[Study of the wave-form of the stapedial reflex in response to sonorous stimuli of different intensity].

The threshold of the acoustic reflex and its pattern in response to different intersity stimuli, was investigated by means of the signal-averaging technique in 10 normal ears. Trains of tone bursts between 100 and 0 dB HL were used. The frequencies tested were 500, 1000, 2000 and 4000 Hz. In all subjects the pattern of the acoustic reflex for stimuli between 110 and 100 dB HL was biphasic, with an initial positive plateau followed by a longer negative one. For stimuli < 80 dB HL the pattern of the reflex was monophasic, characterized by a single positive peak (latency between 120 and 170 msec).