I was once being led through an unknown forest by my baby brother, and when I accused him of not knowing where we were, he assured me that he certainly was NOT lost. He further elucidated that he knew exactly where he was, as he was “right here.” He simply was not completely sure as to where he was in relationship to the things around him, like, say, the path we had wandered away from, or the car, to name two items. He, himself, though, was not “lost”. He held up his hands and showed them to me, to prove that he knew where he was. And he tried to reassure me by adding, “Come on! You know where you are! You’re right here! We’re not lost!”

In certain disease processes, we lose some of our ability to find ourselves in space. I am not talking about getting lost in the forest, or forgetting where we are. But literally not having that natural awareness we take so for granted, of knowing where our hands and feet are, what position we are in, whether our arms are crossed, and such. There are a multitude of feedback loops processed through muscle, joints and tendons that constantly let our brains know where we are and how we are positioned at any given moment. These mechanosensory neurons are known as propioceptors, and give us what some doctors now call our “sixth sense” of body awareness in space: propioception.

I was with a patient whose disease was not named to me, who was undergoing an evaluation of his impaired propioception. They did things like moving his hands or arms into specific positions with his eyes closed, releasing them to neutral, and seeing how closely he could recreate the pose. They also posed one arm to see if he could mirror it with the other arm, eyes closed. But his brain could not receive all the signals we take for granted. He was unable to mirror his arm positions or bend his elbows or hands to match. And like an alcohol-impaired driver at a field sobriety test, he had difficulty in touching the tip of his nose with a finger after stretching out his arm.

Many diseases can impact our ability to locate ourselves in space and get appropriate feedback about how we are positioned and the movements we make. Parkinsons, Huntingtons, ALS, even strokes and arthritis can impact it. I can only imagine what it must be like to lose some of this basic function. To not know where my own arm is in space. To not feel whether it is bent or straight. Imagine how you would walk, stand, or balance, or even pick up a plate, without the myriad of constant and consistent feedback loops that we all take for granted, unless and until they quit working.

Luckily, for this patient, there will be a series of exercises that he can learn in order to stimulate and strengthen these connections and feedback loops. He is also being trained to use his sight more in order to have the additional information about where his limbs are in space. Some balance exercises may help as well. He is strong in limb, and otherwise healthy, and I hope for him that whatever his disease is will progress slowly and allow him many years of active life. Just one more of the countless precious things most of us have and don’t ever have to name or even consider.

There is so much for us to be grateful for at the most basic level. To walk through space on an uneven surface without falling. To dance. To have a sense of where my whole body is at, and to know constantly what I am doing with my hands, how tightly I am grasping something, whether I might burn a finger or drop a glass. To sit here and run my fingers rapidly along the keyboard with such facility. To be fully embodied and in touch with every limb, the tip of each finger and toe, to feel all my skin, and to know where I am in the space that surrounds me. I am right here, right now, and so are you all. Isn’t it a pleasure, isn’t it a huge gift, to feel it?