Cardiogenic ballistograms of chicken eggs: comparison of measurements.

In the incubated avian egg, minute movements occur that are synchronised with embryonic cardiac contractions. We previously developed two systems to noninvasively record this cardiogenic ballistic movement of the egg (referred to as the ballistocardiogram, BCG); one was based on applying an audiocartridge and the other a laser speckle phenomenon. A third system, which detects the ballistic movement as the measurement of displacement (referred to as displacement BCG), is applied in the present study, together with the previous two systems, to the ballistocardiography of the egg. The BCG is measured with three systems simultaneously for comparison. The differentiation of the displacement BCG produces a pattern identical to the BCG recorded by the cartridge method, and the integrated pattern of the latter BCG is identical to the displacement BCG. This indicates that the cartridge system detects the cardiogenic movement as the measure of velocity and it may be referred to as velocity BCG. The BCG by the laser speckle method is not related to that recorded by the other two systems, which may be referred to as movement BCG.