Which statement best defines coma?

• A. Coma is defined by wakefulness with purposeful responses.
• B. Coma is defined by wakefulness with no purposeful responses.
• C. Coma is defined by inconsistent, definite purposeful behaviors.
• D. Coma is defined as no purposeful behavior.

Answer: (D)

Coma is a deep state of unconsciousness in which there is no wakefulness and no awareness, so the person does not exhibit purposeful behavior in response to stimuli. That lack of purposeful behavior is a hallmark of coma, reflecting an inability to engage with or respond to the environment.

The statement that describes no purposeful behavior best fits coma because it captures the essential unresponsiveness to stimuli. The other descriptions imply some level of wakefulness or purposeful response, which would indicate other states (for example, wakefulness without awareness in a vegetative state, or some level of reproducible purposeful behavior in a minimally conscious state). In contrast, coma involves both a loss of wakefulness and a loss of purposeful responsiveness, at least initially.