[Methodological aspects of high resolution manometry of the pharynx and upper esophageal sphincter]

High resolution manometry (HRM) is used increasingly to investigate muscular functions of the pharynx and the upper esophageal sphincter (UES) during swallowing. Beside the use of different manometry systems and catheters the ways in which parameters are calculated differ greatly among studies. The aim of this study was to present and compare these parameters and show which difficulties need to still be overcome.

A selective literature search in PubMed was performed. Only those studies were included which explained in detail how each of the swallowing parameters was obtained. The parameters are presented using our own HRM-data and different ways of evaluation are discussed.

The dynamic opening of the UES, the proceeding of the pressure wave, the functioning of the velopharynx and the tongue base region are of interest when evaluating swallowing function. Minimum and maximum pressures, time intervals, average pressures, pressure gradients, pressure integrals and anatomical parameters are used to describe functioning of these regions.

In order to compare the data collected with HRM-systems, it is necessary to consider catheter specifications, the manometry system involved and also how exactly swallowing parameters were evaluated. It would be helpful to include analysis strategies in the producers software in order to make HRM studies comparable. Moreover, a consensus has to be reached regarding study protocols and which parameters should be collected in order to differentiate normal form pathological swallows.