions. The Stroop Test (Stroop, 1935) is usually used to evaluate selective attention. This study investigated whether children with ADHD could exhibit modified performance in the Stroop Test. Using a computerized version of this test (Capovilla, Montiel, Macedo, & Charin, 2005), the study compared the reaction times (RTs) of 62 Brazilian children, between 8 and 12 years of age, 31 of whom were diagnosed with ADHD and sent to psychiatric clinics, and 31 without ADHD studying in regular schools. All children with ADHD satisfied the criteria of the DSM-IV-TR and were evaluated with the Conners Abbreviated Questionnaire (Goyette, Conners, & Ulrich, 1978), completed by parents and teachers. The results revealed that children with ADHD exhibit greater interference in RT than children without ADHD. This corroborated the hypothesis that children with ADHD exhibit a deficit in selective attention, consisting in augmented RTs, as measured by the Computerized Stroop Test.     

Autism and attention deficit hyperactivity disorder: assessing attention and response control with the integrated visual and auditory continuous performance test.

Symptoms of attention deficit hyperactivity disorder (ADHD) have been widely reported in children with autism spectrum disorder (ASD). The current study investigated attention and response control in children with ASD, ADHD, and typical development using the Integrated Visual and Auditory Continuous Performance Test. Results indicate that many children with ASD show significant deficits in visual and auditory attention and greater deficits in impulsivity than children with ADHD or typical development. These findings suggest that many of the children with ASD demonstrate significant ADHD-like deficits. These findings are discussed in the context of symptoms, subtypes, and comorbidity.     

A controlled clinical comparison of attention performance in children with ADHD in a virtual reality classroom compared to standard neuropsychological methods.

In this initial pilot study, a controlled clinical comparison was made of attention perforance in children with attention deficit-hyperactivity disorder (ADHD) in a virtual reality (VR) classroom. Ten boys diagnosed with ADHD and ten normal control boys participated in the study. Groups did not significantly differ in mean age, grade level, ethnicity, or handedness. No participants reported simulator sickness following VR exposure. Children with ADHD exhibited more omission errors, commission errors, and overall body movement than normal control children in the VR classroom. Children with ADHD were more impacted by distraction in the VR classroom. VR classroom measures were correlated with traditional ADHD assessment tools and the flatscreen CPT. Of note, the small sample size incorporated in each group and higher WISC-III scores of normal controls might have some bearing on the overall interpretation of results. These data suggested that the Virtual Classroom had good potential for controlled performance assessment within an ecologically valid environment and appeared to parse out significant effects due to the presence of distraction stimuli.     

Exploring the dynamics of design fluency in children with and without ADHD using artificial neural networks

The neuropsychology of attention deficit/hyperactivity disorder (ADHD) has been extensively studied, with a general focus on global performance measures of executive function. In this study, we compared how global (i.e., endpoint) versus process (i.e., dynamic) measures of performance may help characterize children with and without ADHD using a design fluency task as a case study. The secondary goal was to compare the sensitivity of standard versus connectionist statistical models to group differences in cognitive data. Thirty-four children diagnosed with ADHD and 37 children without ADHD aged 8–11 years old were tested on the Five-Point Test. The continuous process measure of performance, indexed as the number of produced designs at each consecutive 1 minute interval during 5 minutes, was analyzed against the discrete process measure, that is, the number of designs between first and last intervals and the standard global performance measure of total number of produced designs. Results show that the continuous process measure distinguished the two groups better than the two other measures. The detailed observation of production patterns revealed a decreasing linear trajectory in children without ADHD that contrasts with the flat, but fluctuating productivity pattern of children with ADHD. With regards to the second goal, results show that the connectionist and standard methods are equally sensitive to group differences for the three types of measures. This illustrates the utility of quantitative process measures together with the connectionist method in neuropsychological research and suggests great potential for a dynamical approach to cognition.     

Processing affective stimuli in children with attention-deficit hyperactivity disorder.

Neuropsychological investigations have suggested a contribution of right hemisphere dysfunction in attention-deficit hyperactivity disorder (ADHD). Right hemisphere dysfunction has been implicated in deficits of attention, motor impersistence, and processing emotion-laden stimuli. The current study investigated the ability of ADHD children to perceive emotional stimuli in the form of facial expressions and speech intonation. The subjects consisted of 37 ADHD and 37 control children aged 7 to 12 years. ANCOVA analysis indicated that ADHD children demonstrate mild-to-moderate deficits in the perception of affect. Furthermore, deficits in attention may contribute to inaccurate or incomplete encoding of stimulus properties. The results lend tentative support for the notion that the right cerebral hemisphere may play a critical role in ADHD.     

