Introduction:
The expert medical assesment of acute hearing loss is based primarily on subjective measurement methods. There is a need for objective measuring procedures that are independent of the cooperation of the patient.
Material and methods:
In this study, an audiogram up to 16 kHz was performed on 10 patients who had suffered a single-sided acute acoustic trauma (age 18 to 32 years, 6 occupational noise related incidents, 4 leisure noise accidents) as well as DPOAE (as far as 16 kHz at 500 Hz intervals) The reference group was a collective of normal subjects without noise exposure in medical history.
Results:
All participants had bilaterally detectable TEOAE. Neither conventional (< 8 kHz) and high frequency audiograms (10 – 16 kHz) showed a significant differences.
Mean hearing performance in the lower test tone range (up to 8 kHz) was about 5.5 dB/HL (group without acoustic trauma) and 8.5 dB/HL with trauma. In the upper test tone range (10 to 16 kHz) the average hearing ability was calculated below 10 dB/HL (without trauma) and above 15 dB/HL (with trauma). In contrast, significant side differences in the registration of DPOAE from 4 kHz could be detected. Compared to the same reference group, the traumatized ears showed significant emission losses above 4 kHz. However, the unaffected side also showed significant differences in emissions above 14 kHz.
Conclusion:
By registering the DPOAEs up to 16 kHz, significant differences in hearing can be objectified that are not captured by conventional audiometry. In addition, there are indications that the contralateral ear is also affected by an acute acoustic trauma.
