For anyone interested in evidence-based stroke recovery treatment options, the lower extremity offers a much smaller palette than the upper extremity. Simply, there are a lot less evidence-based treatment options for the lower extremity.
One of the reasons this is true is because the ankle foot orthosis is an effective way of providing compensation for the deficits in gait after stroke. Another reason is that canes and walkers are also extraordinarily effective at compensating for gait deviations and deficits poststroke.
There are other reasons. For instance, there is the general consensus among therapists that what comes back first is the leg, and later on the arm and hand. This is a classic gotcha question for therapists teaching students. "What comes back first the upper or lower extremity?" The wise student will say the politically correct answer; the lower extremity. But this is not necessarily true. We tend to focus very much on hand and all its intricate movements, especially finger extension. But in the lower extremity we don't typically look at the analog of finger extension: toe extension. Why does nobody care about toe extension? Simple: The toes are hidden by the shoes. Also, toe extension is not essential to a functional gait. Toe extension which helps raise the ankle is compensated for by the ankle foot orthosis.
The main reason for the focus on the upper extremity is the hand. Even before brain imaging the hand fascinated researchers. This delicate instrument at the distal end of the limb drives clinical rehabilitation research related to stroke. There is a common belief that if you can get the hand "back in the game" and somehow get the hand to grasp release every other aspect of the upper extremity will come back naturally. This is because the entire upper extremity is there at the behest of the hand. You could further argue, although a bit of a stretch, that the reason we walk is to get the hand where it needs to go so that the hand can do what it needs to do.
But there's another huge reason. The brain. The swath of real estate that hand takes up on the brain is huge. The point to point representation of the brain is called the homunculus. The hand takes up almost as much room as the entire face! The face! Where our mouth is! Where our eyes are! Where are ears are! Our identity! When it comes to the brain the hand is, quite literally, huge.
But there may be another reason that neuroscientists are fascinated with the hand. Imagine if you doing clinical research on stroke survivors. They all are different ages, have had their stroke in different parts of their brain, they're all in different physical shape, they all have different diets, they all have different sequelae, etc. etc.
Now imagine you're doing research and you can have as many study participants as you want and they all have a stroke in exactly the same spot, be the same age, eat the same diet, wake up at the same time in the morning, always show up on time and that you can easily blind (not let them know which group there in) and are genetically related!
Where can you find such study participants? Rats! (And mice) But why rats and mice? Why are rats and mice so important to the equation of figuring out the science of motor learning in the hand? Here's why...