Operating instructions

Glossary

acoustic admittance (Ya) The ease with which acoustic energy is trans-

ferred into a system; the ratio of volume velocity to sound pressure.

acoustic millimho (mmho) The unit of acoustic admittance;

1 mmho = 10

-8

/Pa s.

aural acoustic immittance A term used to refer to aural acoustic admit-

tance, acoustic impedance, or any of their components.

cholesteatoma See keratoma.

compensated static acoustic admittance (Ya, Ytm) The admittance

of the middle ear at the air pressure corresponding to the tympanometric

peak. It is calculated by subtracting the admittance of the ear canal from

the admittance at the tympanometric peak. The MicroTymp2 estimates

compensated admittance by subtracting the admittance at +200 daPa from

the peak admittance.

decapascal (daPa) The unit of air pressure used for tympanometric mea-

surements. 1 daPa = 1.04 mm H

equivalent ear canal volume (+200 Vea) The volume of air that has the

same acoustic admittance as the ear canal/middle ear system when the ear

is pressurized. The MicroTymp2 Handle measures Vea with a 226-Hz probe

tone and an ear canal air pressure of +200 daPa. Under these conditions,

Vea is a good estimate of the volume of air in front of the probe. Vea is

abnormally large in some patients with ear drum perforations and patent

tympanostomy tubes.

keratoma A collection of keratinizing squamous epithelium that invades the

middle ear; keratoma frequently originates from a perforation in Shrapnell’s

membrane (pars flaccida) of the tympanic membrane; also called

cholesteatoma.

lateral ossicular fixation Fixation of the malleus and/or incus, frequently

caused by tympanosclerosis, a complication of chronic otitis media.

middle ear effusion An accumulation of fluid (liquid) in the middle ear.

neomembrane A scar on the tympanic membrane; the scarred region may

be thinner and have a higher admittance than the normal tympanic mem-

brane; also called monomere.

otalgia Ear ache or pain.

otitis media with effusion Inflammation of the middle ear, often accompa-

nied by an accumulation of fluid (liquid).

Glossary

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