The Cognitive, Affective and Neural Correlates of Mental Effort: Integrating Cross-Sectional and Longitudinal Research in Attention-Deficit/Hyperactivity Disorder

Avoidance of tasks required sustained mental effort is a diagnosis criterion of Attention-Deficit/Hyperactivity Disorder (ADHD), yet there is little research investigating the experience of mental effort during cognitively demanding tasks in ADHD. The neural markers underlying the aversion of mental effort in ADHD remains unclear. Moreover, long-term studies on the outcomes of ADHD are rare. The aims of this proposed project including: (1) identifying subjective, cognitive and neural signatures of mental effort; (2) exploring ADHD related abnormalities in mental effort between ADHD and healthy controls; (3) a cross-age comparison in mental effort between children and adults; and (4) a longitudinal follow-up for the associations among trajectory of brain development, mental effort and cognitive performance in ADHD.We will recruit 60 adults with ADHD and 60 age and gender matched healthy controls. The participants will undergo a comprehensive neuropsychological assessment and receive EEG and fMRI recording. We will also recruit (new groups of) adults with and without ADHD (N=30 each group) to receive MEG recording. The purposes of the MEG study include result replication and developing a more child-friendly protocol of mental effort. Depending on the results of adults’ study, we will invite eligible child participant with and without ADHD (N=60 each group, aged 7-16 years) to undergo neuropsychological assessment and EEG/MEG or fMRI recoding. Child participants will be followed up once every year during the project. It is predicted that: (1) the ADHD group would exhibit aversion to tasks requiring mental effort on both trait and state measures as compared to typical developing controls, and mental effort measures will be related to task difficulty and task performance. The ADHD group will display brain abnormalities (e.g. elevated alpha and reduced theta activity, reduced functional connectivity within the default and salience networks). Moreover, subjective and objective measures of mental effort will be significant predictors of ADHD diagnostical status; (3) compared to adults, children are more reluctant to engage into a cognitively effortful task; and (4) the willingness of engaging effort will increase with age. However, the ADHD group will increase in a speed slower than the control group, reflecting as brain development delay. Investigating the experience of mental effort in ADHD will enhance our understanding of the psychopathology of ADHD. It can inform strategies to increase the learning performance of individuals with ADHD in clinical, educational and occupational settings. Ultimately, effort-related measures may be used to facilitate the diagnosis and treatment for ADHD.

Project ID:PF10907-2078
External Project ID:MOST109-2410-H182-008