Clinical correlates of working memory deficits in youth with and without ADHD: A controlled study

Abstract

Objective Both working memory (WM) (a brain system that provides temporary storage and manipulation of the information) and attention-deficit/hyperactivity disorder (ADHD) have been associated with educational deficits. Since WM deficits are prevalent in children with ADHD, the main aim of the present study was to examine whether educational deficits are driven by working memory deficits or driven by the effect of ADHD itself. Method Participants were referred youth with (N=276) and without (N=241) ADHD ascertained from pediatric and psychiatric sources. Assessment included measures of psychiatric, psychosocial, educational, and cognitive functioning. Education deficits were defined as grade retention or placement in special classes, and were assessed using interviews and written rating scales. Working memory was assessed using the WISC-R Freedom from Distractibility (FFD) factor based on digit span, arithmetic and coding. Results Significantly more youth with ADHD had WM deficits than controls (31.9% vs. 13.7%, p< 0.05). In ADHD children, WM deficits were significantly (p<0.01) associated with an increased risk for grade retention and placement in special classes as well as lower scores on reading and math achievement tests, relative to ADHD children without WM deficits. In contrast, no other differences were noted in other areas of functioning. Although WM deficits also had some adverse impact on educational and cognitive correlates in non ADHD controls, these differences failed to attain statistical significance. Conclusion WM deficits significantly and selectively increase the risk for academic deficits and cognitive dysfunction in children with ADHD beyond those conferred by ADHD. Screening for WM deficits may help identify children with ADHD at high risk for academic and cognitive dysfunction.

Increase or Decrease of fMRI Activity in Adult Attention Deficit/ Hyperactivity Disorder: Does It Depend on Task Difficulty?

“…In line with these results, a recent study reports more working memory deficits in children with ADHD than in healthy control children (Fried et al, 2016). Importantly, within this group of children with ADHD, those with pronounced working memory deficits showed worse cognitive functioning and poorer educational outcomes than those without pronounced deficits.…”

A prenatal nicotine exposure mouse model of methylphenidate responsive ADHD‐associated cognitive phenotypes

“…Attention deficit hyperactivity disorder (ADHD) is characterized by hyperactivity, inattention, and impulsivity. In addition, ADHD is frequently associated with executive function deficits, of which working memory deficits are a prominent component (Biederman and Faraone, 2005;Fried et al, 2016;Arnsten, 2009). While both genetic and environmental factors contribute to ADHD risk, cigarette smoking during pregnancy and resulting exposure of the developing fetal brain to nicotine and other constituents of the cigarette smoke ranks very high among the environmental risk factors (Milberger et al, 1996;Linnet et al, 2005;Wilens et al, 2008;Biederman et al, 2012;Pagani, 2014).…”

WISC-IV Intellectual Profiles in Korean Children and Adolescents with Attention Deficit/Hyperactivity Disorder

“…Lower WMI scores in children with ADHD are associated with decreased behavioral function. 35,39 Indeed, a working memory impairment is a core neuropsychological deficit in subjects with ADHD and is proposed as an endophenotype of ADHD. [40][41][42] Working memory deficits involve "cool" executive function, comprising motor response inhibition, sustained attention, response variability, and cognitive switching as well as working memory, and are consistently reported in clinical and cognitive neuroscience studies [43][44][45] Working memory utilizes the inferior fronto-striatal circuit in the brain and is described as a limited-capacity system to manipulate cognitive representations from stimuli, to search for similar or same stimuli in previous experiences, and also to maintain responses.…”

“…Among the subtests included in the WMI, the score for the Digit span subtest were decreased in children with ADHD compared with TC, consistent with a previous study, 52 but the score for the Arithmetic subtest was not. Digit span and Arithmetic subtests, along with the Coding and Symbol search subtest of the WISC-III, were used to measure working memory in a study by Fried et al 39 as Freedom from distractibility factor scores, which are more decreased for children with ADHD than for TC. 53,54 Rosenthal et al 55 also reported lower Digit span scores for individuals with ADHD than for TC, but the difference was not significant after controlling for general cognitive ability.…”