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Carrickmacross, Co. Monaghan

Tympanometry

Tympanometry measures should not be interpreted in isolation. Tympanometry is part of a complete test battery and outcomes from other audiological tests should be considered in conjunction with these results.

The following provides a broad interpretation of typical Tympanograms by type and possible related pathologies and are based on Adult Probe Frequency 226Hz.
Typical Normative Data for an Adult (BSA Guidelines 2013)

  • Admittance / Compliance between 0.3 to 1.6 cm3 (‘Y’ Axis)
  • Middle Ear Pressure +50 to -50 daPa (Deca Pascal) (‘X’ Axis)
  • Ear Canal Volume (ECV) 0.6 to 2.5 cm3

Tympanogram Type A

Normal Tympanogram
Ear Canal Volume (ECV)
0.6 to 2.5 cm³

Middle Ear Pressure (MEP) +50 to -50 daPa
Admittance/Compliance
0.3 to 1.6cm³

Tympanogram Type As

Low Compliance / Stiff
ECV up to 0.4cm³
Normal (MEP) +50 to -50 daPa
  • Scarred/Thickened Drum
  • Ossicular Fixation and/or
  • Tympanosclerosis

Tympanogram Type Ad

High Compliance / Flaccid
ECV above 1.6cm³
  • Scarred/Monomeric T/M
  • Ossicular Disarticulation
  • e.g. Fractured Ossicles
  • Loss of elasticity in T/M

Tympanogram Type B

ECV within normative range
Little or no Peak

  • Effusion - Fluid in Middle Ear

ECV <1.0 (Very Low Volume)

  • Wax Occlusion
  • Blocked Probe

Type B + Large
ECV 3.5 cm3 (High Volume)

  • No Seal
  • Perforation (depending on ECV)
  • Open Grommet

Peak ComplianceTympanogram & Otitis Media

Series of tympanograms illustrating various stages during development of Otitis Media

Tympanogram Type C

Abnormal Pressure (Negative)
i.e. -195 daPa
Ear in Transition

Middle ear reflexes present = recovering

Reflexes absent = getting worse

  • Eustachian Tube Dysfunction

Possibly characterised by a rounded Peak

  • Otitis Media
  • Possible Tympanic Membrane retraction
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