Sustained attention and response inhibition in young children at risk for Attention Deficit/Hyperactivity Disorder

Cross-modal conflict deficit in children with attention-deficit/hyperactivity disorder

The difference between the audiovisual incongruent condition and the audiovisual congruent condition is known as cross-modal conflict, which is an important behavioral index to measure the conflict control function. Previous studies have found conflict control deficits in children with attention-deficit/hyperactivity disorder (ADHD), but it is not clear whether and how cross-modal conflict occurs in children with ADHD at different processing levels. The current study adopted the cross-modal matching paradigm to recruit 25 children with ADHD (19 boys and 6 girls) and 24 TD children (17 boys and 7 girls), aiming to investigate the cross-modal conflict effect at the perception and response levels of children with ADHD. The results showed that both groups of children showed significant cross-modal conflict, and there was no significant difference between the ADHD and TD groups in the number of error trials and mean response time. However, the cross-modal conflict effect caused by auditory distractors was different between the ADHD and TD groups; the TD group had stronger auditory conflict at the response level, whereas the ADHD group had weaker auditory conflict. This indicates that the ADHD group had a deficit of auditory conflict at the response level.

Enhancement of visual dominance effects at the response level in children with attention-deficit/hyperactivity disorder

Previous studies have widely demonstrated that individuals with attention-deficit/hyperactivity disorder (ADHD) exhibit deficits in conflict control tasks. However, there is limited evidence regarding the performance of children with ADHD in cross-modal conflict processing tasks. The current study aimed to investigate whether children with ADHD have poor conflict control, which has an impact on sensory dominance effects at different levels of information processing under the influence of visual similarity. A total of 82 children aged 7 to 14 years, including 41 children with ADHD and 41 age- and sex-matched typically developing (TD) children, were recruited. We used the 2:1 mapping paradigm to separate levels of conflict, and the congruency of the audiovisual stimuli was divided into three conditions. In C trials, the target stimulus and the distractor stimulus were identical, and the bimodal stimuli corresponded to the same response keys. In PRIC trials, the distractor stimulus differed from the target stimulus and did not correspond to any response keys. In RIC trials, the distractor stimulus differed from the target stimulus, and the bimodal stimuli corresponded to different response keys. Therefore, we explicitly differentiated cross-modal conflict into a preresponse level (PRIC > C), corresponding to the encoding process, and a response level (RIC > PRIC), corresponding to the response selection process. Our results suggested that auditory distractors caused more interference during visual processing than visual distractors caused during auditory processing (i.e., typical auditory dominance) at the preresponse level regardless of group. However, visual dominance effects were observed in the ADHD group, whereas no visual dominance effects were observed in the TD group at the response level. A possible explanation is that the increased interference effects due to visual similarity and children with ADHD made it more difficult to control conflict when simultaneously confronted with incongruent visual and auditory inputs. The current study highlights how children with ADHD process cross-modal conflicts at multiple levels of information processing, thereby shedding light on the mechanisms underlying ADHD.

Relationship Between Inhibitory Control and Arithmetic in Elementary School Children With ADHD: The Mediating Role of Working Memory

OBJECTIVES

To test if inhibitory control was a significant predictor for arithmetic in children with ADHD and if the relationship between inhibitory control and arithmetic was mediated by working memory.

METHODS

Eighty-four children (ADHD, n = 54; Non-ADHD, n = 30) were tested on their interference control, behavioral inhibition, working memory, and arithmetic. Regression analysis was used to test the predictive role of inhibitory control in arithmetic. Moreover, mediation analysis was done to test whether working memory mediated the relationship between inhibitory control and arithmetic memory.

RESULTS

Interference control but not behavioral inhibition was a significant predictor for arithmetic. In addition, interference control had direct and indirect effects via working memory on arithmetic.

CONCLUSIONS

Results demonstrated that inhibitory control contributed to arithmetic in children with ADHD. Furthermore, interference control had direct and indirect effects via working memory on arithmetic, suggesting interventions for arithmetic difficulties should involve training on both inhibition and working memory.

Establishment of an objective index for the diagnosis of attention deficit/hyperactivity disorder by the continuous performance test "MOGRAZ"

OBJECTIVE

The diagnosis of attention deficit/hyperactivity disorder (AD/HD) in Japan is mainly based on information obtained from caregivers. There is therefore a need to establish an objectivity index that can be easily used in clinical practice. The purpose of the study was to create a predictive model for the diagnosis of AD/HD using the MOGRAZ, a visual continuous performance test developed in Japan.

METHODS

We collected data from an AD/HD group and a non-AD/HD group. The AD/HD group included 75 children with predominantly inattentive type AD/HD and 48 with combined type AD/HD who were aged 6 to 12 years and diagnosed at our department. The non-AD/HD group included 153 Japanese children aged 6 to 11 years enrolled in regular classes at a public elementary school. In both groups, multiple logistic regression analysis was performed using the results of MOGRAZ, age, and sex as parameters, and algorithms for a predictive diagnostic model of AD/HD were created.

RESULTS

The area under the receiver operating characteristic curve (ROC-AUC) between the predominantly inattentive type AD/HD subgroup and non-AD/HD group was 0.884 (95% confidence interval: 0.837-0.932), and the ROC-AUC between the combined type AD/HD subgroup and non-AD/HD group was 0.914 (95% CI: 0.869-0.959).

