What neurological disorders are being represented in Chapter 3 (The Disembodied Lady)?

In Chapter Three, Christina feels her body is "giving way" and that she is disembodied. Testing shows that she has lost her proprioception from head to toe. The cause of this loss is a polyneuritis that affects "the sensory roots of spinal and cranial nerves throughout the neuraxis." Dr. Sacks explains to Christina that the sense of one's body is given by three things working together: vision, balance organs, and proprioception. Christina then decides she must learn to use her eyes in order to compensate for her loss of proprioception.