Pure-tone audiometry and auditory brainstem responses in noise-induced deafness.
OBJECTIVE
The objective of this study is to find the relationship between pure-tone audiometry results and the auditory brainstem response wave abnormalities.


METHODS
The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied.


RESULTS
In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I-V latency was 20.5%, 18.2%, and 21.1%, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed.


CONCLUSIONS
There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.
Noorhassim
I
I
Department of Community Health, National University of Malaysia, Kuala Lumpur.
Kaga
K
K
Nishimura
K
K
D000368:Aged; D001301:Audiometry, Pure-Tone; D016057:Evoked Potentials, Auditory, Brain Stem; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis*; D006801:Humans; D008875:Middle Aged; D016272:Occupational Health