Neurological Examination - Power, Reflexes, Sensation, and Coordination - Dr Gill

hello my name's dr james gill and welcome back to my kitchen for so we've talked about power how are we going to actually define power power is essentially the ability to overcome gravity and it's important to remember there are normal variations between people age gender fitness occupation all are going to affect power and we need to keep that in mind during our examination a crucial thing that might affect power actually is pain frequently seen in the a e department somebody's had a severe injury and we're not actually able to easily assess them because of that pain they're feeling so in terms of power we're going to rate this with the medical research council scale going from five being normal power all the way down to zero and you'll see that this is relatively straightforward but has a few crucial bits to it normal power is just that you'd expect the patient to be able to push and pull you as you'd expect so with grade five power the patient is able to pull and push against you as you can on them and you feel that their power is reasonable to yours grade four is they can do all the movements and things and they can push against you but they're just weaker than you'd expect and that's the one part of the rating where it's slightly difficult to be confident in grade three power you've got movement against gravity without resistance so for example the patient can flex and extend their arm but if i was to put my hand there they wouldn't be able to do it against me with grade two they can move but not against gravity so they wouldn't be able to pick up their arm but if i could hold their arm they could move it side to side for me with grade one they can't actually move the limb at all now but they are able to contract the muscle on grade zero we've got no movement at all remember weakness to the extend sores in the upper limbs suggests an upper motor neuron lesion whereas weakness to the flexors in the lower limb would also would suggest our upper motor neuron lesion there are some conditions such as mycenia gravis which affect power in a slightly different way with myasthenia gravis patients get tired they fatigue easily so we'll find that if a patient is saying that they get tired they have difficulty doing repetitive movements we test that perhaps getting them to blink rapidly and would expect to see that tiring by about 30 seconds duration in terms of assessing power remembering that other motor neuron lesions will affect muscle groups whereas lower motor neurons will affect single muscles we want to do a series of movements so i'm just going to check your powers if that's okay so we're going to start off at the top and work down so we'll get the patient to put their arms up by their shoulders they'll push us down and we'll push them up to confirm that we've got ab and adduction they will flex and extend the elbow and stay in flex and extend the wrist and we can also look at movement of the fingers and the grip we can also check for ab and adduction of the thumb so a good one there is stop me pushing your thumb up stop me pushing your thumb down and in all ways you're going to be trying to oppose them with cellular muscle groups to ensure it's a fair test we've highlighted the other motor neurons they cause weakness but that tends to be in large muscle groups okay and good examples that you might see with this are a stroke causing pyramidal weakness where we'll get weakness to uh the extensors rather than the flexors in the upper motor neuron lesions of the upper limb having checked powers we need to assess reflexes so we've all come across reflexes in the past but how would we define it a reflex is defined as an unlearned rapid involuntary and predictable response classic one being we touch our fingers against a hot pan and we immediately pull back our hand that requires five features in order to work we need a sensory receptor so the fingertips experiencing the pain the sensory neuron transmitting the pain the integration center in the spinal cord the motor neurone sending back the signal and the effector target bringing the muscle up so reflexes are easily testable and allow us to compare that all this is functioning with the lower motor neuron lesion we lose the whole reflex because there's no this there is a break in that five step chain with an upper motor neuron lesion we get increased reflexes why could that be well this is likely due to loss of inhibition coming down from the central nervous system with the normal reflex as it goes into the spine and the integration center there's actually two processes that go on the alpha motor neuron causing the response in our target muscle is activated but there is also the activation of an inhibitory alpha motor neuron to switch off the opposing muscle to allow maximum speed and contractility getting you out of harm's way it's thought because we've had the uppermost neuron lesion we've lost an additional suppression thus reflexes are going to be much sharper and we can see that with parkinson's disease the substantia is therefore our pattern generation more importantly inhibition of abnormal movements so as the substantia gets damaged in parkinson's we end up with increased tone which we see as an abnormal gait we also get our tremor our pill rolling tremor because we aren't able to inhibit these movements so that supports the theory of the increased reflexes due to loss of upper motor neuron inhibition so there are two types of reflexes that we broadly need to consider but only one are we going to test we have somatic reflexes those simple skeletal muscle reflexes that we we will assess but also we have visceral reflexes so good example of a visceral reflexes you stand up you've got up too quickly you've gone a little bit light headed because your blood pressure