Some Experiments on Temporary Threshold Shifts Produced by Short Tones

Abstract

TTSs produced by short (500-1 000 msec) pure frequency (2000. 3000. 4000 c.p.s.) tones on normal young subjects show, under comparable conditions, the same essential characteristics as TTSs which follow longer stimulations. In particular, they show a tendency to a displacement of their maximal values, as soon as the stimulating tone is presented at adequately high (100 dB SPL) intensity levels, towards a frequency about a half-octave higher than that of the stimulating tone. In our experiments, however, this tendency was more clearly and constantly demonstrable following stimulations with 3000 c.p.s. tones. Significant individual variations in quantitative aspects of the TTSs have been observed. It is suggested that the use of short tones may be easier and more applicable in practice in investigations concerning the after effects of acoustical stimulation and possibly also in procedures aimed at obtaining a better understanding of the significance of individual variations in the behaviour of the receptor organ upon exposure to high intensity stimulations.