Working Memory Deficits in Boys with Attention-deficit/Hyperactivity Disorder (ADHD): The Contribution of Central Executive and Subsystem Processes

Abstract

The current study investigated contradictory findings from recent experimental and meta-analytic studies concerning working memory deficits in ADHD. Working memory refers to the cognitive ability to temporarily store and mentally manipulate limited amounts of information for use in guiding behavior. Phonological (verbal) and visuospatial (nonverbal) working memory were assessed across four memory load conditions in 23 boys (12 ADHD, 11 typically developing) using tasks based on Baddeley's (Working memory, thought, and action, Oxford University Press, New York, 2007) working memory model. The model posits separate phonological and visuospatial storage and rehearsal components that are controlled by a single attentional controller (CE: central executive). A latent variable approach was used to partial task performance related to three variables of interest: phonological buffer/rehearsal loop, visuospatial buffer/rehearsal loop, and the CE attentional controller. ADHD-related working memory deficits were apparent across all three cognitive systems--with the largest magnitude of deficits apparent in the CE--even after controlling for reading speed, nonverbal visual encoding, age, IQ, and SES.

Implicación de la memoria visoespacial y fonológica en la heterogeneidad clínica del Trastorno por Déficit de Atención con Hiperactividad (TDAH)

“…The control group showed a better performance both in phonological (Bolden, Rapport, Raiker, Sarver, & Kofler, 2012) and visuospatial (Kofler et al, 2010;Martinussen et al, 2005;Rapport et al, 2008;Willcutt et al, 2005) working memory than ADHD subgroups Kasper et al, 2012;Schoechlin & Engel, 2005;Schweitzer, Hanford, & Medoff, 2006). However, the difference in phonological WM was limited to Letters and Numbers task, while the performance in Inverse Digits task was similar between ADHD and control groups (Holmes et al, 2014;Rosenthal, Riccio, Gsanger, & Jarratt, 2006).…”

“…Thus, Tillman, Eninger, Forssman, and Bohlin (2011), found a proportionally inverse relationship between the performance in phonological and visuospatial WM tasks and the levels of inattention, as well as a significant relationship between hyperactivity/impulsivity symptoms and the phonological WM performance, not in the visuospatial component. These results suggest the implication of different processes of the components that form the WM given the dimensions of ADHD (Tillman et al, 2011), for example, the symptoms of hyperactivity (Rapport et al, 2008), impulsivity or inattention (Burgess et al, 2010;Holmes et al, 2010;Kane et al, 2007), as well as a greater connection between the central executive dysfunction and inattention (Willcutt et al, 2005b).…”

“…• Working Memory Visuospatial (WMVS) Task (adapted from Rapport et al, 2008). It this task, which is considered as a WM visuospatial measure, the subject has to reproduce a sequential series of black and red points in a matrix of 9 fixed locations (800 ms. y 200 ms. intertapping).…”

“…In this regard, Brocki, Rendall, Bohlin, and Kerns (2008) imply a higher deficit in phonological WM in ADHD, as previous studies suggest ( . However, other studies hint that the deficiencies lie in the visuospatial WM (Martinussen et al, 2005;McInnes, Humphries, HoggJohnson, & Tannock, 2003;Rapport et al, 2008;Rommelse et al, 2008;Westerberg, Hirvikoski, Forssberg, & Klingberg, 2004;Willcutt et al, 2005). A third group of investigations point at a more generalised WM decay, a central executive deficit Dovis, Van der Oord, Wiers, & Prins, 2013;Nyman et al, 2010;van Ewijk et al, 2014).…”

Ten years on: A follow-up review of ERP research in attention-deficit/hyperactivity disorder

“…Barkley, 1997;Quay, 1997), state regulation (Sergeant, 2000), motivational processes (Sonuga-Barke, 2002), or working memory (Rapport et al, 2008). Many of the ERP studies reviewed here do not specifically address or compare these theoretical perspectives, but there are some exceptions.…”