What is Pure Tone Audiometry?

Pure tone audiometry is a diagnostic test used to measure a person’s hearing ability. It is a fundamental tool in audiology and is often used to determine the type and degree of hearing loss. By understanding pure tone audiometry, you can gain insights into how it works and its significance in the field of audiology.

How Does Pure Tone Audiometry Work?

Pure tone audiometry works by presenting a series of pure tones to the individual being tested. These pure tones are single frequencies, and they are presented at different volumes. The audiologist will ask the individual to indicate when they hear the tones, which helps determine the softest sound they can hear at each frequency.The test is typically conducted in a soundproof booth to minimize external noise interference. The audiologist uses a device called an audiometer to generate the pure tones. The audiometer can produce a wide range of frequencies, typically from 250 to 8000 Hz, depending on the individual’s age and specific hearing needs.

During the test, the audiologist will ask you to wear headphones and respond to the tones by pressing a button or raising your hand when you hear them. The audiologist will gradually increase the volume of the tones until you can no longer hear them. The point at which you can no longer hear the tone is called the hearing threshold.

Types of Pure Tone Audiometry

There are several types of pure tone audiometry, each designed to assess different aspects of hearing. Here are some of the most common types:

Conventional Pure Tone Audiometry: This is the most common type of pure tone audiometry. It measures the hearing threshold for each frequency and is used to determine the type and degree of hearing loss.
High-Frequency Audiometry: This type of audiometry focuses on frequencies above 2000 Hz, which are often the first to be affected by hearing loss.
Low-Frequency Audiometry: This type of audiometry focuses on frequencies below 2000 Hz, which are important for understanding speech and environmental sounds.
Frequency Specific Audiometry: This type of audiometry measures the hearing threshold for specific frequencies, such as those used in speech.

Interpreting the Results

The results of a pure tone audiometry test are typically presented in an audiogram, which is a graph that shows the hearing threshold at each frequency. The audiogram can help the audiologist determine the type and degree of hearing loss, as well as identify any specific frequencies that are affected.

Here’s a brief overview of the different types of hearing loss that can be identified through pure tone audiometry:

Sensory Neural Hearing Loss: This type of hearing loss is caused by damage to the inner ear or auditory nerve. It is often permanent and can be identified by a steep decline in hearing thresholds across all frequencies.
Conductive Hearing Loss: This type of hearing loss is caused by a problem in the outer or middle ear, such as a perforated eardrum or earwax buildup. It is often treatable and can be identified by a flat or slightly elevated hearing threshold at low frequencies.
Mixed Hearing Loss: This type of hearing loss is a combination of sensory neural and conductive hearing loss. It can be identified by a combination of a steep decline in hearing thresholds at high frequencies and a flat or slightly elevated hearing threshold at low frequencies.

Applications of Pure Tone Audiometry

Pure tone audiometry has a wide range of applications in audiology and related fields. Here are some of the most common uses:

Diagnosis of Hearing Loss: Pure tone audiometry is the primary tool used to diagnose hearing loss in both children and adults.
Assessment of Hearing Aids: Pure tone audiometry is used to assess the effectiveness of hearing aids and to fine-tune their settings.
Monitoring Hearing Health: Regular pure tone audiometry tests can help monitor the hearing health of individuals with known hearing loss or those at risk of developing hearing loss.
Research and Development: Pure tone audiometry is used in research to study the causes and effects of hearing loss, as well as to develop new hearing aids and other assistive devices.