Working and short-term memory in children with ADHD: an examination of prefrontal cortical functioning using functional Near-Infrared Spectroscopy (fNIRS).

Working memory impairments are an oft-reported deficit among children with ADHD, and complementary neuroimaging studies implicate reductions in prefrontal cortex (PFC) structure and function as a neurobiological explanation. Most imaging studies, however, rely on costly, movement-intolerant, and/or invasive methods to examine cortical differences. This is the first study to use a newer neuroimaging tool that overcomes these limitations, functional Near Infrared Spectroscopy (fNIRS), to investigate hypothesized prefrontal differences. Children (aged 8-12) with ADHD (N = 22) and typically developing (N = 18) children completed phonological working memory (PHWM) and short-term memory (PHSTM) tasks. Children with ADHD evinced poorer performance on both tasks, with greater differences observed in PHWM (Hedges' g = 0.67) relative to PHSTM (g = 0.39). fNIRS revealed reduced hemodynamic response among children with ADHD in the dorsolateral PFC while completing the PHWM task, but not within the anterior or posterior PFC. No between-group fNIRS differences were observed during the PHSTM task. Findings suggest that children with ADHD exhibit an inadequate hemodynamic response in a region of the brain that underlies PHWM abilities. The study also highlights the use of fNIRS as a cost-effective, noninvasive neuroimaging technique to localize/quantify neural activation patterns associated with executive functions.

Development of a Web-Based Training Platform for School Clinicians in Evidence-Based Practices for ADHD.

Lack of training for school clinicians in evidence-based practices (EBPs) contributes to underutilization of such services for youth with attention-deficit/hyperactivity disorder (ADHD). Advances in web-based technology and videoconferencing have allowed for expanded access to and optimization of training. We describe the development and outcomes of a novel web-based platform for training school clinicians to gain skills in EBPs for school-age youth with ADHD. The training platform is adapted from an empirically supported, in-person training for a school-home behavioral intervention (Collaborative Life Skills program) and includes skill modules for working with teachers, parents, and students. Training methods include web-accessed manuals/handouts, skill example video clips, automated progress monitoring tools, and consultation/in-session coaching via videoconferencing. We gathered stakeholder qualitative and quantitative feedback during discovery and design phases of the iterative development. We then evaluated the usability, acceptability, fidelity and clinician and student outcomes of the remote training program. Focus group themes and qualitative feedback identified clinician preferences for remote training features (e.g., interactive, brief, role-plays/coaching methods), video tools (recorded samples of skills and therapy sessions), and progress monitoring tools (e.g., clear, easy to use). Clinician usability ratings of the platform were high with most components rated as moderately to very useful/easy to use. Clinician ratings of usability, fidelity implementing the treatment, and their EBP knowledge and confidence following training were favorable. Student's outcomes were similar to those achieved in prior studies of clinician in-person training. Results support the promise of remote, web-based clinician training for the dissemination of evidence-based practices.

Verbal Memory Interference in Attention-Deficit Hyperactivity Disorder: A Meta-Analytic Review.

OBJECTIVE: Interference control is used to overcome conflict among competing memory representations and may contribute to memory difficulties in ADHD. This meta-analytic review examined memory interference to evaluate susceptibility to proactive, retroactive, and memory control interference among those with ADHD. METHOD: Twenty studies (1987-2019) examining verbal memory interference in ADHD met inclusion criteria (age: 8-36 years). Proactive and retroactive interference indices were extracted from list-learning tasks, and memory control indices were extracted from experimental paradigms (e.g., directed-forgetting). RESULTS: Children with ADHD were less affected by proactive interference (g=-0.53, 95% CI [-0.75, -0.31]), whereas no significant differences were found in adults (g=0.13, 95% CI [-0.02, 0.28]). Adults and children with ADHD exhibited more retroactive interference (g=0.17, 95% CI [0.05, 0.29]) and performed worse on memory control tasks (g=0.35, 95% CI [0.08, 0.62]) relative to controls. CONCLUSION: Differences in verbal memory interference control in ADHD were observed but effects were different depending upon interference type and participant age.

Patterns of Parental Adherence and the Association to Child and Parenting Outcomes Following a Multicomponent School-Home Intervention for Youth With ADHD.

