Local differences in electrogastrographic responses to the stress of the mirror drawing test (MDT) as determined by multichannel electrogastrography

Abstract

Electrogastrograms (EGGs) were recorded in human subjects (n=58) at 16 locations on the thoraco-abdominal surface before (at rest) and during the stress of the mirror drawing test (MDT) and after having a test meal. The power amplitude ratios and power content ratios of MDT to rest (MDT/rest) and postprandial state to rest (PPR/rest) were compared between gastric channels 5 and 8, and the infraumbilical channels 12, 13, 14, 15, and 16. Generally, the ratio of the 3-cpm group in channels 5 and 8 was lower than that of the infraumbilical channels 12-16 during MDT. In contrast, the ratios were higher in the epigastric channels than in the infraumbilical channels after a test meal. Significant differences between the epigstric and infraumbilical channels were found in the comparisons of the power content ratios. The infraumbilical channels were facilitated and the epigastric channels inhibited during MDT. After eating a meal, in contrast, the postprandial epigastric 3-cpm EGGs were facilitated. The epigastric 3-cpm EGG activity reflects gastric myoelectric activity, while the infraumbilical 3-cpm activity reflects that of the colon. Therefore, it is suggested that the acute stress of the MDT generally inhibited the gastric EGG and facilitated the colonic EGG, indicating gastric inhibition and colonic facilitation. The topographic EGG maps of the power content ratios and the absolute power ratios visually confirmed these findings.

Correlations between anxiety and the stress responses of electrogastrography (EGG) induced by the mirror drawing test (MDT)

“…We have previously reported the effects of the acute stress of MDT on the gastric and colonic facilitation or inhibition with EGG. However, MDT stress did not appear to exert effects on the intestinal EGG activity (6, 8, 12). …”

“…However, the finding of a significantly higher power ratio of the MDTr –1 of the infraumbilical 3 cpm than that in the epigastric recording during MDT suggested that the MDT stress inhibited gastric EGG and facilitated colonic EGG. In addition, topographic EGG maps drawn according to the power content ratio of the MDTr –1 and the absolute power ratio of MDTr –1 supported this idea (6). Similar findings of colonic facilitation have been reported with manometry (13, 25, 26, 27, 28, 29).…”

“…Our previous study demonstrated that the local differences in the power content during 16-location EGG were more clearly shown at rest, during the postprandial state and during the mirror drawing test (MDT) (5). Furthermore, we demonstrated the epigastric EGG inhibition (seen in 3 cpm activity) and infraumbilical EGG facilitation (seen in 6 cpm activity) during MDT stress in a numerical comparison of the power content ratio of the MDTr –1 and topographic EGG mapping of MDTr –1 (power content during MDT/power content at rest) (6). Therefore, in the present study, we compared the effects of MDT-related stress on each of the 16 locations of EGG using the power content ratio of the MDTr –1 to clarify the correlation between stress and EGG, which partially reflects gastrointestinal motility (3, 4, 6).…”

“…The power content ratio or the normalization of EGG change, MDTr –1 (power content during MDT/power content at rest) reflects the real change of the local EGG for each electrode as demonstrated in topographic EGG maps (6). …”

“…13–15, 13–16, 13–17, 13–18, 13–19, 13–20, 13–21, and 13–22, P <0.001. Channels 2, 5, 8 are epigastric and channels 10–16 are infraumbilical. lists the figures for the epigastric 2, 5 and 8 channels and the infraumbilical 12–16 channels found in our previous studies for simplicity (5, 6). The anxiety scores were estimated using the HADS (hospital anxiety and depression scales) (9, 10).…”