Signal Averaging

Stability and Reproducibility

Stability and Reproducibility: Peripheral Pulse Volume measurements were made with and without digital enhancement in healthy male subjects (n=8, 26±4y) and repeated in 30 minutes. Without averaging, the reproducibility was poor, with a variability of 19.9±4.5% between measurements, and a re-measurement correlation of only r=0.17. Selective averaging resulted in improved repro­ducibility with the variability reduced to 5.4±2.1% (p<0.01), as well as increased re-measurement correlation (r=0.95). This degree of variability is comparable to that seen with common invasive and non-invasive measure­ments of cardiac function (such as thermodilution cardiac output and Doppler flow velocity).

Marks LA. Digital Enhancement of the Peripheral Admittance Plethysmogram. IEEE Trans Biomed Engr. 1987;34(3):192‑198