The goal of the present study was to evaluate the role of parent adherence in the Collaborative Life Skills (CLS) program, a multicomponent school-home intervention, for predicting child and parenting outcomes. A sample of 129 children (63% male; M age = 8.22, SD = 1.10; grades 2-5) with attention-deficit/hyperactivity disorder (ADHD) and their parents participated in CLS, which included 10 weekly behavioral parent training group sessions. Each week, parents provided information on their CLS skill use between sessions (at home) as part of the intervention. Outcome measures included parent and teacher ratings of child behavior and parenting at post-intervention and 6 months follow-up. Growth mixture models examining weekly parent skill use trajectories throughout the intervention significantly predicted parent- and teacher-reported outcomes including parent-rated child behavior, teacher-rated academic competence, and positive parenting behaviors. Fifty-two percent of parents displayed moderate skill use throughout the intervention, whereas the remaining parents had either low (20%) or high (28%) initial levels of use but demonstrated high skill utilization by the middle of the intervention. Results highlight the importance of examining individual differences in parents between session strategy use for behavioral parent training interventions targeting child and parenting outcomes.

Can School Mental Health Providers Deliver Psychosocial Treatment Improving Youth Attention and Behavior in Mexico? A Pilot Randomized Controlled Trial of CLS-FUERTE.

BACKGROUND: Despite well-established Evidence-Based Treatments (EBTs) for Attention-Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD), many low-resource settings lack EBT access. METHODS: We conducted a school-clustered randomized controlled pilot of CLS-FUERTE (a multicomponent behavioral EBT adapted for children in Mexico) with 58 students. We randomly assigned four schools to receive CLS-FUERTE and four to receive school services as usual. We compared groups post-treatment on parent- and teacher-rated ADHD/ODD symptoms and impairment. RESULTS: CLS-FUERTE fidelity, attendance, engagement, and acceptability was high and students receiving CLS-FUERTE showed greater improvement in teacher-rated ADHD, ODD, and impairment, as well as parent-rated ADHD and impairment, compared to students receiving usual services. CONCLUSIONS: Pilot results suggest that psychosocial EBTs can be successfully implemented by School Mental Health Providers in Mexico.

Working Memory Capacity and ADHD Symptoms in Boys: Examining the Heterogeneity of Working Memory Functioning Using Latent Profile Analysis.

Recent studies demonstrate that working memory (WM) is integral to etiological models of ADHD; however, significant questions persist regarding the relation between WM performance across tasks with varying cognitive demands and ADHD symptoms. The current study incorporates an individual differences approach to WM heterogeneity (i.e., latent profile analysis) to (a) identify differential profiles of WM across the phonological and visuospatial WM subsystems; and (b) characterize differences in symptom presentation among WM profiles. Parent and teacher ratings of child behavior, obtained for boys with (n=51) and without (n=38) a diagnosis of ADHD, were compared across latent classes of visuospatial and phonological WM performance. Latent profile analysis identified three classes of WM functioning: Low WM, Moderate WM, and High WM. Membership in the Low and Moderate WM classes was associated with greater levels of parent- and teacher-rated inattentive and hyperactive symptoms. While 84% of the ADHD group were assigned to the Low and Moderate WM classes, more than a quarter of children without ADHD exhibited Moderate WM limitations. Collectively, these findings extend prior work suggesting that there is substantial heterogeneity in WM functioning in children with and without ADHD and that these differences contribute to the expression of symptoms of inattention and hyperactivity.

Do Parents' ADHD Symptoms Affect Treatment for their Children? The Impact of Parental ADHD on Adherence to Behavioral Parent Training for Childhood ADHD.

