Evaluation of Frequency Weighting (Iso 2631-1) for Acute Effects of Whole-Body Vibration on Gastric Motility

Author: Ishitake T.   Miyazaki Y.   Noguchi R.   Ando H.   Matoba T.  

Publisher: Academic Press

ISSN: 0022-460X

Source: Journal of Sound and Vibration, Vol.253, Iss.1, 2002-05, pp. : 31-36

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Abstract

The aim of this study was to investigate the effects of exposure to whole-body vibration (WBV) and the ISO 2631/1-1997 frequency weighting on gastric motility. The gastric motility was measured by electrogastrography (EGG) in nine healthy volunteers. Sinusoidal vertical vibration at a frequency of 4, 6⋅3, 8, 12, 16, 31⋅5, or 63 Hz was given to the subjects for 10 min. The magnitude of exposure at 4 Hz was 1⋅0m/s2 (r.m.s.). The magnitudes of the other frequencies gave the same frequency-weighted acceleration according to ISO 2631/1-1997. The pattern of the dominant frequency histogram (DFH) was changed to a broad distribution pattern by vibration exposure. Vibration exposure had the effect of significantly reducing the percentage of time for which the dominant component had a normal rhythm and increasing the percentage of time for which there was tachygastria (p<0⋅05). Vibration exposure generally reduced the mean percentage of time with the dominant frequency in normal rhythm component. There was a significant difference between the condition of no vibration and exposure to 4 and 6·3 Hz of vibration frequency (p<0⋅05). The frequency weighting curve given in ISO 2631/1-1997 was not adequate for use in evaluating the physiological effects of WBV exposure on gastric motility.