الفهرس 
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Abstract
impedance audiometry is one of the advanced
audiological tests applied in the field of audiology.
Its principle is based on the acoustic impedance
which is the resistance offered by the conductive
system of the ear to an acoustic signal. In normal
ear Borne of the acoustic signal is absorbed to the
middle ear and the rest is reflected back at the
tympanic membrane. The amount absorbed and that
reflected depend on the compliance and the resis-
tance of the conducting system, that is to say tympanic
membrane, ossicles and ligaments. By knowing the
compliance and the impedance of the normal ear, we
can detect any shift from the normal.
The instrument used in these measurements is
the Electroacoustic impedance dridge.
Change of pressure in the ear canal and contrac-
tion of the intratympanic muscles change the impedance.