Nearly half of all youth with Attention-Deficit Hyperactivity Disorder (ADHD) have at least one parent who also meets criteria for the disorder, and intergenerational ADHD is a significant risk factor for poor outcomes following evidence-based behavioral parent training (BPT) programs. Given that BPT is predicated on consistent parental involvement, symptoms of ADHD in parents may be a significant barrier to effective engagement with BPT treatment. In the present investigation, we examine the effect of parental ADHD symptoms on BPT treatment engagement for children with ADHD-predominantly inattentive presentation (N = 148, ages 7-11). We examine the following parent- and clinician-rated treatment engagement domains: between-session skill adherence, in-session participation, perceived skill understanding, treatment-engagement attitudes, and session attendance. Parent- and clinician-rated between-session adherence was the only treatment engagement domain related significantly to parental ADHD symptoms. This finding was robust and remained even after accounting for symptoms of parental anxiety and depression, child ADHD symptom severity, and various sociodemographic factors (parental education level, household income, employment status, and being a single parent). These findings suggest that targeting parental ADHD symptoms in the context of parenting interventions may be a promising approach for improving adherence and treatment outcomes for BPT interventions.

Outcomes of School-Home Intervention for Attention and Behavior Problems: Teacher Adherence Matters.

This study evaluated the effects of teacher adherence to behavioral treatment on student outcomes. Eighty-four children (ages 7-11) completed a 12-week, collaborative school-home behavioral intervention designed for youth with significant attention-deficit/hyperactivity disorder symptoms and impairment. Teacher adherence was assessed via school mental health provider (SMHP) ratings and Daily Report Card (DRC) implementation. Pre- and post-treatment outcomes included parent and teacher ratings of organizational skills and problem behaviors, observational measures of classroom task engagement and off task behaviors and report card standard grades. Using multi-level models to account for clustering by school, teacher adherence rated by SMHPs predicted improvement across teacher- and parent-rated organizational skills, parent-rated problem behaviors, and classroom observations of task engagement and off-task behavior. Higher rates of DRC implementation only predicted improvements in parent-rated organizational skills; percentage of days parents signed the DRC only predicted teacher-rated improvement in organizational skills. Post-hoc analyses indicated that teacher adherence and child success with academic targets on the DRC during the first month predicted parent-rated improvement in organizational skills. These results suggest that teacher adherence, particularly when rated by SMHPs, is an important predictor of positive treatment outcomes across both school and home settings. Future research is needed to better understand methods for measuring and optimizing teacher adherence to classroom behavioral interventions.

Learning Disorder Confers Setting-Specific Treatment Resistance for Children with ADHD, Predominantly Inattentive Presentation.

Attention deficit/hyperactivity disorder-predominantly inattentive presentation (ADHD-I) and specific learning disorder (SLD) are commonly co-occurring conditions. Despite the considerable diagnostic overlap, the effect of SLD comorbidity on outcomes of behavioral interventions for ADHD-I remains critically understudied. The current study examines the effect of reading or math SLD comorbidity in 35 children with comorbid ADHD-I+SLD and 39 children with ADHD-I only following a behavioral treatment integrated across home and school (Child Life and Attention Skills [CLAS]). Pre- and posttreatment outcome measures included teacher-rated inattention, organizational deficits, and study skills and parent-rated inattention, organizational deficits, and homework problems. A similar pattern emerged across all teacher-rated measures: Children with ADHD-I and comorbid ADHD-I+SLD did not differ significantly at baseline, but between-group differences were evident following the CLAS intervention. Specifically, children with ADHD-I and comorbid ADHD-I+SLD improved on teacher-rated measures following the CLAS intervention, but children with ADHD-I only experienced greater improvement relative to those with a comorbid SLD. No significant interactions were observed on parent-rated measures-all children improved following the CLAS intervention on parent-rated measures, regardless of SLD status. The current results reveal that children with ADHD-I+SLD comorbidity benefit significantly from multimodal behavioral interventions, although improvements in the school setting are attenuated significantly. A treatment-resistant fraction of inattention was identified only in the SLD group, implying that this fraction is related to SLD and becomes apparent only when behavioral intervention for ADHD is administered.

Phonological Working Memory Deficits in ADHD Revisited: The Role of Lower Level Information-Processing Deficits in Impaired Working Memory Performance.

