Efficiency and Efficacy of the Electrogastrogram
The efficiency and efficacy of theelectrogastrogram (EGG) involve a few practical factors,including recording length, sample size, and thecharacteristics of subjects. The aim of this study wasto investigate the effect of these factors on the accuracy ofEGG analysis. Gastric myoelectrical activity wasrecorded using electrogastrography in 24 subjects (ages22-91 years) for 1 hr in the fasting state and 2 hr after a test meal. Computerized spectralanalysis was performed to compute EGG parameters,including dominant frequency, dominant power, and thepercentage of 2-4 cycles per minute (cpm) slow waves. A parameter called misinterpretation was definedto investigate the effect of recording length. Theresults were as follows: (1) Using the recording lengthof 1 hr in each state as a gold standard, themisinterpretation for the recording length of 30 min was 27% forthe dominant frequency and 17% for the dominant power.When the recording length was reduced to 15 min, themisinterpretation increased to 61% for the dominant frequency and 38% for the dominant power. (2)With a sample size of 10 subjects and a recording lengthof 60 min, a statistically significant postprandialincrease was observed in the dominant frequency and power, and a trend in the postprandialincrease of the regularity of the EGG was noted. Whenthe sample size increased to 24 subjects, a significantpostprandial increase was found in all these parameters. (3) None of the EGG parameters exhibited anysignificant difference between the younger and oldersubjects or between men and women. In conclusion, arecording length of 30-60 min seems to be appropriate and produces reliable and predictable results.Age and gender do not affect any of the EGGparameters.
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