Impact of Brief Training on Spatial Hearing and Motion Perception While Wearing Hearing Protection

Hearing protection devices (HPDs) impair spatial hearing and situational awareness in military settings. These impairments decrease HPD usage, which subsequently increases exposure to loud noises that can produce hearing loss. This study builds on previous research by investigating whether brief training can improve spatial hearing performance with stationary and moving sounds. The impact of training on subjective listening effort was also examined.

Young adults were randomly assigned to training (n = 24) or control groups (n = 23). All participants performed a spatial hearing task on Days 1 (baseline) and 5 (post-training) while wearing HPDs and in an open ear condition without HPDs. On Days 2 to 4, participants in the training group received auditory and visual feedback after each trial while wearing HPDs. The spatial hearing task presented a white noise target from a speaker array surrounding the participant. The target either remained stationary or moved clockwise or counterclockwise within the speaker array. Participants then aligned a white noise "auditory pointer" to the perceived offset location. Spatial hearing measures were the percent of front-back confusions, absolute localization, as defined by the difference between the pointer location and the true offset location. Displacement illusions created by motion were also examined. Listening effort measures include self-reported fatigue and mood before and after training sessions, as well as online pupillometry during training.

When wearing HPDs on Day 1, the percentage of front-back confusions more than doubled, and localization was ∼50% worse relative to the open ear condition. Performance in the training group significantly improved from baseline (Day 1) to post-training Day 5, with reductions in front-back confusions and absolute localization error. There were no significant differences in spatial hearing performance from Day 1 to 5 in the control group. Moving stimuli have slightly more front-back confusions and decreased absolute localization compared to stationary stimuli. Motion-produced displacements did not significantly vary from Days 1 to 5; however, all displacements were behind the true location. Listening effort measures did not significantly vary from Days 2 to 4.

These findings show that brief training can substantially reduce HPD impairments on spatial hearing for both moving and stationary sounds. The combined gains from training with the stability of listening effort over time further support potentially increased HPD compliance in military settings.