WEBER AND RINNE TEST | WEBER AND RINNE TEST EXPLAINED | WEBER TEST AND RINNE TEST MADE SIMPLE - Online learning king

WEBER AND RINNE TEST

In this short post, we're going to have a look at the Rinne and Weber tests. Now, these are a couple of tests involving the use of a tuning fork that can be used to supplement your examination. When a patient presents with hearing loss, of course, there are many different causes for why someone might present with hearing loss, and for the most part from history alone, you will probably be able to reach an appropriate diagnosis. However, sometimes you may require some further steps in your examination to try and localize the pathology that may be causing the patient's hearing loss.

CONDUCTIVE AND SENSORYNEURAL HEARING LOSS

Broadly speaking hearing loss can be categorized as either conductive or sensory neural. A conductive hearing loss occurs when there is a problem somewhere within the external ear namely the external auditory meatus or a problem within the middle ear. Whereas a sensorineural hearing loss implies that the pathology is within the in-ear. So the cochlea or somewhere along the vestibular cochlear nerve or the auditory pathway towards the area of the brain in which we perceive sound following your initial history and examination of the ear.

You may decide that it's appropriate to try and further define the potential cause for someone's hearing loss. It is not being immediately apparent from your initial history and exam. To do this you obviously will require a tuning fork usually 512 Hertz is what should be used for this test.

WEBER TEST

So let's start with the Weber test. Weber's test involves the placement of a vibrating tuning fork on the top of the patient's head or on the forehead so long as it's in the midline. The tuning fork which is vibrating will then send the sound through the bone towards the inner ear. For just demonstrate this on this diagram, here we see that the vibrating tuning fork is placed on to the top of the skull in the midline pressing firmly and the vibration will be carried through the bone towards the inner ear. The inner ear is working as it should do the vibration or the sound vibration through the bone will reach the cochlea equally on both sides. Therefore be heard the same on both sides as a result when you ask the patient to indicate whether they hear the sound equal in both ears, or whether they hear it loudly toward one side or the other.

The patient with normal hearing and will describe hearing it equally on both sides. Both ears and will often describe sensing that sounds as centrally in the middle of their head. Now while we have this sound reaching the cochlea through the bone from this vibrating tuning fork at the top of the head, it's important to remember that we also have general ambient noise from the external environment also reaching the cochlea through the normal route through the external and middle ear towards the cochlea. This external ambient does not use even if you're conducting the examination in a very quiet room. The room actually acts to mask some of the input from the sound that's coming through the bone towards the cochlea now, of course, if both ears are normal and there is no impedance to noise from the external environment reaching the cochlea then the masking from the external environment on both cochlear will be equal on both sides. This comes important is that if you had a patient with a conductive hearing loss then that the patient will have a pathology that is impeding this external ambient noise reaching the cochlea on that side.

 For example, if a patient has a large amount of wax that's impacted in one of the ear canals say on the right side then when you place the tuning fork on top of their head and the vibration the sound is transmitted to the cochlea on both sides through the bone. The problem ear on the right with the wax will lose the masking influence of the external noise because it's blocked by the wax. Thus when you ask such a patient which side they hear the noise allowed us they will describe it as being loudest on the side of the conductive hearing loss I decide with the impacted wax for example.  That's because this cochlea now is only having to pick up the signals carried through the bone from the vibration tuning fork and they are not masked by any external ambient noise coming in through the external and their middle ear. Because it's not being able to do that on this side however on the normal side say, on the left-hand side, we also have this sound vibrating through the bone towards the inner ear but we still have some masking of that sound from the external ambient noise. On which this site has been able to pass through the external and middle ear to reach the inner ear itself.

Thus in a weber test, if a patient has a conductive hearing loss the patient will well hear the sound generated by the tuning fork on top of their head loudest on the sound of the pod pathology and that is because of the loss of this masking of noise coming through the normal route through the ear i.e., the external or the middle ear. so any condition that affects the external ear such as wax or attached sextaenia external or indeed the middle ear, for example, an acute otitis media glue ear otosclerosis and when you perform a Weber's test on that patient, they will hear the vibrating tuning fork loudest on that side so what about sensorineural hearing loss so concerns for neural hearing loss. The problem is not with the signal getting from the external and middle ear towards the inner ear the problem is actually within the inner ear itself. So again coming back to Weber's test and placement of the tuning fork on top of the head we will get vibration and conduction of sound through the bone both cochlea not if we have a sensorineural hearing loss on the right-hand side then this cochlea is not going to be as receptive to these sounds that are reaching it. Whether that be from the external environment or through born from the vibrating tuning fork as such a patient with a sensorineural hearing loss. For example, on this, the right side will not hear that bone conduction of sound as well on this side. However in the normal working in-ear, the patient will hear it perfectly as such. In a sensorineural hearing loss the patient will lateralize the sound during Weber tests towards the normal ear.

