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Video transcript

you can develop all sorts of symptoms after having a stroke because if something's happen to your master control center your brain then all sorts of stuff all sorts of functions can be compromised and that will manifest as you having symptoms right that makes sense but there are certain groups of symptoms that happen the most frequently and I want to take a look at these and these happen the most because well remember strokes happen when blood flow is compromised right so these groups of symptoms are the result of common blockages in certain arteries and we'll explore this so the first one we'll look at is sudden numbness or weakness of the face the arm or their leg so immediately a few questions pop into your mind right why would you develop numbness or weakness why commonly the face the arm or the leg and also does this happen on both sides of the body or is it just one side of the body and these are all great questions thank you so let's look at each one in turn for some possible reasons so why would you develop numbness or weakness well the numbness might happen if you developed a stroke in this area here called the primary somatosensory cortex right and as its name implies it's the key part of your brain that allows you to feel stuff so if it gets damaged you might end up with a change in your sensation for example numbness and the weakness could happen if you developed a stroke next door in this motor cortex area here right again the the name kind of lets you know it's a major player in controlling your movements so damage could result in weakness of your movements and let me just clarify that it's a little bit more complicated than just the sensory cortex is in charge of your sensation and your motor cortex is in charge of your movements there's a lot more bits of your brain that have inputs to all these things but we won't worry about those for now because I just want to focus on some of the concepts here now why the face the arm the leg why why different parts of the body well the short answer is that it depends on which part of the motor or the sensory cortex gets damaged let me put it to you this way the different parts of the body are sort of represented on the motor and sensory cortices in different places so this isn't perfect but surely a common way to think of it is as this guy sort of draped over right sort of lying down on the brain with his legs dangling in the longitudinal fissure and his arm sort of about here and is facedown here because it turns out that the neurons in roughly this area supply the motor and sensory for the legs and neurons in roughly this area supply motor and sensory for your body and the ones in this area here control the bulk of your upper limbs and then these ones here for your face and you might actually notice that the lips in that and the face and the hands aren't proportional to the rest of the body here and that's because more sensitive parts of the body like your lips and your face in your hands they get dibs on more neurons to supply them so this is usually drawn to reflect that so you can probably see where I'm going with this but if you get some compromise of your anterior cerebral artery or a CA which supplies this part of your brain here you'd get possible motor or sensory symptoms in your legs or if you get some compromise of your middle cerebral artery your MCA which supplies all of this area here you'd end up with symptoms affecting your face in your upper limbs right so finally one or both sides of the body well most of the brain is set up in this interesting way where and actually we won't go into details but it's set up so that this motor and sensory cortex on say the left side are controlling and interpreting sensations for the opposite the right side of the body and vice versa and that just has to do with the way that their neurons are connected up to send and receive signals the neurons actually cross from one side of the body to the other and that happens either in the spinal cord in the brainstem or in the brain itself you get this crossing over but I digress so if you have damage to one side you'd end up with symptoms on the opposite side and if you have damage to both sides then you get symptoms on both sides of the body savy I just watched 11 hours of Pirates of the Caribbean so I might use pirates speak a lot savvy all right so that's one major set of symptoms sensory changes or weakness what's next sudden trouble speaking or understanding others and why would this happen well the most common reason you might have trouble with your speech is that the stroke has affected some of the key parts of your brain that deal with your speech which are served by the middle cerebral artery and actually almost 40% of people who have a stroke end up with some problems with expression of their language so let me give you an example here of two important areas you've got this area of the brain here in your frontal lobe called your Broca's area which is involved in nice fluid speech production so if this gets damaged you might end up with sort of slow and poorly articulated speech and you've got this area right here near the junction of your temporal and parietal lobes called your Verna keys area which is important in your ability to understand what people say to you it's actually also really important in producing nice meaningful specific speech so if you damage this area you'd end up with poor comprehension of what people are saying to you and when you speak you wouldn't really be able to pick the right words to express what you want to say so you kind of just end up rambling a bit unfortunately so next up we have sudden trouble seeing in one or both eyes and here's a top-down view of the brain to help us understand this and so up here is the front and back here is the back and this is the left eye and this is the right eye so there's really two sort of overarching parts to proper vision you need a healthy set of eyes to bring in the visual information and you need a healthy brain to process and interpret that information right so if you add some stroke related damage to one of the parts of the brain that manage your vision right let's say you had a blockage in your in your posterior cerebral artery your PCA which supplies your occipital lobe that's the major lobe that allows you to have vision you could actually end up with some vision loss and the occipital lobe is also wired up in an interesting way where actually let me let me just draw out the two fields of vision to make this really clear so here's your left field of vision from your left eye and here's your right field of vision from your right eye so if you sustained some damage to this left side of the occipital Loeb you actually end up with loss of vision in the right halves of both your left and your right visual fields that's weird right and that just has to do it the way your your neurons are connected up from your eyes to your occipital lobe and then similarly if you have a stroke affecting your right side of your occipital lobe then you'd lose vision in both your left visual fields right very interesting all right what's next another common set of symptoms are ones to do with balance so you get the sudden feeling of dizziness or loss of balance or coordination so you might have trouble say walking and this can happen if you have a stroke in your cerebellum so a substantial enough blockage in at least one of the three main arteries that supply it with blood and why would this result in dizziness or loss of balance well because the cerebellum is a major coordinator of our movements if something happens to it we start to get imprecise and uncoordinated and we end up having poor timing to our movements okay so the last symptom I'll cover is just a sudden severe headache with no known cause no cause that you can sort of think of so you might remember that there's a subtype of stroke called a hemorrhagic stroke which is where a blood vessel in the brain actually bursts and causes a stroke by loss of blood from the cerebral circulation well this is probably not so surprising but when a blood vessel bursts in your head it hurts a lot so you get a sudden severe headache with no explanation so there you go those were five of the most common stroke signs and symptoms