On auditory evoked potentials and heart rate in man during whole-body vibration

Auditory evoked brain potentials and heart rate were recorded from three healthy male subjects during sinusoidal whole-body vibration exposure in the longitudinal (+/- aZ) direction (two intensities: I1 = 0.57 ms-2 r.m.s., I2 = 3.2 ms-2 r.m.s., frequency: 4 HZ) and under no-vibration control conditions according to a change-over design. All conditions were performed at a constant noise level. The part of vibration-synchronous activity contaminating the averaged evoked potentials (AEP) was eliminated by means of a subtraction technique. The AEP amplitude N1--P2 showed a significant decrease during vibration exposure; this decrease was slightly greater during I2 than during I1. Except for a shortening of P2 due to vibration of I1, the peak latencies did not change significantly. The heart rate increased when subjects were exposed to vibration at I1; there were interindividually opposite significant changes under I2 exposure. Time effects and subject effects were also proved. The AEPs are considered to be an informative measure for studying the effect of vibration on central nervous information processing.