CONCLUSION

The prediction model using the MOGRAZ score allowed us to create an objectivity index to determine the diagnosis of AD/HD that can be easily used in clinical practice. We plan additional verification of this prediction model with additional participants.

Evidence towards a continuum of impairment across neurodevelopmental disorders from basic ocular-motor tasks

Findings of genetic overlap between Schizophrenia, Attention-Deficit/Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) contributed to a renewed conceptualization of these disorders as laying on a continuum based on aetiological, pathophysiological and neurodevelopmental features. Given that cognitive impairments are core to their pathophysiology, we compared patients with schizophrenia, ADHD, ASD, and controls on ocular-motor and manual-motor tasks, challenging crucial cognitive processes. Group comparisons revealed inhibition deficits common to all disorders, increased intra-subject variability in schizophrenia and, to a lesser extent, ADHD as well as slowed processing in schizophrenia. Patterns of deviancies from controls exhibited strong correlations, along with differences that posited schizophrenia as the most impaired group, followed by ASD and ADHD. While vector correlations point towards a common neurodevelopmental continuum of impairment, vector levels suggest differences in the severity of such impairment. These findings argue towards a dimensional approach to Neurodevelopmental Disorders’ pathophysiological mechanisms.

Training Executive, Attention, and Motor Skills (TEAMS): a Preliminary Randomized Clinical Trial of Preschool Youth with ADHD

This preliminary randomized controlled trial compared Training Executive, Attention and Motor Skills (TEAMS), a played-based intervention for preschool children with attention-deficit/hyperactivity disorder (ADHD), to an active comparison intervention consisting of parent education and support (ClinicalTrials.gov Identifier: NCT01462032). The primary aims were to gauge preliminary efficacy and assist in further development of TEAMS. Four- and 5-year-old children with ADHD were randomly assigned to receive TEAMS (N = 26) or the comparison intervention (N = 26) with blinded assessments by parents, teachers and clinicians ascertained pretreatment, post-treatment, and 1- and 3-months post-treatment. Changes in ADHD severity, impairment, parenting factors, and neuropsychological functioning over time as a function of treatment condition were assessed using the PROC MIXED procedure in SAS. Across most measures, significant main effects for Time emerged; both treatments were associated with reduced ADHD symptoms that persisted for three months post-treatment. There were no significant Treatment effects or Time x Treatment interactions on symptom and impairment measures, suggesting that the magnitude of improvement did not differ between the two interventions. However, significant correlations emerged between the magnitude of behavioral change, as assessed by parents and clinicians, and the amount of time families engaged in TEAMS-related activities during treatment. Across a wide array of parenting and neuropsychological measures, there were few significant group differences over time. TEAMS and other psychosocial interventions appear to provide similar levels of benefit. Play-based interventions like TEAMS represent a potentially viable alternative/addition to current ADHD treatments, particularly for young children, but more research and further development of techniques are necessary.

Neuropsychological Measures in the Diagnosis of ADHD in Preschool: Can Developmental Research Inform Diagnostic Practice?

Objective: The diagnosis of ADHD in preschool is challenging. Behavioral ratings are less reliable, but the value of neuropsychological tests in the diagnosis of ADHD has been debated. Method: This article provides an overview of neuropsychological measures utilized in preschoolers with ADHD (3-5 years). In addition, the manuscript discusses the extent to which these measures have been tested for their diagnostic capacity. Results: The diagnostic utility of computerized continuous performance tests and working memory subtests from IQ-batteries has been demonstrated in a number of studies by assessing their psychometric properties, sensitivity, and specificity. However, findings from developmental and basic research attempting to describe risk factors that explain variance in ADHD show the most consistent associations of ADHD with measures of delay aversion. Conclusion: Results from developmental research could benefit studies that improve ADHD diagnosis at the individual level. It might be helpful to consider testing as a structured situation for behavioral observation by the clinician.

Prediction of Reading and Writing in Elementary Education through Early Childhood Education

Abstract The study investigated the predictive role of executive functions, language, initial reading and writing abilities, teacher’s perception of the students’ difficulties and family characteristics, evaluated in Early Childhood Education (ECE) (Jardim I and Jardim II), in relation to reading and writing performance in the first year of Elementary Education. A total of 71 children were monitored in a longitudinal manner from ECE up to the first year, and evaluated in Oral Language (OL), Executive Functions (EF), initial Reading and Writing skills in ECE and, in the first year, evaluated by means of Reading and Writing tests. Parents provided information on socioeconomic status (SES) and teachers indicated children with difficulties. After the data imputation process, regression tree analysis showed that OL skills and initials skills of reading and writing in ECE explained a mean of 43% of the reading variability in the first year. For writing, the models also included performances in EF, income, father’s age and indication of difficulty by the teacher in ECE, explaining a mean of 78% of the variability in writing in the first year. The results allowed identifying abilities and variables that can be considered precursors of subsequent performances in Elementary Education, providing guidance for actions of early identification and intervention.

Executive function deficits in children born preterm or at low birthweight: a meta-analysis

AIM

To investigate the magnitude of executive function deficits and their dependency on gestational age, sex, age at assessment, and year of birth for children born preterm and/or at low birthweight.

METHOD

PubMed, PsychINFO, Web of Science, and ERIC were searched for studies reporting on executive functions in children born preterm/low birthweight and term controls born in 1990 and later, assessed at a mean age of 4 years or higher. Studies were included if five or more studies reported on the same executive function measures.

