Things are generally directionless
Can a damaged brain change its own structure and learn to replace lost functions? Conventional neuroscience once said no, but pioneers in the field have achieved miraculous transformations. From his investigation of their work, Norman Doidge tells the story of the perpetually falling woman.
Cheryl Schiltz feels like she is perpetually falling. And because she feels like she is falling, she falls. When she stands up without support, she looks as if she were on a precipice, about to plummet. First her head wobbles and tilts to one side and her arms reach out to try to stabilise her stance. Soon her whole body is moving chaotically back and forth, like a person walking a tightrope in that frantic see-saw moment before losing his balance - except that both her feet are firmly planted on the ground, wide apart. When she tries to walk she has to hold on to a wall, and still she staggers like a drunk. For Cheryl there is no peace, even after she has fallen to the floor. (…)
Cheryl’s problem is that her vestibular apparatus, the sensory organ for the balance system, does not work. Soon after her problem began, she lost her job as an international sales representative and now lives on a disability allowance of $1,000 a month. She has a new-found fear of growing old. And she has a rare form of anxiety that has no name.
An unspoken and yet profound aspect of our well-being is based on having a normally functioning sense of balance. The balance system gives us our sense of orientation in space. Its vestibular apparatus consists of three semi-circular canals in the inner ear that tell us when we are upright and how gravity is affecting our bodies by detecting motion in three-dimensional space. One canal detects movement in the horizontal plane, another in the vertical plane, and another when we are moving forwards or backwards. The signals from the vestibular apparatus go along a nerve to a specialised clump of neurons in the brain, the vestibular nuclei, which process them, then send commands to our muscles to adjust themselves. (…)
By any conventional standard, Cheryl’s case is hopeless. (…) But today all that is about to be challenged. She is wearing a construction hat with holes in the side and a device inside called an accelerometer. Cheryl licks a thin plastic strip with small electrodes on it, and places it on her tongue. The accelerometer and the tongue strip are connected to a computer. This machine, a bizarre-looking Bach-y-Rita prototype, will replace Cheryl’s vestibular apparatus by sending balance signals to her brain from her tongue. (…)
The first time they tried the hat, Cheryl wore it for only a minute. They noticed that after she took it off, there was a ‘residual effect’ that lasted about 20 seconds, a third of the time she wore the device. Then Cheryl wore the hat for two minutes and the residual effect lasted about 40 seconds. Then they went up to about 20 minutes, expecting a residual effect of just under seven minutes. But instead it lasted triple the time, a full hour. (…) Over the next year Cheryl wore the device more frequently to get relief and build up her residual effect, which progressed to multiple hours, to days, and then to four months. Now she does not use the device at all. (…)
When Cheryl’s brain developed a renewed vestibular sense, these changes were not the mysterious exception to the rule but the rule: the sensory cortex is plastic and adaptable.
photo { Dana Lauren Goldstein }
