Overview of Rinne Test
There are many ways to check for hearing loss. However, two tests called Rinne and Weber are the most reliable and are used often. These tests are taught in medical schools and used frequently to see if a patient has hearing problems. The Rinne test, named after a German doctor who invented it, checks for hearing loss in one ear.
In a nutshell, the Rinne test works by comparing sounds that reach your ear through the air with sounds that reach your ear through a bone in your head, the mastoid bone. If you can hear better through the mastoid bone, you might have what’s called a conductive hearing loss in one ear. This type of hearing loss typically happens when there’s a problem with the ear canal, ear drum, or middle ear and its little bones (the malleus, incus, and stapes).
The Weber test, on the other hand, helps determine what kind of hearing loss you may have – either conductive or sensorineural. Conductive hearing loss happens when sound vibrations are not effectively transferred from the outer ear to the inner ear. Sensorineural hearing loss happens when there’s a problem with the inner ear or the pathway from the inner ear to the brain.
The Rinne test is often given if a doctor thinks you might have conductive hearing loss. Also, for some people with a condition called otosclerosis, in which one of the bones in the middle ear grows abnormally, the Rinne test can help decide if they can have a certain kind of surgery.
Anatomy and Physiology of Rinne Test
The external ear, the part of your ear that you can see, helps to capture sound waves from your environment and focus them onto your eardrum, also known as the tympanic membrane. Inside your ear, a small chain of bones known as the ossicles (which includes the malleus, incus, and stapes) work together to transmit these sound vibrations through the middle part of your ear. The stapes bone then pushes these vibrations into the cochlea, the spiral-shaped inner part of your ear, via a small opening called the oval window. Sound can also reach the cochlea by vibrating the bones of your skull.
In the cochlea, thousands of tiny hair-like cells convert the physical sound vibrations into signals, or action potentials, which are then relayed to your brain by the auditory nerve for interpretation. If there is a problem at any stage in this process, it can result in hearing loss.
Your doctor may use a Rinne test to check your hearing. This involves attaching a tuning fork to your ear skull bone and then moving it near the outer part of the ear. This test compares how well you hear sounds that are transmitted through the air (known as air conduction) as compared to sounds transmitted through your bones (known as bone conduction). The parts of the ear including the external ear, ear canal, eardrum, and ossicles work together to amplify and direct sound during air conduction. Meanwhile, with bone conduction, your ear bones transmit sound vibrations through the bones of your skull directly to your inner ear. This method causes sound to be heard at a lower volume in the other ear.
Why do People Need Rinne Test
To understand the Rinne test, you need to know a little bit about how our hearing works. Normally, we hear sounds better when they travel through the air into our ear (air conduction) than when they go through the bone behind our ear, known as the mastoid (bone conduction). In the Rinne test, a tuning fork is used. When this tuning fork is placed next to the patient’s ear and then against the mastoid, a person with normal hearing will hear the sound from the tuning fork more clearly when it is by the ear, compared to when it is against the bone behind the ear.
Equipment used for Rinne Test
The doctor performing the test should use a tuning fork that vibrates at 512 Hz. It’s important they don’t use a tuning fork that vibrates at 128 Hz or 256 Hz. This is because these particular ones are reserved for checking how well you can feel vibrations, which is part of a different type of test called a neurological examination.
How is Rinne Test performed
The bone conduction test is a simple procedure that helps doctors understand if you have hearing problems. Here’s how it works:
1. First, the doctor will make a tuning fork vibrate and place it on a hard area right behind your ear, known as the mastoid process.
2. They will ask you to cover your other ear with your hand.
3. You will be asked to tell the doctor the moment you can’t hear the sound from the tuning fork anymore.
4. Once you can’t hear the sound through the mastoid process, the doctor will move the tuning fork next to your ear canal. The fork’s prongs will be at a 90-degree angle to the ear canal, about one to one and a half inches away from the ear.
5. Your job is to let the doctor know when you can’t hear the sound through the air anymore.
The results of this test can tell us a lot about your hearing:
– Normal result: If you can hear the tuning fork sound next to your ear opening for about twice as long as you could when it was on the mastoid bone, that’s a good sign. It means that you hear sounds through the air better than through the bone, which is what we want – this is called a “positive test.”
– Abnormal result: If you can’t hear the sound next to your ear canal after it’s moved away from the bone behind your ear, it means you hear better through the bone than the air. This could suggest you have hearing loss related to sound conduction, and this is called a “negative test”.
What Else Should I Know About Rinne Test?
A tuning fork test can help doctors understand if your hearing is normal. If during the test, the sound of the tuning fork is louder when placed next to your ear opening, this is a positive sign, and your ear is working correctly. The inner parts of your ear are meant to amplify sound, but if the sound heard through the bone behind your ear is louder, it is considered abnormal, indicating that there might be a problem.
If during the test, the sound is not properly transmitted through your ear, there could be several reasons why. This could be due to issues with your ear canal, like a foreign object in your ear or an ear infection. Also, it could be related to problems with your eardrum, like a hole caused by an injury or infection. Problems with the middle parts of your ear, including an infection or build-up of fluid (also known as glue ear), could also be a cause. Lastly, abnormal bone growth hindering sound transmission to your inner ear might also be a possible reason.
Sometimes, the test can falsely indicate that your hearing is fine when you have profound hearing loss. This is because the sound can travel to your functional ear through your head, making you unable to identify which ear you’re hearing the sound from. The wrong ear could be subtly tested, suggesting that bone-conducted sound is louder when in fact, the ear is not functioning. To confirm if it’s a true or false test result, your doctor will perform another test known as the Weber test.