RESULTS

Thirty-five studies (3360 children born preterm/low birthweight, 2812 controls) were included. Children born preterm/low birthweight performed 0.5 standardized mean difference (SMD) lower on working memory and cognitive flexibility and 0.4 SMD lower on inhibition. SMDs for these executive functions did not significantly differ from each other. Meta-regression showed that heterogeneity in SMDs for working memory and inhibition could not be explained by study differences in gestational age, sex, age at assessment, or year of birth.

INTERPRETATION

Children born preterm/low birthweight since 1990 perform half a SMD below term-born peers on executive function, which does not seem to improve with more recent advances in medical care or with increasing age.

WHAT THIS PAPER ADDS

Children born preterm/low birthweight perform below term-born children on core executive functions. Lower gestational age or male sex are not risk factors for poorer executive functions. Executive function difficulties in children born preterm/low birthweight remain stable across childhood. Executive function difficulties are similar for children born recently and children born in earlier eras.

Association of the Conners' Kiddie Continuous Performance Test (K-CPT) Performance and Parent-Report Measures of Behavior and Executive Functioning

OBJECTIVE

To explore the relationship between the Conners' Kiddie Continuous Performance Test (K-CPT) performance and parent-report measures of child behavior and executive functioning, and clarify the role of sex in K-CPT performance in preschoolers.

METHOD

Mothers and children recruited to the Health Outcomes and Measures of the Environment Study with complete 5-year assessment data relevant to the analyses were included ( N = 127). We examined the association between K-CPT scores and Behavior Assessment System for Children-Second Edition (BASC-2) and Behavior Rating Inventory of Executive Function (BRIEF) scores, with covariate adjustment.

RESULTS

We found no significant associations between K-CPT, BASC-2, and BRIEF scores in the full sample. In sex-stratified analyses, we found unusually fast reaction time on K-CPT was related to executive control difficulties in girls, whereas unusually slow reaction time was related to the same difficulties in boys. Omission errors were associated with executive difficulties only in boys.

CONCLUSION

The K-CPT may prove to be a useful indicator for early onset of executive control difficulties in preschool-aged children.

Executive Function, Chaos and Temperament: Specificities in Preschoolers with Externalizing Behaviors

Various factors may contribute to the emergence of externalizing behavior (EB) problems in the preschool period. At the child level, temperament and executive function (EF) seem to play an important role, as well as environmental variables such as household chaos. In this study, we examined the profiles of 49 EB preschoolers compared to 49 typically developing (TD) preschoolers matched on age and gender. To evaluate the behavioral aspect of EB, we asked teachers and parents to fill out questionnaires, but we also used an observational paradigm. We assessed executive functions using attention, inhibition, flexibility and working memory tests. Finally, we used questionnaires to assess household chaos and child temperament. Results showed that children rated by parents as presenting EB were also assessed so by teachers and exhibited more agitation in our observational paradigm. As expected, EB children also presented weaker performance than the TD children in all EF tasks, except those measuring attention, and showed a larger reaction-time variability. Parents of the EB group reported a more chaotic environment at home. Finally, we found that child temperament (i.e., emotionality) also plays a role in group belonging. This study shows that EB children already exhibit specific characteristics by the time they are of preschool age, not only in the behavioral sphere, but also in the cognitive and environmental areas. However, despite all the differences between the two groups, a discriminant analysis showed that EF capacities have a weak power for EB diagnosis.

Effects of anterior cingulate cortex lesions on a continuous performance task for mice

Important tools in the study of prefrontal cortical-dependent executive functions are cross-species behavioural tasks with translational validity. A widely used test of executive function and attention in humans is the continuous performance task (CPT). Optimal performance in variations of this task is associated with activity along the medial wall of the prefrontal cortex, including the anterior cingulate cortex (ACC), for its essential components such as response control, target detection and processing of false alarm errors. We assess the validity of a recently developed rodent touchscreen continuous performance task (rCPT) that is analogous to typical human CPT procedures. Here we evaluate the performance of mice with quinolinic acid-induced lesions centred on the ACC in the rCPT following a range of task parameter manipulations designed to challenge attention and impulse control. Lesioned mice showed a disinhibited response profile expressed as a decreased response criterion and increased false alarm rates. ACC lesions also resulted in a milder increase in inter-trial interval responses ('ITI touches') and hit rate. Lesions did not affect discriminative sensitivity d'. The disinhibited behaviour of ACC lesioned animals was stable and not affected by the manipulation of variable task parameter manipulations designed to increase task difficulty. The results are in general agreement with human studies implicating the ACC in the processing of inappropriate responses. We conclude that the rCPT may be useful for studying prefrontal cortex function in mice and has the capability of providing meaningful links between animal and human cognitive tasks.

How neuropsychology can inform our understanding of preschool ADHD: Clinical and research implications

Neuropsychological assessments in preschoolers have not received as much attention as in older children and adults. Attention-deficit/hyperactivity disorder (ADHD) is a common disorder that occurs in early childhood associated with poor academic and personal outcomes, such as learning and social difficulties. Preschoolers with ADHD may present cognitive deficits that are related with the ADHD symptoms of inattention, hyperactivity, and impulsivity, but may also interfere, beyond and above the ADHD symptoms, with everyday functioning. Most importantly, cognitive deficits in preschoolers seem to predict future ADHD symptoms. Yet, the practice of neuropsychological assessment in this age-group has been limited. The present selective review highlights the contribution of comprehensive neuropsychological assessments to the early identification of symptomatic preschoolers and to our understanding of the nature and developmental trajectory of ADHD.

