Automobile airbag impulse noise: otologic symptoms in six patients

Automobile airbag safety systems have successfully reduced the number of occupant injuries from motor vehicle accidents. Unfortunately, airbags are also associated with some inherent risk, including a high-amplitude, short-duration noise from airbag deployment. A review of the available research in the automobile industry indicates that the peak amplitude of this noise may exceed 170 dB sound pressure level. Despite the increasingly wide application of airbags in automobiles, there have been no previous reports of airbag-related otologic injuries. We have encountered six patients with otologic symptoms that appear to be related to airbag impulse noise. Five of these patients have documented hearing loss, one patient reported persistent tinnitus, and two patients have significant dysequilibrium. Although permanent hearing loss from airbag noise appears to be rare, temporary threshold shifts are probably much more common. It is important, therefore, that the clinician be aware of the noise associated with airbag inflation and the possibility of acoustic trauma from these safety devices.