The Effects of High Intensity Noise on Human Equilibrium
Abstract : Five experiments were conducted on the effects of broadband, high intensity noise on human equilibrium. The ability of subject to balance on narrow rails was measured during exposure to the noise; and immediately after termination of the noise. Four different noise conditions were used in each experiment: control, 120, 130, and 140 dB (re. 0.0002 dyne/sq cm). In the first experiment subjects wore earmuffs and earplugs; in the second, only earplugs were worn; and in the third experiment, subjects wore earplugs and one earmuff to produce an asymmetrical exposure. At an ambient level of 140 dB, a detrimental effect was obtained in all three experiments. At lower intensities of noise, there were performance decrements only for the asymmetrical exposure. In the remaining two experiments, conducted after termination of the noise, detrimental effects were obtained for asymmetrical auditory exposure but not for equal auditory exposure. The results of these experiments are interpreted as a possible quantitative demonstration of the direct effect of high intensity noise on the vestibular system.
Physiological Effects of Intense Sound
Abstract : Conclusions: Noise fields sufficiently intense seriously impair human hearing. These noise fields are produced by turbo-jet power plants currently in use; The frequency spectrum of the turbo-jet noise field is such that the hearing loss produced in man interferes markedly with the reception and understanding of speech; Sound energy will kill rats and guinea pigs; Effects reported have been produced by intense sound fields in the audible range; Because the effects described have been the result of exposure to intense sound in the audible range it is suggested that the important parameter may be intensity rather than frequency.
A Clinical Survey into the Effects of Turbo-Jet Engine Noise on Service Personnel: Some Preliminary Remarks
THE jet engine and the approach of transonic flight, by their emphasis on the possibilities of ill-effects from ultrasonic vibrations, have stimu-lated enquiry into the physiological effects of vibrations as a whole. Ultrasonic vibrations and frequencies develop in aircraft from two sources.