The Behavior Rating Inventory of Executive Function and Continuous Performance Test in Preschoolers with Attention Deficit Hyperactivity Disorder

OBJECTIVE

The aim of this study is to examine performance-based measures and behavioral ratings of executive functions (EF) as a component of preschool attention deficit hyperactivity disorder (ADHD).

METHODS

Twenty-one 4-to-6-year-old children with ADHD and 52 children with no psychopathology, matched on age, gender, socioeconomic status, and parental education, were enrolled. Parents were interviewed with the use of The Schedule for Affective Disorders and Schizophrenia for School-Age Children Present and Lifetime version. The Conners' Kiddie Continuous Performance Test (K-CPT) was administered to the children, and the Behavior Rating Inventory of Executive Function-Preschool version (BRIEF-P) and the Conners' Parent Rating Scale-Revised/Short Form (CPRS-R/S) were filled out by the parents.

RESULTS

All BRIEF-P and CPRS-R/S scores, the K-CPT measures of inattention and impulsivity were higher in the ADHD group. The CPRS-R/S ADHD index was strongly correlated with inhibition and related indexes in the BRIEF-P and was moderately correlated with inattention measures in the K-CPT.

CONCLUSION

The current study is one of the few to investigate the features of preschool ADHD with the use of behavioral ratings of EF and a performance-based measure. Our results suggest that the BRIEF-P was able to identify behavioral difficulties in inhibition and working memory and that the K-CPT identified difficulties indicating inattention. The findings of this study support the use of a combination of methods for a complete evaluation of preschoolers with inattentive and hyperactive/impulsive behavior, the application of rating scales for screening ADHD symptoms, and the measurement of behavioral correlates of EF, along with performance-based measures.

Virtual-reality-based attention assessment of ADHD: ClinicaVR: Classroom-CPT versus a traditional continuous performance test

Virtual-reality-based assessment may be a good alternative to classical or computerized neuropsychological assessment due to increased ecological validity. ClinicaVR: Classroom-CPT (VC) is a neuropsychological test embedded in virtual reality that is designed to assess attention deficits in children with attention deficit hyperactivity disorder (ADHD) or other conditions associated with impaired attention. The present study aimed to (1) investigate the diagnostic validity of VC in comparison to a traditional continuous performance test (CPT), (2) explore the task difficulty of VC, (3) address the effect of distractors on the performance of ADHD participants and typically-developing (TD) controls, and (4) compare the two measures on cognitive absorption. A total of 33 children diagnosed with ADHD and 42 TD children, aged between 7 and 13 years, participated in the study and were tested with a traditional CPT or with VC, along with several cognitive measures and an adapted version of the Cognitive Absorption Scale. A mixed multivariate analysis of covariance (MANCOVA) revealed that the children with ADHD performed worse on correct responses had more commissions and omissions errors than the TD children, as well as slower target reaction times . The results showed significant differences between performance in the virtual environment and the traditional computerized one, with longer reaction times in virtual reality. The data analysis highlighted the negative influence of auditory distractors on attention performance in the case of the children with ADHD, but not for the TD children. Finally, the two measures did not differ on the cognitive absorption perceived by the children.

AULA-Advanced Virtual Reality Tool for the Assessment of Attention: Normative Study in Spain

OBJECTIVE

The present study describes the obtention of normative data for the AULA test, a virtual reality tool designed to evaluate attention problems, especially in children and adolescents.

METHOD

The normative sample comprised 1,272 participants (48.2% female) with an age range from 6 to 16 years (M = 10.25, SD = 2.83). The AULA test administered to them shows both visual and auditory stimuli, while randomized distractors of ecological nature appear progressively.

RESULTS

Variables provided by AULA were clustered in different categories for their posterior analysis. Differences by age and gender were analyzed, resulting in 14 groups, 7 per sex group. Differences between visual and auditory attention were also obtained.

CONCLUSION

Obtained normative data are relevant for the use of AULA for evaluating attention in Spanish children and adolescents in a more ecological way. Further studies will be needed to determine sensitivity and specificity of AULA to measure attention in different clinical populations. (J. of Att. Dis. 2016; 20(6) 542-568).

Measuring the development of inhibitory control: The challenge of heterotypic continuity

Inhibitory control is thought to demonstrate heterotypic continuity, in other words, continuity in its purpose or function but changes in its behavioral manifestation over time. This creates major methodological challenges for studying the development of inhibitory control in childhood including construct validity, developmental appropriateness and sensitivity of measures, and longitudinal factorial invariance. We meta-analyzed 198 studies using measures of inhibitory control, a key aspect of self-regulation, to estimate age ranges of usefulness for each measure. The inhibitory control measures showed limited age ranges of usefulness owing to ceiling/floor effects. Tasks were useful, on average, for a developmental span of less than 3 years. This suggests that measuring inhibitory control over longer spans of development may require use of different measures at different time points, seeking to measure heterotypic continuity. We suggest ways to study the development of inhibitory control, with overlapping measurement in a structural equation modeling framework and tests of longitudinal factorial or measurement invariance. However, as valuable as this would be for the area, we also point out that establishing longitudinal factorial invariance is neither sufficient nor necessary for examining developmental change. Any study of developmental change should be guided by theory and construct validity, aiming toward a better empirical and theoretical approach to the selection and combination of measures.

