Computerized Audiogram and Computerized Impedance test results of a normal hearing individual

Anatomy and Physiology of the Ear Click here

Examination of a patient with a hearing loss

It is important to determine the type of hearing loss – Conductive, Sensori-neural or Mixed
The level of hearing – HTL (Hearing Threshold Level) has to be determined.
Whether the high frequencies or low frequencies are affected
Whether speech discrimination is affected or not

A physical exam, using a ear microscope or endoscope, will evaluate the ear canal and tympanic membrane. The nose, nasopharynx, paranasal sinuses, throat, larynx and neckand upper respiratory tract will also be examined as the ear and nose has close anatomical relationship and disease conditions in one often affects the other ( eg one becomes temporarily deaf during a “cold”.

Primary tests done in a hard of hearing patient

Pure Tone Audiometry – Pure tones are presented to each individually via head phones at frequencies of 0.128 KHz to 10 KHz. The patients responses are recorded as a graph.

Acoustic Impedance Audiometry (Immitance Audiomety)– Tests the Acoustic Reflex the contraction of a tiny ear muscle that responds to sounds at different volumes. Also Tympanometry measures the impedance of the middle ear to sound. Tympanometry is useful in distinguishing between types of conductive deafnes – due to middle effusions, disruption or fixation of the small chain of bones, negative middle ear pressure in the middle ear.

A graphical computerized report of hearing function (Audiogram) and pressure within the middle ear and measurement of reflex movements of tiny muscles in the middle ear (Acoustic Impedance) are the basic tests for diagnosis of hearing disorders.

This information is the first step to diagnosis. Once a correct diagnosis is made, proper treatment is instituted.

Basic types of Deafness – Conductive and Sensori –neural deafness

Conductive DeafnessWhen deafness is caused by disease of the outer (external) ear, ear drum or mddle ear, it is referred to as a conductive deafness.

Sensori neural DeafnessWhen deafness is caused by disease of the inner ear, nerveof hearing or brain centres, it is referred to as a Sensori neural Deafness.

“Mixed” Deafness – Both Conductive and Sensori-neural components are present

Computerised Audiogram and Computerised Impedance test results of a normal –hearing individual

 

 

Approximate sound levels in decibels (dB) of common daily experiences amongst 21st century “civilized” people

Values for   (Patient Name) - Date -
Event Approx. levelin dB
Ordinary breathing (barely audible) 0 – 10
Rustle of leaves. Quiet country side 10 – 20
Whisper 20 – 30
Average quiet household. Singing birds 40 dB = Borderline level for Socially Adequate Hearing 30 – 40
Ordinary conversation. 40 – 50
Average restaurant. Crying infant.  General office. Classroom 50 – 60
Loud voice. Average air conditioner. Vacuum cleaner.  T.V. 60 – 70
Inside a motor car. Barking dog. Printing press. Piano. Doorbell 70 – 80
Street traffic. Shouted speech. Food mixer 80 – 90
Railway train. Power tools. Pneumatic drills 90 – 100
Helicopter. Rock bands. Motor cycles. Large orchestra 100 – 110
Jet aircraft taking off.  Fire cracker 110 – 120
Artillery. Rifles. Gunfire at close range. 120 – 130
Explosions. Machine guns. Nearby thunder 140 & above