Impaired Recognition of Emotional Facial Expressions in Adults with Attention Deficit/Hyperactivity Disorder: A Review of Event Related Potential (ERP) Studies

Abstract

Background: The link between attention deficit/hyperactivity disorder (ADHD) and impaired recognition of emotional facial expressions is well documented. The cause for this impairment is, however, unclear. Some studies suggest that it may be due to deficits in emotional processing, while others attribute it to inattention. Purpose: This review examines the temporal evolution of the response of adults with ADHD to emotional facial expressions. The process is assessed using Event Related Potential (ERP), a technique that follows the response with millisecond resolution. Method: An integrated, systematic search of relevant databases based on the Whittemore and Knafl and the PRISMA 2020 review methodologies was applied. Ten studies met all the inclusion criteria. Results: Behavioral data (such as response time) confirm that adults with ADHD have some deficits in their ability to identify emotional facial expressions when compared to healthy controls. However, their degree of impairment varies with expression type. Analysis of the time-evolution of the response, as measured by ERP, shows that the response of adults with ADHD is heightened, when compared to healthy peers, in both initial and later stages. In the intermediate window, at approximately 300 ms, adults with ADHD show muted EPR amplitudes when compared to their healthy peers. The same time-evolution of response was observed for both emotional expressions and neutral ones. Conclusions: Overall, adults with ADHD display some level of impairment in their ability to recognize emotional facial expressions that is dependent on the expression valence. The time-evolution of the responses suggests the impairment might be linked to a lapse in attention at roughly 300 ms post-stimulus.