Autism spectrum disorder and attention-deficit/hyperactivity disorder in early childhood: A review of unique and shared characteristics and developmental antecedents

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have overlapping characteristics and etiological factors, but to which extent this applies to infant- and preschool age is less well understood. Comparing the pathways to ASD and ADHD from the earliest possible stages is crucial for understanding how phenotypic overlap emerges and develops. Ultimately, these insights may guide preventative and therapeutic interventions. Here, we review the literature on the core symptoms, temperament and executive function in ASD and ADHD from infancy through preschool age, and draw several conclusions: (1) the co-occurrence of ASD and ADHD increases with age, severity of symptoms and lower IQ, (2) attention problems form a linking pin between early ASD and ADHD, but the behavioral, cognitive and sensory correlates of these attention problems partly diverge between the two conditions, (3) ASD and ADHD share high levels of negative affect, although the underlying motivational and behavioral tendencies seem to differ, and (4) ASD and ADHD share difficulties with control and shifting, but partly opposite behaviors seem to be involved.

Cognitive Translation Using the Rodent Touchscreen Testing Approach

The development of novel therapeutic avenues for the treatment of cognitive deficits in psychiatric and neurodegenerative disease is of high importance, yet progress in this field has been slow. One reason for this lack of success may lie in discrepancies between how cognitive functions are assessed in experimental animals and humans. In an attempt to bridge this translational gap, the rodent touchscreen testing platform is suggested as a translational tool. Specific examples of successful cross-species translation are discussed focusing on paired associate learning (PAL), the 5-choice serial reaction time task (5-CSRTT), the rodent continuous performance task (rCPT) and reversal learning. With ongoing research assessing the neurocognitive validity of tasks, the touchscreen approach is likely to become increasingly prevalent in translational cognitive research.

Good Holders, Bad Shufflers: An Examination of Working Memory Processes and Modalities in Children with and without Attention-Deficit/Hyperactivity Disorder

The aim of this study was to examine working memory (WM) modalities (visual-spatial and auditory-verbal) and processes (maintenance and manipulation) in children with and without attention-deficit/hyperactivity disorder (ADHD). The sample consisted of 63 8-year-old children with ADHD and an age- and sex-matched non-ADHD comparison group (N=51). Auditory-verbal and visual-spatial WM were assessed using the Digit Span and Spatial Span subtests from the Wechsler Intelligence Scale for Children Integrated - Fourth Edition. WM maintenance and manipulation were assessed via forward and backward span indices, respectively. Data were analyzed using a 3-way Group (ADHD vs. non-ADHD)×Modality (Auditory-Verbal vs. Visual-Spatial)×Condition (Forward vs. Backward) Analysis of Variance (ANOVA). Secondary analyses examined differences between Combined and Predominantly Inattentive ADHD presentations. Significant Group×Condition (p=.02) and Group×Modality (p=.03) interactions indicated differentially poorer performance by those with ADHD on backward relative to forward and visual-spatial relative to auditory-verbal tasks, respectively. The 3-way interaction was not significant. Analyses targeting ADHD presentations yielded a significant Group×Condition interaction (p=.009) such that children with ADHD-Predominantly Inattentive Presentation performed differentially poorer on backward relative to forward tasks compared to the children with ADHD-Combined Presentation. Findings indicate a specific pattern of WM weaknesses (i.e., WM manipulation and visual-spatial tasks) for children with ADHD. Furthermore, differential patterns of WM performance were found for children with ADHD-Predominantly Inattentive versus Combined Presentations. (JINS, 2016, 22, 1-11).

The continuous performance test (rCPT) for mice: a novel operant touchscreen test of attentional function

RATIONALE

Continuous performance tests (CPTs) are widely used to assess attentional processes in a variety of disorders including Alzheimer's disease and schizophrenia. Common human CPTs require discrimination of sequentially presented, visually patterned 'target' and 'non-target' stimuli at a single location.

OBJECTIVES

The aims of this study were to evaluate the performance of three popular mouse strains on a novel rodent touchscreen test (rCPT) designed to be analogous to common human CPT variants and to investigate the effects of donepezil, a cholinesterase inhibitor and putative cognitive enhancer.

METHODS

C57BL/6J, DBA/2J and CD1 mice (n = 15-16/strain) were trained to baseline performance using four rCPT training stages. Then, probe tests assessed the effects of parameter changes on task performance: stimulus size, duration, contrast, probability, inter-trial interval or inclusion of flanker distractors. rCPT performance was also evaluated following acute administration of donepezil (0-3 mg/kg, i.p.).

RESULTS

C57BL/6J and DBA/2J mice showed similar acquisition rates and final baseline performance following rCPT training. On probe tests, rCPT performance of both strains was sensitive to alteration of visual and/or attentional demands (stimulus size, duration, contrast, rate, flanker distraction). Relative to C57BL/6J, DBA/2J mice exhibited (1) decreasing sensitivity (d') across the 45-min session, (2) reduced performance on probes where the appearance of stimuli or adjacent areas were changed (size, contrast, flanking distractors) and (3) larger dose- and stimulus duration-dependent changes in performance following donepezil administration. In contrast, CD1 mice failed to acquire rCPT (stage 3) and pairwise visual discrimination tasks.

