How to Use a Medical Tuning Fork - Assessing Vibration Sense - Clinical Skills - Dr Gill

[Music] hello and welcome back to the channel my name is dr james gill and you've joined me for another clinical skills video today we're going to look at one of my favorite tools from my medical kit bag the tuning fork which we're going to use for vibration sense as well as for testing hearing in the weber's and rene's test now i'm sure many of you will have already seen that we've recently put out a a video looking at the webers and the rhines test looking at sensory neural and conductive hearing loss similarly we have videos on the neurological examination given previous discussions with students i want to dig into exactly how it is that we're using the tuning fork um both the webbers and rinnie's test and how it's going to be used when we're looking for sensation changes particularly to the vibration sensors there are several different types of tuning forks available personally i prefer this type where we can hold the tuning fork by the base and applying a flattened piece of metal to the patient as a way of stimulating them the nice thing about these tuning forks is the plates that allows you to easily grip onto their surface meaning that we can manipulate the fork and easily apply it to the patient without similarly affecting the vibration now there are two main tuning forks that we're going to use one is the 512 hertz fork this would be used for the vevers and the rinis test particularly because the vibration sound is going to very quickly dissipate meaning it's much more effective when we're trying to test hearing then we have the larger 128 hertz tuning fork the difference here obviously is going to be in both amplitude and vibration frequency now the 128 hertz fork is much better when it comes for testing vibration sense which is what we're going to be looking at with regard to the dorsal columns [Music] i'm going to tap it and place it on your forehead you can now hear a noise in your head is that correct yeah okay which ear can you hear it in the left right or the center center okay so that's fine so we've got a normal balance there i'm just going to do the same to the back of the ears so if you could move your hair back so we can see the side of your head okay so tell me when you can't hear the noise anymore no and again bringing it around directly in front of the ear can you hear that yeah super bad and final one on the side okay so you can hear the noise okay tell me when you can't no can you hear it now yeah super thank you and specifically for the vibration by the ear i'm making sure that the tuning forks are going directly into the ear as the sound will propagate in this fashion so in terms of using the 512 hertz form we're going to apply it initially to the patient's mastoid process waiting for the sound to disappear before moving around so the tuning fork prongs are directing the vibration into the ear it's very important that the tuning forks aren't parallel to the ear because that will send the sound away from the patient in terms of using the tuning fork we can either strike it with a tendon hammer or we can flick it with our fingers it's also potential to strike it against another soft object which would allow the fork to vibrate and thus sound to propagate out that will also mean that there is the vibration coming through the end of the tuning fork which the patient will pick up on [Music] when it comes to using the tuning fork as a method of checking vibration sense we'll strike it and place it on the patient's chest specifically over the maneuvering at this point we'd expect the patient to be able to feel both the metal being applied to the skin but also the sense of vibration we will then stop the tuning fork with our fingers whereupon we would also expect the patient to no longer be able to feel the vibration so what i'd like to do now if you don't mind um i'd just like to use this tuning fork and see if you can feel the vibration sense so to start off i'm going to strike the tuning fork and place it on your chest there so you can feel the vibration there yeah okay and tell when it stops no perfect so we can see the difference between the two this will form the basis of the test that will apply to the peripheries again striking the tuning fork and placing it over bony prominence such as the distal phalanx and please close your eyes and tell me when um this vibration stops hello super thank you the very act of applying the tuning fork to the finger may be sufficient to stimulate the patient's sensation of touch which will provide a false positive so what we're going to do again is stop the tuning fork and we're going to ask the patient to confirm when they can no longer feel the vibration [Music] now obviously there's the question about what's the clinical significance of you know paying attention to a patient's vibration sense when we have neurological issues we make at reduction in peripheral reflexes impairment of vibration sense and position as well if there's a problem with the posterior column pathways then we're likely to see this loss of vibration sense the dorsal columns are involved in sensation particularly dealing with conscious appreciation of fine touch two-point discrimination proprioception so understanding where the body is in space and also vibration sensors specifically so in terms of diseases that might cause problems with vibration sense we're looking at degenerative diseases or potentially demyelinating diseases so two possible options are tabs dorsalis where we're looking at a late manifestation of tertiary syphilis thankfully not something we see today but if it was then we get neurological deficits due to the damage of the posterior columns here conversely we can have something much more severe that being sub-acute combined degeneration the chord this is seen when we have a vitamin b12 deficiency the b12 deficiency causing subacute combined degeneration in the chord will lead to axonal myelination abnormalities essentially that's going to slow down nerve conduction so again we're going to see things such as pins and needles and loss of vibration sense and proprioception whilst it must be said that most of these are very rare and sometimes outmoded conditions such as our tertiary syphilis for tabs or salis it's still important that students are aware of the posterior columns and how vibration sense is affected by problems with the posterior columns [Music] now previously you may have found expedition medics and orthopedic surgeons carrying a 128 hertz tuning fork in their kit the reason being is it's been held that applying the 128 hertz fork to the site of a suspected fracture may cause the periosteum to similarly vibrate and generate a pain signal suggesting that there's a fracture underneath now whilst i like that as a possibility we do have the problem that we can have false positives applying the tuning fork over a strain for example now a bmj open article in 2014 i'll put the link down below did highlight that clinically speaking this isn't accurate enough to form a good basis for your management of your patient but frankly if you're doing expedition medicine and you're in the middle of nowhere it's going to add extra data to your decision-making processes in terms of whether or not you're going to abandon that expedition for that individual or perhaps the whole party so yeah maybe not the most accurate tool particularly compared to the benefits of a full um you know x-ray but if you've not got anything more than just your clinical intuition it's certainly at least going to give me something more to try to help make those decisions hopefully this has been a useful overview of how to correctly use the tuning fork and to help you maximize your clinical practice if there's any questions you've got please drop them down below and we'll see you in the next one take care [Music] do you