Perspectives of electrogastrography and motion sickness

Electrogastrography (EGG) is a noninvasive measurement of stomach activity using surface electrodes positioned over the abdominal surface. For over 10 years, EGG has been used as an objective measure of epigastric symptoms an d nausea experienced in visually induced sickness provoked by circularvecti on. It was reported that during sickness, there is a shift in the dominant basal electrical activity, The 3 cycles per minute activity decrease and th e 4-9 cycles per minute activity increase. This technique has also been use d to evaluate the efficacy of antimotion sickness drugs and to monitor sick ness induced by other provocative stimuli such as Coriolis cross-coupling, parabolic flight manoeuvres and microgravity. It has been further postulate d that peripheral changes in gastric myoelectrical activity in response to visually induced sickness are detected centrally and lead to the generation of motion sickness. However, other studies using either identical or equal ly effective motion stimuli failed to support the positive correlation of c hanges in gastric activity with the incidence and severity of motion sickne ss. The interpretation of spectral analysis on EGG during motion sickness m ust be taken with great caution. The inherent variability of the EGG and in tersubject variability makes it difficult to consider EGG a reliable and ro bust indicator of motion sickness. its relation to motion sickness and the underlying mechanism remains unclear. The true diagnostic value of EGG in m otion sickness has yet to be determined, Crown Copyright (C) 1999. Publishe d by Elsevier Science Inc.