OBJECTIVE: The current study dissociates lower level information-processing abilities (visual registration/encoding, visual-to-phonological conversion, and response output) and examines their contribution to ADHD-related phonological working memory (PHWM) deficits. METHOD: Twenty children with ADHD and 15 typically developing (TD) children completed tasks assessing PHWM, visual registration/encoding, visual-to-phonological conversion, and response output. RESULTS: Relative to TD children, children with ADHD exhibited deficient visual registration/encoding ( d = 0.60), visual-to-phonological conversion ( d = 0.56), and PHWM ( d = 0.72) but faster response output ( d = -0.66). Bias-corrected, bootstrapped mediation analyses revealed that visual registration/encoding, but not visual-to-phonological conversion, partially mediated ADHD-related PHWM impairments. In contrast, faster response output in children with ADHD served as a suppressor variable, such that greater PHWM deficits were observed in children with ADHD after controlling for their faster response output ( d = 0.72 vs. 0.85). CONCLUSION: Results implicate both lower level (visual registration/encoding) and higher order (PHWM) impairments in ADHD. Implications for designing educationally relevant cognitive interventions are discussed.

Written expression in boys with ADHD: The mediating roles of working memory and oral expression.

The written expression difficulties experienced by children with ADHD are widely recognized; however, scant empirical evidence exists concerning the cognitive mechanisms and processes underlying these deficiencies. The current study investigated the independent and potentially interactive contributions of two developmentally antecedent cognitive processes - viz., working memory (WM) and oral expression - hypothesized to influence written expression ability in boys. Thirty-three boys with ADHD-Combined Presentation and 27 neurotypical (NT) boys 8-12 years of age were administered standardized measures of oral and written expression, and multiple counterbalanced tasks to assess WM central executive (CE) processes, WM phonological short-term memory (PH STM), and WM visuospatial short-term memory (VS STM). Bias-corrected bootstrapped mediation analyses revealed a significant mediation effect, wherein the independent and interactive effects of PH STM and oral expression collectively explained 76% of the diagnostic status to written expression relation. The implications of the obtained results for clinical practice suggest that children with ADHD may benefit by incorporating a blended approach that simultaneously strengthens PH STM capacity and oral expression abilities as antecedents to engaging in writing-related activities.

Inattentive Behavior in Boys with ADHD during Classroom Instruction: the Mediating Role of Working Memory Processes.

Children with ADHD exhibit clinically impairing inattentive behavior during classroom instruction and in other cognitively demanding contexts. However, there have been surprisingly few attempts to validate anecdotal parent/teacher reports of intact sustained attention during 'preferred' activities such as watching movies. The current investigation addresses this omission, and provides an initial test of how ADHD-related working memory deficits contribute to inattentive behavior during classroom instruction. Boys ages 8-12 (M = 9.62, SD = 1.22) with ADHD (n = 32) and typically developing boys (TD; n = 30) completed a counterbalanced series of working memory tests and watched two videos on separate assessment days: an analogue math instructional video, and a non-instructional video selected to match the content and cognitive demands of parent/teacher-described 'preferred' activities. Objective, reliable observations of attentive behavior revealed no between-group differences during the non-instructional video (d = -0.02), and attentive behavior during the non-instructional video was unrelated to all working memory variables (r = -0.11 to 0.19, ns). In contrast, the ADHD group showed disproportionate attentive behavior decrements during analogue classroom instruction (d = -0.71). Bias-corrected, bootstrapped, serial mediation revealed that 59% of this between-group difference was attributable to ADHD-related impairments in central executive working memory, both directly (ER = 41%) and indirectly via its role in coordinating phonological short-term memory (ER = 15%). Between-group attentive behavior differences were no longer detectable after accounting for ADHD-related working memory impairments (d = -0.29, ns). Results confirm anecdotal reports of intact sustained attention during activities that place minimal demands on working memory, and indicate that ADHD children's inattention during analogue classroom instruction is related, in large part, to their underdeveloped working memory abilities.

Applied Problem Solving in Children with ADHD: The Mediating Roles of Working Memory and Mathematical Calculation.