has dropped down ever so slightly the baroreceptors or pressure receptors in your neck note that reduction in pressure so cause your heart rate and go up and your heart a bit more forcefully increasing up the pressure thankfully we don't routinely test things like that but we stay with the somatic skeletal muscle reflexes in terms of the reflexes we're going to use a tendon hammer of which there are multiple different types the two classic ones that you'll come across will be the taylor hammer and the queen's square hammer the total hammer is probably the earlier of the hammers invented in 1881 after the doctor had seen previous chest hammers now the chest hammer came about as a doctor leopold aubry i think i've pronounced it correctly would watch his father working as a hotel manager tapping down on barrels of wine to work out where the level is and he considered that it may be possible to do the same making a chest hammer to assess the patient's internal organs now yes we do still percuss the chest but we use fingers rather than hammers now because they weren't shown to be particularly useful but those hammers have evolved into the tendon hammers have a very different function now i'm personally quite a fan of the taylor hammer we've got a nice broad flat edge which is good for the broad reflexes such as at the knee or at the elbow however the apex there is very effective for deep tendons such as the bicep or over the carpal tunnel now a comparison is made with the queen's square hammer this actually initially started off life as basically a homemade tool by one of the nurses who worked in the national hospital of nervous diseases queen square london which is where the name comes from she took a pessary put it on a brass weight which she then attached to a bamboo stick and found that she was able to reliably induce reflexes with it now we use these classically at medical school but also going further because these can be very effective because they allow 10 newton meters of force to be generated with their simple drop from on high with the taylor hammer you have to be ever slightly more cautious simply because you've not got that same degree of movement with it but the queen's road hammer obviously has slightly less focus to its movement but both are equally valid tools in terms of testing the reflex we need to ensure the patient is calm at rest because we want to try and have no active tone in their muscles so we're going to place our thumb over the biceps tendon as an example because we don't want to hurt the patient and strike directly onto our bicep now we may find that we're unable to generate a reflex in which case we want to try reinforcing actions so getting the patient to close their eyes and grit their teeth which then may allow us to increase that reflex if we're trying to do the same with the lower limbs we've got an additional movement we can do by getting the hands getting the patient close their eyes and pull apart this reinforcing reflex can be particularly useful and again when comparing all the reflexes we need to get the patient to try and relax as much as they can to allow us to hold their arm so there is minimal tone there i often find that patients have difficulty with this so it can be a case that after a couple of tries it is worthwhile leaving the patient and coming back again shortly afterwards in terms of the upper limb reflexes we want to do the biceps reflex we want to do the supinator reflex and we want to do the triceps reflex in some cases it can be worthwhile doing a finger jerk reflex as well but that isn't commonly looked at reflexes can use the same dermatomal map as we've had for power and if there's a problem with the reflex then we're going to be able to trace that back to particular nerve roots that have been affected that's particularly the case in a lower motor neuron lesion where an absent reflex can be traced back remember we're looking at much more focal issues there at medical school there's a simple phrase that allows us to remember our reflexes s1 s2 put on a shoe three four stamp on the floor five six pickup sticks seven eight close the gate so what that's looking at is the s12 is that the ankle reflex 3 4 is the knee jerk reflex 7 8 close the gate is our tricep reflex and 5 6 pickup sticks is our biceps moving on having done appearance tone power reflexes we need to check sensation this is going to be done with soft touch so cotton wool or tissue paper superficial pain using a neurotip sometimes patients will check temperature but realistically this is often done just by can they feel the cool of the tuning fork that is also going to be used for vibration and we'll check joint position and proprioception in terms of sensation patients can obviously often say that they are numb we need to clarify exactly what that means and the certain vocabulary that's important to be aware of so pins and needles meaning paresthesia diastasis meaning unpleasant pins and needles high prosthesis reduced sensation analgesia the complete loss of sensation remember that's what we're trying to do with painkillers and analgesics we're trying to remove that pain we're trying to get rid of that sensation with that we have hyper anesthesia that will be an increased sensitivity and hyper algesia and increased sensitivity specifically to pain there's also aladinia which is painful stimuli from a non-painful stimulus where something's going wrong clearly with the wiring so in terms of sensation we want to be touching up and down up and down up and down we don't want to stroke the patient the reason being is we don't want to get increased numbers of sensory sensational fibers firing we just want that straight forward up and down up and down broadly we're going to test over the shoulder tip the deltoid the inner outer aspect of the arm the thumb little finger and the back of the