Figure 4 - Example of intercordal and intratracheal pressure during phonation.

Both productions of continuous AAAA and EEEE vowels were associated with a spike-like pressure, 220 mmHg for AAAA and 120 mmHg for EEEE, respectively, followed by a flat pressure of about 10 mmHg. These events were accompanied by a negligible increase in intratracheal pressure. (Source: Shaker et al.⁸ with permission from Springer Science and Business Media)