Headphone Listening Levels During Passive Listening and Simultaneous Interpretation in Conference Interpreters

Background: Conference interpreters (CIs) routinely listen to speech through headphones while simultaneously interpreting the incoming message into another language. The required sound levels (RSLs) for this demanding task, compared to passive listening, remain poorly documented despite potential implications for auditory exposure. Objective: To evaluate an adapted method for estimating RSLs and examine how listening tasks [passive listening vs. simultaneous interpretation (SI)] and competing background noise influence these levels. Methods: An adapted procedure was used to determine RSLs based on participants’ judgments of the presentation level needed to meet task-specific listening requirements. In phase 1, professional CIs listened monaurally through headphones to English and French versions of an audiobook. RSLs were determined for passive listening and SI, both in quiet and in the presence of ipsilateral babble noise. In phase 2, the same procedure was applied using a single language version and three levels of competing babble noise (30, 40, and 50 dB HL). RSLs corresponded to experimenter-adjusted and verified audiometer settings and were expressed in dB HL. Results: Within-session reliability across language versions was good for passive listening [intraclass correlation coefficient (ICC) = 0.82, 95% confidence interval (0.68, 0.90)] and moderate for SI [ICC = 0.71, 95% confidence interval (0.50, 0.84)]. In quiet, RSLs during SI were approximately 13 dB HL higher, on average, than during passive listening, with significant differences observed in both phases ( P < 0.001). Competing babble noise increased RSLs and progressively reduced the difference between passive listening and SI as noise level increased. At the highest babble noise level (50 dB HL), RSLs during SI reached 80 dB HL. Conclusion: The adapted procedure measures task-specific listening level requirements in CIs. Findings indicate that listening levels vary with the listening task and acoustic environment, supporting assessment of listening levels during SI rather than passive listening.