What is the meaning of "locked in" in the novel, Lock In?

Locked in is the phrase representative of the way that Haden's syndrome patients are paralyzed but have fully functional minds. The body is stored in electronic cradles while the minds have the ability to travel in Personal Transports (see definition) or able to use a human host, known as an Integrator. Lock in can occur at any age. Chris became locked in as an infant, therefore he does not really know what it is like to have a fully functioning human body.