Lisa A. Jacobson

Working memory influences processing speed and reading fluency in ADHD

Processing-speed deficits affect reading efficiency, even among individuals who recognize and decode words accurately. Children with ADHD who decode words accurately can still have inefficient reading fluency, leading to a bottleneck in other cognitive processes. This “slowing” in ADHD is associated with deficits in fundamental components of executive function underlying processing speed, including response selection. The purpose of the present study was to deconstruct processing speed in order to determine which components of executive control best explain the “processing” speed deficits related to reading fluency in ADHD. Participants (41 ADHD, 21 controls), ages 9–14 years, screened for language disorders, word reading deficits, and psychiatric disorders, were administered measures of copying speed, processing speed, reading fluency, working memory, reaction time, inhibition, and auditory attention span. Compared to controls, children with ADHD showed reduced oral and silent reading fluency and reduced processing speed—driven primarily by deficits on WISC-IV Coding. In contrast, groups did not differ on copying speed. After controlling for copying speed, sex, severity of ADHD-related symptomatology, and GAI, slowed “processing” speed (i.e., Coding) was significantly associated with verbal span and measures of working memory but not with measures of response control/inhibition, lexical retrieval speed, reaction time, or intrasubject variability. Further, “processing” speed (i.e., Coding, residualized for copying speed) and working memory were significant predictors of oral reading fluency. Abnormalities in working memory and response selection (which are frontally mediated and enter into the output side of processing speed) may play an important role in deficits in reading fluency in ADHD, potentially more than posteriorally mediated problems with orienting of attention or perceiving the stimulus.

The Role of Executive Function in Children’s Competent Adjustment to Middle School

Executive function (EF) skills play an important role in childrens cognitive and social functioning. These skills develop throughout childhood, concurrently with a number of developmental transitions and challenges. One of these challenges is the transition from elementary into middle-level schools, which has the potential to significantly disrupt childrens academic and social trajectories. However, little is known about the role of EF in childrens adjustment during this transition. This study investigated the relation between childrens EF skills, assessed both before and during elementary school, and sixth grade academic and social competence. In addition, the influences of the type of school setting attended in sixth grade on childrens academic and behavioral outcomes were examined. EF assessed prior to and during elementary school significantly predicted sixth grade competence, as rated by teachers and parents, in both academic and social domains, after controlling for background characteristics. The interactions between type of school setting and EF skills were significant: Parents tended to report more behavioral problems and less regulatory control in children with weaker EF skills who were attending middle school. In contrast, teachers reported greater academic and behavioral difficulty in students with poorer EF attending elementary school settings. In conclusion, childrens performance-based EF skills significantly affect adjustment to the academic and behavioral demands of sixth grade, with parent report suggesting greater difficulty for children with poorer EF in settings where children are provided with less external supports (e.g., middle school).

Factor Structure of a Sluggish Cognitive Tempo Scale in Clinically-Referred Children

Abstract“Sluggish cognitive tempo” (SCT) is a construct hypothesized to describe a constellation of behaviors that includes daydreaming, lethargy, drowsiness, difficulty sustaining attention, and underactivity. Although the construct has been inconsistently defined, measures of SCT have shown associations with symptoms of attention-deficit/hyperactivity disorder (ADHD), particularly inattention. Thus, better characterization of SCT symptoms may help to better predict specific areas of functional difficulty in children with ADHD. The present study examined psychometric characteristics of a recently developed 14-item scale of SCT (Penny et al., Psychological Assessment 21:380–389, 2009), completed by teachers on children referred for outpatient neuropsychological assessment. Exploratory factor analysis identified three factors in the clinical sample: Sleepy/Sluggish, Slow/Daydreamy, and Low Initiation/Persistence. Additionally, SCT symptoms, especially those loading on the Sleepy/Sluggish and Slow/Daydreamy factors, correlated more strongly with inattentive than with hyperactive/impulsive symptoms, while Low Initiation/Persistence symptoms added significant unique variance (over and above symptoms of inattention) to the predictions of impairment in academic progress.

