Quantitative Evaluations of the Effects of Noise on Mental Workloads Based on Pupil Dilation during Laparoscopic Surgery

Noise can exert undeniable pressure on human minds, especially during tasks that require high precision and attention, such as those performed during surgery. To investigate whether auditory stimuli increases mental loads during laparoscopic surgery, we examined the effects of operating room (OR) noises and music by measuring mean changes in pupil sizes and subjectively assessing performances during surgery. We recruited 24 subjects with varying laparoscopic surgery experience levels to perform complete appendectomy using a laparoscopic simulator. Wearable eye trackers were worn by all subjects to monitor pupil sizes during surgery, and surgical tasks were performed under conditions of silence, background OR noise, and music. National Aeronautics and Space Administration-Task Load Index scores and performance parameters were also recorded during surgical tasks. Noise distractions were associated with significant increases in pupil sizes compared with those observed in silence, and the related increases in mental loads may have affected surgical performance. However, more experienced operators had smaller changes in pupil sizes because of auditory disturbances than moderately experienced surgeons. Noise stimulation in the OR increases surgeon's mental workload and performance. Auditory regulation of the OR may be better standardized using data from studies of the effects of acoustic stimulation in the OR, and mental stresses during surgery could be considered in a more humane manner. Further investigations are necessary to determine the cognitive consequences of various auditory stimuli.