The difficulties children with ADHD experience solving applied math problems are well documented; however, the independent and/or interactive contributions of cognitive processes underlying these difficulties are not fully understood and warrant scrutiny. The current study examines two primary cognitive processes integral to children's ability to solve applied math problems: working memory (WM) and math calculation skills (i.e., the ability to utilize specific facts, skills, or processes related to basic math operations stored in long-term memory). Thirty-six boys with ADHD-combined presentation and 33 typically developing (TD) boys aged 8-12 years old were administered multiple counterbalanced tasks to assess upper (central executive [CE]) and lower level (phonological [PH STM] and visuospatial [VS STM] short-term memory) WM processes, and standardized measures of mathematical abilities. Bias-corrected, bootstrapped mediation analyses revealed that CE ability fully mediated between-group differences in applied problem solving whereas math calculation ability partially mediated the relation. Neither PH STM nor VS STM was a significant mediator. When modeled together via serial mediation analysis, CE in tandem with math calculation ability fully mediated the relation, explained 79% of the variance, and provided a more parsimonious explication of applied mathematical problem solving differences among children with ADHD. Results suggest that interventions designed to address applied math difficulties in children with ADHD will likely benefit from targeting basic knowledge of math facts and skills while simultaneously promoting the active interplay of these skills with CE processes.

Intrathecal catheter-associated inflammatory mass in a neurofibromatosis type-1 patient receiving fentanyl and bupivacaine.

BACKGROUND: Catheter-associated inflammatory masses (CIMs) are a rare but serious complication of intrathecal drug delivery devices. CIM formation is influenced by local medication concentration, which is determined in part by flow dynamics at the catheter tip. Underlying spinal pathologies, such as neoplasms, may alter flow at the catheter tip, thereby contributing to CIM formation. Moreover, they may also complicate the clinical and radiologic diagnosis of a CIM. CASE DESCRIPTION: A 36-year-old man with neurofibromatosis type 1 presented to our emergency department with complaints of increased back pain and leg weakness. To treat pain secondary to his multiple spinal masses, he had previously undergone placement of an implantable drug delivery system, which infused a compounded drug of fentanyl and bupivacaine. Imaging studies depicted numerous masses consistent with neurofibromatosis, including a compressive mass located circumferentially at the porous catheter terminus and proximal to the catheter tip. Surgical removal of this mass was performed; pathologic findings were consistent with a catheter tip granuloma. CONCLUSIONS: In the described case, CIM formation likely resulted from a combination of, 1) an unusually high fentanyl concentration, and, 2) altered infusate flow due to spinal neurofibromas. Consideration of underlying spinal pathologies, particularly mass lesions, is critical to the management of intrathecal drug delivery devices.

Reading Comprehension in Boys with ADHD: The Mediating Roles of Working Memory and Orthographic Conversion.

Reading comprehension difficulties in children with ADHD are well established; however, limited information exists concerning the cognitive mechanisms that contribute to these difficulties and the extent to which they interact with one another. The current study examines two broad cognitive processes known to be involved in children's reading comprehension abilities-(a) working memory (i.e., central executive processes [CE], phonological short-term memory [PH STM], and visuospatial short-term memory [VS STM]) and (b) orthographic conversion (i.e., conversion of visually presented text to a phonological code)-to elucidate their unique and interactive contribution to ADHD-related reading comprehension differences. Thirty-one boys with ADHD-combined type and 30 typically developing (TD) boys aged 8 to 12 years (M = 9.64, SD = 1.22) were administered multiple counterbalanced tasks assessing WM and orthographic conversion processes. Relative to TD boys, boys with ADHD exhibited significant deficits in PH STM (d = -0.70), VS STM (d = -0.92), CE (d = -1.58), and orthographic conversion (d = -0.93). Bias-corrected, bootstrapped mediation analyses revealed that CE and orthographic conversion processes modeled separately mediated ADHD-related reading comprehension differences partially, whereas PH STM and VS STM did not. CE and orthographic conversion modeled jointly mediated ADHD-related reading comprehension differences fully wherein orthographic conversion's large magnitude influence on reading comprehension occurred indirectly through CE's impact on the orthographic system. The findings suggest that adaptive cognitive interventions designed to improve reading-related outcomes in children with ADHD may benefit by including modules that train CE and orthographic conversion processes independently and interactively.

Hyperactivity in Attention-Deficit/Hyperactivity Disorder (ADHD): Impairing Deficit or Compensatory Behavior?