Early Reading Instruction for Children with Reading Difficulties Meeting the Needs of Diverse Learners

Several multiple-probe-across-participants design studies were employed to evaluate the effectiveness of a supplemental tutoring intervention using Read Well (Sprick, Howard, & Fidanque, 1998—2000). In Year 1, we conducted two studies with 7 first-, second-, and third-grade children (1 girl and 6 boys), who were classified as having learning disabilities, having attention-deficit disorder, or being English language learners and were identified by their teachers as poor readers. The results of the two studies indicated that 3 of the 5 children who received Read Well instruction showed improvement in passage fluency. Student performance on other measures of reading and comprehension was varied. Differences in student characteristics and in the amount of Read Well instruction received (2 to 7 weeks) seemed to account for the differences in performance. In Year 2, we implemented the same tutoring intervention for a longer duration (up to 16 weeks) and included 5 children in second and third grades (2 girls and 3 boys) with reading difficulties. Two of these children had previously participated in the Year 1 studies. The results indicated growth in reading, spelling, and comprehension for most children. Overall, the findings from Year 1 and 2 studies indicate the benefits of increased instructional intensity and duration for children who struggle with emerging reading skills.

The Role of Neuropsychological Assessment in the Functional Outcomes of Children with ADHD

The value of evidence-based services is now recognized both within clinical communities and by the public at large. Increasingly, neuropsychologists must justify the necessity of often costly and time-consuming neuropsychological assessments in the diagnosis and treatment of common childhood disorders, such as Attention-deficit/Hyperactivity Disorder (ADHD). Published medical guidelines and prominent researchers, however, have argued against the need for formal neuropsychological assessment of ADHD. The present review examines the literature on developmental outcomes in childhood ADHD, with emphasis on the utility of formal neuropsychological assessment among children diagnosed and treated in primary care settings. The review yields three central findings: 1) adherence to published diagnostic guidelines for ADHD is poor among pediatric and primary care physicians; 2) ADHD most often co-exists with other disorders, thus diagnoses made without formal psychometric assessment can be incomplete or incorrect, ultimately increasing treatment costs; and, 3) untreated children with ADHD, and those who have untreated comorbidities, are at greater risk for poor outcomes in social, academic, vocational, and practical settings. The available literature suggests that neuropsychological assessment provides information that can potentially reduce risks for poor outcomes and improve quality of life among children with ADHD. Controlled studies directly examining the impact of neuropsychological assessments in improving outcomes among children with ADHD are needed.

Connectivity supporting attention in children with attention deficit hyperactivity disorder

Intra-subject variability (ISV) is the most consistent behavioral deficit in Attention Deficit Hyperactivity Disorder (ADHD). ISV may be associated with networks involved in sustaining task control (cingulo-opercular network: CON) and self-reflective lapses of attention (default mode network: DMN). The current study examined whether connectivity supporting attentional control is atypical in children with ADHD. Group differences in full-brain connection strength and brain–behavior associations with attentional control measures were examined for the late-developing CON and DMN in 50 children with ADHD and 50 typically-developing (TD) controls (ages 8–12 years). Children with ADHD had hyper-connectivity both within the CON and within the DMN. Full-brain behavioral associations were found for a number of between-network connections. Across both groups, more anti-correlation between DMN and occipital cortex supported better attentional control. However, in the TD group, this brain–behavior association was stronger and occurred for a more extensive set of DMN–occipital connections. Differential support for attentional control between the two groups occurred with a number of CON–DMN connections. For all CON–DMN connections identified, increased between-network anti-correlation was associated with better attentional control for the ADHD group, but worse attentional control in the TD group. A number of between-network connections with the medial frontal cortex, in particular, showed this relationship. Follow-up analyses revealed that these associations were specific to attentional control and were not due to individual differences in working memory, IQ, motor control, age, or scan motion. While CON–DMN anti-correlation is associated with improved attention in ADHD, other circuitry supports improved attention in TD children. Greater CON–DMN anti-correlation supported better attentional control in children with ADHD, but worse attentional control in TD children. On the other hand, greater DMN–occipital anti-correlation supported better attentional control in TD children.

