Investigation of acoustic trauma from the airbag.

Since the automobile-airbag passive restraint system may be in general use in early 1976, and, the fact, is now an opinion on some automobiles, its potential biomedical hazards need to be examined. The objective of this study was to investigate the effects of local slap pressure of airbag deployment against the external ear and tympanic membrane and to measure its effects on subsequential hearing acuity. Adult and infant squirrel monkeys were used as experimental subjects. To create an adequate simulation of the airbag trauma, a small airbag was fabricated and mounted on a pneumatic impact facility. This device was designed to produce a specific velocity to determine the behavior of objects under impact conditions simulating accident kinematics. Cochlear nerve action potentials were measured in both ears of 10 subjects prior to blast, immediately post-blast and several weeks post-blast. High-speed photography recorded events of the blast as well as the technique of recording the electrical potential from the cochlea. No permanent hearing damage, eardrum perforation, disruption of ossicles, or loss of hair cells occurred at airbag velocities up to 100 mph and a sound intensity level of 150 db.