Audiometer

An audiometer is an instrument used to determine a person’s hearing threshold. Audiometric is a test of sound that determines the range of the person’s hearing capability. 

An audiometer and special audiometric testing procedures are used by an audiologist or other qualified individuals to assess the hearing threshold and to diagnose and understand the degree of hearing loss in a person. The necessary referral for hearing aid fitting or medical care relies on the output of the test. The audiometer is used to deliver tones of various frequencies to the patient’s ear at varying volumes. A person’s hearing threshold is the point at which they can only hear stimuli at a given loudness.

What Are the Different Types of Audiometers?

A variety of equipment is used in audiometric testing to conduct various sorts of tests of sound. Clinical audiometers, diagnostic audiometers, and screening audiometers are the three types of audiometers. 

For instance, an audiometer is used to determine whether or not a person is suffering from hearing loss. If the screening fails, the patient will be referred for a full diagnostic test battery. The first item in the comprehensive diagnostic test battery would be a diagnostic audiometer. It has more features and flexibility than a screening audiometer since it is used to diagnose and measure hearing abnormalities as well as their likely causes.

What is the purpose of an audiometry test of sound?

An audiometry test of sound assesses a person’s hearing abilities. The loudness (intensity) of sounds and the speed at which sound waves vibrate varies (tone).

Sound waves activate the nerves in the inner ear, which causes hearing. The sound then gets to the brain through nerve connections.

The eardrum, ear canal, and middle ear bones can all carry sound waves to the inner ear (air conduction). They can also travel through and behind the ear’s bones (bone conduction).

Pure Tone Audiometry

Pure-tone audiometry is widely regarded as the gold standard for assessing auditory sensitivity. Pure-tone audiometry is used to detect the amount of hearing loss and its etiology. It aids in the determination of hearing thresholds at various frequencies.

Pure-tone audiometry ranges from basic, low-cost devices to complicated, high-cost diagnostic audiometers. A pure tone is supplied to the ear through an earphone in this test, and the decibel level at which the tone is perceived 50% of the time is measured (dB). The term ‘threshold’ refers to this measurement. The audiogram is a graph that represents the output. Specific frequencies spanning from 250 to 8000 Hz are used in the testing method.

Speech Audiometry

The goal of speech audiometry is to evaluate the hearing abilities and examine the integrity of the complete auditory system. Speech audiometry can be used to identify the type of hearing loss that is occurring. Speech reception threshold and speech discrimination tests are two types of speech audiometric tests.

Both tests are designed to find the lowest decibel level at which a patient can properly repeat 50% of the phrases. Speech reception threshold tests employ two-syllable words with equal stress (sometimes known as “spondees”), whereas speech discrimination tests use monosyllable test items.

Suprathreshold audiometry

Suprathreshold audiometry is a kind of audiometry that measures sound levels above the threshold. Patients with varying degrees of hearing loss in both ears have a rise in perceived loudness in response to a slight increase in intensity, which is known as recruitment.

Suprathreshold audiometry is a type of recruitment detection test. It aids in determining if the listener can properly recognize the speech at a regular conversational speech level. This test can also identify the benefits to a patient from wearing a hearing aid.

Self-recording audiometry

Bekesy audiometry is another name for self-recording audiometry. George von Bekesy was the first to offer this test of sound in 1947. With the aid of a motor, the frequency and intensity are automatically modified in this method.

The frequency may be adjusted in either a forward or backward direction. A recording attenuator is used in this hearing test. The attenuator may either decrease or increase the signal strength at a set rate of so many dB per second. The listener can control the attenuator’s activity.

Impedance audiometry

Impedance audiometry measures the air pressure and mobility of the middle ear reflexes and also the middle ear system.

Computer-administered (microprocessor) audiometry

In 1975, the first microprocessor audiometer for commercial purposes was released. A multifunctional keypad is found on most microprocessor audiometer instruments. Microprocessor audiometers have several benefits over manual and self-recording audiometers.

Subjective audiometry

The individuals are instructed to reply when they hear the delivered sound in this test. This audiometric test of sound may offer the subjects a variety of sound stimuli and record their reactions.

Objective Audiometry

Unlike subjective audiometry, this test does not rely on the patients’ replies. The subjects, on the other hand, are requested to cooperate when the probes and measuring electrodes are attached for the objective test.

Conclusion

An audiometer is a device that measures hearing acuity. They typically comprise an embedded hardware unit coupled to a set of headphones and a feedback button for the test participant, which is occasionally operated by a conventional PC. To assess conductive hearing processes, such devices can be combined with bone vibrators.

ENT (ear, nose, and throat) clinics and audiology facilities include audiometers as standard equipment. Software audiometers, which come in a variety of configurations, are an alternative to hardware audiometers. A regular computer is used to screen PC-based audiometers. Hospitals, audiology centers, and research institutions are the most typical places to find them. Industrial audiometric testing is also done using these audiometers.