Tone decay test

== tone decay test

==

Audiology A hearing test that evaluates defects in adaptation to sounds, formally known as auditory fatigue–tone decay, which indicates a defect in transmission of nerve impulses from the ear, possibly caused by pressure or 8th cranial nerve damage

Normally person can hear a tone continue for 60 sec. in nerve fatigue ; one can stop hearing earlier ; it is a simple test.

Method

A tone of 4000hz is presented at 5dB above the patient’s threshold of hearing; continuously for a period of 60 sec.if patient stops hearing earlier; intensity is increased by another 5 dB. the procedure is continued till patient can hear the tone continuously for 60 s. Or no level exists above the threshold where tone is audible foe full 60 s.

Result

Result is expressed as number of db of decay. A decay more than 25 dB is diagnostic for retrochochler lesion.

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