Which tympanogram indicates negative middle ear pressure?

Which tympanogram indicates negative middle ear pressure?

• A. Type A
• B. Type B
• C. Type C
• D. Type D

Answer: (C)

The main idea is that tympanometry shows how the eardrum moves as the ear canal pressure is varied, and the position of the peak reveals the middle ear pressure. When the middle ear is vented normally, the peak sits around zero daPa. If the peak shifts toward negative pressures, that means the middle ear pressure is negative, which happens when the Eustachian tube isn’t ventilating properly. That pattern—peak at negative ear canal pressure—indicates negative middle ear pressure and is commonly seen with Eustachian tube dysfunction, sometimes accompanying or preceding middle-ear effusion. In contrast, a normal peak near zero daPa indicates normal pressure, a flat tympanogram suggests little or no tympanic membrane movement due to fluid or perforation, and peaks shifted to high positive or low amplitudes reflect other changes in tympanic membrane mobility rather than negative pressure.

The main idea is that tympanometry shows how the eardrum moves as the ear canal pressure is varied, and the position of the peak reveals the middle ear pressure. When the middle ear is vented normally, the peak sits around zero daPa. If the peak shifts toward negative pressures, that means the middle ear pressure is negative, which happens when the Eustachian tube isn’t ventilating properly. That pattern—peak at negative ear canal pressure—indicates negative middle ear pressure and is commonly seen with Eustachian tube dysfunction, sometimes accompanying or preceding middle-ear effusion.

In contrast, a normal peak near zero daPa indicates normal pressure, a flat tympanogram suggests little or no tympanic membrane movement due to fluid or perforation, and peaks shifted to high positive or low amplitudes reflect other changes in tympanic membrane mobility rather than negative pressure.