Sensitivity of the BASC-2 Adaptive Skills Composite in Detecting Adaptive Impairment in a Clinically Referred Sample of Children and Adolescents

The Behavior Assessment Scale for Children (BASC-2) is widely used to assess for internalizing/externalizing behavior problems; however, the role of its adaptive scales is not well established. This study examined the sensitivity of the parent version of the BASC-2 Adaptive Skills Composite (ASC) in identifying children with impairments on a more comprehensive measure of adaptive functioning, the Adaptive Behavior Assessment System (ABAS-II). Participants were referred for neuropsychological assessment (N = 1884, M age = 10.96 years, SD = 3.50, 65% male). The ASC, rather than individual BASC-2 adaptive scales, showed the strongest correlations with the ABAS-II General Adaptive Composite (GAC) and domains. Receiver operating characteristic analysis showed that the BASC-2 ASC discriminated children with impaired adaptive functioning on the ABAS-II ( –2 SD) from those without impairment (area under curve range = .86[social domain] to .78[practical domain]); however, sensitivity was inadequate at the typical –2 SD cut-off (48%). A –1 SD cut-off on the BASC-2 (T-score 40) was more appropriate for predicting impairment on the ABAS-II (89%). Among children with impaired IQ, the ABAS-II GAC was impaired in 69% compared to only 36% on the ASC. Findings have implications for the diagnosis of Intellectual Disability and for quantifying the functional impact of other diagnoses, particularly with the release of DSM-5.

Jitter Reduces Response-Time Variability in ADHD: An Ex-Gaussian Analysis.

Objective: “Jitter” involves randomization of intervals between stimulus events. Compared with controls, individuals with ADHD demonstrate greater intrasubject variability (ISV) performing tasks with fixed interstimulus intervals (ISIs). Because Gaussian curves mask the effect of extremely slow or fast response times (RTs), ex-Gaussian approaches have been applied to study ISV. Method: This study applied ex-Gaussian analysis to examine the effects of jitter on RT variability in children with and without ADHD. A total of 75 children, aged 9 to 14 years (44 ADHD, 31 controls), completed a go/no-go test with two conditions: fixed ISI and jittered ISI. Results: ADHD children showed greater variability, driven by elevations in exponential (tau), but not normal (sigma) components of the RT distribution. Jitter decreased tau in ADHD to levels not statistically different than controls, reducing lapses in performance characteristic of impaired response control. Conclusion: Jitter may provide a nonpharmacologic mechanism to facilitate readiness to respond and reduce lapses from sustained (controlled) performance.

More than Intelligence: Distinct Cognitive/Behavioral Clusters Linked to Adaptive Dysfunction in Children

Impairments in adaptive functioning are frequently associated with intellectual disability (ID); however, adaptive dysfunction can be seen in many individuals with a variety of neurological conditions without ID. The extent to which other variables may be associated with adaptive dysfunction is unclear. In a mixed clinical sample of children (n = 348) consecutively referred for neuropsychological evaluation, the majority were rated as showing weak adaptive skills (ABAS-II, >1 SD below the mean; 71%), with a substantial proportion evidencing frank impairment (>2 SD below the mean, 45%). We examined patterns of scores on measures of intelligence (WISC-IV) and behavioral/affective dysregulation (BRIEF and BASC-2). Using hierarchical cluster analysis, a four cluster model yielded the most appropriate fit and adaptive functioning was subsequently examined across clusters. As expected, adaptive functioning was most intact in the cluster characterized by average IQ and minimal behavioral dysregulation. Other clusters were marked by adaptive dysfunction and distinguished by sub-average intellectual functioning and varying behavioral/emotional dysregulation. In contrast to traditional views associating low IQ with adaptive dysfunction, adaptive impairment was comparable between the cluster characterized by low intelligence and the cluster with average intelligence but significant behavioral dysregulation. These data suggest that adaptive functioning should be considered across various cognitive/behavioral conditions.

Parent-and self-ratings of executive functions in adolescents and young adults with spina bifida

This study examined the agreement and consistency of parent- and self-report of executive functioning (EF) (Behavior Rating Inventory of Executive Functions; BRIEF) in an adolescent cohort of youth with myelomeningocele and shunted hydrocephalus (MMH). A total of 30 youth participants with MMH and their parents were recruited during adolescence (age 11–18, mean age 14), and a smaller sample (n = 13) was re-evaluated during young adulthood (age 18–26, mean age 22). Parent- and self-report T-scores were moderately correlated during adolescence (General Executive Composite, GEC, r = .504, p = .007) and adulthood (GEC, r = .571, p = .041). Compared to adolescent self-ratings, parent-ratings suggested higher levels of overall executive dysfunction and problems with metacognitive abilities during adolescence. Preliminary results from a small follow up sample, however, suggest that self- and parent-report of executive functioning may become more comparable during young adulthood. These preliminary data also suggest stability of deficit and/or possible improvement in executive presentation during the transition from adolescence to adulthood in this clinical population. Implications of these findings are discussed.