Hello, my name is Christy O'Fallon. I am Director of Neurocritical Care at the University of Miami, and we are going to talk for the next several minutes about the neurologic exam and localization. I have no relevant disclosures for this talk. So briefly, our objectives, we're going to describe the neurologic exam in critically ill patient. We'll review some case-based approaches to highlighting localization of lesions using the neurologic exam, and we will talk a little bit about the neurologic exam in patients with coma. So first, the approach to the patient. History is very important. Sometimes it's difficult to acquire a full history, especially if patients are altered. So it's important to use family members, neighbors, friends, et cetera, to give extra history. Physical exam is extremely important, and a complete physical exam can really make your work much easier. So this is a picture of a patient who presented with an acute encephalopathy, and it was not discovered until after his admission through the emergency department that he had this significant rash, which really did change the direction of the workup considerably to look at viral encephalitis as an important cause of his symptoms. So without the full exam, including skin, the differential diagnosis was much broader and the workup was taking quite a while. So this can really direct your diagnostic studies, your imaging, in this case, a lumbar puncture and initiation of IV antiviral therapy. So your neurologic exam is performed and presented in a typical fashion. So in general, we do mental status followed by cranial nerves, a motor exam, a sensory exam, coordination, and then if the patient is able to ambulate, we check gait. The way to think about level of consciousness is more than one-dimensional. So this is a figure from a recent paper looking at approaches to level of consciousness. On the x-axis, you have cognitive function. So the cognitive ability of the patient, including executive functions, language, etc. And on the y-axis, you have motor function. So the ability to communicate effectively, move their arms and legs and reflexes. At the very bottom left, you see coma, which is a person that really doesn't have motor function and really does not have cognitive function. At the top right, in green, you see full function or full recovery, where the patient has full motor function and full executive function. On the left side of the figure, in purple, you see what's called cognitive motor dissociation. Patients that may have the ability to understand commands or to process information. They may have preserved executive function, but they cannot have motor function or motor expression when you ask them to do things. And those patients are either minimally conscious or completely locked in, depending on their level of ability to respond to commands. So there is a spectrum of these disorders. And it's important to be able to distinguish where on this spectrum your patient is at the time that you're examining them. So you will include parts of your exam of the motor function and the cognitive function to be able to determine this. So mental status evaluation includes speech, expression, comprehension, and fluency, and also the ability to repeat. So this is a CT scan of a patient with a typical left MCA infarct. These patients almost always have an expressive aphasia. So when testing patients that have language abnormalities, you need to have them attempt to name objects. Common objects or less common objects are useful. Being able to test their receptive ability and ask them to follow directions. To comment on whether their speech is fluent or non-fluent. Do they have nonsensical words that come out easily? Those are often referred to as word salad. And then the ability to repeat. So you can give them a short phrase. If he comes, we will go and see if they can repeat that. Cranial nerves are important to test. They help us understand the area that may be involved in some sort of pathologic process. They each have distinctive functions, so it's easy to test different areas of the brain and brain stem looking at different functions. So here on the left side of the figure are listed the functions of the different cranial nerves. You can test these by asking patients to move their eyes. You can test their visual fields, which we'll talk more about a little later. You can look at facial movement, hearing, movement of the head with the sternocleidomastoid muscle and tongue movements. Visual fields are important to test. They can be tested in both patients who are awake and who are not as able to respond. And we will discuss that when we talk about the coma exam. If a patient is awake and can interact with you, you stand four to five feet away from the patient. You ask the patient to close one eye. The examiner closes the opposite eye. And you can hold fingers out in the periphery where you can still see them. And you can ask the patient to either count fingers or to point to the hand when it's moving and see if the patient can see movement in the different visual fields. And you're testing only the peripheral visual fields in this manner. And you can do it on both sides to see if there's an abnormality on one side or the other. And that helps you decide where the pathology may exist. Oculomotor nerve is important in that it involves movement of the eyeball in the orbit as well as pupillary function. And it is fairly easy to test. And it is often involved in important structural lesions such as herniation syndromes or aneurysms. So in patients who are not awake enough to