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A normal tympanogram (left) is labelled Type A. There is a normal pressure in the middle ear with normal mobility of the eardrum and ossicles. Type B tympanogram may reveal (a) fluid in the middle ear, (b) perforation of the tympanic membrane or patent pressure equalization tube, or (c) a tumor in the middle ear.
The absolute threshold of hearing (ATH), also known as the absolute hearing threshold or auditory threshold, is the minimum sound level of a pure tone that an average human ear with normal hearing can hear with no other sound present. The absolute threshold relates to the sound that can just be heard by the organism.
The ear canal volume indicates whether a perforation in the eardrum (tympanic membrane) may be present. The middle ear pressure indicates whether any fluid is present in the middle ear space (also called "glue ear" or "otitis media with effusion"). Compliance measurement indicates how well the eardrum and ossicles (the three ear bones) are moving.
The ART is a function of sound pressure level and frequency. People with normal hearing have an acoustic reflex threshold (ART) around 70–100 dB SPL. People with conductive hearing loss (i.e., bad transmission in the middle ear) may have a greater or absent acoustic reflex threshold. [8]
Ears detect changes in sound pressure. Human hearing does not have a flat spectral sensitivity ... Normal conversation 1 m 2×10 −3 –0.02 40–60
A healthy middle ear is filled with air, not fluid. Having fluid in there can be uncomfortable, serve as a breeding ground for infection, and not to mention cause a lot of pressure and pain in the ...
The middle ear is hollow in the tympanic cavity and Eustachian tube. In a high-altitude environment or on diving into water, there will be a pressure difference between the middle ear and the outside environment. This pressure will pose a risk of bursting or otherwise damaging the tympanum (eardrum) if it is not relieved.
For cases of baro-challenge induced Eustachian tube dysfunction, diagnosis usually relies on the history of the patient and their reported symptoms, as otoscopy and tympanometry is sometimes normal at normal ambient pressure. [1]