Apraxia

"So we're going to be talking today about apraxia. So apraxia is a very strange word and what it means is that you know how to do something, the muscles are intact, the nerve is intact, and the junction is intact, but you can't make it happen. So, in neurologic conditions, you might have an apraxia, for example, for dressing. Your arms and legs can move, but you forgot how to put your clothes on. Or you have an apraxia of gait where you just forget how to move. Your arm, your legs can move. There's no weakness, there's no sensory loss, but then once you get started. you're fine. And the same kinds of apraxias we can see in neuro-ophthalmology. And so, these are motor apraxias. And because it's the eye, they are ocular motor apraxias. And that can be either for the lid or for the eye movement, the motility. So, you could have this on a congenital basis, so this is oculomotor apraxia. And if you have it on a congenital basis, that is a congenital ocular motor apraxia, so that kid is going to be born with what looks like they can't see. And the reason it looks like they can't see is because their eyes aren't following their mom's face or their bottle. And really this congenital ocular motor apraxia is a motor problem. It's not a vision problem, but because you can't ask the kid what they can see, that it looks like they can't see, but their pupils will be normal. Their eye exam will be normal. They often over time develop this head thrusting maneuver so that they can use their vestibular ocular reflex by rotating their head to drive their eyes passively by doing a doll's head on themselves. So they're doing a doll's head maneuver on themselves to make the eyes move. So that combination of the kid has an apraxia of eye movement that can be overcome either on their own or with the physician, the doll's head maneuver, suggests that it is a supranuclear problem. There's nothing wrong with the nucleus. There's nothing wrong with the nerve. There's nothing wrong with the junction or the muscle. It's a supranuclear problem and that is the congenital form of ocular motor apraxia. However, we've got this acquired form of ocular motor apraxia. It's the same concept. The nerve, the muscle, and the junction are all intact. It's a supranuclear problem and they can't move their eyes. The most common acquired ocular motor apraxia that we see is an acquired supranuclear ocular motor paresis, also known as, ASOMP (acquired supranuclear oculomotor paresis). This is also able to be overcome with the doll's head maneuver. And the most common scenario that we see this after is after cardiac surgery. So if they've had a heart transplant or they had some sort of cardiac procedure, aortic valve replacement, they might wake up just like that kid who has the coma. And it looks like they can't move their eyes, but when you do the doll's head on them, they can move their eyes which proves that it is a supranuclear problem. And that is an ocular motor apraxia that's acquired after surgery. It's different than the congenital one, obviously, because you're born with it. And then, finally, you can have the apraxia of lid opening. So this is an eye apraxia eyelid opening and their eyes close and then they can't open them, but it's not because it's weak. And sometimes they can just lift up your lid and the lid opens up magically because it's a apraxia of eyelid opening. There's actually nothing wrong with the lid, the muscle, or the junction. This is common in benign essential blepharospasm and some neurodegenerative motor conditions, like Parkinson's disease, where they just- they just can't open their eyelids, but when they open them, it just opens up and stays open. So you need to know about this strange condition, apraxia. It can be congenital or acquired. It can affect the lid or the motility and we can overcome the deviation with the doll's head maneuver in both cases. It occurs after cardiac surgery, which is the acquired supranuclear ocular motor paresis."