perform all of these evaluations, you can examine them in coma. And the Glasgow Coma Scale is very commonly used. It's been around for a while, was first presented by Teasdale and Genet in the early 70s. And it has 15 points in three sections. Eye response, verbal response, and motor response. Perfect score is 15. And you get three for showing up. So the best thing about the Glasgow Coma Scale is that it is easily taught and easily reproduced. And so it is a way of having patients be monitored by staff and have consistent evaluations of their level of consciousness over time. It is not a replacement for the full coma exam, but it gives you some idea of where the patient is at that moment in time depending on their ability to speak and obey commands or not, or open their eyes. You can do oculocephalic or cold caloric testing in patients who are not awake in order to test their vestibular system. And this actually looks at a fairly lengthy area of the brainstem. You are able to elicit eye movements by moving the head back and forth. And that tells you that the third and sixth nerves are talking to the eighth nerve. So that's a fairly long area of the brainstem that needs to be working in order for oculocephalics to be intact. In patients with C-spine injuries or cervical collars, you would not do an oculocephalic testing. You would do cold caloric testing where cold water is infused into the external auditory canal and eye movements are observed. And you can see the normal response is for the slow component of nystagmus to move the eyes slowly towards the cold water stimulus. Motor examination includes tone and bulk, important to pick the limbs up and to feel how they move across a joint. And to also notice things such as fasciculations and atrophy. Movements can be normal, purposeful movements or abnormal movements such as tremors may be noted and are important to take note of during your examination. Strength is graded on a 0 to 5 range with 5 being full strength and 0 being no movement. And posturing is noted in patients specifically who are not awake enough to cooperate with normal or traditional strength testing. You can see what kinds of movements happen when you stimulate the patient, usually with noxious stimulation. Reflex movements or posturing usually reflect some sort of problem in the corticospinal tract with decorticate posturing happening when there's injury above the red nucleus, which looks like this, and decerebrate posturing with injuries below the red nucleus which looks like this figure here. You notice that the legs are actually in extension with both decorticate and decerebrate upper extremity posturing. And that is very typical of brainstem level dysfunction. So here's a case, a 54 year old female presents with the worst headache of her life while she's watching TV. She has a history of hypertension. On exam, she's awake. She's able to give her own history. She's not oriented to place or time, but she is oriented to herself. She's able to follow directions and she has fluent speech and symmetric motor function. So all of this does not lateralize. This does not show you that there is a problem in one side or the other of her brain. But she does have nuchal rigidity and this is an abnormality that is focal. There's something going on with the meninges. So this should prompt imaging to try to understand what her problem is. And I think coupled with the worst headache of her life history, the concern is for this. So this is an example of subarachnoid hemorrhage from an aneurysm rupture in a patient who has an otherwise non-focal exam. So what do we mean by focal versus non-focal? So in the last case we discussed, the only thing that was specific to a particular area in the nervous system was her nuchal rigidity and her loss of orientation. So a focal exam demonstrates an abnormal function of a specific part in the nervous system. So it can be speech. It can be movement. It can be a cranial nerve. They're more likely associated with structural lesions, acute strokes, or hemorrhages. Non-focal exams, the patient may have diffusely affected level of consciousness or arousal. And these are often associated with toxidromes, metabolic derangements, or medication side effects. Here's another case, a 58-year-old male who came in after body surfing. On admission, he's awake. He's oriented times three. His speech is fluent and appropriate. On motor examination, you notice that he has weakness in his deltoids and biceps, as well as bilateral hand grip strength. And his legs have mild weakness, not as much as his arms. But his mentation is perfectly normal. And this helps you understand where his problem may be. He is unlikely to have a brain problem and more likely to have a problem either in the spinal cord or the peripheral nervous system, given his abnormalities. So imaging based on that would focus on spinal problems. And here you see that he has a cervical spine, fracture stenosis, and spinal cord compression. The sensory examination is important. It is difficult to do in patients who are not fully awake, but it includes all modalities. You try vibration and position sense for the dorsal columns and temperature and light touch. You look for symmetry between the left and the right sides and patterns of dysfunction, which might help you understand if the problem is in the brain, the spinal cord, or the peripheral nerves. Coordination can be tested with finger-nose-finger testing or heel-to-shin testing, and it will point towards a cerebellar problem. Gait abnormalities can help you with abnormalities due to either balance