arm as well again these boundaries um aren't absolute but if we find an area of altered sensation we want to make sure we map that out and as we're doing that we're going to be checking the opposite side of the body and we need to make sure the patient can't predict where it is we're going to be assessing next in terms of vibration we want to use a 128 hertz tuning fork to begin we strike it and place the tuning fork on the patient's chest the theory being that the patient should be able to feel vibration here if the patient is unable to feel the vibration of the chest we're certainly not going to be able to find vibration at any of the peripheral regions and we know that patient has a lot of unfortunate problems in terms of examinations we want to check distally to approximately on the bony prominences so we'll start off on the fingertip if the patient can't feel vibration here we're going to move up to the distal interphalangeal joints the proximity phalangeal joints and up to the metacarpal phalangeal joints we'll continue up to the wrist the elbow and the shoulder tip before looking over the clavicle trying to find somewhere where the patient is able to detect the vibration finally we need to look at proprioception and coordination proprioception is the knowledge of the position of your body in space and the strength employed in that movement in terms of assessing proprioception we need to start off on the upper limb with the fingers holding the lateral sides of the finger on either side not on the pulp and over nail because that increased pressure there can help the patient determine where the finger is being held and we're going to demonstrate upwards and downward movement of the distal interphalangeal joint with the patient's eyes open we'll then get to them close their eyes we'll do the same again and we're going to get them to determine where they can feel the fingertip in terms of position is it up or down if the patient again is unable to identify proprioception the fingertip we're going to continue moving more approximately until the patient is able to identify the joint position sense coordination is the act of having muscles move together in concert to perform intentional smooth movements a good example here testing coordination and also activities of daily living is get the patient to do up a button or tie their shoelaces in order to be able to effectively perform coordinated movements we need to have good sensory input good muscle function and good higher function coordination so a simple test like opening buttons or checking shoelaces it does quite a lot with the patient but also allows us to assess how the patient is likely able to cope and what impact their condition is going to be having on their quality of life other testing that we can do is with a finger nose test so get the patient to stretch their arm out as far as they can and you raise your finger to meet them it's important that arm is stretched all the way out because if not then we may find that they're able to compensate or suppress certain errors which may be more evident at full extension we're going to get the patient to put their finger to their nose and back to our finger quickly as they can but as doing so on the return journey once we've established one or two normal movements we will be able to move our finger as well and increase the difficulty of that test here we may be looking for pass pointing so the patient trying to touch our fingertip are missing and going beyond our finger other examinations that we can do will be ddk checking for dystocodyskinesia i hate that phrase really have difficulty saying it in terms of the ddk we're checking back to front back to front back to front and we want to make sure we're doing both sides checking for the coordination and getting them to alternate as quickly as possible now we can make that a little bit easier to start off with by getting the patient to do just simple tapping first and then move on to the ddk part of the assessment because if the patient is unable to do the simple tapping it's unlikely that they're going to get good coordination for their ddk for the upper neuro for the upper limb neurological assessment we can also check for carpal tunnel which allows me to go back to the the taylor hammer whereupon we can use the apex to strike if desired directly over the carpal tunnel and in doing so just hitting that with myself i obviously am right handed and have spent a little bit too long working the computer so that strike there directly over the nerve is giving me a little bit of tingling on the thumb the index and the middle finger that being the distribution of the median nerve showing a positive tennos test you can attempt to do tunnels test by simply tapping over there but personally i find the taylor hammer to provide a more focused effective examination because of the weight there we also have phalen's test where we're putting additional stress on the carpal tunnel bringing the elbows and hands and wrists to 90 degrees straining the carpal tunnel and having the patient sat in that position for 60 seconds that can also be further enhanced with a reverse phalanx again looking for that same tingling in the median nerve distribution well i hope that's been an effective run through on the upper limb neurological examination as i say it's a very complex examination in terms of the underlying science behind it but as you've seen the actual performance is much simpler so hopefully it's something that you can build on at home as long as you're understanding the underlying science behind it thanks very much for watching this far i appreciate this has been one of the longer videos if you'd be kind enough to give it a like and subscribe to the channel if you think it's been useful and we'll see you for the next clinical examination deep dive take [Music] [Music] you