Pure Tone Audiometry || PTA || Audiometry Test
Pure Tone Audiometry test also known as Audiometry test or PTA test. This test is used to measure hearing sensitityvity of an individual. It indicates the ability of hearing sensitivity of centeral and peripheral auditory system. The softest sound audible to an individual measured by using an Audiometer in an acoustically controlled room. Through this test Audiologist measure the hearing thresholds of an individual between frequency range 250Hz to 8KHz (in common). And the lowest audioble sound thresholds are plotted in a graph known as Audiogram.
This test evalutes degree of audibility in several frequencies. An average of these thresholds (Speech freq. thresholds are known as PTA1 average) are calculated and defined as degree of hearing loss.
Degree of Hearing Loss as per Audiogram :
0-25 dB average - Normal hearing sensitivity.
26-40 dB - Mild degree hearing loss. In this degree of loss patinents may not hear soft sound properly. Causes are - inattention to sound, difficulty in speech sound recognition when exposed to background noise and sometimes patiens may increased listening stress.
41-55 dB - Moderate degree hearing loss. In this degree of loss patients may face trouble in conversational speech.
56-70 dB - Moderately Severe degree hearing loss. In this degree of loss patients unable to hear most conversational speech.
71-90 dB - Severe degree hearing loss. In this degree of loss patients fails to hearing almost all conversational speech and it affects patients own voice quality.
91- > above dB - Profound degree hearing loss. In this degree of loss patients can't hearing anything of conversational speech and discriminition of speech is not possible.
Types of hearing loss as per audiogram :
Conductive Hearing Loss
Sensori Neural Hearing Loss
Mixed Hearing Loss