Noninvasive measurement of heart rate from chicken embryos in the egg

Noninvasive detection of avian heart rate remains a challenge clue to the small amplitude of the signals. Dedicated systems however allow to measure heart rate from 11-13 of the incubation. The mechanical action of the heart (contraction-expansion) induces vibrations in the eggshell. A new method was developed based on the measurement of eddy currents induced by the displacement of the eggshell, due to the motions of the contracting-expanding heart. Results were checked against classic ECG recordings as a reference method. The coherence function was used to measure the degree of similarity that both signals exhibit. An excellent agreement between both methods was shown.