problems or some degenerative diseases may have specific gait dysfunction. And then reflexes are graded on a one to four plus, with normal being two plus, one plus being reduced, and four plus being pathologic hyperreflexia, including clonus and spread. It is helpful when you're testing reflexes to distract the patient so that they can fully relax and you can see the muscle stretching. So a little more about localization. Localization is the ability to see the forest and the trees to understand how a specific area of dysfunction is leading to the overall problem that you are seeing in the patient or addressing in the patient. So looking at changes in visual fields, for example, or gaze may help you understand where the problem occurs. So a loss of vision in a particular visual field will help you understand if the injury is in the optic nerve, the optic chiasm, or the cortex, for example. And these are examples of monocular vision loss on the top, hemianopsia on the middle, and bitemporal would be actually loss in the both sides, the temporal fields bilaterally, and that's more typical of a problem in the chiasm. Abnormal gaze can be a preference. So we see that with strokes that have a visual field cut, for example, or a tonic deviation, which means that you cannot overcome the deviation with head turning. And we see this with seizures. If the eyes are away from the area of injury, then that's often a seizure that localizes to the affected brain, and it should not be able to be overcome with head turning. Ocular movements and pupillary exams are important, and they can often alert you to a particular area of dysfunction. I think that pupillary dilation is probably the easiest to see. You can also see third nerve palsies with the affected eye being rotated downwards and outwards because of loss of the medial rectus and superior rectus function of the third nerve. Pupillary constriction is mediated by the oculomotor nerve as well as the sympathetics up from the cervical ganglion. So on the right, you see an innervation from the eye that includes the third nerve as well as the fifth nerve to the cornea, and then sympathetics that come up from the superior cervical ganglion as well. So there's multiple areas that can be affected, but examining the eye movement and the pupillary function can tell you a lot about a very wide range of brain stem. Pupillary exams are helpful. As you can see on the left side, the figure will depict different areas of the brain stem which are associated with different types of pupillary abnormalities. I think the most common that we see are the pontine pupils, which are small pinpoint pupils. The third nerve dysfunction of the midbrain may cause pupillary dilation on one side or the other, or in the dorsal part of the midbrain, you may have pre-tectal pupils that are fixed mid-position with some hippus. Reflexes may be helpful if they are asymmetric. You can notice if there is a central nervous system lesion, you will have hyperreflexia on the side that is affected. If they are symmetrically elevated or decreased, it may imply that there is a diffuse problem in the peripheral nervous system, for example, with Guillain-Barré syndrome, or that you have bilateral CNS involvement or a drug effect or toxin. So here's another case, an 18-year-old female who was brought in from a music festival by EMS because of altered mental status. She developed headache and lethargy followed by unresponsiveness, and on exam, when you see her, she has no eye opening, her pupils are 4mm and sluggish bilaterally. She does have cough and gag and corneal reflexes present, and with noxious stimulation, she has extensor posturing. This exam localizes to a central problem, she has decreased level of consciousness, and you see extensor posturing, which localizes to the brainstem, and so you know that there is a diffuse problem in the CNS with brainstem dysfunction, and when you do imaging, it confirms that this person has diffuse cerebral edema with loss of her basal cisterns, and so she has pressure on her brainstem causing her extensor posturing. This is an example of a 70-year-old female recently in the hospital for an acute ischemic stroke, so you know that she has a right MCA stroke from before. Now she's brought in from the rehab service because of altered mental status. When you see her, she has no eye opening, her pupils are reactive, she does not follow directions, and she has a tonic gaze deviation to the left side with nystagmus. She minimally withdraws to pain. Now normally with a right MCA stroke, you would expect somebody to be awake, to be weak on their left side, and they may have some neglect, but they should be able to respond to you, and they should not have a tonic gaze deviation to the left. If anything, their gaze should go towards the right because they wouldn't necessarily pay attention to the left side of space. So the fact that she has a tonic gaze deviation to the left should be a focal sign that is concerning to you. And so this is her CT scan, which shows, as expected, her right MCA distribution stroke there, and an EEG shows that she has spike and wave pattern diffusely consistent with status epilepticus, which is what you would suspect given her clinical exam. So thank you for your attention. I hope this helps you put into perspective how the neurologic exam, if done carefully and systematically, can really help you in your approach to the patient and localization of area of dysfunction. Thank you.

neurologic exam

lesion localization

Glasgow Coma Scale

visual fields

pupillary exams

patient care