Single and joint actions of noise and sinusoidal whole body vibration on TTS2 values and low frequency upright posture sway in men

Abstract

In the present study the changes in the TTS2 values and body upright posture sway were examined after exposure of subjects (n = 10) to stable broadband (white) noise (90 dB) alone, to sinusoidal vibration alone [directed vertically at the whole body (Z axis)], and to simultaneous exposure combinations of noise and vibrations of the same type. The frequency of the vibration was 5 Hz, but its acceleration was either 2.12 or 2.44 m/s2. There were six exposure combinations, and subsequently 60 tests were carried out in an exposure chamber. One test consisted of a control period of 30 min, of three consecutive exposure periods of 16 min each and of a recovery period of 15 min. After the three exposure combinations which included noise, half of the subjects were exposed to vibration during the recovery period. Apart from indicating an increase in the temporary hearing threshold, the results showed that simultaneous exposure to noise and vibration increases the instability of the body upright posture. The TTS2 values at the 4 and 6 kHz frequencies increased considerably more rapidly when the subjects were exposed simultaneously to noise and vibration than when exposed to noise alone. Without exception, the TTS2 values increased most during the first exposure period. It was noteworthy that exposure to vibration during the recovery period accelerated the recursion of the TTS2 values, especially in cases where the subjects had been exposed to noise alone. The variance of the body sway amplitudes and the standard deviation increased within the frequency range 0.063-2.000 Hz owing to noise alone and simultaneous noise and vibration. In the directions X and Y, within the frequency ranges 0.063-0.100 Hz and 0.100-0.600 Hz, the means of the maximum amplitudes of body sway increased especially in connection with those tests in which the subjects had been simultaneously exposed to noise and vibration.

The effect of vibration exposure during haul truck operation on grip strength, touch sensation, and balance

“…Both types of vibration contribute to fatigue and can have detrimental effects on health and job performance (Goglia et al, 2003). The effects of WBV exposure on postural stability have been examined in laboratory studies, and results show inconsistent effects on balance (Cornelius et al, 1994; Mannin and Ekblom, 1984; Santos et al, 2008a). Cornelius et al (1994) exposed six male participants to uniaxial (vertical) WBV levels which were simulated to represent values measured from an underground mining shuttle car.…”

“…The researchers were unable to find any statistically significant changes in balance measures following vibration exposure and argued that the relationship between WBV and postural stability may depend on both frequency and duration. Mannin and Ekblom (1984) exposed ten male participants to noise, vibration, or a combination of both. Results showed an increase in body sway when exposed to noise alone, vibration alone, and a combination of noise and vibration.…”

Combined Effects of Exposure to Noise and Vibration on Human Postural Equilibrium under Simulated Driving Conditions

“…Also, the combined noise and WBV exposure showed more adverse effects on body balance compared with WBV exposure alone, which indicated that there are some interaction effects of noise and WBV on human body balance. Manninen et al stated that body balance decreased more in the combined exposure to noise and vibration [40]. Also, Yilmaz et al [29] proposed some synergistic effects of the combined exposure to noise and vibration on the vestibular system disturbances.…”

Whole-body vibration and occupational physical performance: a review

“…For the six studies which investigated balance following WBV, the balance was assessed using either force plate technology (Cornelius et al 1994;Santos et al 2008b) or kinematic analysis, especially stabilometric measures (Manninen 1986;Manninen and Ekblom 1984;Martin et al 1980;Slota et al 2008). Measurement techniques are an important consideration as balance scores can differ between modes of assessment (Chaudhry et al 2011).…”