CONCLUSIONS

rCPT is a potentially useful translational tool for assessing attention in mice and for detecting the effects of nootropic drugs.

Latent profile analysis of neuropsychological measures to determine preschoolers' risk for ADHD

BACKGROUND

Hyperactive/Inattentive preschool children show clear evidence of neuropsychological dysfunction. We examined whether patterns and severity of test scores could reliably identify subgroups of preschoolers with differential risk for ADHD during school-age.

METHOD

Typically developing (TD: n = 76) and Hyperactive/Inattentive (HI: n = 138) 3-4 year olds were assessed annually for 6 years (T1-T6). Latent profile analysis (LPA) was used to form subgroups among the HI group based on objective/neuropsychological measures (NEPSY, Actigraph and Continuous Performance Test). Logistic regression assessed the predictive validity of empirically formed subgroups at risk for ADHD diagnosis relative to the TD group and to each other from T2 to T6.

RESULTS

Latent profile analysis yielded two subgroups of HI preschoolers: (a) selectively weak Attention/Executive functions, and (b) pervasive neuropsychological dysfunction across all measures. Both subgroups were more likely to have ADHD at all follow-up time-points relative to the TD group (OR range: 11.29-86.32), but there were no significant differences between the LPA-formed subgroups of HI children at any time-point.

CONCLUSIONS

Objective/neuropsychological measures distinguish HI preschoolers from their TD peers, but patterns and severity of neuropsychological dysfunction do not predict risk for ADHD during school-age. We hypothesize that trajectories in at-risk children are influenced by subsequent environmental and neurodevelopmental factors, raising the possibility that they are amenable to early intervention.

The Promotion of Executive Functioning in a Brazilian Public School: A Pilot Study

Studies have highlighted the role of early Executive Functioning (EF) interventions with regard to preventing behavioral and mental health problems. In this sense, interventions to promote EF have been developed and tested; however, in Latin America, evidence of early EF-related interventions is still limited. We developed a program for EF promotion in children and applied it to first-grade students. Sixty-eight six-year-old children and their five teachers were divided into an experimental group (EG) and a control group (CG). EG teachers administered the Intervention Program for Self-regulation and Executive Functions in a classroom context. The results of the ANCOVAs showed that children in the EG had significantly better performance in measures of cognitive flexibility (Trail Making Test for Preschoolers; p = .05), attention (Cancellation Attention Test – errors in the Part 3; p = .027), inhibition (Simon Task – interference score in the part 1; p = .008 and interference reaction time in the part 2; p = .010), and planning (CHEXI - planning scale; p = .041) than those in the CG. The results show that EF can be promoted using classroom intervention in public schools. These results expand previous findings for Latin America.

ADHD symptoms and attachment representations: considering the role of conduct problems, cognitive deficits and narrative responses in non-attachment-related story stems

The overall aim of the present study was to investigate ADHD symptoms in relation to attachment representations. We used both attachment- and non-attachment-related story stems, which allowed us to investigate whether problems with narrative production can explain the relation between ADHD symptoms and attachment representations. We also investigated the role of cognitive deficits and conduct problems in these relations. The sample consisted of 89 children (27 % girls) between 6 and 10 years old, with an oversampling of children with high levels of ADHD symptoms. ADHD symptoms and conduct problems were rated by parents and teachers. Cognitive functioning was investigated using laboratory tests of inhibition, working memory and sustained attention. Attachment representations were coded as secure, organized insecure and disorganized categories. Narrative responses to non-attachment-related story stems were coded for incoherence and negative content. Results showed that children in the disorganized attachment category had significantly higher levels of ADHD symptoms compared to those in the secure category. Both ADHD symptoms and disorganized attachment were related to incoherence and negative content. Attachment representations were not associated with ADHD symptoms when controlling for negative content in response to non-attachment-related story stems. These results suggest that the associations between attachment security and ADHD are yet to be fully understood. Importantly, a propensity to envisage negative events seems to characterize children with high levels of ADHD symptoms.

Relations between response trajectories on the continuous performance test and teacher-rated problem behaviors in preschoolers

Although both the continuous performance test (CPT) and behavior rating scales are used in both practice and research to assess inattentive and hyperactive/impulsive behaviors, the correlations between performance on the CPT and teachers' ratings are typically only small-to-moderate. This study examined trajectories of performance on a low target-frequency visual CPT in a sample of preschool children and how these trajectories were associated with teacher-ratings of problem behaviors (i.e., inattention, hyperactivity/impulsivity [H/I], and oppositional/defiant behavior). Participants included 399 preschool children (mean age = 56 months; 49.4% female; 73.7% White/Caucasian). An attention deficit/hyperactivity disorder (ADHD) rating scale was completed by teachers, and the CPT was completed by the preschoolers. Results showed that children's performance across 4 temporal blocks on the CPT was not stable across the duration of the task, with error rates generally increasing from initial to later blocks. The predictive relations of teacher-rated problem behaviors to performance trajectories on the CPT were examined using growth curve models. Higher rates of teacher-reported inattention and H/I were uniquely associated with higher rates of initial omission errors and initial commission errors, respectively. Higher rates of teacher-reported overall problem behaviors were associated with increasing rates of omission but not commission errors during the CPT; however, the relation was not specific to 1 type of problem behavior. The results of this study indicate that the pattern of errors on the CPT in preschool samples is complex and may be determined by multiple behavioral factors. These findings have implications for the interpretation of CPT performance in young children.

