The Effect of Task Demand on EEG Responses to Irrelevant Sound and Speech in Simulated Surgical Environments.

Complex soundscapes in high-stakes environments, such as the operating room (OR), are characterized by a variety of overlapping auditory stimuli and present significant challenges for personnel, particularly during periods of high demand. This study investigates how task demand and an OR soundscape including irrelevant speech influence perceived workload, surgical performance, and auditory processing in a simulated surgical environment, using mobile electroencephalography (EEG). Participants performed two simulated surgical tasks, namely peg transfer and suturing, representing a low-demand and high-demand task, respectively. The tasks were performed under two sound conditions: an OR soundscape was presented with irrelevant speech or alone. Neural responses to transient and continuous auditory stimuli were analyzed using event-related potentials (ERPs) and temporal response functions (TRFs), respectively. Results showed that irrelevant speech increased self-reported workload, whereas task performance remained unaffected. EEG analyses revealed reduced neural tracking of the speech envelope under high task demand. This can be interpreted as a reduced processing of subjectively distracting sound that is not necessary for task completion and may point to a successful suppression of irrelevant speech. Notably, an inverse relationship was observed between neural responses to speech and self-reported workload, indicating that the speech responses may serve as a marker for perceived workload. Overall, this study demonstrates the potential of EEG to assess irrelevant sound processing in realistic work-like settings and highlights the critical role of task demand in modulating neural responses and self-reported workload to soundscapes.