Excess gross motor activity (hyperactivity) is considered a core diagnostic feature of childhood ADHD that impedes learning. This view has been challenged, however, by recent models that conceptualize excess motor activity as a compensatory mechanism that facilitates neurocognitive functioning in children with ADHD. The current study investigated competing model predictions regarding activity level's relation with working memory (WM) performance and attention in boys aged 8-12 years (M = 9.64, SD = 1.26) with ADHD (n = 29) and typically developing children (TD; n = 23). Children's phonological WM and attentive behavior were objectively assessed during four counterbalanced WM tasks administered across four separate sessions. These data were then sequenced hierarchically based on behavioral observations of each child's gross motor activity during each task. Analysis of the relations among intra-individual changes in observed activity level, attention, and performance revealed that higher rates of activity level predicted significantly better, but not normalized WM performance for children with ADHD. Conversely, higher rates of activity level predicted somewhat lower WM performance for TD children. Variations in movement did not predict changes in attention for either group. At the individual level, children with ADHD and TD children were more likely to be classified as reliably Improved and Deteriorated, respectively, when comparing their WM performance at their highest versus lowest observed activity level. These findings appear most consistent with models ascribing a functional role to hyperactivity in ADHD, with implications for selecting behavioral treatment targets to avoid overcorrecting gross motor activity during academic tasks that rely on phonological WM.

Do programs designed to train working memory, other executive functions, and attention benefit children with ADHD? A meta-analytic review of cognitive, academic, and behavioral outcomes.

Children with ADHD are characterized frequently as possessing underdeveloped executive functions and sustained attentional abilities, and recent commercial claims suggest that computer-based cognitive training can remediate these impairments and provide significant and lasting improvement in their attention, impulse control, social functioning, academic performance, and complex reasoning skills. The present review critically evaluates these claims through meta-analysis of 25 studies of facilitative intervention training (i.e., cognitive training) for children with ADHD. Random effects models corrected for publication bias and sampling error revealed that studies training short-term memory alone resulted in moderate magnitude improvements in short-term memory (d=0.63), whereas training attention did not significantly improve attention and training mixed executive functions did not significantly improve the targeted executive functions (both nonsignificant: 95% confidence intervals include 0.0). Far transfer effects of cognitive training on academic functioning, blinded ratings of behavior (both nonsignificant), and cognitive tests (d=0.14) were nonsignificant or negligible. Unblinded raters (d=0.48) reported significantly larger benefits relative to blinded raters and objective tests (both p<.05), indicating the likelihood of Hawthorne effects. Critical examination of training targets revealed incongruence with empirical evidence regarding the specific executive functions that are (a) most impaired in ADHD, and (b) functionally related to the behavioral and academic outcomes these training programs are intended to ameliorate. Collectively, meta-analytic results indicate that claims regarding the academic, behavioral, and cognitive benefits associated with extant cognitive training programs are unsupported in ADHD. The methodological limitations of the current evidence base, however, leave open the possibility that cognitive training techniques designed to improve empirically documented executive function deficits may benefit children with ADHD.

Reaction time variability in ADHD: a meta-analytic review of 319 studies.

Individuals with ADHD are characterized as ubiquitously slower and more variable than their unaffected peers, and increased reaction time (RT) variability is considered by many to reflect an etiologically important characteristic of ADHD. The present review critically evaluates these claims through meta-analysis of 319 studies of RT variability in children, adolescents, and adults with ADHD relative to typically developing (TD) groups, clinical control groups, and themselves (subtype comparisons, treatment and motivation effects). Random effects models corrected for measurement unreliability and publication bias revealed that children/adolescents (Hedges' g=0.76) and adults (g=0.46) with ADHD demonstrated greater RT variability relative to TD groups. This increased variability was attenuated by psychostimulant treatment (g=-0.74), but unaffected by non-stimulant medical and psychosocial interventions. Individuals with ADHD did not evince slower processing speed (mean RT) after accounting for RT variability, whereas large magnitude RT variability deficits remained after accounting for mean RT. Adolescents and adults with ADHD were indistinguishable from clinical control groups, and children with ADHD were only minimally more variable than clinical control children (g=0.25). Collectively, results of the meta-analysis indicate that RT variability reflects a stable feature of ADHD and other clinical disorders that is robust to systematic differences across studies.