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

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.

A rapid systematic review of attention-deficit/hyperactivity disorder (ADHD) and high order writing: Current findings and implications for intervention

BACKGROUND

Theoretical writing models and empirical studies have suggested a possible strong association between attention-deficit/hyperactivity disorder (ADHD) and high order writing (e.g., planning, text production, and revising).

AIM

A rapid systematic review was conducted to examine this relationship with the aim of informing writing interventions specific to the ADHD population.

METHOD

A systematic search for empirical studies on ADHD and high order writing performance from the last two decades identified 18 eligible studies.

RESULTS

Most studies showed that, compared to their peers, students with ADHD have more significant difficulties in high order writing performance. Writing quality and writing process (e.g., planning and editing) were identified as a challenge for ADHD students and may be more challenging than writing productivity and meta-cognitive knowledge of writing. Individuals' inattention, short-term memory, working memory, executive functions, reading, oral language skills, and externalising behavioural problems were identified as significant predictors of high order writing performance.

CONCLUSIONS AND IMPLICATIONS

The findings support theoretical writing models that propose writing as a complex process influenced by multiple cognitive factors, which are commonly impaired in individuals with ADHD. Interventions specific to the identified problems are discussed.

ADHD and hyperactivity: The influence of cognitive processing demands on gross motor activity level in children

Excessive gross motor activity is a prominent feature of children with ADHD, and accruing evidence indicates that their gross motor activity is significantly higher in situations associated with high relative to low working memory processing demands. It remains unknown, however, whether children's gross motor activity rises to an absolute level or accelerates incrementally as a function of increasingly more difficult cognitive processing demands imposed on the limited capacity working memory (WM) system - a question of both theoretical and applied significance. The present investigation examined the activity level of 8- to 12-year-old children with ADHD (n = 36) and Typically Developing (TD) children (n = 24) during multiple experimental conditions: a control condition with no storage and negligible WM processing demands; a short-term memory (STM) storage condition; and a sequence of WM conditions that required both STM and incrementally more difficult higher-order cognitive processing. Relative to the control condition, all children, regardless of diagnostic status, exhibited higher levels of gross motor activity while engaged in WM tasks that required STM alone and STM combined with upper level cognitive processing demands, and children with ADHD were motorically more active under all WM conditions relative to TD children. The increase in activity as a consequence of cognitive demand was similar for all experimental conditions. Findings suggest that upregulation of physical movement rises and remains relatively stable to promote arousal related mechanisms when engaged in cognitive activities involving WM for all children, and to a greater extent for children with ADHD.

Statistical analysis of childhood and early adolescent externalizing behaviors in a middle low income country

The article show the pattern of externalizing behavior across age, gender, school type, and school level, with reference to aggression, delinquency, and hyperactivity. The study samples were primary school pupils and secondary school students from three selected Local Government Areas (LGA) in Ogun State, Nigeria [Ado-Odo/Ota, Ifo, and Yewa South]. Their ages ranged from 10 to 20 years. The student/pupil sample was 1770 in all. The instrument used was an adapted version of Achenbach's child behavior checklist and youth self-report. Basic descriptive statistics like frequency, percentage, mean, standard deviation, as well as non-parametric statistics like Phi-coefficient, Chi-square, Goodman and Kruskal's gamma, Mann Whitney U test and Kruskal Wallis H test were utilized. Inferential parametric statistics like Pearson r, analysis of variance and simple regression were also utilized. Four major findings were reported. Firstly, the private schools irrespective of age, gender and level, scored higher than the public school in aggression, delinquency, and hyperactivity. Secondly, aggression is higher in secondary schools, while delinquency and hyperactivity are more prevalent in primary schools. Thirdly, school level and school type are the strongest predictors of externalizing behavior. Lastly, correspondence analysis showed a similar behavioral pattern for the three behaviors and three distinct behavioral patterns. i). Respondents aged 10 and below and those in primary schools (ii). Male, public and between 16 and 20. iii). Private, secondary, female and between 11 and 15. Implications of the study are discussed.

A meta-analysis on verbal working memory in children and adolescents with ADHD

Objective: Previous meta-analyses have demonstrated verbal working memory (WM) dysfunction in children and adolescents with attention deficit/hyperactivity disorder (ADHD); however, the findings are inconsistent. The main objective of this meta-analysis was to investigate the performance of children and adolescents with ADHD in the Digit Span Backwards (DSB) subtest from the Wechsler Intelligence Scale for Children or Wechsler Adult Intelligence Scale. We also sought to provide an updated meta-analysis on WM in children and adolescents with ADHD.Method: PubMed, PsyINFO, Scopus, and Web of Science were searched to locate studies published between 1990 and 2016 that report DSB scores both of children and adolescents with ADHD and matched controls. Potential moderator variables were also analyzed.Results: Forty-nine studies comparing children and adolescents with ADHD (n = 4956) against healthy controls (n = 3249) generated a medium-sized effect (Hedges' g) of 0.56 (95% CI [0.49, 0.64]), indicating poorer verbal WM performance in those with ADHD. A subgroup meta-analysis of studies with participants aged 8-16 years only demonstrated low heterogeneity (I² = 17.06, cf. 55.50 for the main analysis). Moreover, the meta-regression showed a negative association (β = -.05, p = .02) between DSB performance differences and increasing age, indicating that for every one year increase in age the effect size decreased by .05.Conclusion: These results, which emanated from the largest meta-analysis concerning verbal WM in ADHD reported to date, reinforce WM as a key domain of cognitive dysfunction in ADHD, and point to age as the main variable influencing DSB performance difficulties.