Question

which statement about coma is true?
a) during coma, brain oxygen consumption resembles that of a waking state.
b) coma may be caused by widespread cerebral or brain stem trauma.
c) coma is a form of deep sleep.
d) coma is neurologically identical to syncope.

Explanation:

• Option A: During coma, brain oxygen consumption is much lower than in a waking state.
• Option B: Coma can be caused by widespread cerebral or brain - stem trauma. For example, severe head injuries that damage large areas of the brain or the brain stem (which controls many vital functions related to consciousness) can lead to coma.
• Option C: Coma is not a form of deep sleep. In sleep, there are normal sleep - wake cycles, and the brain has different patterns of electrical activity compared to coma. In coma, the person is unresponsive and lacks normal sleep - related brain activity.
• Option D: Syncope is a temporary loss of consciousness (fainting) usually due to a brief reduction in blood flow to the brain. Coma is a more prolonged and severe state of unconsciousness with different underlying neurological mechanisms.

Answer:

B. Coma may be caused by widespread cerebral or brain stem trauma.