Pure tone audiometry is considered to be the gold standard for measuring hearing sensitivity. It is the most popular hearing test used by audiologists to identify hearing threshold levels. The results (called audiograms) of pure tone audiometry can help audiologists determine the degree, type, and configuration and provide a basis for diagnosis and management.
The problem with pure tone audiometry
Pure tone audiometry is a subjective test based on the behavioral measurement of a hearing threshold. The test relies on a patient’s response to pure tone stimuli. Because of the subjective nature of the test that requires a good amount of cooperation from the patient, pure tone audiometry is only used on adults and children old enough to cooperate with the test procedure.
The limitations of pure tone audiometry
Standardized calibration of the test environment, the equipment, and the stimuli need to be done before pure tone audiometry can be conducted. The test only measures audibility thresholds and no other aspects of hearing such as sound localization and speech recognition. There are clinical benefits to pure tone audiometry as it includes both air and bone conduction audiometry. However, it is not perfect at identifying all types of hearing losses such as “dead regions” of the cochlea and neuropathies such as auditory processing disorders. This raises doubt on whether pure tone audiometry can accurately predict someone’s perceived degree of hearing loss or hearing disability. While pure tone audiometry has long been used as the gold standard for measuring hearing sensitivity at specific frequencies, it is often inadequate when it comes to predicting speech understanding, especially in noise. Pure tone thresholds mainly reflect the mechanical amplification of quiet sounds provided by the outer hair cells. Thus, an audiogram is a reflection of pure hearing sensitivity. In contrast, it is the inner hair cells that are responsible for sending most of the auditory signals to the brain. If there is damage in their inner hair cells, individuals typically suffer from a loss of clarity rather than a loss of sensitivity. As we have seen above, pure tone audiometry is not the best choice for children. The Screening Guidelines for school-based hearing services from the American Speech-Language-Hearing Association (ASHA), World Health Organisation (WHO), and the American Academy of Audiology (AAA) recommend screening down to 25 dB. In order to negate the effects of the presence of adverse background noise, a higher screening intensity is used which can lead to several misdiagnoses of hearing impairment. Ideally, pure tone audiometry should be conducted by trained personnel who can distinguish between false positive and false negative reports. In the absence of an audiologist, or trained personnel, such “misses” can lead to delays in treatments and patient outcomes. For children, this is especially critical. Early diagnosis and intervention can ensure optimal educational, social, and behavioral development of children. It can therefore be concluded that pure tone audiometry in isolation should not be the only primary test that providers of hearing services use to detect issues. We recommend that audiologists perform the tympanometry test in combination with pure tone audiometry.
What is tympanometry?
Tympanometry is a commonly used procedure that provides information about the condition of the tympanic member (eardrum) and the middle ear. It is frequently used to evaluate the eardrum of children who are prone to ear infections where fluid accumulates in the middle ear space, which is normally filled with air.
What are the types of tympanometry?
The American Family Physician states that “Tympanogram tracings are classified as type A (normal), type B (flat, clearly abnormal), and type C (indicating significant negative pressure in the middle ear, possibly indicative of pathology).”
The advantages of tympanometry
For better direction and management of hearing disorders, it is necessary for audiologists and their teams to make a good diagnosis at the outset. A battery of tests should be conducted which could include a combination of pure tone audiometry, speech evaluation, immittance assessment, and auditory steady-state response (ASSR) to avoid misdiagnosis. This kind of procedure can greatly improve audiological practice, early intervention, and better patient outcomes. Tympanometry has several advantages. It is not a subjective procedure that can result in false-positive responses. The objective test requires no active participation from the patient and therefore, tympanometry can significantly increase the reliability of results. Other benefits include:
- Tympanometry is highly sensitive to middle ear status revealing hearing abnormalities not visible with the otoscopic examination
- It can indicate eustachian tube dysfunction and ossicular discontinuity and otosclerosis
- Tympanometry can assess patients of all ages but is especially useful in testing children
- The tympanometer can be operated by personnel who are trained but not necessarily skilled as an audiologist
- Tympanometry assesses a patient’s eardrum and can indicate when it is perforated
The best choice for audiologists: Portable Tympanometers
The KUDUwave Pro TMP combines pure tone audiometry (both air and bone conduction) and speech recognition with tympanometry in a single device. This enables audiologists to conduct a full battery of tests with testing times being significantly reduced. The tympanometer is a portable, software-controlled, Type 1 aural acoustic immittance instrument incorporated into the KUDUwave audiometer. It connects to your computer with a USB cable and test measurements are displayed on the screen. The configuration of the KUDUwave Pro TMP incorporates all audiological screening and diagnostic features of the KUDUwave and adds to it bilateral tympanometry and acoustic reflexes. Tympanometry results are quick (often less than a minute for testing both ears) which is especially useful in testing children. Weighing just under 4 lbs., the KUDUwave Pro TMP can be easily carried and set up at educational settings, mines, industrial sites, clinics, hospitals, or even shopping malls and supermarkets. Other features include:
- Enables booth-free audiometry
- Enables tele-audiology
- Measures reflex delay
- Customizes stimuli testing
- Provides accurate calibration verification in 30 seconds
- Enables bilateral tympanometry testing through dual tympanometers integrated into the audiometric headsets
Improve quality patient care while being able to test more patients with the KUDUwave Pro TMP. Use the automatic mode option to set defined testing parameters and let the KUDUwave Pro TMP work for you while you focus on patient care. Hearing services can add to their suite of hearing offerings for increased revenue. The portable audiometry can be easily carried to industrial sites and school settings. Where care is inaccessible, such as during the recent COVID-19 pandemic, audiologists can enable tele-audiology testing. Click here for a more detailed list of the features and capabilities of the KUDUwave Pro TMP.