“…Numerous positions have been used to improve the sensitivity and accuracy of c-TCD, including sitting upright, right lateral decubitus, right lateral leaning, recumbent and standing. Higher MB counts or higher frequency of RLS in the standing position at rest (Caputi et al 2008) or in the upright sitting position with the VM (Agustin et al 2011;Lao et al 2007), which are all erect postures, have been reported. It has also been argued (Agustin et al 2011;Telman et al 2003) that the erect posture allows MBs in the right atrium to rise to the PFO and pass easily into the left atrium because the right atrium is relatively higher than the right ventricle.…”