Hearing protection in acute acoustic trauma in Finnish conscripts

A prospective study was performed in all Finnish conscripts who were referred to the Central Military Hospital for acute acoustic trauma (AAT) in 1989-93. The study was designed to provide information on hearing protection at the time of AAT and also on the general habits of using hearing protection at shooting drills and combat training in the field. Altogether 449 conscripts with verified AAT were included. According to their statements, all conscripts always used hearing protectors at shooting drills on the range and 97% always or nearly always during combat training in the field. At the moment when AAT occurred, hearing protectors were not used in 83% of cases. Accidental shots or explosions (25.6%), unforeseen exposure to impulse noise, e.g. during combat training (17.5%), and loss of applied protectors (14.9%) were the most common reasons for absence of hearing protection. AATs can be avoided by improving instruction in handling firearms, planning combat training more carefully and making sure that application of earplugs is properly taught and mastered.