Transcutaneous Electrorectography: Human Electrorectogram from Surface Electrodes

The rectal electric activity or electrorectography was recorded transcutaneously in 24 healthy volunteers (mean age 39.6 years). A silver-silver chloride electrode was applied lateral to each of the two sacroiliac joints, and a third one was placed midway between the left greater trochanter and the ischial tuberosity. The reference electrode was applied to the right lower limb. At least two 20-min recording sessions were performed for each of the 24 subjects. In addition, an intrarectal electrorectographic recording was done in 10 of the 24 subjects using silver-silver chloride electrodes attached to the rectal mucosa by suction. Pacesetter potentials (PPs) were recorded transcutaneously. The wave was triphasic with a small positive, a large negative and another small positive deflection. PPs had a regular rhythm and were reproducible. The mean frequency was 3.1 cycles/min. The transcutaneously recorded PPs could be confirmed by the intrarectal route. Both routes had similar electrorectographic recordings, except for the action potentials (APs) which did not show in the transcutaneous electrorectogram. In conclusion, the study demonstrates that PPs could be recorded transcutaneously. Transcutaneous electrorectography is simple, easy, reproducible and cost-effective, and may prove to be a useful investigative tool in the diagnosis of anorectal disorders.