Within-subject variability during spatial working memory in children with ADHD: an event-related potentials study

Abstract

Working memory (WM) dysfunction and increased within-subject variability are known issues in attention deficit/hyperactivity disorder (ADHD) patients. Little is known about the electrophysiological characteristics of this variability. We evaluated behavioral and electrophysiological within-subject variability taking developmental aspects into account in a group of ADHD patients. Multichannel (n = 31) event-related potentials (ERP) were measured during a visuo-spatial backmatching task; 44 children (8-16 years old) were tested: 22 children with ADHD, combined (n = 17) and inattentive (n = 5) type, and 22 age- and intelligence-matched control children. One-backmatching (BM1) and two-backmatching (BM2) tasks were performed. Classical behavioral parameters and target and nontarget ERP were compared between groups. In addition, motor response variability and ERP amplitude variability were studied. Age-related changes in both motor response and ERP amplitude variability were analyzed in each group. Attention deficit/hyperactivity disorder children made more commission errors, which was more pronounced in the difficult (BM2) task. No difference between groups was found in ERP amplitude and in motor response variability. However, ADHD patients had higher ERP amplitude variability, which was again more pronounced in the difficult WM task. A delayed maturation of amplitude variability was seen in ADHD patients with a slower than in controls decrease in variability with age. This amplitude variability was correlated with the number of commissions, but in an opposite way for ADHD and control children. Our findings indicate an impaired visuo-spatial WM processing in ADHD children with greater ERP amplitude variability compared to controls. Our results also support the view of a delayed cortical development of visuo-spatial WM circuits in this disorder.

Atypical neural variability in carriers of 16p11.2 copy number variants

“…Previous studies also found higher timecourse variability in ADHD (time window: 0–500 ms [Gonen‐Yaacovi et al, ] and time window: 0–600 ms [Myatchin, Lemiere, Danckaerts, & Lagae, ]), similar to our finding in relation to timecourse variability in DEL. Gonen‐Yaacovi et al [] also computed baseline variability (previsual stimulus onset; time window: −200‐0 ms) and reported higher variability in ADHD—again consistent with our DEL findings.…”

Deficient interference control during working memory updating in adults with ADHD: An event-related potential study

“…However, abnormalities such as increased ERP amplitude variability (Myatchin et al, 2012), reduced ERP amplitudes (Keage et al, 2008;Kim et al, 2014), or atypical WM load effects on ERPs (Gomarus et al, 2009, Spronk et al, 2013 have been consistently found in children, adolescents, and adults with ADHD. Gomarus et al (2009) found the SRN (search-related negativity; a long latency wave 300 -600 ms post-stimulus) in a visual selective memory task to be insensitive to WM load in children with ADHD.…”

Is the Cogmed program effective for youths with ADHD under pharmacological treatment ?

“…Regarding methodology, the results of our study confirm the relevance of including two baseline measurement time points, at least for the nonverbal reasoning test, given that the participants in the Cogmed group improved their performance from T1 to T2, which corresponds to a learning effect. These results indicate that nonverbal reasoning capacity tends to vary for a given person with ADHD (Borella, de Ribaupierre, Cornoldi, & Chicherio, 2013;Myatchin et al, 2012). This observation sheds a different light on the effects of the Cogmed program on nonverbal reasoning reported by Klingberg et al (2005).…”

“…Finally, no study reviewed included repeated baseline measurements of ADHD symptoms and cognitive functions prior to beginning the Cogmed program. Yet, it is acknowledged that ADHD symptoms and cognitive test performances tend to vary in the same participant from one evaluation to the next (Borella, De Ribaupierre, Cornoldi, & Chicherio, 2013;Myatchin, Lemiere, Danckaerts, & Lagae, 2012).…”