Which sequence correctly orders impairment of consciousness from mild to deepest level?

• A. Lethargy, obtundation, stupor, coma
• B. Coma, stupor, obtundation, lethargy
• C. Obtundation, lethargy, coma, stupor
• D. Stupor, coma, lethargy, obtundation

Answer: (A)

The key idea is a graded progression of consciousness from mild to deepest. Lethargy is a light level of impairment—drowsiness with reduced alertness, but the person can be aroused relatively easily. Obtundation is more pronounced: the person requires more stimulation to awaken and is less responsive. Stupor represents a still deeper level, where vigorous or repeated stimulation is needed to elicit any purposeful response, and usually only briefly. Coma is the deepest state, with unarousability and no meaningful response to stimuli.

Therefore, the correct order from mild to deepest is lethargy → obtundation → stupor → coma. The other sequences mix up these levels, placing deeper states earlier or placing the mild state last, which contradicts the progressive nature of impairment.