Temporary threshold shift in human subject exposed to noise

Using an audiometer,the effect of the noise level upon temporarythreshold shift(TTS)for five trained normal subjects(left ear only)was studied.The measurements were carried out after 6 min exposure(in third octave band)for different sound pressure levels ranging between 75-105 dB at three test fre-quencies 2,3,and 4 kHz.The results indicated that at exposure to noise of soundpressure level(SPL)above 85 dB,TTS increases linearly with ths SPL for all thetest frequencies.The work had extended to study the recovery curves for the sameears.The results indicated that the reduction in TTS on doubling the recoverytimes,for the two sound pressure levels 95 dB and 105 dB,occurs at a rate of near-ly 3 dB.The comparison of the recovery curve at 3 kHz with that calculated usingWard's general equation for recovery was made.Finally,to study the values ofTTS produced by exposure to certain noise at different test frequencies,distribu-tion curves for two recovery times were plotted representing TTS values,for anexposure

Temporary threshold shift in human subject exposed to noise

Using an audiometer, the effect of the noise level upon temporary threshold shift (TTS) for five trained normal subjects (left ear only) was studied. The measurements were carried out after 6 min exposure (in third octave band) for different sound pressure levels ranging between 75-105 dB at three test frequencies 2,3, and 4 kHz. The results indicated that at exposure to noise of sound pressure level (SPL) above 85 dB, TTS increases linearly with ths SPL for all the test frequencies. The work had extended to study the recovery curves for the same ears. The results indicated that the reduction in TTS on doubling the recovery times, for the two sound pressure levels 95 dB and 105 dB, occurs at a rate of nearly 3 dB. The comparison of the recovery curve at 3 kHz with that calculated using Ward's general equation for recovery was made. Finally, to study the values of TTS produced by exposure to certain noise at different test frequencies, distribution curves for two recovery times were plotted representing TTS values, for an exposure noise of 1 / 3 octave band and centre frequency 2 kHz, at different test frequencies.