Scientific Abstract

Previous research examining intraindividual variability (IIV) on cognitive tasks among individuals with ADHD has tended to focus on variability in reaction times on cognitive task trials. However, intraindividual variability that occurs in moment-to-moment daily cognition has not been examined thus far. This study utilized an Ecological Momentary Assessment (EMA) methodology to investigate within-individual variability across measurement occasions and its association with self-reported ADHD symptoms as well as daily lifestyle activities. Data was collected from 116 young adults (Mage = 19.9 years, 68% female, and 44% White) who completed a baseline session in the lab, followed by three semi-randomized EMA sessions per day over two weeks. Each EMA session included three cognitive tasks and a counterbalanced selection of additional surveys. Data was analyzed using Mixed Effects Location Scale models. Results indicated that higher ADHD symptoms were associated with greater variability in reaction times for tasks requiring cognitive flexibility and working memory, but less variability in reaction times on an inhibitory control task. Several interaction models were then conducted to investigate if daily activities influenced the association between self-reported ADHD symptoms and cognitive variability. Several of these were found to be significant, however there was considerable heterogeneity in the results. This study is the first to examine intraindividual variability across occasions in the context of ADHD symptomology and represent an important step towards better understanding of daily cognition in young adults with ADHD symptoms. 

General Audience Abstract

Although our cognitive abilities are generally thought to be stable overall, they actually tend to fluctuate quite a bit over time depending on lifestyle activities and environmental or contextual influences. Recently, scientists have started looking at these fluctuations in cognition (termed intraindividual cognitive variability) as meaningful indicators of the processes that are responsible for everyday cognitive functioning. Previous studies have shown that individuals with ADHD tend to be more variable in their response times on cognitive tasks, meaning that they alternate between being very slow or very fast when responding and are less consistent overall. However, previous work has primarily focused on within-person variability on cognitive tasks at a single measurement occasion, not within-person cognitive fluctuations that might occur at different times, day to day. This study consists of 116 young adults (Mage = 19.9 years, 68% female, 44% White) who completed cognitive tasks as well as surveys on recent activities such as physical activity, sleep, video gaming and so on, three times a day for two weeks following a lab visit. The data was then analyzed using Mixed Effect Location Scale models, which allow variability to be studied instead of ignored. The results showed that individuals who reported higher ADHD symptoms had more cognitive variability on tasks that required cognitive flexibility (the ability to juggle between multiple tasks or rules at the same time) as well as working memory (the ability to remember information temporarily and modify it). However, they also were less variable on a task that required inhibitory control (the ability to stop a dominant response). There were also links between daily activities and cognitive variability, however these results varied highly across different lifestyle activities. These findings may represent an important first step to better understand how ADHD symptoms may influence cognition in real-world settings.  

Type 1 diabetes (T1D) is a chronic disease that is due to the dysregulation of glucose in the blood when insulin is not made endogenously. Patients rely on a combination of exogenic insulin, medications, blood glucose monitoring, and healthy lifestyle activities such as dietary control and exercise to manage their blood glucose levels. T1D typically begins its onset during childhood or adolescence, where it may also affect the development of executive function (EF) processes which are also relevant for self-regulation, or goal-directed behavior. This in turn may affect individuals’ adherence to their T1D management regimens, which can result in severe short- and long-term complications. Despite evidence for the plasticity of EF during childhood, previous research has not frequently focused on EF or self-regulation (SR) as a possible mechanism for improving health outcomes in adolescents with T1D. This study focused on the dosage of EF training and its possible effects on both cognitive and health outcomes for 47 adolescents (M= 15.4, SD =1.45) with T1D undergoing a larger adherence intervention. EF was measured by the Digit Span and Go/No-Go tests, while composite measures of T1D treatment adherence were aggregated via separate parent and adolescent reports. It was hypothesized that both cognitive measures and treatment adherence would have a dose-dependent relationship with n-back training. However, no association was found between training dosage and EF outcomes or treatment adherence. The study’s limitations include a relatively small sample size along with low participant compliance for the EF training. It also might be that the relationship between EF, SR, and health behaviors is more nuanced than previously suggested and that there are a variety of reasons why dosage of training was not linked to differential outcomes. As such, further investigation is required to better understand this relationship in the search for effective interventions for health behavior.