Acoustic Reflex Growth Function in Noise Induced Hearing Loss / 听力学及言语疾病杂志

ABSTRACT

Objective To explore the effects of noise exposure on acoustic reflex growth function (ARGF).Methods 106 ears of 57 industrial workers that exposed to high level continuous noise during their work day were divided into three groups according to pure-tone threshold average (PTA) normal hearing group, mild hearing loss group and moderately severe hearing loss group. The control group consisted of 50 ears of 25 young persons with normal hearing. The contralateral acoustic reflex thresholds (ART) were obtained from all individuals.1 000 Hz pure-tone stimuli was wsed to elicit the acoustic reflex at hearing levels from ART to 125 dB in 5 dB steps during ascending intensity level runs. The growth functions were observed as changes in acoustic reactance with increases in activator-signal intensity level.Results The noise exposed groups had smaller acoustic reflex dynamic ranges, smaller acoustic reactance growth magnitudes and shallow slopes compared with those of the control group. Data showed that there were significant differences among the control and the noise exposed groups (P0.05).Conclusion The influence of noise exposure on ARGF is significant. The results of this study suggest that ARGF could be used in the monitoring of the noise-induced hearing loss as an indicator of subtle alterations of the hearing function.