The simulations will be interrupted at the first report of an inability to "clear" their ears by swallowing or other maneuvers typically used for that purpose. At that pressure, the subjects will again attempt to equalize the ME-chamber pressure by swallowing, and if unsuccessful, will attempt to open the ET using a Valsalva maneuver, jaw movements/rotations and voluntary yawning. If these maneuvers are unsuccessful, instrumented nasopharyngeal overpressures using the "ear popper"® or Otovent® devices will be tried. If successful, the simulation will be continued, else the chamber pressure will be reduced to atmospheric and ME pressure equalized with ambient pressure. Then, only in subjects entered as symptomatic subjects, a video-nasoendoscopic exam of the nasopharynx will be performed to diagnose nasal and nasopharyngeal pathologies and physical obstruction of the ET orifice.