Feature Binding and Working Memory in Children with ADHD: Evidence of Episodic Buffer Impairment

Abstract

Previous examinations of working memory impairments in children with attention-deficit/hyperactivity disorder (ADHD) have predominantly focused on discreet visuospatial and phonological subsystem processes, as well as the domain-general central executive. The episodic buffer component of working memory, a neurocognitive process that allows for temporary storage and maintenance of bound episodes/features of information, is understudied in ADHD and initial findings have been equivocal. Heterogeneity in previous findings may reflect between-study methodological variability, floor effects unrelated to episodic buffer processes (i.e., excessive central executive demands), and limitations associated with previous investigations' use of novel paradigms. This study examined ADHD-related episodic buffer processing via an established paradigm (Allen et al., 2006) in well-defined groups of children with attention-deficit/hyperactivity disorder (ADHD) and typically developing peers (TD). Seventy-one children (ADHD n = 34, TD n = 37) aged 8-12 years (M = 9.81, SD = 1.50; 32% female) completed two conditions of a computerized working memory task that presented single feature stimuli (color and shape), and a third condition that presented dual-feature stimuli (color/shape binding). Overall, the ADHD group exhibited a large-magnitude deficit during the color/shape binding condition (d = .77), and both groups evinced worse performance accuracy in the color/ shape binding condition compared to the single feature color and shape conditions. Collectively, these findings appear to provide evidence that children with ADHD exhibit large magnitude episodic buffer deficits that are not attributable to visuospatial subsystem or domain-general central executive processes.

Working memory and math skills in children with and without ADHD.

“…Similarly, future studies may benefit from including additional tasks that require episodic buffer processes to provide a more complete representation of the most recent version of the Baddeley (2017) working memory model, despite recent experimental evidence indicating that the episodic buffer is likely intact in most children with ADHD (Kofler et al, 2017; cf. Alderson et al, 2022). Next, despite the inclusion of practice trials to ensure task comprehension, future research is needed to determine the role of language processes in the association between phonological short-term memory, ADHD, and math (Korrel et al, 2017).…”

“…The episodic buffer component was not investigated in the present study; prior experimental work suggests that the episodic buffer is likely intact in pediatric ADHD (Kofler et al, 2017; cf. Alderson et al, 2022).…”

Social functioning in children with ADHD: an examination of inhibition, self-control, and working memory as potential mediators

“…Willcutt and colleagues (2005) modeling approach, and found that children with ADHD showed no significant deficits in VS storage/rehearsal processes, small-magnitude deficits in PH storage/rehearsal processes, and large-magnitude deficits in domain-general CE processes. Finally, recent studies have begun to examine the relatively new episodic buffer component of working memory and findings appear to suggest episodic buffer deficits in children with ADHD (Kofler et al, 2018;Alderson et al, 2021).…”

Phonological working memory in children with and without ADHD: A systematic evaluation of recall errors.

“…Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood (Perou et al, 2013) and is recognized as a psychiatric condition associated with adverse outcomes that significantly affect individuals throughout the lifespan (Shaw et al, 2012). Experimental (Alderson et al, 2010; Rapport et al, 2008) and meta-analytic (Kasper et al, 2012; Martinussen et al, 2005) research has provided extensive evidence of working memory impairments in ADHD, and converging evidence indicates that children with ADHD are impaired across each domain of working memory, including the central executive (Rapport et al, 2008), the visuospatial and phonological storage/rehearsal subsystems (Kasper et al, 2012; Martinussen et al, 2005; Rapport et al, 2008), and more recently, the episodic buffer (Alderson et al, 2022). In particular, ADHD-related phonological working memory impairments have garnered interest due to reliable evidence of moderate- to large-magnitude between-group (ADHD vs. typically developing [TD]) effects (ranging from d = 0.42 to 2.78; Kasper et al, 2012; Martinussen et al, 2005), as well their association with comorbid learning disorders (DuPaul et al, 2013) and a wide range of academic difficulties, including math performance (Rogers et al, 2011), word recognition skills (Swanson & Howell, 2001), and reading comprehension (Rogers et al, 2011).…”

“…that children with ADHD are impaired across each domain of working memory, including the central executive (Rapport et al, 2008), the visuospatial and phonological storage/rehearsal subsystems (Kasper et al, 2012;Martinussen et al, 2005;Rapport et al, 2008), and more recently, the episodic buffer (Alderson et al, 2022). In particular, ADHD-related phonological working memory impairments have garnered interest due to reliable evidence of moderate-to large-magnitude between-group (ADHD vs. typically developing [TD]) effects (ranging from d = 0.42 to 2.78; Kasper et al, 2012;Martinussen et al, 2005), as well their association with comorbid learning disorders (DuPaul et al, 2013) and a wide range of academic difficulties, including math performance (Rogers et al, 2011), word recognition skills (Swanson & Howell, 2001), and reading comprehension (Rogers et al, 2011).…”