Bilateral hearing loss as a sequel to unilateral acoustic trauma

Within the framework of a study on the natural history of acoustic trauma, over 600 soldiers were examined. A higher rate of bilateral acoustic trauma was observed among soldiers with longer service. Comparison between unilateral and bilateral acoustic trauma showed a greater severity of damage in both ears of the latter group. Comparison of the progression of the damage in the same persons on two consecutive examinations suggested the same trend. It is suggested that bilateral acoustic trauma may be a later and more severe stage in some types of noise-induced damage.