Examining Heterogeneity in Short-Term Memory via Autonomic Nervous System Functioning Among Youth with ADHD: A...

Short-term memory (STM) impairments are common among youth with attention-deficit/hyperactivity disorder (ADHD), but not inherent to the disorder. Little is known about predictors driving heterogeneity in STM among youth with ADHD. Prior work (i.e., Ward et al., 2015) has shown that parasympathetic nervous system functioning may play a role explaining this heterogeneity. The current study sought to replicate and extend this study with a diverse sample of 285 children (N = 143 clinically recruited with ADHD) ages 6 to 12 years. Parents reported on child psychopathology and youth completed a visual spatial STM task while psychophysiological data (i.e., heart rate, respiration rate, skin conductance) were recorded, then derived to relevant parasympathetic (i.e., respiratory sinus arrhythmia [RSA]) and sympathetic (i.e., electrodermal activity [EDA]) indexes. Youth with ADHD exhibited lower STM, lower resting RSA, and task-based RSA increase from baseline compared to typically developing peers. RSA moderated the association between STM and ADHD, such that low STM was associated with ADHD in the context of RSA increase from baseline. This was in contrast to Ward and colleagues (2015), which reported that low STM was associated with ADHD in the context of RSA withdrawal from baseline. When analyses were limited to youth with ADHD only, EDA moderated the association between STM and ADHD symptoms, such that low STM performance was associated with elevated symptoms in the context of EDA augmentation from baseline. Findings are discussed in comparison to the original study, and possible explanations for discrepancies in results are explored. Future research directions are proposed.