Interference and negative priming effects in adolescents with attention deficit hyperactivity disorder

Three visual selective attention tasks were used to measure potential differences in susceptibility to interference and inhibitory cognitive control processes in 16 adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) and 45 similar-aged controls. Susceptibility to interference was assessed using the Stroop color and word naming test. Efficiency of distractor inhibition was assessed in two conceptual negative priming tasks. The majority of studies in this area indicate that people with ADHD demonstrate higher levels of interference and lower negative priming effects in comparison with age-matched peers. However, we found that although the ADHD group was consistently slower to name target stimuli than the control group, there were no differences in interference or negative priming between the two groups.     

Stimulus-dependent dopamine release in attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is related to an attenuated and dysfunctional dopamine system. Normally, a high extracellular dopamine level yields a tonic dopaminergic input that down-regulates stimuli-evoked phasic dopamine responses through autoreceptors. Abnormally low tonic extracellular dopamine in ADHD up-regulates the autoreceptors so that stimuli-evoked phasic dopamine is boosted. The authors propose that these boosted phasic responses yield hypersensitivity to environmental stimuli in ADHD. Stimuli evoking moderate brain arousal lead to well-functioning performance, whereas either too little or too much stimuli attenuate cognitive performance. Strong, salient stimuli may easily disrupt attention, whereas an environment with impoverished stimuli causes low arousal, which is typically compensated for by hyperactivity. Stochastic resonance is the phenomenon that makes a moderate noise facilitate stimulus discrimination and cognitive performance. Computational modeling shows that more noise is required for stochastic resonance to occur in dopamine-deprived neural systems in ADHD. This prediction is supported by empirical data.     

Inattentional blindness for a noxious multimodal stimulus

Previous research has shown that people can miss salient stimuli outside the focus of their attention. This phenomenon, called inattentional blindness, typically is observed when people are given a task requiring them to focus their attention on one aspect of a complex visual scene. While participants are doing this task, an unexpected stimulus appears, and participants' awareness of it is tested shortly thereafter. In the present experiments, noxious bimodal stimuli were used as a test case to measure the strength of inattentional blindness. We tested whether participants would notice a person enter a scene and scratch her fingernails down a chalkboard (thus making a sound called a "gride"). A large proportion of participants failed to detect this event even when the noxious audio associated with it was strengthened and isolated in time from surrounding noises.     

Perceptual asymmetries in normal children and children with attention deficit/hyperactivity disorder

Perceptual asymmetries in normal right-handed children (7-12 years of age) and children with attention deficit/hyperactivity disorder (ADHD), combined type, were investigated using various chimeric stimuli in free-viewing conditions. In the face-matching task, participants indicated which of two symmetrical face chimeras more closely resembled the original; in the chimeric faces task, participants indicated which of a pair of faces appeared happier; and in the grey scales task participants indicated which of two shaded rectangles appeared to be darker overall. Leftward biases were found for normal children with no effects of age. Contrary to expectations, normal leftward biases were also found for ADHD children in the face-matching and the chimeric faces tasks; however, a significant leftward bias was not observed in the grey scales task. The absence of anomalous perceptual bias in ADHD children on these purely perceptual tasks, suggests that anomalous perceptual asymmetries observed in other tasks (line bisection and cancellation tasks) may have been confounded by the motor response, and/or the explicit spatial components of those tasks.     

Faking of the Implicit Association Test Is Statistically Detectable and Partly Correctable

Male and female participants were instructed to produce an altered response pattern on an Implicit Association Test measure of gender identity by slowing performance in trials requiring the same response to stimuli designating own gender and self. Participants' faking success was found to be predictable by a measure of slowing relative to unfaked performances. This combined task slowing (CTS) indicator was then applied in reanalyses of three experiments from other laboratories, two involving instructed faking and one involving possibly motivated faking. Across all studies involving instructed faking, CTS correctly classified 75% of intentionally faking participants. Using the CTS index to adjust faked Implicit Association Test scores increased the correlation of CTS-adjusted measures with known group membership, relative to unadjusted (i.e., faked) measures.     

Quantitative EEG Assessment During Neuropsychological Task Performance in Adults with Attention Deficit Hyperactivity Disorder

This study evaluated the neuropsychological performance of adults with and without Attention Deficit Hyperactivity Disorder (ADHD) during the Paced Auditory Serial Addition Test (PASAT), Wisconsin Card Sorting Test: Computerized Version 3 (WCST), and the Integrated Visual and Auditory Continuous Performance Test (IVA). Quantitative electroencephalographic (QEEG) data were also collected during task performance to examine differences in cortical activity between groups and tasks. Results suggest that adults with ADHD demonstrated lower levels of performance on the PASAT and IVA, tasks that involve working memory and processing speed, and sustained attention, respectively. Adults with ADHD also had more upper alpha activity during the IVA. Lastly, for the ADHD group, an increased theta/beta ratio during the IVA was significantly related to poorer attentional performance. The current results support reinforcing specific types of cortical activity though EEG operant conditioning (neurofeedback) as a treatment option in adults with ADHD. This paper is based largely in part on a dissertation by J. Noland White in partial fulfillment of the requirements of his doctoral program at The University of Tennessee. Portions of this study have been presented in summary form at several professional conferences.