Continuing Education Activity

The Rinne test differentiates sound transmission via air conduction from sound transmission via bone conduction. It can serve as a quick screen for conductive hearing loss. A Rinne test should be done with a Weber test to detect sensorineural hearing loss. Over the years, many tuning fork tests have been developed to assess hearing loss, but today, only 2 have withstood the test of time: Rinne and Weber. These tests are now routinely taught in medical schools and performed regularly to evaluate patients with hearing problems. The Rinne test is used when conductive hearing loss is suspected and is used in patients with otosclerosis to determine if a patient might benefit from stape surgery. This activity describes the technique of conducting the Rinne test and its clinical relevance. This activity reviews the indications and techniques for performing the Rinne test and interpreting the results. This activity highlights the interprofessional team's role in caring for patients with hearing problems.

Objectives:

• Assess the anatomical structures involved in hearing loss.

• Identify the technique for performing the Rinne test.

• Evaluate how to interpret the findings of the Rinne test.

• Communicate interprofessional team strategies for enhancing care coordination to advance the diagnosis and management of hearing loss and improve outcomes.

Introduction

Over the years, many tuning fork tests have been developed to assess hearing loss, but today, only 2 have withstood the test of time: Rinne and Weber. These tests are now routinely taught in medical schools and performed regularly to assess patients with hearing problems. Heinrich Adolph Rinne (1819-1868), a German otologist, proposed the test, subsequently named after him. The Rinne test is used to evaluate hearing loss in 1 ear. The Rinne test differentiates sound transmitted through air conduction from those transmitted through bone conduction via the mastoid bone. By comparing air and bone conduction, it helps detect conductive hearing loss in 1 ear. A Rinne test should be performed with a Weber test to help distinguish between conductive hearing loss and sensorineural hearing loss.[1][2][3] The Rinne test is frequently recommended when one suspects a conductive hearing loss. In some patients with otosclerosis, the Rinne test is performed to determine if the patient is eligible for stapes surgery.[4][5][6]

Anatomy and Physiology

The external ear collects sound vibrations from the air and focuses these sounds onto the tympanic membrane. The ossicular chain (malleus, incus, and stapes) transmits vibrations through the middle ear. The stapes transmit these vibrations to the cochlea through the oval window (fenestra ovalis). Sound can also be transmitted through the bones of the skull to the cochlea. The hair cells in the cochlea convert the physical vibrations into action potentials transmitted via the nerves in the vestibulocochlear (auditory) nerve to the brainstem for further processing. Deafness may occur due to interruption at any point along this pathway. The Rinne test is conducted by placing a tuning fork on the mastoid bone and then adjacent to the outer ear. Air conduction uses the apparatus of the ear (pinna, ear canal, tympanic membrane, and ossicles) to amplify and direct the sound. Bone conduction allows the vibration sound to be transmitted to the inner ear. The ear bones transmit reduced volume audition via the bones of the skull to the other ear.

Indications

Before performing the Rinne test, it is important to know that individuals with normal hearing have greater air conduction than bone conduction. This means that the individual can hear the tuning fork adjacent to the outer ear, even after they can no longer hear it when held against the mastoid.

Equipment

The examiner should use a 512 Hz tuning fork. One should avoid using a 128 Hz or 256 Hz tuning fork, as these are used to assess vibration sensation in neurological examinations.

Preparation

The room should be reasonably quiet.

Technique or Treatment

Test Bone Conduction

1. Initiate the tuning fork's vibration and then place the vibrating tuning fork onto the patient's mastoid process of the tested ear.
2. Ask the patient to cover the opposite ear with their hand.
3. Ask the patient to report when the sound can no longer be heard.
4. After the patient can no longer hear the tuning fork placed on the mastoid process, move the vibrating tuning fork adjacent to the ear canal with the tines oriented perpendicular to the ear canal, approximately 3 to 4 cm from the ear.[4]
5. The patient should indicate when they can no longer hear the sound conducted through the air.

Interpretation

Normal finding: Air conduction is better than bone conduction. The patient should be able to hear the sound of the tuning fork adjacent to their ear, which persists for approximately twice as long as the sound they heard over their mastoid process. This is considered a "positive test." Abnormal: Bone conduction is better than air conduction. The patient cannot hear sound conducted through the air after the fork is moved from the mastoid process. This suggests conductive hearing loss and is called a "negative test."

Clinical Significance

The tuning fork can be perceived as being louder when placed at the external auditory meatus.

• Rinne Positive: The patient is positive on that side (the ossicular chain is doing what it should be doing, acting as an amplifier). If the bone conduction through the mastoid process is heard louder than through the air, the patient is Rinne negative. This is always abnormal.
• If the patient has negative or abnormal Rinne negative, air vibrations are not transmitted across the external auditory canal, the tympanic membrane, the ossicular chain, or the oval window.

Causes in the external auditory canal:

• Wax in the external canal
• Otitis externa or outer ear canal infection
• Foreign body in the ear canal

Causes due to the drum:

• Perforation of the drum due to trauma or infection

Causes in the middle ear:

• Infection (acute otitis media) in the middle ear
• Serous otitis media (glue ear) can result from repeated episodes of acute otitis media.

Causes at the oval window:

• Otosclerosis results in the failure to transmit sound from the stapes through the oval window due to abnormal bone growth. 

False Negative Rinne test

A patient with profound sensorineural deafness may have a false negative Rinne. With complete loss of innervation to that ear, the patient does not hear anything from the tuning fork on the mastoid or near the canal. The sound transmits through their skull to the ear on the other side, and they may be unable to identify in which ear they hear the sound. It seems that bone conduction is better than air conduction, but the ear is nonfunctional. The way to determine the difference between a true and a false Rinne negative test is to perform the Weber test. For example, if the left ear is completely dead, the sound waves travel to the right ear to test the bone conduction on the left. However, the sounds are not heard when the tuning fork is held next to the external auditory meatus on the side being tested (left). In this case, the patient stated that bone conduction is louder than air conduction, which gave a falsely negative Rinne test.

Enhancing Healthcare Team Outcomes

Limitations of the Rinne test

Like its complementary test, the Weber test, both are screening tests that do not replace formal audiometry. Additionally, the validity of the Rinne test as a screening test is often questioned. The test is not sensitive in differentiating conductive and sensorineural loss, which causes total sensorineural or severe unilateral hearing loss. False negatives are common in such situations. In any situation with a question about the Rinne test, the patient must be referred to an ear, nose, and throat surgeon for formal audiometry. Another important caveat about the Rinne test is that the technique is not uniform. The orientation of the tuning fork and its exact placement varies from individual to individual. All physicians who perform the Rinne test must pay attention to the orientation of the tines of the tuning fork relative to the long axis of the external auditory canal when testing for air conduction.