Inner Ear Damage by Firecracker Trauma

Abstract

Firecrackers are still popular among the general public of various populations worldwide. This study investigated inner ear damage in patients with firecracker trauma and analyzed noise levels in 6 kinds of commercially available firecrackers. During the past 20 years, we have experienced 30 patients with firecracker trauma. An inner ear test battery comprising audiometry, cervical and ocular vestibular-evoked myogenic potential (cVEMP and oVEMP) tests and a caloric test was performed. The real-time noise levels were measured outdoors at a distance of 2, 4 and 6 m away from a lighting firecracker to mimic a noise event. Mean hearing levels at high frequencies (4,000 and 8,000 Hz) were significantly higher than those at the low and middle frequencies, indicating that firecrackers mostly cause high-tone hearing loss. For the vestibular damage, abnormality percentages were higher in the results of cVEMP (80%) and oVEMP (60%) tests, but not in the caloric test (8%). In conclusion, most firecrackers exhibited noise levels > 110 dB SPL even at a distance of 6 m. This blast injury simultaneously damaged the cochlea, saccule and utricle, but spared the semicircular canals, indicating that blast exposure potentiates the adverse effect of noise exposure on both cochlear and vestibular partitions.