For the anterior-emphasis tasks, patients are instructed to place a pressure bulb in the front of the mouth and squeeze the bulb by using the front of the tongue.
Before further analysis, all range data were normalized relative to a standardized value of 600 mmHg assigned to the maximum range of anterior-emphasis maximum isometric tongue-palate pressure rise registered at the anterior pressure bulb for each participant: normalized pressure range = (pressure range/ maximum isometric pressure range) x 600.
The smaller value for the error df in this analysis reflects exclusion of the AHMAX tasks from the model, based on the fact that these involved no activation of the posterior pressure bulb.
Chi-square statistics were used to compare the frequency with which activation of both the anterior and posterior pressure bulbs occurred in the different tasks included in the study.
The DSW and DSANEC tasks typically elicited activation of both the anterior and posterior pressure bulbs.