Development of holistic vs. featural processing in face recognition

According to a classic view developed by Carey and Diamond (1977), young children process faces in a piecemeal fashion before adult-like holistic processing starts to emerge at the age of around 10 years. This is known as the encoding switch hypothesis. Since then, a growing body of studies have challenged the theory. This article will provide a critical appraisal of this literature, followed by an analysis of some more recent developments. We will conclude, quite contrary to the classical view, that holistic processing is not only present in early child development, but could even precede the development of part-based processing.

Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics.

The effect of environmental distractors incorporation into a CPT on sustained attention and ADHD diagnosis among adolescents

BACKGROUND

Diagnosis of ADHD in adolescents involves specific challenges. Conventional CPT's may fail to consistently distinguish ADHD from non-ADHD due to insufficient cognitive demands. The aim of this study was to explore whether the incorporation of environmental distractors into a CPT would increase its ability to distinguish ADHD from non-ADHD adolescents.

NEW METHOD

Using the rate of omission errors as a measure of difficulty in sustained attention, this study examined whether ADHD adolescents are more distracted than controls and which type of distractors is more effective in terms of ADHD diagnosis. The study employed the MOXO-CPT version which includes visual and auditory stimuli serving as distractors. Participants were 176 adolescents aged 13-18 years, 133 diagnosed with ADHD and 43 without ADHD.

RESULTS AND COMPARISON WITH EXISTING METHODS

Results showed that ADHD adolescents produced significantly more omission errors in the presence of pure visual distractors and the combination of visual and auditory distractors than in no-distractors conditions. Distracting stimuli had no effect on CPT performance of non-ADHD adolescents. ROC analysis further demonstrated that the mere presence of distractors improved the utility of the test.

CONCLUSIONS

This study provides evidence that incorporation of environmental distractors into a CPT is useful in term of ADHD diagnosis. ADHD adolescents were more distracted than controls by all types of environmental distractors. ADHD adolescents were more distracted by pure visual distractors and by the combination of distractors than by pure auditory ones.

The effect of noradrenergic attenuation by clonidine on inhibition in the stop signal task

Understanding the neuropharmacology of inhibition is of importance to fuel optimal treatment for disorders such as Attention Deficit/Hyperactivity Disorder. The aim of the present study was to assess the effect of noradrenergic antagonism by clonidine on behavioral-performance and brain-activity indices of inhibition. A placebo-controlled, double-blind, randomized, crossover design was implemented. Male (N=21) participants performed in a visual stop signal task while EEG was recorded under clonidine in one session and under placebo in another. We expected that 100 μg clonidine would have a negative effect on EEG indices of inhibition, the Stop N2 and Stop P3. Furthermore, we expected that clonidine would negatively affect the behavioral measure of inhibition, the stop signal reaction time (SSRT). Behavioral analyses were performed on data of 17 participants, EEG analyses on a subset (N=13). Performance data suggested that clonidine negatively affected attention (response variability, omissions) without affecting inhibition as indexed by SSRT. Electrophysiological data show that clonidine reduced the Stop P3, but not the Stop N2, indicating a partial negative effect on inhibition. Results show that it is unlikely that the Stop P3 reduction was related to the effect of clonidine on lapses of attention and on peripheral cardiovascular functioning. In conclusion, the current dose of clonidine had a negative effect on attention and a partial effect on inhibitory control. This inhibitory effect was restricted to the dorsal region of the prefrontal cortex (presumably the superior frontal gyrus) as opposed to the ventral region of the prefrontal cortex (right inferior frontal gyrus).

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.

Assessment of attention in preschoolers

In the past two decades, there has been an increased interest in the assessment and treatment of preschool children presenting with concerns about attention problems. This article reviews the research and clinical literature involving assessment of attention and related skills in the preschool years. While inattention among preschoolers is common, symptoms alone do not necessarily indicate a disorder, and most often represent a normal variation in typical preschool child development. Thus, accurate identification of "disordered" attention in preschoolers can be challenging, and development of appropriate, norm-referenced tests of attention for preschoolers is also difficult. The current review suggests that comprehensive assessment of attention and related functions in the preschool child should include thorough review of the child's history, planned observations, and formal psychometric testing. The three primary methods of psychometric assessment that have been used to characterize attentional functioning in preschool children include performance-based tests, structured caregiver interviews, and rating scales (parent, teacher, and clinician). Among performance-based methods for measurement of attention in the preschool years, tests have been developed to assess sustained attention, selective (focused) attention, span of attention (encoding/manipulation), and (top-down) controlled attention--including freedom from distractibility and set shifting. Many of these tests remain experimental in nature, and review of published methods yields relatively few commercially available, nationally normed tests of attention for preschoolers, and an overall dearth of reliability and validity studies on the available measures.

The effect of delayed responding on Stroop-like task performance among preschoolers

Forty-four preschoolers completed 2 conditions of a Stroop-like procedure (e.g., saying "boat" for car and "car" for boat) that differed in whether a 3-s delay was imposed before responding. The test card was visible during the delay period for half of the children and occluded for the other children. Preschoolers' interference control was significantly improved in the delay condition. There was no difference between the two delay variants (test card visible or occluded). Children were more prone to interference as testing progressed regardless of whether the delay was present. These results suggest that delays effectively reduce interference by reducing the potency of the competing response during test trials, although memory demands may moderate the effectiveness of delays.

