Normal values and influence of antropometric and demographic factors on ambulatory cutaneous electrogastrography in healthy volunteers

Introduction: Cutaneous Electrogastrography (EGGc) is a technique used for recording the Gastric Electrical Activity by means of electrodes placed on the abdominal skin. The aim of the present study was to determine normal va lues in healthy volunteers, as well as the influence of factors such as age , gender, Body Mass Index (BMI) and echographic location of the gastric ant rum. Methods: an abdominal echography was initially performed in 35 of the 44 he althy volunteers in order to locate the gastric an trum and to place along its axis the skin electrodes, whereas in the other 9, the electrodes were p laced according to anatomical references. Afterwards. the echography was al so performed in those 9 volunteers in order to have all the 44 baseline ech ographic records. In every case, a record of ambulatory EGGc over 60 minute s was obtained, along with other record over the same period after eating a standard meal. The analysis of data was conducted through visual inspectio n and combined computer analysis. Results: eighty per cent of the study subjects showed a dominant frequency ranging from 2 to 4 cpm during both periods. After the meal, the parameters showed a characteristic variation. A significant difference was found when comparing subjects under 40 years of age versus subjects between 40 and 60 years of age in terms of preprandial dominant frequency instability coeffi cient (DLIC) (p=0.002) and bradygastria (p=0.03). Subjects with BMI < 25 kg /m2 showed preprandially a smaller dominant power instability coefficient ( DPIC) (p=0.035) and a greater Dominant Power (DP) (p=0.045). In subjects wi thout echograhic control, DLIC (p=0.001). bradygastria (p=0.016) and tachyg astria (p=0.02) were more frequent, with a shorter period of normogastria ( p=0.001) during the postprandial period. Conclusions: normogastria is the predominant rhythm in healthy people, alth ough brief dysrhytmias can be recorded that do not have any pathological me aning. Age and BMI, but not sex, seem to influence the Gastric Electrical A ctivity. The percentage of gastric dysrhytmias decreases when the electrode s are placed along the longitudinal axis of the gastric antrum through echo graphic control.