Auditory distortion products as predictors of TTS: A final look

Abstract

There is a long history suggesting a relation between the nonlinear amplitude response of the auditory system, physical overload, and the development of threshold shift. In a previous report, I showed a relation in three subjects between TTS2 and the amplitude of the distortion product ∫1 + ∫2 measured behaviorally. This relation has been examined more fully in a population of 20 listeners. Complete data were obtained in 13 of these listeners. The relation between TTS2 and the amplitude of the ∫1 + ∫2 and 2∫1 + ∫2 was examined at ∫1 = 500, 1000, and 2000 Hz. Distortion product amplitudes were measured for ∫1 and ∫2 = 1.2∫1, each at 70 dB SPL. TTS2 was measured at 1.5∫1 for pure tones at ∫1, either at 90 or 100 dB SPL. Results are mixed. For a 1‐kHz fatiguer, a relation exists between distortion product amplitude and TTS2. The relation is TTS2 = 0.25 ADP‐1.2 with r = 0.52. This may not be meaningful. At 500 Hz, no TTS was produced by the exposures although there was variability in the level of ∫1 + ∫2 betw...