RESUMEN
Objective To investigate the effects of different intensity of wide band noise on acoustic stapedius reflex amplitude in sound field. Methods Acoustical reflex amplitude(at ART+10 dB)were obtained at three fre-quencies (1,2, 4 kHz) from 80 normally hearing subjects with wide band noise at 30,40,50 and 60 dB SL in sound field. Results Acoustical reflex amplitude was significantly decreased in the presence of wide band noise (P 0. 01). The most significant decrease of acoustic reflex amplitude could be observed in the present of 40 dB SL wide band noise. In comparison with the 1 kHz group, significant decrease was found in 2 kHz group and 4 kHz group(P <0. 01),but there was no difference between the 2 kHz group and 4 kHz group(P>0.05). Conclusion Since the decrease of the acoustic stapedius reflex amplitude is mediated by the auditory efferent system in sound field, in clini-cal practice the function of the auditory efferents can be evaluated by testing the change of acoustic stapedius reflex amplitude with the stimulation of the wide band noise in sound field.