Sustained Attention Development during the Toddlerhood to Preschool Period: Associations with Toddlers' Emotion Regulation Strategies and Maternal Behavior

The current study examined the role of maternal behavior and toddlers' emotion regulation strategies in the development of children's sustained attention abilities. Participants for this study included 447 children (232 girls) obtained from three different cohorts participating in a larger ongoing longitudinal study. When the children were 2 years of age, mothers brought their children to the laboratory and were videotaped during several tasks designed to elicit emotion regulation and mother- child interaction. Sustained attention was also measured at the same visit via a laboratory task and in a subsequent visit when children were 4.5 years of age. Results indicated that toddlers' use of help-seeking emotion regulation strategies was positively related to sustained attention while avoidance behaviors and maternal behavior characterized by high levels of overcontrolling/intrusiveness were negatively related to sustained attention at age 2. Significant interactions emerged such that high levels of maternal warmth/responsiveness buffered the negative associations between low use of distraction and high use of self-comforting emotion regulation strategies and sustained attention at age 2. Maternal behavior characterized by high levels of warmth/responsiveness also predicted greater growth in sustained attention from age 2 to 4.5. These findings are discussed in terms of how maternal behaviors and children's use of active versus passive emotion regulation strategies relate to sustained attention abilities.

The development of selective attention and inhibition in NICU graduates during the preschool years

Neonatal intensive care unit (NICU) graduates have a higher incidence of attention problems including attention deficit hyperactivity disorder (ADHD). Thus, we examined the effect of risk factors (birth weight (BW), central nervous system (CNS) injury, gender, maternal education) on attention/inhibition during reaction time, continuous performance and Go/No-Go tasks at 42, 51, and 60 months (n = 271). Very low BW NICU graduates (<1,500 g) performed worse than typical BW ones (>2,500 g), displaying poorer target/non-target discrimination. Males responded faster than females, but made more false alarms and random responses. Despite short duration tasks, attention waned. Performance improved with age, but even at 60 months children had difficulty inhibiting random responding.

Traumatic brain injury and secondary attention-deficit/hyperactivity disorder in children and adolescents: the effect of reward on inhibitory control

Poor inhibitory control and abnormalities in responding to rewards are characteristic of the developmental or primary form of attention-deficit/hyperactivity disorder (P-ADHD). A secondary form of ADHD (S-ADHD) may occur as a consequence of childhood traumatic brain injury (TBI), but the similarities and differences between these two forms of ADHD have not been well characterized. To address these issues, we studied two inhibitory control tasks under different reward conditions in four groups of children and adolescents: TBI who did not exhibit S-ADHD, TBI who did exhibit S-ADHD, P-ADHD, and healthy controls. Participants with TBI exhibited poor cancellation inhibition relative to controls. Although reward facilitated both cancellation and restraint inhibition similarly across groups, poor performance persisted in the P-ADHD group, and participants with S-ADHD exhibited a selective deficit in cancellation inhibition.

Intraindividual variability in ADHD and its implications for research of causal links

Intraindividual variability (IIV) - reflecting short-term (within-session), within-person fluctuations in behavioral performance - and, specifically, reaction time (RT) variability, is strongly linked with attention-deficit hyperactivity disorder (ADHD) both at the phenotypic and genetic levels. Phenotypic case-control comparisons show a consistent and robust association between ADHD and RT variability across a broad range of cognitive tasks, samples, and age ranges (from childhood to adulthood). The association does not appear to be a nonspecific effect mediated by lower general cognitive ability. The finding from quantitative genetic studies of the shared genetic etiology between ADHD and RT variability is similarly robust, replicating across tasks, samples, and definitions of ADHD. Molecular genetic studies have produced intriguing initial findings: increasing sample sizes and replications across datasets remain priorities for future efforts. While the field has come a long way from considering increased RT variability in ADHD as the "noise" or "error" that we need to reduce in our data, the investigation of the causal pathways is only beginning. The neural basis of IIV is being investigated, with initial data pointing to a crucial role of fronto-striatal systems in controlling behavioral consistency. Several theories have been put forward to account for the observed IIV in ADHD, including accounts of arousal regulation, temporal processing and the "default-mode network." For the wider implications of the IIV phenomenon to be fully realized, we need to learn further about the underlying processes, their developmental context, and about shared and unique causal pathways across disorders where high RT variability is observed.

Executive control and dimensions of problem behaviors in preschool children

BACKGROUND

Despite the widespread recognition of the importance of executive control (EC) in externalizing psychopathology, the relation between EC and problem behavior has not been well characterized, particularly in typically developing preschoolers.

METHOD

Using the sample, battery of laboratory tasks, and latent variable modeling methods described in Wiebe, Espy, and Charak (2008), systematic latent dimensions of parent-rated problem behavior, measured by integrating scales from developmental and clinical traditions, were determined empirically, and then were related to EC.

RESULTS

Substantial relations between EC and problem behaviors were revealed by extracting the common variance of interest and eliminating extraneous variance, which were robust to estimated child intelligence and differed somewhat in preschool boys and girls.

CONCLUSION

Preschool EC measured by laboratory tasks appears to tap abilities that strongly and robustly support broad control processes enabling behavioral regulation across cognitive and emotional domains.