Tesla underwent another debilitating trauma a few years after recovering from
cholera. This time, the nature of the illness and its causes were a complete
mystery. Tesla's physical senses, which had always been remarkably acute,
seemed to go inexplicably into overdrive, paralyzing him with an
overabundance of sensation. The ticking of a pocket watch had become
painfully deafening to him, even from several rooms away. He needed rubber
cushion inserted beneath the feet of his bed to lessen the vibrations from
outside passersby, which felt to him like an earthquake. Exposure to light was
excruciating not only for his eyes, but to the surface of his skin, as well. After a
time, the crippling condition eased, and Tesla returned to normal sensory
perception with a mental breakthrough that led him to the invention of the
alternating current motor.