Before I had my own neurologists, I had Oliver Sacks.
Sacks feels like the best kind of personal physician, his gentle voice speaking to you straight out of the page as he discusses the many cruel deficits that neurology trades in. My favorite of his books may look like collections of Sherlock Holmes stories—and the case histories they present have titles that any detective would be happy to have tidied away in the files: The Man Who Mistook His Wife for a Hat, The Visions of Hildegard—but these mysteries are solved by kindness and quiet perception rather than violence and the clanging arrival of justice.
Over the years I would occasionally read that Sacks was not always considered to be a great clinician. Some have argued that he exploited his patients by turning them into literature. I found that last criticism false as soon as I became a neurology patient myself. Sacks gives the newly diagnosed permission to find their predicament interesting and human. He says: This is not the end of experience, but the beginning of a new strain of experience. He says: What is happening to you has value.
At times in the early months of my own neurological confusion, when I was fumbling with handles and light switches, I would imagine myself as a character in one of Sacks’s narratives. “The Man Who Couldn’t Open a Door,” perhaps, or “The Case of the Misplaced Hands.” But what I did not realize was that Sacks had already tackled this problem I was having—albeit from a far more frightening vantage point. What does it mean to misplace your body? he asks in a story titled “The Disembodied Lady.” It turns out that the stagy Wellsian nightmare conjured in that title is well earned. To misplace your body is the stuff of horror.
“The Disembodied Lady” describes an encounter between Sacks and a patient who has lost not just her hands but her entire physical being. Christine, a young computer programmer, is admitted to hospital to have her gall bladder removed. On the first night on the ward she dreams that she is losing control of her limbs, and when she awakes, the dream has come true. Over the course of a few days, simply standing up becomes impossible, while her hands start to wander by themselves if she isn’t looking at them.
A complete disintegration of her body’s awareness of its own spatial reality is under way. There is no cure. But with time, Christine is able to make a partial functional recovery through compensating systems. When Sacks leaves her at the end of the narrative, she is guiding each movement by sight—an exhausting, debilitating workaround. “I feel my body is blind and deaf to itself,” Christine tells Sacks. “It has no sense of itself.”
“The Disembodied Lady” exists within the strange spook country of proprioception, the means—along with vision and the balance organs of the vestibular system—by which the body creates a sense of itself in space. Proprioception is a deeply physical business, and yet it’s simultaneously a largely intangible one. It is not just the brain’s idea of where the body is from moment to moment. It is part of what makes a person’s physical experiences feel real and personal in the first place.
This process depends upon sensory receptors called muscle spindles that are attached to individual muscles throughout the body, alongside the motor neurons. The motor neurons convey signals from the brain telling the muscles to move. The sensory neurons relay information about movements back to the brain, so that the brain can then construct an idea of exactly where everything is—a sense of what the hands are doing, where the feet are resting, whether the back is bent or straight, and even whether a person is speaking too loudly. A proprioceptive deficit is therefore an intelligence deficit: it means that the messages being sent back to the brain are not being properly understood.
Most people have little need or opportunity to acquaint themselves with proprioception, for the same reason you don’t often ponder the dance of electrical energy and resistance that occurs when you fire up your kettle. Generally, this stuff just works. Proprioception is a guiding hand so deft and considerate that you might never come close to spotting it, and this is the tragedy of the body’s most elegant systems. You only learn how clever they are when they break—and when it becomes a matter of how clever they once were. I feel lucky, in a chilly, rather blasphemous way, to have been given this fleeting glimpse of the inner workings, just as I feel lucky that proprioception was my introduction to the world of neurological disarray. I suspect that proprioception is an ideal introduction: a gentle indicator that there is always a level of mediation between the world and our experience of it.
As Sacks explains, however, a proprioceptive deficit isn’t always so gentle. What has happened to me is nowhere near as all-consuming as what happened to Christine. She had horror; I have had pratfalls. A very slight deficit has turned my house into a riot of impediments. My shins are constantly bruised from chair legs and low tables, while a cat becomes a silent movie set-piece as it darts about, brushing in and out of flickering zones of awareness, sending me into an elbowy panic. I go to the kitchen before bed to get a glass of water, and my wife hears the enthusiastic Foley effects of a man klutzing through the darkness, even though all the lights are still on.
At its most insidious, though—and I wonder, honestly, if this is still neurological territory or something else—the comedy retreats a little. The mystery of proprioception seems tangled up with its mundanity. Over the last few years, my relationship with my own domestic landscape has become ever so slightly dreamlike: I’m left endlessly exploring places that I should already know—and making fresh discoveries. Light switches in my house fascinate me: I swear they take playful journeys up and down the walls, settling at unlikely heights.
I have read about this sort of thing too, but not in Oliver Sacks’s books. Philip K. Dick was troubled by light switches moving around, never settling quite where he remembered them being before. He saw this as proof that the world was being edited and updated around him. I don’t really blame him. How could I? It is a small step from neurological complaint to generalized ontological conspiracy.
Part of the reason I struggled to see the problems I was having with proprioception is that they seemed so personal, so private, so tightly woven into the texture of my life that I could not be sure they hadn’t always been there. It is hard to spot the things that happen when your brain starts to go wrong, because your brain is the last thing that is going to be able to tell you about it.
Yet Sacks could tell me about it. And here is the thing I will never get used to about neurology: when you finally look up some private and wordless sensation, you often find that it has already been cataloged and codified. You discover that it is not as private as you have suspected, or as wordless as you have feared.