Vibration Effects on Digit-Symbol Coding

Abstract

Performance of a Digit Symbol Coding task was investigated with three trials each before, during, and after whole-body sinusoidal vibration. Four inexperienced (i.e., not previously vibration-exposed) and two experienced subjects were tested at 8 Hz at 0.21 gz (rms). Results indicated that individual differences and related (group) interactions accounted for respectively 51.1% and 5.0% of the total sum-of-squares. Simple vibration effects accounted for 14.8% of the variance. The present and previous results indicate: (1) performance decrement reductions with practice under vibration; and (2) the operation of an experience-practice interaction on performance after vibration. It was concluded that research into human performance under vibration should utilize control groups, randomization, and repeated measures methodologies. With regard to the current international standard on human whole-body vibration exposure, ISO 26, 1–1978, it is recommended that research be directed at the underexplored realm of psychophysiological and biomechanical effects during long-term exposures.