A comparative study: TTS Vs wave V after exposure to noise.

The pattern of recovery from noise exposure was monitored, with regards to the behaviour and electrophysiology in 25 normal-hearing subjects, at 4 KHz frequency for 30 min. Fatiguing stimulus was an octave band noise with centre frequency of 3 KHz. Subject's behaviour following to the auditory fatigue was studied by temporary threshold shift (TTS) paradigm. In the electrophysiological study, the auditory fatigue was measured as a shift of the wave V latency in the auditory brainstem responses (ABR) after noise exposure. This shift was measured at 40 dB nHL stimulus intensity ("Logon" with centre frequency at 4 KHz). The ABR recordings started immediately after cessation of noise exposure and threshold measurements 2 min later. The recovery of latency shift began immediately after the exposure and ended faster than the auditory threshold. From a practical point of view it means that in order to measure maximal values of latency shift, the ABR recordings should be performed immediately after cessation of noise exposure.