For example, a patient presents to you with a unique lateral hearing loss you take history and you perform an examination. Have a look in the external ear canal and you're not quite sure that you can see anything abnormal and when you perform the Weber test and you ask the patient whether they lateralize it to one side or the other they report that they hear it loudest in the left ear. Now at this stage, we don't know whether they heard it allowed us in the left ear because they have a conductive hearing loss on this side or they heard it allowed us on this side because the right ear is the problem they have a sensorineural hearing loss on the right side. This is where the use of the Rinne test, therefore, help to further determine whether the problem is indeed on the left or the right side so anyways tested again.

RINNE TEST

We used the vibrating tuning fork and the principle with Rinne test is that sound that is conducted through the air through the external and middle ear to the inner ear he's heard loudest. If we purely transmitted that sound straight through bone to the inner ear and then the reason that air conduction is better than bone conduction in terms of hearing is that the external ear helps to obviously, funnel and focus our vibration and sound onto the tympanic membrane. Then the middle ear with the presence of the ossicles help to amplify that sound onto the oval window into the inner ear so that the very presence of having an external and middle ear actually I was to hear a lot better than if we didn't have an external middle yet and required on that vibration simply going through born towards the inner ear.

PROCEDURE TO CONDUCT RINNE TEST

 Rinne test essentially plays on that first of all we would place the vibrating tuning fork on the mastoid process just behind the ear and that is to convey that vibration is through the bones straight to the inner ear and therefore bypassing the external and middle ear we then place the tuning fork as it continues to vibrate in front of the external auditory meatus. Therefore allowing the vibration to pass through the normal route which is the external and middle ear to reach the inner ear and we ask the patient whether it sounds allowed us with the tuning fork placed over the mastoid a process on the bone or whether it sounds loudest when it placed just in front of their ear and a normal Rinne test positive. Rinne test will be the patient reporting that he sounds a lot louder when it's placed just in front of the area because that's using air conduction to get the sound.

Now where we might lose that relationship of air being better than born is, if there is something inside the external or middle ear that is impeding the transmission of vibration through that route towards the inner ear. In such instances then the air conduction won't be better than bone conduction, because the air can't actually get to the inner ear through the normal route. But rather going through bone can bypass that problem and go straight to the inner ear or the cochlea. So a Rinnie's test, if it's normal, implies that everything is okay in terms of the external in the middle ear.

However, if the patient reports that actually bone conduction sending the signal straight to the cochlear and bypassing the external in the middle ear is actually better than air conduction. Then it actually tells you that the problem is somewhere within the external or the middle ear. In the case of this, a particular patient who said lateralized their Weber's tests to the left ear if we were to perform the Rinnie test on the left ear and found that air conduction was better than bone. Then that would imply actually there isn't a conductive problem on this side the external and the middle ear are working as they should and that the problem, therefore, must lie on the right-hand side the sensory neural hearing loss on the right.

If we were to do a Rinne test on an ear that did have sensory neural hearing loss The relationship of air being better than born would be maintained because the problem lies at the level of the inner ear. So if there is some reduction in what we hear and reaching the cochlear whether it comes through the normal route through the external and the middle ear or whether we pass like that and comes through the bone it will be equally diminished. But the relationship will still remain the same.

So that essentially concludes this post on the weber and Rinne test obviously if you identify that a patient has a unilateral hearing loss or indeed bilateral hearing loss and it isn't something that you feel is immediately treatable so, it's important that the patient is obviously referred on for further investigations and Langley also audiometry and some more formal hearing tests to determine the underlying cause.

So that in total is our Rinne and Weber test and it's one of the most important and well-known methods. I hope you enjoyed this post and there will definitely be more like this coming up as well as analyses of great information about the Rinne and weber test. so please do subscribe if you want to see more and share this post if you liked it thanks for reading........