Static and dynamic sonography of facial muscles in healthy subjects – Intra-observer and inter-observer reliability in dependence of time interval between measurements

Purpose: Are static and dynamic ultrasound measurements of facial muscles reliable when measuring with two week intervals? The intra- and inter-observer reliability has shown good results in facial muscle area measurements, but high variability in longitudinal and cross-diameter when measuring twice within ≤48 hours (Sauer, 2014). Short timeframes seem to improve the intraclass correlation coefficient (ICC), because the observer has the chance to remember the position of the probe and the ultrasound scan plane (Satiroglu et al. 2005). In clinical practise, patients are typically followed over larger time interva…